mm/vma: return the exact errno in vms_gather_munmap_vmas()

__split_vma() and mas_store_gfp() returns several types of errno on
failure so don't ignore them in vms_gather_munmap_vmas().  For example,
__split_vma() returns -EINVAL when an unaligned huge page is unmapped.
This issue is reproduced by ltp memfd_create03 test.

Don't initialise the error variable and assign it when a failure actually
occurs.

[akpm@linux-foundation.org: fix whitespace, per Liam]
Link: https://lkml.kernel.org/r/20240909125621.1994-1-ice_yangxiao@163.com
Fixes: 6898c9039bc8 ("mm/vma: extract the gathering of vmas from do_vmi_align_munmap()")
Signed-off-by: Xiao Yang <ice_yangxiao@163.com>
Suggested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202409081536.d283a0fb-oliver.sang@intel.com
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

memcg: cleanup with !CONFIG_MEMCG_V1

Extern declarations have no definitions with !CONFIG_MEMCG_V1 and no
users, drop them altogether.

Link: https://lkml.kernel.org/r/20240909163223.3693529-1-mkoutny@suse.com
Link: https://lkml.kernel.org/r/20240909163223.3693529-2-mkoutny@suse.com
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Chen Ridong <chenridong@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/show_mem.c: report alloc tags in human readable units

We already do this when reporting slab info - more consistent and more
readable.

Link: https://lkml.kernel.org/r/20240906005337.1220091-1-kent.overstreet@linux.dev
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: support poison recovery from copy_present_page()

Similar to other poison recovery, use copy_mc_user_highpage() to avoid
potentially kernel panic during copy page in copy_present_page() from
fork, once copy failed due to hwpoison in source page, we need to break
out of copy in copy_pte_range() and release prealloc folio, so
copy_mc_user_highpage() is moved ahead before set *prealloc to NULL.

Link: https://lkml.kernel.org/r/20240906024201.1214712-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: support poison recovery from do_cow_fault()

Patch series "mm: hwpoison: two more poison recovery".

One more CoW path to support poison recorvery in do_cow_fault(), and the
last copy_user_highpage() user is replaced to copy_mc_user_highpage() from
copy_present_page() during fork to support poison recorvery too.

This patch (of 2):

Like commit a873dfe1032a ("mm, hwpoison: try to recover from copy-on
write faults"), there is another path which could crash because it does
not have recovery code where poison is consumed by the kernel in
do_cow_fault(), a crash calltrace shown below on old kernel, but it
could be happened in the lastest mainline code,

  CPU: 7 PID: 3248 Comm: mpi Kdump: loaded Tainted: G           OE     5.10.0 #1
  pc : copy_page+0xc/0xbc
  lr : copy_user_highpage+0x50/0x9c
  Call trace:
    copy_page+0xc/0xbc
    do_cow_fault+0x118/0x2bc
    do_fault+0x40/0x1a4
    handle_pte_fault+0x154/0x230
    __handle_mm_fault+0x1a8/0x38c
    handle_mm_fault+0xf0/0x250
    do_page_fault+0x184/0x454
    do_translation_fault+0xac/0xd4
    do_mem_abort+0x44/0xbc

Fix it by using copy_mc_user_highpage() to handle this case and return
VM_FAULT_HWPOISON for cow fault.

[wangkefeng.wang@huawei.com: unlock/put vmf->page, per Miaohe]
Link: https://lkml.kernel.org/r/20240910021541.234300-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240906024201.1214712-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240906024201.1214712-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

resource, kunit: add test case for region_intersects()

Patch series "resource: Fix region_intersects() vs
add_memory_driver_managed()", v3.

The patchset fixes a bug of region_intersects() for systems with CXL
memory.  The details of the bug can be found in [1/3].  To avoid similar
bugs in the future.  A kunit test case for region_intersects() is added in
[3/3].  [2/3] is a preparation patch for [3/3].

This patch (of 3):

region_intersects() is important because it's used for /dev/mem permission
checking.  To avoid possible bug of region_intersects() in the future, a
kunit test case for region_intersects() is added.

Link: https://lkml.kernel.org/r/20240906030713.204292-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20240906030713.204292-4-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

resource: make alloc_free_mem_region() works for iomem_resource

During developing a kunit test case for region_intersects(), some fake
resources need to be inserted into iomem_resource.  To do that, a resource
hole needs to be found first in iomem_resource.

However, alloc_free_mem_region() cannot work for iomem_resource now.
Because the start address to check cannot be 0 to detect address wrapping
0 in gfr_continue(), while iomem_resource.start == 0.  To make
alloc_free_mem_region() works for iomem_resource, gfr_start() is changed
to avoid to return 0 even if base->start == 0.  We don't need to check 0
as start address.

Link: https://lkml.kernel.org/r/20240906030713.204292-3-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: z3fold: deprecate CONFIG_Z3FOLD

The z3fold compressed pages allocator is rarely used, most users use
zsmalloc.  The only disadvantage of zsmalloc in comparison is the
dependency on MMU, and zbud is a more common option for !MMU as it was the
default zswap allocator for a long time.

Historically, zsmalloc had worse latency than zbud and z3fold but offered
better memory savings.  This is no longer the case as shown by a simple
recent analysis [1].  That analysis showed that z3fold does not have any
advantage over zsmalloc or zbud considering both performance and memory
usage.  In a kernel build test on tmpfs in a limited cgroup, z3fold took
3% more time and used 1.8% more memory.  The latency of zswap_load() was
7% higher, and that of zswap_store() was 10% higher.  Zsmalloc is better
in all metrics.

Moreover, z3fold apparently has latent bugs, which was made noticeable by
a recent soft lockup bug report with z3fold [2].  Switching to zsmalloc
not only fixed the problem, but also reduced the swap usage from 6~8G to
1~2G.  Other users have also reported being bitten by mistakenly enabling
z3fold.

Other than hurting users, z3fold is repeatedly causing wasted engineering
effort.  Apart from investigating the above bug, it came up in multiple
development discussions (e.g.  [3]) as something we need to handle, when
there aren't any legit users (at least not intentionally).

The natural course of action is to deprecate z3fold, and remove in a few
cycles if no objections are raised from active users.  Next on the list
should be zbud, as it offers marginal latency gains at the cost of huge
memory waste when compared to zsmalloc.  That one will need to wait until
zsmalloc does not depend on MMU.

Rename the user-visible config option from CONFIG_Z3FOLD to
CONFIG_Z3FOLD_DEPRECATED so that users with CONFIG_Z3FOLD=y get a new
prompt with explanation during make oldconfig.  Also, remove
CONFIG_Z3FOLD=y from defconfigs.

[1]https://lore.kernel.org/lkml/CAJD7tkbRF6od-2x_L8-A1QL3=2Ww13sCj4S3i4bNndqF+3+_Vg@mail.gmail.com/
[2]https://lore.kernel.org/lkml/EF0ABD3E-A239-4111-A8AB-5C442E759CF3@gmail.com/
[3]https://lore.kernel.org/lkml/CAJD7tkbnmeVugfunffSovJf9FAgy9rhBVt_tx=nxUveLUfqVsA@mail.gmail.com/

[arnd@arndb.de: deprecate ZSWAP_ZPOOL_DEFAULT_Z3FOLD as well]
Link: https://lkml.kernel.org/r/20240909202625.1054880-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20240904233343.933462-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vitaly Wool <vitaly.wool@konsulko.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

vfio/pci: implement huge_fault support

With the addition of pfnmap support in vmf_insert_pfn_{pmd,pud}() we can
take advantage of PMD and PUD faults to PCI BAR mmaps and create more
efficient mappings.  PCI BARs are always a power of two and will typically
get at least PMD alignment without userspace even trying.  Userspace
alignment for PUD mappings is also not too difficult.

Consolidate faults through a single handler with a new wrapper for
standard single page faults.  The pre-faulting behavior of commit
d71a989cf5d9 ("vfio/pci: Insert full vma on mmap'd MMIO fault") is removed
in this refactoring since huge_fault will cover the bulk of the faults and
results in more efficient page table usage.  We also want to avoid that
pre-faulted single page mappings preempt huge page mappings.

Link: https://lkml.kernel.org/r/20240826204353.2228736-20-peterx@redhat.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/arm64: support large pfn mappings

Support huge pfnmaps by using bit 56 (PTE_SPECIAL) for "special" on
pmds/puds.  Provide the pmd/pud helpers to set/get special bit.

There's one more thing missing for arm64 which is the pxx_pgprot() for
pmd/pud.  Add them too, which is mostly the same as the pte version by
dropping the pfn field.  These helpers are essential to be used in the new
follow_pfnmap*() API to report valid pgprot_t results.

Note that arm64 doesn't yet support huge PUD yet, but it's still
straightforward to provide the pud helpers that we need altogether.  Only
PMD helpers will make an immediate benefit until arm64 will support huge
PUDs first in general (e.g.  in THPs).

Link: https://lkml.kernel.org/r/20240826204353.2228736-19-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/x86: support large pfn mappings

Helpers to install and detect special pmd/pud entries.  In short, bit 9 on
x86 is not used for pmd/pud, so we can directly define them the same as
the pte level.  One note is that it's also used in _PAGE_BIT_CPA_TEST but
that is only used in the debug test, and shouldn't conflict in this case.

One note is that pxx_set|clear_flags() for pmd/pud will need to be moved
upper so that they can be referenced by the new special bit helpers.
There's no change in the code that was moved.

Link: https://lkml.kernel.org/r/20240826204353.2228736-18-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: remove follow_pte()

follow_pte() users have been converted to follow_pfnmap*().  Remove the
API.

Link: https://lkml.kernel.org/r/20240826204353.2228736-17-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/access_process_vm: use the new follow_pfnmap API

Use the new API that can understand huge pfn mappings.

Link: https://lkml.kernel.org/r/20240826204353.2228736-16-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

acrn: use the new follow_pfnmap API

Use the new API that can understand huge pfn mappings.

Link: https://lkml.kernel.org/r/20240826204353.2228736-15-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

vfio: use the new follow_pfnmap API

Use the new API that can understand huge pfn mappings.

Link: https://lkml.kernel.org/r/20240826204353.2228736-14-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/x86/pat: use the new follow_pfnmap API

Use the new API that can understand huge pfn mappings.

Link: https://lkml.kernel.org/r/20240826204353.2228736-13-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

s390/pci_mmio: use follow_pfnmap API

Use the new API that can understand huge pfn mappings.

Link: https://lkml.kernel.org/r/20240826204353.2228736-12-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

KVM: use follow_pfnmap API

Use the new pfnmap API to allow huge MMIO mappings for VMs.  The rest work
is done perfectly on the other side (host_pfn_mapping_level()).

Link: https://lkml.kernel.org/r/20240826204353.2228736-11-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: new follow_pfnmap API

Introduce a pair of APIs to follow pfn mappings to get entry information.
It's very similar to what follow_pte() does before, but different in that
it recognizes huge pfn mappings.

Link: https://lkml.kernel.org/r/20240826204353.2228736-10-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: always define pxx_pgprot()

There're:

  - 8 archs (arc, arm64, include, mips, powerpc, s390, sh, x86) that
  support pte_pgprot().

  - 2 archs (x86, sparc) that support pmd_pgprot().

  - 1 arch (x86) that support pud_pgprot().

Always define them to be used in generic code, and then we don't need to
fiddle with "#ifdef"s when doing so.

Link: https://lkml.kernel.org/r/20240826204353.2228736-9-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/fork: accept huge pfnmap entries

Teach the fork code to properly copy pfnmaps for pmd/pud levels.  Pud is
much easier, the write bit needs to be persisted though for writable and
shared pud mappings like PFNMAP ones, otherwise a follow up write in
either parent or child process will trigger a write fault.

Do the same for pmd level.

Link: https://lkml.kernel.org/r/20240826204353.2228736-8-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/pagewalk: check pfnmap for folio_walk_start()

Teach folio_walk_start() to recognize special pmd/pud mappings, and fail
them properly as it means there's no folio backing them.

[peterx@redhat.com: remove some stale comments, per David]
Link: https://lkml.kernel.org/r/20240829202237.2640288-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20240826204353.2228736-7-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/gup: detect huge pfnmap entries in gup-fast

Since gup-fast doesn't have the vma reference, teach it to detect such huge
pfnmaps by checking the special bit for pmd/pud too, just like ptes.

Link: https://lkml.kernel.org/r/20240826204353.2228736-6-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: allow THP orders for PFNMAPs

This enables PFNMAPs to be mapped at either pmd/pud layers.  Generalize the
dax case into vma_is_special_huge() so as to cover both.  Meanwhile, rename
the macro to THP_ORDERS_ALL_SPECIAL.

Link: https://lkml.kernel.org/r/20240826204353.2228736-5-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: mark special bits for huge pfn mappings when inject

We need these special bits to be around on pfnmaps.  Mark properly for
!devmap case, reflecting that there's no page struct backing the entry.

Link: https://lkml.kernel.org/r/20240826204353.2228736-4-peterx@redhat.com
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: drop is_huge_zero_pud()

It constantly returns false since 2017.  One assertion is added in 2019 but
it should never have triggered, IOW it means what is checked should be
asserted instead.

If it didn't exist for 7 years maybe it's good idea to remove it and only
add it when it comes.

Link: https://lkml.kernel.org/r/20240826204353.2228736-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: introduce ARCH_SUPPORTS_HUGE_PFNMAP and special bits to pmd/pud

Patch series "mm: Support huge pfnmaps", v2.

Overview
========

This series implements huge pfnmaps support for mm in general.  Huge
pfnmap allows e.g.  VM_PFNMAP vmas to map in either PMD or PUD levels,
similar to what we do with dax / thp / hugetlb so far to benefit from TLB
hits.  Now we extend that idea to PFN mappings, e.g.  PCI MMIO bars where
it can grow as large as 8GB or even bigger.

Currently, only x86_64 (1G+2M) and arm64 (2M) are supported.  The last
patch (from Alex Williamson) will be the first user of huge pfnmap, so as
to enable vfio-pci driver to fault in huge pfn mappings.

Implementation
==============

In reality, it's relatively simple to add such support comparing to many
other types of mappings, because of PFNMAP's specialties when there's no
vmemmap backing it, so that most of the kernel routines on huge mappings
should simply already fail for them, like GUPs or old-school follow_page()
(which is recently rewritten to be folio_walk* APIs by David).

One trick here is that we're still unmature on PUDs in generic paths here
and there, as DAX is so far the only user.  This patchset will add the 2nd
user of it.  Hugetlb can be a 3rd user if the hugetlb unification work can
go on smoothly, but to be discussed later.

The other trick is how to allow gup-fast working for such huge mappings
even if there's no direct sign of knowing whether it's a normal page or
MMIO mapping.  This series chose to keep the pte_special solution, so that
it reuses similar idea on setting a special bit to pfnmap PMDs/PUDs so
that gup-fast will be able to identify them and fail properly.

Along the way, we'll also notice that the major pgtable pfn walker, aka,
follow_pte(), will need to retire soon due to the fact that it only works
with ptes.  A new set of simple API is introduced (follow_pfnmap* API) to
be able to do whatever follow_pte() can already do, plus that it can also
process huge pfnmaps now.  Half of this series is about that and
converting all existing pfnmap walkers to use the new API properly.
Hopefully the new API also looks better to avoid exposing e.g.  pgtable
lock details into the callers, so that it can be used in an even more
straightforward way.

Here, three more options will be introduced and involved in huge pfnmap:

  - ARCH_SUPPORTS_HUGE_PFNMAP

    Arch developers will need to select this option when huge pfnmap is
    supported in arch's Kconfig.  After this patchset applied, both x86_64
    and arm64 will start to enable it by default.

  - ARCH_SUPPORTS_PMD_PFNMAP / ARCH_SUPPORTS_PUD_PFNMAP

    These options are for driver developers to identify whether current
    arch / config supports huge pfnmaps, making decision on whether it can
    use the huge pfnmap APIs to inject them.  One can refer to the last
    vfio-pci patch from Alex on the use of them properly in a device
    driver.

So after the whole set applied, and if one would enable some dynamic debug
lines in vfio-pci core files, we should observe things like:

  vfio-pci 0000:00:06.0: vfio_pci_mmap_huge_fault(,order = 9) BAR 0 page offset 0x0: 0x100
  vfio-pci 0000:00:06.0: vfio_pci_mmap_huge_fault(,order = 9) BAR 0 page offset 0x200: 0x100
  vfio-pci 0000:00:06.0: vfio_pci_mmap_huge_fault(,order = 9) BAR 0 page offset 0x400: 0x100

In this specific case, it says that vfio-pci faults in PMDs properly for a
few BAR0 offsets.

Patch Layout
============

Patch 1:         Introduce the new options mentioned above for huge PFNMAPs
Patch 2:         A tiny cleanup
Patch 3-8:       Preparation patches for huge pfnmap (include introduce
                 special bit for pmd/pud)
Patch 9-16:      Introduce follow_pfnmap*() API, use it everywhere, and
                 then drop follow_pte() API
Patch 17:        Add huge pfnmap support for x86_64
Patch 18:        Add huge pfnmap support for arm64
Patch 19:        Add vfio-pci support for all kinds of huge pfnmaps (Alex)

TODO
====

More architectures / More page sizes
------------------------------------

Currently only x86_64 (2M+1G) and arm64 (2M) are supported.  There seems
to have plan to support arm64 1G later on top of this series [2].

Any arch will need to first support THP / THP_1G, then provide a special
bit in pmds/puds to support huge pfnmaps.

remap_pfn_range() support
-------------------------

Currently, remap_pfn_range() still only maps PTEs.  With the new option,
remap_pfn_range() can logically start to inject either PMDs or PUDs when
the alignment requirements match on the VAs.

When the support is there, it should be able to silently benefit all
drivers that is using remap_pfn_range() in its mmap() handler on better
TLB hit rate and overall faster MMIO accesses similar to processor on
hugepages.

More driver support
-------------------

VFIO is so far the only consumer for the huge pfnmaps after this series
applied.  Besides above remap_pfn_range() generic optimization, device
driver can also try to optimize its mmap() on a better VA alignment for
either PMD/PUD sizes.  This may, iiuc, normally require userspace changes,
as the driver doesn't normally decide the VA to map a bar.  But I don't
think I know all the drivers to know the full picture.

Credits all go to Alex on help testing the GPU/NIC use cases above.

[0] https://lore.kernel.org/r/73ad9540-3fb8-4154-9a4f-30a0a2b03d41@lucifer.local
[1] https://lore.kernel.org/r/20240807194812.819412-1-peterx@redhat.com
[2] https://lore.kernel.org/r/498e0731-81a4-4f75-95b4-a8ad0bcc7665@huawei.com

This patch (of 19):

This patch introduces the option to introduce special pte bit into
pmd/puds.  Archs can start to define pmd_special / pud_special when
supported by selecting the new option.  Per-arch support will be added
later.

Before that, create fallbacks for these helpers so that they are always
available.

Link: https://lkml.kernel.org/r/20240826204353.2228736-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20240826204353.2228736-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/codetag: add pgalloc_tag_copy()

Add pgalloc_tag_copy() to transfer the codetag from the old folio to the
new one during migration.  This makes original allocation sites persist
cross migration rather than lump into the get_new_folio callbacks passed
into migrate_pages(), e.g., compaction_alloc():

  # echo 1 >/proc/sys/vm/compact_memory
  # grep compaction_alloc /proc/allocinfo

Before this patch:
  132968448  32463  mm/compaction.c:1880 func:compaction_alloc

After this patch:
          0      0  mm/compaction.c:1880 func:compaction_alloc

Link: https://lkml.kernel.org/r/20240906042108.1150526-3-yuzhao@google.com
Fixes: dcfe378c81f7 ("lib: introduce support for page allocation tagging")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/codetag: fix pgalloc_tag_split()

The current assumption is that a large folio can only be split into
order-0 folios.  That is not the case for hugeTLB demotion, nor for THP
split: see commit c010d47f107f ("mm: thp: split huge page to any lower
order pages").

When a large folio is split into ones of a lower non-zero order, only the
new head pages should be tagged.  Tagging tail pages can cause imbalanced
"calls" counters, since only head pages are untagged by pgalloc_tag_sub()
and the "calls" counts on tail pages are leaked, e.g.,

  # echo 2048kB >/sys/kernel/mm/hugepages/hugepages-1048576kB/demote_size
  # echo 700 >/sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
  # time echo 700 >/sys/kernel/mm/hugepages/hugepages-1048576kB/demote
  # echo 0 >/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
  # grep alloc_gigantic_folio /proc/allocinfo

Before this patch:
  0  549427200  mm/hugetlb.c:1549 func:alloc_gigantic_folio

  real  0m2.057s
  user  0m0.000s
  sys   0m2.051s

After this patch:
  0          0  mm/hugetlb.c:1549 func:alloc_gigantic_folio

  real  0m1.711s
  user  0m0.000s
  sys   0m1.704s

Not tagging tail pages also improves the splitting time, e.g., by about
15% when demoting 1GB hugeTLB folios to 2MB ones, as shown above.

Link: https://lkml.kernel.org/r/20240906042108.1150526-2-yuzhao@google.com
Fixes: be25d1d4e822 ("mm: create new codetag references during page splitting")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/codetag: fix a typo

Link: https://lkml.kernel.org/r/20240906042108.1150526-1-yuzhao@google.com
Fixes: 22d407b164ff ("lib: add allocation tagging support for memory allocation profiling")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Muchun Song <muchun.song@linux.dev>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/vmalloc.c: use "high-order" in description non 0-order pages

In many places, in the comments, we use both "higher-order" and
"high-order" to describe the non 0-order pages.  That is confusing,
because a "higher-order" statement does not reflect what it is compared
with.

Link: https://lkml.kernel.org/r/20240906095049.3486-1-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Suggested-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/vmalloc.c: use helper function va_size()

Use helper function va_size() to improve code readability. No functional
modification involved.

Link: https://lkml.kernel.org/r/20240906102539.3537207-1-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: replace xa_get_order with xas_get_order where appropriate

The tracing of invalidation and truncation operations on large files
showed that xa_get_order() is among the top functions where kernel spends
a lot of CPUs.  xa_get_order() needs to traverse the tree to reach the
right node for a given index and then extract the order of the entry.
However it seems like at many places it is being called within an already
happening tree traversal where there is no need to do another traversal.
Just use xas_get_order() at those places.

Link: https://lkml.kernel.org/r/20240906230512.124643-1-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

maple_tree: mark three functions as __maybe_unused

People keep trying to remove three functions that are going to be used in
a feature that is being developed.  Dropping the functions entirely may
end up with people trying to use the bit for other uses, as people have
tried in the past.

Adding __maybe_unused stops compilers complaining about the unused
functions so they can be silently optimised out of the compiled code and
people won't try to claim the bit for another use.

Link: https://lore.kernel.org/all/20230726080916.17454-2-zhangpeng.00@bytedance.com/
Link: https://lore.kernel.org/all/202408310728.S7EE59BN-lkp@intel.com/
Link: https://lkml.kernel.org/r/20240907021506.4018676-1-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: clean up mem_cgroup_iter()

A clean up to make variable names more clear and to improve code
readability.

No functional change.

Link: https://lkml.kernel.org/r/20240905003058.1859929-6-kinseyho@google.com
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: restart if multiple traversals raced

Currently, if multiple reclaimers raced on the same position, the
reclaimers which detect the race will still reclaim from the same memcg.
Instead, the reclaimers which detect the race should move on to the next
memcg in the hierarchy.

So, in the case where multiple traversals race, jump back to the start of
the mem_cgroup_iter() function to find the next memcg in the hierarchy to
reclaim from.

Link: https://lkml.kernel.org/r/20240905003058.1859929-5-kinseyho@google.com
Reported-by: syzbot+e099d407346c45275ce9@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/000000000000817cf10620e20d33@google.com/
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: increment gen # before restarting traversal

The generation number in struct mem_cgroup_reclaim_iter should be
incremented on every round-trip.  Currently, it is possible for a
concurrent reclaimer to jump in at the end of the hierarchy, causing a
traversal restart (resetting the iteration position) without incrementing
the generation number.

By resetting the position without incrementing the generation, it's
possible for another ongoing mem_cgroup_iter() thread to walk the tree
twice.

Move the traversal restart such that the generation number is
incremented before the restart.

Link: https://lkml.kernel.org/r/20240905003058.1859929-4-kinseyho@google.com
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: don't hold css->refcnt during traversal

To obtain the pointer to the next memcg position, mem_cgroup_iter()
currently holds css->refcnt during memcg traversal only to put css->refcnt
at the end of the routine.  This isn't necessary as an rcu_read_lock is
already held throughout the function.  The use of the RCU read lock with
css_next_descendant_pre() guarantees that sibling linkage is safe without
holding a ref on the passed-in @css.

Remove css->refcnt usage during traversal by leveraging RCU.

Link: https://lkml.kernel.org/r/20240905003058.1859929-3-kinseyho@google.com
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

cgroup: clarify css sibling linkage is protected by cgroup_mutex or RCU

Patch series "Improve mem_cgroup_iter()", v4.

Incremental cgroup iteration is being used again [1]. This patchset
improves the reliability of mem_cgroup_iter(). It also improves
simplicity and code readability.

[1] https://lore.kernel.org/20240514202641.2821494-1-hannes@cmpxchg.org/

This patch (of 5):

Explicitly document that css sibling/descendant linkage is protected by
cgroup_mutex or RCU.  Also, document in css_next_descendant_pre() and
similar functions that it isn't necessary to hold a ref on @pos.

The following changes in this patchset rely on this clarification for
simplification in memcg iteration code.

Link: https://lkml.kernel.org/r/20240905003058.1859929-1-kinseyho@google.com
Link: https://lkml.kernel.org/r/20240905003058.1859929-2-kinseyho@google.com
Suggested-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: T.J. Mercier <tjmercier@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_alloc: fix build with CONFIG_UNACCEPTED_MEMORY=n

When has_unaccepted_memory() is unused, it prevents kernel builds
with clang, `make W=1` and CONFIG_WERROR=y:

mm/page_alloc.c:7036:20: error: unused function 'has_unaccepted_memory' [-Werror,-Wunused-function]
7036 | static inline bool has_unaccepted_memory(void)
|                    ^~~~~~~~~~~~~~~~~~~~~

Fix it by removeing the CONFIG_UNACCEPTED_MEMORY=n stub.

Link: https://lkml.kernel.org/r/20240905142220.49d93337a0abce5690e515d9@linux-foundation.org
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Closes: https://lkml.kernel.org/r/20240905171553.275054-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: migrate: remove unused includes

random.h is not needed since commit 6c542ab75714 ("mm/demotion: build
demotion targets based on explicit memory tiers"), all functions moved
into memory-tiers.

nsproxy.h is not needed since commit 228ebcbe634a ("Uninline
find_task_by_xxx set of functions"), no nsproxy, we only call
find_task_by_vpid() now.

hugetlb_cgroup.h is not needed since commit ab5ac90aecf5 ("mm, hugetlb: do
not rely on overcommit limit during migration"), move_hugetlb_state() is
called and it belongs to hugetlb.h, which is already included.

balloon_compaction.h, we have more general movable_operations for non-lru
movable page migration, so it could be dropped.

memremap.h, userfaultfd_k.h and oom.h are introduced for zone device page
migration, but all functions are moved into migrate_device.c, so no needed
anymore too.

Link: https://lkml.kernel.org/r/20240905152432.626877-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: thp: simplify split_huge_pages_pid()

The helper find_get_task_by_vpid() can totally replace the task_struct
find logic in split_huge_pages_pid(), so use it to simplify the code.
Also delete the needless comments for the helper function name already
explains what it's doing here.

Link: https://lkml.kernel.org/r/20240905153028.1205128-1-sunnanyong@huawei.com
Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: migrate: simplify find_mm_struct()

Use find_get_task_by_vpid() to replace the task_struct find logic in
find_mm_struct(), note that this patch move the ptrace_may_access() call
out from rcu_read_lock() scope, this is ok because it actually does not
need it, find_get_task_by_vpid() already get the pid and task safely,
ptrace_may_access() can use the task safely, like what
sched_core_share_pid() similarly do.

Link: https://lkml.kernel.org/r/20240905153118.1205173-1-sunnanyong@huawei.com
Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/tests/core-kunit: skip damon_test_nr_accesses_to_accesses_bp() if aggr_interval is zero

The aggregation interval of test purpose damon_attrs for
damon_test_nr_accesses_to_accesses_bp() becomes zero on 32 bit
architecture, since size of int and long types are same.  As a result,
damon_nr_accesses_to_accesses_bp() call with the test data triggers
divide-by-zero exception.  damon_nr_accesses_to_accesses_bp() shouldn't
be called with such data, and the non-test code avoids that by checking
the case on damon_update_monitoring_results().  Skip the test code in
the case, and add an explicit caution of the case on the comment for the
test target function.

Link: https://lkml.kernel.org/r/20240905162423.74053-1-sj@kernel.org
Fixes: 5e06ad590096 ("mm/damon/core-test: test max_nr_accesses overflow caused divide-by-zero")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/c771b962-a58f-435b-89e4-1211a9323181@roeck-us.net
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

uprobes: use vm_special_mapping close() functionality

The following KASAN splat was shown:

[   44.505448] ==================================================================                                                                      20:37:27 [3421/145075]
[   44.505455] BUG: KASAN: slab-use-after-free in special_mapping_close+0x9c/0xc8
[   44.505471] Read of size 8 at addr 00000000868dac48 by task sh/1384
[   44.505479]
[   44.505486] CPU: 51 UID: 0 PID: 1384 Comm: sh Not tainted 6.11.0-rc6-next-20240902-dirty #1496
[   44.505503] Hardware name: IBM 3931 A01 704 (z/VM 7.3.0)
[   44.505508] Call Trace:
[   44.505511]  [<000b0324d2f78080>] dump_stack_lvl+0xd0/0x108
[   44.505521]  [<000b0324d2f5435c>] print_address_description.constprop.0+0x34/0x2e0
[   44.505529]  [<000b0324d2f5464c>] print_report+0x44/0x138
[   44.505536]  [<000b0324d1383192>] kasan_report+0xc2/0x140
[   44.505543]  [<000b0324d2f52904>] special_mapping_close+0x9c/0xc8
[   44.505550]  [<000b0324d12c7978>] remove_vma+0x78/0x120
[   44.505557]  [<000b0324d128a2c6>] exit_mmap+0x326/0x750
[   44.505563]  [<000b0324d0ba655a>] __mmput+0x9a/0x370
[   44.505570]  [<000b0324d0bbfbe0>] exit_mm+0x240/0x340
[   44.505575]  [<000b0324d0bc0228>] do_exit+0x548/0xd70
[   44.505580]  [<000b0324d0bc1102>] do_group_exit+0x132/0x390
[   44.505586]  [<000b0324d0bc13b6>] __s390x_sys_exit_group+0x56/0x60
[   44.505592]  [<000b0324d0adcbd6>] do_syscall+0x2f6/0x430
[   44.505599]  [<000b0324d2f78434>] __do_syscall+0xa4/0x170
[   44.505606]  [<000b0324d2f9454c>] system_call+0x74/0x98
[   44.505614]
[   44.505616] Allocated by task 1384:
[   44.505621]  kasan_save_stack+0x40/0x70
[   44.505630]  kasan_save_track+0x28/0x40
[   44.505636]  __kasan_kmalloc+0xa0/0xc0
[   44.505642]  __create_xol_area+0xfa/0x410
[   44.505648]  get_xol_area+0xb0/0xf0
[   44.505652]  uprobe_notify_resume+0x27a/0x470
[   44.505657]  irqentry_exit_to_user_mode+0x15e/0x1d0
[   44.505664]  pgm_check_handler+0x122/0x170
[   44.505670]
[   44.505672] Freed by task 1384:
[   44.505676]  kasan_save_stack+0x40/0x70
[   44.505682]  kasan_save_track+0x28/0x40
[   44.505687]  kasan_save_free_info+0x4a/0x70
[   44.505693]  __kasan_slab_free+0x5a/0x70
[   44.505698]  kfree+0xe8/0x3f0
[   44.505704]  __mmput+0x20/0x370
[   44.505709]  exit_mm+0x240/0x340
[   44.505713]  do_exit+0x548/0xd70
[   44.505718]  do_group_exit+0x132/0x390
[   44.505722]  __s390x_sys_exit_group+0x56/0x60
[   44.505727]  do_syscall+0x2f6/0x430
[   44.505732]  __do_syscall+0xa4/0x170
[   44.505738]  system_call+0x74/0x98

The problem is that uprobe_clear_state() kfree's struct xol_area, which
contains struct vm_special_mapping *xol_mapping. This one is passed to
_install_special_mapping() in xol_add_vma().
__mput reads:

static inline void __mmput(struct mm_struct *mm)
{
        VM_BUG_ON(atomic_read(&mm->mm_users));

        uprobe_clear_state(mm);
        exit_aio(mm);
        ksm_exit(mm);
        khugepaged_exit(mm); /* must run before exit_mmap */
        exit_mmap(mm);
        ...
}

So uprobe_clear_state() in the beginning free's the memory area
containing the vm_special_mapping data, but exit_mmap() uses this
address later via vma->vm_private_data (which was set in
_install_special_mapping().

Fix this by moving uprobe_clear_state() to uprobes.c and use it as
close() callback.

[usama.anjum@collabora.com: remove unneeded condition]
Link: https://lkml.kernel.org/r/20240906101825.177490-1-usama.anjum@collabora.com
Link: https://lkml.kernel.org/r/20240903073629.2442754-1-svens@linux.ibm.com
Fixes: 223febc6e557 ("mm: add optional close() to struct vm_special_mapping")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: page_alloc: fix missed updates of PGFREE in free_unref_{page/folios}

PGFREE is currently updated in two code paths:

- __free_pages_ok(): for pages freed to the buddy allocator.
- free_unref_page_commit(): for pages freed to the pcplists.

Before commit df1acc856923 ("mm/page_alloc: avoid conflating IRQs disabled
with zone->lock"), free_unref_page_commit() used to fallback to freeing
isolated pages directly to the buddy allocator through free_one_page().
This was done _after_ updating PGFREE, so the counter was correctly
updated.

However, that commit moved the fallback logic to its callers (now called
free_unref_page() and free_unref_folios()), so PGFREE was no longer
updated in this fallback case.

Now that the code has developed, there are more cases in free_unref_page()
and free_unref_folios() where we fallback to calling free_one_page() (e.g.
!pcp_allowed_order(), pcp_spin_trylock() fails).  These cases also miss
updating PGFREE.

To make sure PGFREE is updated in all cases where pages are freed to the
buddy allocator, move the update down the stack to free_one_page().

This was noticed through code inspection, although it should be noticeable
at runtime (at least with some workloads).

Link: https://lkml.kernel.org/r/20240904205419.821776-1-yosryahmed@google.com
Fixes: df1acc856923 ("mm/page_alloc: avoid conflating IRQs disabled with zone->lock")
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: care about shadow stack guard gap when getting an unmapped area

As covered in the commit log for c44357c2e76b ("x86/mm: care about shadow
stack guard gap during placement") our current mmap() implementation does
not take care to ensure that a new mapping isn't placed with existing
mappings inside it's own guard gaps.  This is particularly important for
shadow stacks since if two shadow stacks end up getting placed adjacent to
each other then they can overflow into each other which weakens the
protection offered by the feature.

On x86 there is a custom arch_get_unmapped_area() which was updated by the
above commit to cover this case by specifying a start_gap for allocations
with VM_SHADOW_STACK.  Both arm64 and RISC-V have equivalent features and
use the generic implementation of arch_get_unmapped_area() so let's make
the equivalent change there so they also don't get shadow stack pages
placed without guard pages.  x86 uses a single page guard, this is also
sufficient for arm64 where we either do single word pops and pushes or
unconstrained writes.

Architectures which do not have this feature will define VM_SHADOW_STACK
to VM_NONE and hence be unaffected.

Link: https://lkml.kernel.org/r/20240904-mm-generic-shadow-stack-guard-v2-3-a46b8b6dc0ed@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Suggested-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Acked-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Chris Zankel <chris@zankel.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: pass vm_flags to generic_get_unmapped_area()

In preparation for using vm_flags to ensure guard pages for shadow stacks
supply them as an argument to generic_get_unmapped_area().  The only user
outside of the core code is the PowerPC book3s64 implementation which is
trivially wrapping the generic implementation in the radix_enabled() case.

No functional changes.

Link: https://lkml.kernel.org/r/20240904-mm-generic-shadow-stack-guard-v2-2-a46b8b6dc0ed@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Chris Zankel <chris@zankel.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: make arch_get_unmapped_area() take vm_flags by default

Patch series "mm: Care about shadow stack guard gap when getting an
unmapped area", v2.

As covered in the commit log for c44357c2e76b ("x86/mm: care about shadow
stack guard gap during placement") our current mmap() implementation does
not take care to ensure that a new mapping isn't placed with existing
mappings inside it's own guard gaps.  This is particularly important for
shadow stacks since if two shadow stacks end up getting placed adjacent to
each other then they can overflow into each other which weakens the
protection offered by the feature.

On x86 there is a custom arch_get_unmapped_area() which was updated by the
above commit to cover this case by specifying a start_gap for allocations
with VM_SHADOW_STACK.  Both arm64 and RISC-V have equivalent features and
use the generic implementation of arch_get_unmapped_area() so let's make
the equivalent change there so they also don't get shadow stack pages
placed without guard pages.  The arm64 and RISC-V shadow stack
implementations are currently on the list:

   https://lore.kernel.org/r/20240829-arm64-gcs-v12-0-42fec94743
   https://lore.kernel.org/lkml/20240403234054.2020347-1-debug@rivosinc.com/

Given the addition of the use of vm_flags in the generic implementation we
also simplify the set of possibilities that have to be dealt with in the
core code by making arch_get_unmapped_area() take vm_flags as standard.
This is a bit invasive since the prototype change touches quite a few
architectures but since the parameter is ignored the change is
straightforward, the simplification for the generic code seems worth it.

This patch (of 3):

When we introduced arch_get_unmapped_area_vmflags() in 961148704acd ("mm:
introduce arch_get_unmapped_area_vmflags()") we did so as part of properly
supporting guard pages for shadow stacks on x86_64, which uses a custom
arch_get_unmapped_area().  Equivalent features are also present on both
arm64 and RISC-V, both of which use the generic implementation of
arch_get_unmapped_area() and will require equivalent modification there.
Rather than continue to deal with having two versions of the functions
let's bite the bullet and have all implementations of
arch_get_unmapped_area() take vm_flags as a parameter.

The new parameter is currently ignored by all implementations other than
x86.  The only caller that doesn't have a vm_flags available is
mm_get_unmapped_area(), as for the x86 implementation and the wrapper used
on other architectures this is modified to supply no flags.

No functional changes.

Link: https://lkml.kernel.org/r/20240904-mm-generic-shadow-stack-guard-v2-0-a46b8b6dc0ed@kernel.org
Link: https://lkml.kernel.org/r/20240904-mm-generic-shadow-stack-guard-v2-1-a46b8b6dc0ed@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Helge Deller <deller@gmx.de> [parisc]
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Chris Zankel <chris@zankel.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/tests/vaddr-kunit: init maple tree without MT_FLAGS_LOCK_EXTERN

damon_test_three_regions_in_vmas() initializes a maple tree with
MM_MT_FLAGS.  The flags contains MT_FLAGS_LOCK_EXTERN, which means mt_lock
of the maple tree will not be used.  And therefore the maple tree
initialization code skips initialization of the mt_lock.  However,
__link_vmas(), which adds vmas for test to the maple tree, uses the
mt_lock.  In other words, the uninitialized spinlock is used.  The problem
becomes clear when spinlock debugging is turned on, since it reports
spinlock bad magic bug.

Fix the issue by excluding MT_FLAGS_LOCK_EXTERN from the maple tree
initialization flags.  Note that we don't use empty flags to make it
further similar to the usage of mm maple tree, and to be prepared for
possible future changes, as suggested by Liam.

Link: https://lkml.kernel.org/r/20240904172931.1284-1-sj@kernel.org
Fixes: d0cf3dd47f0d ("damon: convert __damon_va_three_regions to use the VMA iterator")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/1453b2b2-6119-4082-ad9e-f3c5239bf87e@roeck-us.net
Suggested-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: Kconfig: fixup zsmalloc configuration

zsmalloc is not exclusive to zswap.  Commit b3fbd58fcbb1 ("mm: Kconfig:
simplify zswap configuration") made CONFIG_ZSMALLOC only visible when
CONFIG_ZSWAP is selected, which makes it impossible to menuconfig
zsmalloc-specific features (stats, chain-size, etc.) on systems that use
ZRAM but don't have ZSWAP enabled.

Make zsmalloc depend on both ZRAM and ZSWAP.

Link: https://lkml.kernel.org/r/20240903040143.1580705-1-senozhatsky@chromium.org
Fixes: b3fbd58fcbb1 ("mm: Kconfig: simplify zswap configuration")
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

filemap: fix the last_index of mm_filemap_get_pages

In commit b6273b55d885 ("filemap: add trace events for get_pages,
map_pages, and fault"), mm_filemap_get_pages was added to trace page cache
access.  However, it tracks an extra page beyond the end of the accessed
range.  This patch fixes it by replacing last_index with last_index - 1.

Link: https://lkml.kernel.org/r/20240903102100.70405-1-takayas@chromium.org
Fixes: b6273b55d885 ("filemap: add trace events for get_pages, map_pages, and fault")
Signed-off-by: Takaya Saeki <takayas@chromium.org>
Cc: Junichi Uekawa <uekawa@chromium.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm,tmpfs: consider end of file write in shmem_is_huge

Take the end of a file write into consideration when deciding whether or
not to use huge pages for tmpfs files when the tmpfs filesystem is mounted
with huge=within_size

This allows large writes that append to the end of a file to automatically
use large pages.

Doing 4MB sequential writes without fallocate to a 16GB tmpfs file with
fio.  The numbers without THP or with huge=always stay the same, but the
performance with huge=within_size now matches that of huge=always.

huge before after
4kB pages 1560 MB/s 1560 MB/s
within_size 1560 MB/s 4720 MB/s
always: 4720 MB/s 4720 MB/s

[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20240903111928.7171e60c@imladris.surriel.com
Signed-off-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: support priority parameter in recompression

recompress device attribute supports alg=NAME parameter so that we can
specify only one particular algorithm we want to perform recompression
with.  However, with algo params we now can have several exactly same
secondary algorithms but each with its own params tuning (e.g.  priority 1
configured to use more aggressive level, and priority 2 configured to use
a pre-trained dictionary).  Support priority=NUM parameter so that we can
correctly determine which secondary algorithm we want to use.

Link: https://lkml.kernel.org/r/20240902105656.1383858-25-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/zram: add documentation for algorithm parameters

Document brief description of compression algorithms' parameters:
compression level and pre-trained dictionary.

[senozhatsky@chromium.org: trivial fixup]
Link: https://lkml.kernel.org/r/20240903063722.1603592-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20240902105656.1383858-24-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: add dictionary support to zstd backend

This adds support for pre-trained zstd dictionaries [1] Dictionary is
setup in params once (per-comp) and loaded to Cctx and Dctx by reference,
so we don't allocate extra memory.

TEST
====

*** zstd
/sys/block/zram0/mm_stat
1750654976 504565092 514203648        0 514203648        1        0    34204    34204

*** zstd dict=/etc/zstd-dict-amd64
/sys/block/zram0/mm_stat
1750638592 465851259 475373568        0 475373568        1        0    34185    34185

*** zstd level=8 dict=/etc/zstd-dict-amd64
/sys/block/zram0/mm_stat
1750642688 430765171 439955456        0 439955456        1        0    34185    34185

[1] https://github.com/facebook/zstd/blob/dev/programs/zstd.1.md#dictionary-builder

Link: https://lkml.kernel.org/r/20240902105656.1383858-23-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: add dictionary support to lz4hc

Support pre-trained dictionary param.  Just like lz4, lz4hc doesn't
mandate specific format of the dictionary and zstd --train can be used to
train a dictionary for lz4, according to [1].

TEST
====

*** lz4hc
/sys/block/zram0/mm_stat
1750638592 608954620 621031424        0 621031424        1        0    34288    34288

*** lz4hc dict=/etc/lz4-dict-amd64
/sys/block/zram0/mm_stat
1750671360 505068582 514994176        0 514994176        1        0    34278    34278

[1] https://github.com/lz4/lz4/issues/557

Link: https://lkml.kernel.org/r/20240902105656.1383858-22-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: add dictionary support to lz4

Support pre-trained dictionary param.  lz4 doesn't mandate specific format
of the dictionary and even zstd --train can be used to train a dictionary
for lz4, according to [1].

TEST
====

*** lz4
/sys/block/zram0/mm_stat
1750654976 664188565 676864000        0 676864000        1        0    34288    34288

*** lz4 dict=/etc/lz4-dict-amd64
/sys/block/zram0/mm_stat
1750638592 619891141 632053760        0 632053760        1        0    34278    34278

*** lz4 level=5 dict=/etc/lz4-dict-amd64
/sys/block/zram0/mm_stat
1750638592 727174243 740810752        0 740810752        1        0    34437    34437

[1] https://github.com/lz4/lz4/issues/557

Link: https://lkml.kernel.org/r/20240902105656.1383858-21-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: move immutable comp params away from per-CPU context

Immutable params never change once comp has been allocated and setup, so
we don't need to store multiple copies of them in each per-CPU backend
context.  Move those to per-comp zcomp_params and pass it to backends
callbacks for requests execution.  Basically, this means parameters
sharing between different contexts.

Also introduce two new backends callbacks: setup_params() and
release_params().  First, we need to validate params in a driver-specific
way; second, driver may want to allocate its specific representation of
the params which is needed to execute requests.

Link: https://lkml.kernel.org/r/20240902105656.1383858-20-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: introduce zcomp_ctx structure

Keep run-time driver data (scratch buffers, etc.) in zcomp_ctx structure.
This structure is allocated per-CPU because drivers (backends) need to
modify its content during requests execution.

We will split mutable and immutable driver data, this is a preparation
path.

Link: https://lkml.kernel.org/r/20240902105656.1383858-19-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: introduce zcomp_req structure

Encapsulate compression/decompression data in zcomp_req structure.

Link: https://lkml.kernel.org/r/20240902105656.1383858-18-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: add support for dict comp config

Handle dict=path algorithm param so that we can read a pre-trained
compression algorithm dictionary which we then pass to the backend
configuration.

Link: https://lkml.kernel.org/r/20240902105656.1383858-17-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: introduce algorithm_params device attribute

This attribute is used to setup compression algorithms' parameters, so we
can tweak algorithms' characteristics.  At this point only 'level' is
supported (to be extended in the future).

Each call sets up parameters for one particular algorithm, which should be
specified either by the algorithm's priority or algo name.  This is
expected to be called after corresponding algorithm is selected via
comp_algorithm or recomp_algorithm.

 echo "priority=0 level=1" > /sys/block/zram0/algorithm_params
or
 echo "algo=zstd level=1" > /sys/block/zram0/algorithm_params

Link: https://lkml.kernel.org/r/20240902105656.1383858-16-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: recalculate zstd compression params once

zstd compression params depends on level, but are constant for a given
instance of zstd compression backend.  Calculate once (during ctx
creation).

Link: https://lkml.kernel.org/r/20240902105656.1383858-15-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: introduce zcomp_params structure

We will store a per-algorithm parameters there (compression level,
dictionary, dictionary size, etc.).

Link: https://lkml.kernel.org/r/20240902105656.1383858-14-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: check that backends array has at least one backend

Make sure that backends array has anything apart from the sentinel NULL
value.

We also select LZO_BACKEND if none backends were selected.

Link: https://lkml.kernel.org/r/20240902105656.1383858-13-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: add 842 compression backend support

Add s/w 842 compression support.

Link: https://lkml.kernel.org/r/20240902105656.1383858-12-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: add zlib compression backend support

Add s/w zlib (inflate/deflate) compression.

Link: https://lkml.kernel.org/r/20240902105656.1383858-11-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: pass estimated src size hint to zstd

zram works with PAGE_SIZE buffers, so we always know exact size of the
source buffer and hence can pass estimated_src_size to zstd_get_params().

This hint on x86_64, for example, reduces the size of the work memory
buffer from 1303520 bytes down to 90080 bytes.  Given that compression
streams are per-CPU that's quite some memory saving.

Link: https://lkml.kernel.org/r/20240902105656.1383858-10-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: add zstd compression backend support

Add s/w zstd compression.

Link: https://lkml.kernel.org/r/20240902105656.1383858-9-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: add lz4hc compression backend support

Add s/w lz4hc compression support.

Link: https://lkml.kernel.org/r/20240902105656.1383858-8-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: add lz4 compression backend support

Add s/w lz4 compression support.

Link: https://lkml.kernel.org/r/20240902105656.1383858-7-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: add lzo and lzorle compression backends support

Add s/w lzo/lzorle compression support.

Link: https://lkml.kernel.org/r/20240902105656.1383858-6-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zram: introduce custom comp backends API

Moving to custom backends implementation gives us ability to have our own
minimalistic and extendable API, and algorithms tunings becomes possible.

The list of compression backends is empty at this point, we will add
backends in the followup patches.

Link: https://lkml.kernel.org/r/20240902105656.1383858-5-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib: zstd: fix null-deref in ZSTD_createCDict_advanced2()

ZSTD_createCDict_advanced2() must ensure that
ZSTD_createCDict_advanced_internal() has successfully allocated cdict.
customMalloc() may be called under low memory condition and may be unable
to allocate workspace for cdict.

Link: https://lkml.kernel.org/r/20240902105656.1383858-4-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib: lz4hc: export LZ4_resetStreamHC symbol

This symbol is needed to enable lz4hc dictionary support.

Link: https://lkml.kernel.org/r/20240902105656.1383858-3-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib: zstd: export API needed for dictionary support

Patch series "zram: introduce custom comp backends API", v7.

This series introduces support for run-time compression algorithms tuning,
so users, for instance, can adjust compression/acceleration levels and
provide pre-trained compression/decompression dictionaries which certain
algorithms support.

At this point we stop supporting (old/deprecated) comp API.  We may add
new acomp API support in the future, but before that zram needs to undergo
some major rework (we are not ready for async compression).

Some benchmarks for reference (look at column #2)

*** init zstd
/sys/block/zram0/mm_stat
1750659072 504622188 514355200        0 514355200        1        0    34204    34204

*** init zstd dict=/home/ss/zstd-dict-amd64
/sys/block/zram0/mm_stat
1750650880 465908890 475398144        0 475398144        1        0    34185    34185

*** init zstd level=8 dict=/home/ss/zstd-dict-amd64
/sys/block/zram0/mm_stat
1750654976 430803319 439873536        0 439873536        1        0    34185    34185

*** init lz4
/sys/block/zram0/mm_stat
1750646784 664266564 677060608        0 677060608        1        0    34288    34288

*** init lz4 dict=/home/ss/lz4-dict-amd64
/sys/block/zram0/mm_stat
1750650880 619990300 632102912        0 632102912        1        0    34278    34278

*** init lz4hc
/sys/block/zram0/mm_stat
1750630400 609023822 621232128        0 621232128        1        0    34288    34288

*** init lz4hc dict=/home/ss/lz4-dict-amd64
/sys/block/zram0/mm_stat
1750659072 505133172 515231744        0 515231744        1        0    34278    34278

Recompress
init zram zstd (prio=0), zstd level=5 (prio 1), zstd with dict (prio 2)

*** zstd
/sys/block/zram0/mm_stat
1750982656 504630584 514269184        0 514269184        1        0    34204    34204

*** idle recompress priority=1 (zstd level=5)
/sys/block/zram0/mm_stat
1750982656 488645601 525438976        0 514269184        1        0    34204    34204

*** idle recompress priority=2 (zstd dict)
/sys/block/zram0/mm_stat
1750982656 460869640 517914624        0 514269184        1        0    34185    34204

This patch (of 24):

We need to export a number of API functions that enable advanced zstd
usage - C/D dictionaries, dictionaries sharing between contexts, etc.

Link: https://lkml.kernel.org/r/20240902105656.1383858-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20240902105656.1383858-2-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

maple_tree: fix comment typo on ma_flag of allocation tree

The maple tree flag of allocation tree is MT_FLAGS_ALLOC_RANGE.

Just correct it.

Link: https://lkml.kernel.org/r/20240809020115.31575-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: fix folio_alloc_noprof()

folio_alloc_noprof) wasn't calling the _noprof version, causing
allocations to be accounted here instead of to the caller

Link: https://lkml.kernel.org/r/20240901202459.4867-1-kent.overstreet@linux.dev
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

maple_tree: cleanup function descriptions

This patch tries to cleanup some function description:

  * function name mismatch
  * parameter name mismatch
  * parameter all end up with ':'
  * not prefix '*' if parameter is a pointer

There is still some missing description of parameters, I didn't add them
since I am not sure the exact meaning.

Link: https://lkml.kernel.org/r/20240830220400.2007-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: page_alloc: simpify page del and expand

When page del from buddy and need expand, it will account free_pages in
zone's migratetype.

The current way is to subtract the page number of the current order when
deleting, and then add it back when expanding.

This is unnecessary, as when migrating the same type, we can directly
record the difference between the high-order pages and the expand added,
and then subtract it directly.

This patch merge that, only when del and expand done, then account
free_pages.

Link: https://lkml.kernel.org/r/20240826064048.187790-1-link@vivo.com
Signed-off-by: Huan Yang <link@vivo.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: relax test to fail after 100 migration failures

It was recently observed at [1] that during the folio unmapping stage of
migration, when the PTEs are cleared, a racing thread faulting on that
folio may increase the refcount of the folio, sleep on the folio lock (the
migration path has the lock), and migration ultimately fails when
asserting the actual refcount against the expected.  Thereby, the
migration selftest fails on shared-anon mappings.  The above enforces the
fact that migration is a best-effort service, therefore, it is wrong to
fail the test for just a single failure; hence, fail the test after 100
consecutive failures (where 100 is still a subjective choice).  Note that,
this has no effect on the execution time of the test since that is
controlled by a timeout.

[1] https://lore.kernel.org/all/20240801081657.1386743-1-dev.jain@arm.com/

Link: https://lkml.kernel.org/r/20240830051609.4037834-1-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Tested-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/vmalloc.c: make use of the helper macro LIST_HEAD()

list_head can be initialized automatically with LIST_HEAD() instead of
calling INIT_LIST_HEAD().  Here we can simplify the code.

Link: https://lkml.kernel.org/r/20240828041216.1222582-1-lihongbo22@huawei.com
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: add sysfs entry to disable splitting underused THPs

If disabled, THPs faulted in or collapsed will not be added to
_deferred_list, and therefore won't be considered for splitting under
memory pressure if underused.

Link: https://lkml.kernel.org/r/20240830100438.3623486-7-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Cc: Alexander Zhu <alexlzhu@fb.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <zhais@google.com>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: split underused THPs

This is an attempt to mitigate the issue of running out of memory when THP
is always enabled.  During runtime whenever a THP is being faulted in
(__do_huge_pmd_anonymous_page) or collapsed by khugepaged
(collapse_huge_page), the THP is added to _deferred_list.  Whenever memory
reclaim happens in linux, the kernel runs the deferred_split shrinker
which goes through the _deferred_list.

If the folio was partially mapped, the shrinker attempts to split it.  If
the folio is not partially mapped, the shrinker checks if the THP was
underused, i.e.  how many of the base 4K pages of the entire THP were
zero-filled.  If this number goes above a certain threshold (decided by
/sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none), the
shrinker will attempt to split that THP.  Then at remap time, the pages
that were zero-filled are mapped to the shared zeropage, hence saving
memory.

Link: https://lkml.kernel.org/r/20240830100438.3623486-6-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Suggested-by: Rik van Riel <riel@surriel.com>
Co-authored-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexander Zhu <alexlzhu@fb.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <zhais@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: introduce a pageflag for partially mapped folios

Currently folio->_deferred_list is used to keep track of partially_mapped
folios that are going to be split under memory pressure.  In the next
patch, all THPs that are faulted in and collapsed by khugepaged are also
going to be tracked using _deferred_list.

This patch introduces a pageflag to be able to distinguish between
partially mapped folios and others in the deferred_list at split time in
deferred_split_scan.  Its needed as __folio_remove_rmap decrements
_mapcount, _large_mapcount and _entire_mapcount, hence it won't be
possible to distinguish between partially mapped folios and others in
deferred_split_scan.

Eventhough it introduces an extra flag to track if the folio is partially
mapped, there is no functional change intended with this patch and the
flag is not useful in this patch itself, it will become useful in the next
patch when _deferred_list has non partially mapped folios.

Link: https://lkml.kernel.org/r/20240830100438.3623486-5-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Cc: Alexander Zhu <alexlzhu@fb.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <zhais@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: selftest to verify zero-filled pages are mapped to zeropage

When a THP is split, any subpage that is zero-filled will be mapped to the
shared zeropage, hence saving memory.  Add selftest to verify this by
allocating zero-filled THP and comparing RssAnon before and after split.

Link: https://lkml.kernel.org/r/20240830100438.3623486-4-usamaarif642@gmail.com
Signed-off-by: Alexander Zhu <alexlzhu@fb.com>
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: Rik van Riel <riel@surriel.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <zhais@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: remap unused subpages to shared zeropage when splitting isolated thp

Patch series "mm: split underused THPs", v5.

The current upstream default policy for THP is always.  However, Meta uses
madvise in production as the current THP=always policy vastly
overprovisions THPs in sparsely accessed memory areas, resulting in
excessive memory pressure and premature OOM killing.  Using madvise +
relying on khugepaged has certain drawbacks over THP=always.  Using
madvise hints mean THPs aren't "transparent" and require userspace
changes.  Waiting for khugepaged to scan memory and collapse pages into
THP can be slow and unpredictable in terms of performance (i.e.  you dont
know when the collapse will happen), while production environments require
predictable performance.  If there is enough memory available, its better
for both performance and predictability to have a THP from fault time,
i.e.  THP=always rather than wait for khugepaged to collapse it, and deal
with sparsely populated THPs when the system is running out of memory.

This patch series is an attempt to mitigate the issue of running out of
memory when THP is always enabled.  During runtime whenever a THP is being
faulted in or collapsed by khugepaged, the THP is added to a list.
Whenever memory reclaim happens, the kernel runs the deferred_split
shrinker which goes through the list and checks if the THP was underused,
i.e.  how many of the base 4K pages of the entire THP were zero-filled.
If this number goes above a certain threshold, the shrinker will attempt
to split that THP.  Then at remap time, the pages that were zero-filled
are mapped to the shared zeropage, hence saving memory.  This method
avoids the downside of wasting memory in areas where THP is sparsely
filled when THP is always enabled, while still providing the upside THPs
like reduced TLB misses without having to use madvise.

Meta production workloads that were CPU bound (>99% CPU utilzation) were
tested with THP shrinker.  The results after 2 hours are as follows:

                            | THP=madvise |  THP=always   | THP=always
                            |             |               | + shrinker series
                            |             |               | + max_ptes_none=409
-----------------------------------------------------------------------------
Performance improvement     |      -      |    +1.8%      |     +1.7%
(over THP=madvise)          |             |               |
-----------------------------------------------------------------------------
Memory usage                |    54.6G    | 58.8G (+7.7%) |   55.9G (+2.4%)
-----------------------------------------------------------------------------
max_ptes_none=409 means that any THP that has more than 409 out of 512
(80%) zero filled filled pages will be split.

To test out the patches, the below commands without the shrinker will
invoke OOM killer immediately and kill stress, but will not fail with the
shrinker:

echo 450 > /sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none
mkdir /sys/fs/cgroup/test
echo $$ > /sys/fs/cgroup/test/cgroup.procs
echo 20M > /sys/fs/cgroup/test/memory.max
echo 0 > /sys/fs/cgroup/test/memory.swap.max
# allocate twice memory.max for each stress worker and touch 40/512 of
# each THP, i.e. vm-stride 50K.
# With the shrinker, max_ptes_none of 470 and below won't invoke OOM
# killer.
# Without the shrinker, OOM killer is invoked immediately irrespective
# of max_ptes_none value and kills stress.
stress --vm 1 --vm-bytes 40M --vm-stride 50K

This patch (of 5):

Here being unused means containing only zeros and inaccessible to
userspace.  When splitting an isolated thp under reclaim or migration, the
unused subpages can be mapped to the shared zeropage, hence saving memory.
This is particularly helpful when the internal fragmentation of a thp is
high, i.e.  it has many untouched subpages.

This is also a prerequisite for THP low utilization shrinker which will be
introduced in later patches, where underutilized THPs are split, and the
zero-filled pages are freed saving memory.

Link: https://lkml.kernel.org/r/20240830100438.3623486-1-usamaarif642@gmail.com
Link: https://lkml.kernel.org/r/20240830100438.3623486-3-usamaarif642@gmail.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Tested-by: Shuang Zhai <zhais@google.com>
Cc: Alexander Zhu <alexlzhu@fb.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: warn about illegal __GFP_NOFAIL usage in a more appropriate location and manner

Three points for this change:

1. We should consolidate all warnings in one place. Currently, the
   order > 1 warning is in the hotpath, while others are in less
   likely scenarios. Moving all warnings to the slowpath will reduce
   the overhead for order > 1 and increase the visibility of other
   warnings.

2. We currently have two warnings for order: one for order > 1 in
   the hotpath and another for order > costly_order in the laziest
   path. I suggest standardizing on order > 1 since it's been in
   use for a long time.

3. We don't need to check for __GFP_NOWARN in this case. __GFP_NOWARN
   is meant to suppress allocation failure reports, but here we're
   dealing with bug detection, not allocation failures. So replace
   WARN_ON_ONCE_GFP by WARN_ON_ONCE.

[v-songbaohua@oppo.com: also update the doc for __GFP_NOFAIL with order > 1]
Link: https://lkml.kernel.org/r/20240903223935.1697-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240830202823.21478-4-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eugenio Pérez" <eperezma@redhat.com>
Cc: Hailong.Liu <hailong.liu@oppo.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Xie Yongji <xieyongji@bytedance.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: document __GFP_NOFAIL must be blockable

Non-blocking allocation with __GFP_NOFAIL is not supported and may still
result in NULL pointers (if we don't return NULL, we result in busy-loop
within non-sleepable contexts):

static inline struct page *
__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
struct alloc_context *ac)
{
...
/*
 * Make sure that __GFP_NOFAIL request doesn't leak out and make sure
 * we always retry
 */
if (gfp_mask & __GFP_NOFAIL) {
/*
 * All existing users of the __GFP_NOFAIL are blockable, so warn
 * of any new users that actually require GFP_NOWAIT
 */
if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask))
goto fail;
...
}
...
fail:
warn_alloc(gfp_mask, ac->nodemask,
"page allocation failure: order:%u", order);
got_pg:
return page;
}

Highlight this in the documentation of __GFP_NOFAIL so that non-mm
subsystems can reject any illegal usage of __GFP_NOFAIL with GFP_ATOMIC,
GFP_NOWAIT, etc.

Link: https://lkml.kernel.org/r/20240830202823.21478-3-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eugenio Pérez" <eperezma@redhat.com>
Cc: Hailong.Liu <hailong.liu@oppo.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Xie Yongji <xieyongji@bytedance.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

vduse: avoid using __GFP_NOFAIL

Patch series "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL
and improve related doc and warn", v4.

__GFP_NOFAIL carries the semantics of never failing, so its callers do not
check the return value:

  %__GFP_NOFAIL: The VM implementation _must_ retry infinitely: the caller
  cannot handle allocation failures. The allocation could block
  indefinitely but will never return with failure. Testing for
  failure is pointless.

However, __GFP_NOFAIL can sometimes fail if it exceeds size limits or is
used with GFP_ATOMIC/GFP_NOWAIT in a non-sleepable context.  This patchset
handles illegal using __GFP_NOFAIL together with GFP_ATOMIC lacking
__GFP_DIRECT_RECLAIM(without this, we can't do anything to reclaim memory
to satisfy the nofail requirement) and improve related document and
warnings.

The proper size limits for __GFP_NOFAIL will be handled separately after
more discussions.

This patch (of 3):

mm doesn't support non-blockable __GFP_NOFAIL allocation.  Because
persisting in providing __GFP_NOFAIL services for non-block users who
cannot perform direct memory reclaim may only result in an endless busy
loop.

Therefore, in such cases, the current mm-core may directly return a NULL
pointer:

static inline struct page *
__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
                                                struct alloc_context *ac)
{
        ...
        if (gfp_mask & __GFP_NOFAIL) {
                /*
                 * All existing users of the __GFP_NOFAIL are blockable, so warn
                 * of any new users that actually require GFP_NOWAIT
                 */
                if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask))
                        goto fail;
                ...
        }
        ...
fail:
        warn_alloc(gfp_mask, ac->nodemask,
                        "page allocation failure: order:%u", order);
got_pg:
        return page;
}

Unfortuantely, vpda does that nofail allocation under non-sleepable lock.
A possible way to fix that is to move the pages allocation out of the lock
into the caller, but having to allocate a huge number of pages and
auxiliary page array seems to be problematic as well per Tetsuon: " You
should implement proper error handling instead of using __GFP_NOFAIL if
count can become large."

So I chose another way, which does not release kernel bounce pages when
user tries to register userspace bounce pages.  Then we can avoid
allocating in paths where failure is not expected.(e.g in the release).
We pay this for more memory usage as we don't release kernel bounce pages
but further optimizations could be done on top.

[v-songbaohua@oppo.com: Refine the changelog]
Link: https://lkml.kernel.org/r/20240830202823.21478-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240830202823.21478-2-21cnbao@gmail.com
Fixes: 6c77ed22880d ("vduse: Support using userspace pages as bounce buffer")
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Xie Yongji <xieyongji@bytedance.com>
Tested-by: Xie Yongji <xieyongji@bytedance.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hailong.Liu <hailong.liu@oppo.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Eugenio Pérez" <eperezma@redhat.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/hugetlb: sort out global lock annotations

The mutex array pointer shares a cacheline with the spinlock:
ffffffff84187480 B hugetlb_fault_mutex_table
ffffffff84187488 B hugetlb_lock

This is because the former is annotated with a macro forcing cacheline
alignment.  I suspect it was meant to be the variant which on top of it
makes sure the object does not share the cacheline with anyone.

Since array pointer itself is de facto read-only such an annotation does
not make sense there anyway.  Instead mark it __ro_after_init along with
the size var.

Do however move the spinlock out of the way.

[akpm@linux-foundation.org: move section directives to the end of the definitions, per convention]
[akpm@linux-foundation.org: DEFINE_SPINLOCK doesn't permit section modifiers at end-of-definition]
Link: https://lkml.kernel.org/r/20240828160704.1425767-1-mjguzik@gmail.com
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: shmem: extend shmem_unused_huge_shrink() to all sizes

Although shmem_get_folio_gfp() is correctly putting inodes on the
shrinklist according to the folio size, shmem_unused_huge_shrink() was
still dealing with that shrinklist in terms of HPAGE_PMD_SIZE.

Generalize that; and to handle the mixture of sizes more sensibly,
shmem_alloc_and_add_folio() give it a number of pages to be freed
(approximate: no need to minimize that with an exact calculation) instead
of a number of inodes to split.

[akpm@linux-foundation.org: comment tweak, per David]
Link: https://lkml.kernel.org/r/d8c40850-6774-7a93-1e2c-8d941683b260@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: shmem: fix minor off-by-one in shrinkable calculation

There has been a long-standing and very minor off-by-one, where
shmem_get_folio_gfp() decides if a large folio extends beyond i_size far
enough to leave a page or more for freeing later under pressure.

This is not something needed for stable: but it will be proportionately
more significant as support for smaller large folios is added, and is best
fixed before duplicating the check in other places.

Link: https://lkml.kernel.org/r/d8e75079-af2d-8519-56df-6be1dccc247a@google.com
Fixes: 779750d20b93 ("shmem: split huge pages beyond i_size under memory pressure")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

maple_tree: dump error message based on format

Just do what mt_dump_range64() does.

Dump the error message based on format.

Link: https://lkml.kernel.org/r/20240826012422.29935-2-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

maple_tree: arange64 node is not a leaf node

mt_dump_arange64() only applies to an entry whose type is maple_arange_64,
in which mte_is_leaf() must return false.

Since mte_is_leaf() here is always false, we can remove this condition
check.

Link: https://lkml.kernel.org/r/20240826012422.29935-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Docs/damon/maintainer-profile: document Google calendar for bi-weekly meetups

We added a public Google calendar for easy sharing of DAMON bi-weekly
meetups[1].  Add it to the official document for a better visibility.

[1] https://lore.kernel.org/all/20240717235812.53087-1-sj@kernel.org/

Link: https://lkml.kernel.org/r/20240826015741.80707-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Docs/damon/maintainer-profile: add links in place

maintainer-profile.rst for DAMON separates the links and target
definitions.  It is not really necessary, and only makes the readability
worse.  At least the definitions need the section title (say,
"References").  Just add the links in place on the doc.

Link: https://lkml.kernel.org/r/20240826015741.80707-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Docs/damon: use damonitor GitHub organization instead of awslabs

Patch series "Docs/damon: update GitHub repo URLs and maintainer-profile".

Replace GitHub URLS on DAMON documents for none-kernel parts DAMON repos
with new ones[1] via the first patch.  With following two patches,
wordsmith maitnainer-profile for better readability, and document the
Google clendsar for bi-weekly meetups, respectively.

[1] https://lore.kernel.org/20240813232158.83903-1-sj@kernel.org

This patch (of 3):

GitHub repos for non-kernel parts of DAMON project including 'damo',
'damon-tests' and 'damoos' will be moved[1] from 'awslabs' org to
'damonitor', by 2024-09-05.  Update related URLs in kernel tree.

[1] https://lore.kernel.org/20240813232158.83903-1-sj@kernel.org

Link: https://lkml.kernel.org/r/20240826015741.80707-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240826015741.80707-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Revert "mm/damon/lru_sort: adjust local variable to dynamic allocation"

This reverts commit 0742cadf5e4c ("mm/damon/lru_sort: adjust local
variable to dynamic allocation").

The commit was introduced to avoid unnecessary usage of stack memory for
per-scheme region priorities histogram buffer.  The fix is nice, but the
point of the fix looks not very clear if the commit message is not read
together.  That's mainly because the buffer is a private field, which
means it is hidden from the DAMON API users.  That's not the fault of the
fix but the underlying data structure.

Now the per-scheme histogram buffer is gone, so the problem that the
commit was fixing is also removed.  The use of kmemdup() has no more point
but just making the code bit difficult to understand.  Revert the fix.

Link: https://lkml.kernel.org/r/20240826042323.87025-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>