hugetlb rmap handling differs quite a lot from "ordinary" rmap code. For
example, hugetlb currently only supports entire mappings, and treats any
mapping as mapped using a single "logical PTE". Let's move it out of the
way so we can overhaul our "ordinary" rmap. implementation/interface.
Right now we're using page_dup_file_rmap() in some cases where "ordinary"
rmap code would have used page_add_file_rmap(). So let's introduce and
use hugetlb_add_file_rmap() instead. We won't be adding a
"hugetlb_dup_file_rmap()" functon for the fork() case, as it would be
doing the same: "dup" is just an optimization for "add".
What remains is a single page_dup_file_rmap() call in fork() code.
Add sanity checks that we end up with the right folios in the right
functions.
Link: https://lkml.kernel.org/r/20231220224504.646757-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
void hugetlb_add_new_anon_rmap(struct folio *, struct vm_area_struct *,
unsigned long address);
+static inline void hugetlb_add_file_rmap(struct folio *folio)
+{
+ VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio);
+ VM_WARN_ON_FOLIO(folio_test_anon(folio), folio);
+
+ atomic_inc(&folio->_entire_mapcount);
+}
+
static inline void hugetlb_remove_rmap(struct folio *folio)
{
VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio);
* sleep during the process.
*/
if (!folio_test_anon(pte_folio)) {
- page_dup_file_rmap(&pte_folio->page, true);
+ hugetlb_add_file_rmap(pte_folio);
} else if (page_try_dup_anon_rmap(&pte_folio->page,
true, src_vma)) {
pte_t src_pte_old = entry;
if (anon_rmap)
hugetlb_add_new_anon_rmap(folio, vma, haddr);
else
- page_dup_file_rmap(&folio->page, true);
+ hugetlb_add_file_rmap(folio);
new_pte = make_huge_pte(vma, &folio->page, ((vma->vm_flags & VM_WRITE)
&& (vma->vm_flags & VM_SHARED)));
/*
goto out_release_unlock;
if (folio_in_pagecache)
- page_dup_file_rmap(&folio->page, true);
+ hugetlb_add_file_rmap(folio);
else
hugetlb_add_new_anon_rmap(folio, dst_vma, dst_addr);
hugetlb_add_anon_rmap(folio, vma, pvmw.address,
rmap_flags);
else
- page_dup_file_rmap(new, true);
+ hugetlb_add_file_rmap(folio);
set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte,
psize);
} else
unsigned int nr_pmdmapped = 0, first;
int nr = 0;
+ VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
VM_WARN_ON_FOLIO(compound && !folio_test_pmd_mappable(folio), folio);
/* Is page being mapped by PTE? Is this its first map to be added? */