hugetlb: allow to free gigantic pages regardless of the configuration

On systems without CONTIG_ALLOC activated but that support gigantic pages,
boottime reserved gigantic pages can not be freed at all.  This patch
simply enables the possibility to hand back those pages to memory
allocator.

Link: http://lkml.kernel.org/r/20190327063626.18421-5-alex@ghiti.fr
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Acked-by: David S. Miller <davem@davemloft.net> [sparc]
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7f7fbd8bd9d5b4402ee3d2660a93b6b5f5749c07..7a1aa53d188d339ff75cdade361a57223938514c 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -19,7 +19,7 @@ config ARM64
        select ARCH_HAS_FAST_MULTIPLIER
        select ARCH_HAS_FORTIFY_SOURCE
        select ARCH_HAS_GCOV_PROFILE_ALL
-       select ARCH_HAS_GIGANTIC_PAGE if CONTIG_ALLOC
+       select ARCH_HAS_GIGANTIC_PAGE
        select ARCH_HAS_KCOV
        select ARCH_HAS_KEEPINITRD
        select ARCH_HAS_MEMBARRIER_SYNC_CORE

diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
index c6a07a3b433e3d09b9b0ff08ed53a881470b6508..4aad6382f6319198f9df0e24df297e5c7b0a61bf 100644 (file)
--- a/arch/arm64/include/asm/hugetlb.h
+++ b/arch/arm64/include/asm/hugetlb.h
@@ -70,8 +70,4 @@ extern void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,
 
 #include <asm-generic/hugetlb.h>
 
-#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
-static inline bool gigantic_page_supported(void) { return true; }
-#endif
-
 #endif /* __ASM_HUGETLB_H */

diff --git a/arch/powerpc/include/asm/book3s/64/hugetlb.h b/arch/powerpc/include/asm/book3s/64/hugetlb.h
index 56140d19c85fcb21d6265799e290fc553dfcbf6f..12e150e615b7756d040f256bd841bfb60c41e072 100644 (file)
--- a/arch/powerpc/include/asm/book3s/64/hugetlb.h
+++ b/arch/powerpc/include/asm/book3s/64/hugetlb.h
@@ -36,8 +36,8 @@ static inline int hstate_get_psize(struct hstate *hstate)
        }
 }
 
-#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
-static inline bool gigantic_page_supported(void)
+#define __HAVE_ARCH_GIGANTIC_PAGE_RUNTIME_SUPPORTED
+static inline bool gigantic_page_runtime_supported(void)
 {
        /*
         * We used gigantic page reservation with hypervisor assist in some case.
@@ -49,7 +49,6 @@ static inline bool gigantic_page_supported(void)
 
        return true;
 }
-#endif
 
 /* hugepd entry valid bit */
 #define HUGEPD_VAL_BITS                (0x8000000000000000UL)

diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 3a31d4289ea4fe8b0f02d365ecbbb2173d839487..2794235e9d3eab5e1791210c3a5d810283df36cb 100644 (file)
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -331,7 +331,7 @@ config ARCH_ENABLE_SPLIT_PMD_PTLOCK
 config PPC_RADIX_MMU
        bool "Radix MMU Support"
        depends on PPC_BOOK3S_64 && HUGETLB_PAGE
-       select ARCH_HAS_GIGANTIC_PAGE if CONTIG_ALLOC
+       select ARCH_HAS_GIGANTIC_PAGE
        select PPC_HAVE_KUEP
        select PPC_HAVE_KUAP
        default y

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 724dbc6b7d33409913ccd5f054dd3b8e023095c5..d0c046af65fa4d6816e9369e145d83992339d1f8 100644 (file)
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -63,7 +63,7 @@ config S390
        select ARCH_HAS_ELF_RANDOMIZE
        select ARCH_HAS_FORTIFY_SOURCE
        select ARCH_HAS_GCOV_PROFILE_ALL
-       select ARCH_HAS_GIGANTIC_PAGE if CONTIG_ALLOC
+       select ARCH_HAS_GIGANTIC_PAGE
        select ARCH_HAS_KCOV
        select ARCH_HAS_PTE_SPECIAL
        select ARCH_HAS_SET_MEMORY

diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
index 2d1afa58a4b6bf92c9fab01c021f7923dc199bc3..bb59dd9645909207351edc8d3577985f1aead9fb 100644 (file)
--- a/arch/s390/include/asm/hugetlb.h
+++ b/arch/s390/include/asm/hugetlb.h
@@ -116,7 +116,9 @@ static inline pte_t huge_pte_modify(pte_t pte, pgprot_t newprot)
        return pte_modify(pte, newprot);
 }
 
-#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
-static inline bool gigantic_page_supported(void) { return true; }
-#endif
+static inline bool gigantic_page_runtime_supported(void)
+{
+       return true;
+}
+
 #endif /* _ASM_S390_HUGETLB_H */

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 2a5ec643fec0dc3091859186d2e5b71e6a130184..2a77033e1e7cf0737001340cc1faf437e29a7e4e 100644 (file)
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -53,7 +53,7 @@ config SUPERH
        select HAVE_FUTEX_CMPXCHG if FUTEX
        select HAVE_NMI
        select NEED_SG_DMA_LENGTH
-       select ARCH_HAS_GIGANTIC_PAGE if CONTIG_ALLOC
+       select ARCH_HAS_GIGANTIC_PAGE
 
        help
          The SuperH is a RISC processor targeted for use in embedded systems

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 566de738e4877975533e852280ecf8a607871683..7c93f3121ee6bab8cbd1477420df9906a9c15b2f 100644 (file)
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -92,7 +92,7 @@ config SPARC64
        select ARCH_CLOCKSOURCE_DATA
        select ARCH_HAS_PTE_SPECIAL
        select PCI_DOMAINS if PCI
-       select ARCH_HAS_GIGANTIC_PAGE if CONTIG_ALLOC
+       select ARCH_HAS_GIGANTIC_PAGE
 
 config ARCH_DEFCONFIG
        string

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 526d95abfe5ef571c621ce8f854745e868884ca2..f21bc56e5d7b55a50f53d6fc518119a01034c830 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -22,7 +22,7 @@ config X86_64
        def_bool y
        depends on 64BIT
        # Options that are inherently 64-bit kernel only:
-       select ARCH_HAS_GIGANTIC_PAGE if CONTIG_ALLOC
+       select ARCH_HAS_GIGANTIC_PAGE
        select ARCH_SUPPORTS_INT128
        select ARCH_USE_CMPXCHG_LOCKREF
        select HAVE_ARCH_SOFT_DIRTY

diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h
index 7469d321f07221a201ace98623f2b34b379b57f9..f65cfb48cfddad0079d45b9a0721b5fec2904a2f 100644 (file)
--- a/arch/x86/include/asm/hugetlb.h
+++ b/arch/x86/include/asm/hugetlb.h
@@ -17,8 +17,4 @@ static inline void arch_clear_hugepage_flags(struct page *page)
 {
 }
 
-#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
-static inline bool gigantic_page_supported(void) { return true; }
-#endif
-
 #endif /* _ASM_X86_HUGETLB_H */

diff --git a/include/asm-generic/hugetlb.h b/include/asm-generic/hugetlb.h
index 71d7b77eea50f9c8724d0220fdad17bf4f67db7e..822f433ac95cb665387cffe17198d0d860836d64 100644 (file)
--- a/include/asm-generic/hugetlb.h
+++ b/include/asm-generic/hugetlb.h
@@ -126,4 +126,11 @@ static inline pte_t huge_ptep_get(pte_t *ptep)
 }
 #endif
 
+#ifndef __HAVE_ARCH_GIGANTIC_PAGE_RUNTIME_SUPPORTED
+static inline bool gigantic_page_runtime_supported(void)
+{
+       return IS_ENABLED(CONFIG_ARCH_HAS_GIGANTIC_PAGE);
+}
+#endif /* __HAVE_ARCH_GIGANTIC_PAGE_RUNTIME_SUPPORTED */
+
 #endif /* _ASM_GENERIC_HUGETLB_H */

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index e77ab30e93284dd2aed01b091115ddca7b2d6812..fb07b503dc453ddfe16c5f0f959d46be01ad55ba 100644 (file)
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -589,8 +589,8 @@ static inline bool pm_suspended_storage(void)
 /* The below functions must be run on a range from a single zone. */
 extern int alloc_contig_range(unsigned long start, unsigned long end,
                              unsigned migratetype, gfp_t gfp_mask);
-extern void free_contig_range(unsigned long pfn, unsigned nr_pages);
 #endif
+void free_contig_range(unsigned long pfn, unsigned int nr_pages);
 
 #ifdef CONFIG_CMA
 /* CMA stuff */

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index dffe5d9d03ae96ddb00d0146e51d2c69309e1b89..2f901a6e13d23f3e54795084d9a8534068b661c6 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1059,6 +1059,7 @@ static void free_gigantic_page(struct page *page, unsigned int order)
        free_contig_range(page_to_pfn(page), 1 << order);
 }
 
+#ifdef CONFIG_CONTIG_ALLOC
 static int __alloc_gigantic_page(unsigned long start_pfn,
                                unsigned long nr_pages, gfp_t gfp_mask)
 {
@@ -1143,11 +1144,20 @@ static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
 
 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
 static void prep_compound_gigantic_page(struct page *page, unsigned int order);
+#else /* !CONFIG_CONTIG_ALLOC */
+static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
+                                       int nid, nodemask_t *nodemask)
+{
+       return NULL;
+}
+#endif /* CONFIG_CONTIG_ALLOC */
 
 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
-static inline bool gigantic_page_supported(void) { return false; }
 static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
-               int nid, nodemask_t *nodemask) { return NULL; }
+                                       int nid, nodemask_t *nodemask)
+{
+       return NULL;
+}
 static inline void free_gigantic_page(struct page *page, unsigned int order) { }
 static inline void destroy_compound_gigantic_page(struct page *page,
                                                unsigned int order) { }
@@ -1157,7 +1167,7 @@ static void update_and_free_page(struct hstate *h, struct page *page)
 {
        int i;
 
-       if (hstate_is_gigantic(h) && !gigantic_page_supported())
+       if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
                return;
 
        h->nr_huge_pages--;
@@ -2278,13 +2288,27 @@ found:
 }
 
 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
-static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
-                                               nodemask_t *nodes_allowed)
+static int set_max_huge_pages(struct hstate *h, unsigned long count,
+                             nodemask_t *nodes_allowed)
 {
        unsigned long min_count, ret;
 
-       if (hstate_is_gigantic(h) && !gigantic_page_supported())
-               return h->max_huge_pages;
+       spin_lock(&hugetlb_lock);
+
+       /*
+        * Gigantic pages runtime allocation depend on the capability for large
+        * page range allocation.
+        * If the system does not provide this feature, return an error when
+        * the user tries to allocate gigantic pages but let the user free the
+        * boottime allocated gigantic pages.
+        */
+       if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
+               if (count > persistent_huge_pages(h)) {
+                       spin_unlock(&hugetlb_lock);
+                       return -EINVAL;
+               }
+               /* Fall through to decrease pool */
+       }
 
        /*
         * Increase the pool size
@@ -2297,7 +2321,6 @@ static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
         * pool might be one hugepage larger than it needs to be, but
         * within all the constraints specified by the sysctls.
         */
-       spin_lock(&hugetlb_lock);
        while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
                if (!adjust_pool_surplus(h, nodes_allowed, -1))
                        break;
@@ -2352,9 +2375,10 @@ static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
                        break;
        }
 out:
-       ret = persistent_huge_pages(h);
+       h->max_huge_pages = persistent_huge_pages(h);
        spin_unlock(&hugetlb_lock);
-       return ret;
+
+       return 0;
 }
 
 #define HSTATE_ATTR_RO(_name) \
@@ -2406,7 +2430,7 @@ static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
        int err;
        NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
 
-       if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
+       if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) {
                err = -EINVAL;
                goto out;
        }
@@ -2430,15 +2454,13 @@ static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
        } else
                nodes_allowed = &node_states[N_MEMORY];
 
-       h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
+       err = set_max_huge_pages(h, count, nodes_allowed);
 
+out:
        if (nodes_allowed != &node_states[N_MEMORY])
                NODEMASK_FREE(nodes_allowed);
 
-       return len;
-out:
-       NODEMASK_FREE(nodes_allowed);
-       return err;
+       return err ? err : len;
 }
 
 static ssize_t nr_hugepages_store_common(bool obey_mempolicy,

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2efb6525d932a6376f0359ff23b511635af1cb4d..4ea71bc7041381ca6dda1aa5ae53e8a3c66f3ed1 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8346,8 +8346,9 @@ done:
                                pfn_max_align_up(end), migratetype);
        return ret;
 }
+#endif /* CONFIG_CONTIG_ALLOC */
 
-void free_contig_range(unsigned long pfn, unsigned nr_pages)
+void free_contig_range(unsigned long pfn, unsigned int nr_pages)
 {
        unsigned int count = 0;
 
@@ -8359,7 +8360,6 @@ void free_contig_range(unsigned long pfn, unsigned nr_pages)
        }
        WARN(count != 0, "%d pages are still in use!\n", count);
 }
-#endif
 
 #ifdef CONFIG_MEMORY_HOTPLUG
 /*