From: Will Deacon <will.deacon@arm.com>
Date: Mon, 8 Oct 2012 23:29:32 +0000 (-0700)
Subject: mm: hugetlb: add arch hook for clearing page flags before entering pool
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5d3a551c28c6669dc43be40d8fafafbc2ec8f42b;p=linux.git
mm: hugetlb: add arch hook for clearing page flags before entering pool
The core page allocator ensures that page flags are zeroed when freeing
pages via free_pages_check. A number of architectures (ARM, PPC, MIPS)
rely on this property to treat new pages as dirty with respect to the data
cache and perform the appropriate flushing before mapping the pages into
userspace.
This can lead to cache synchronisation problems when using hugepages,
since the allocator keeps its own pool of pages above the usual page
allocator and does not reset the page flags when freeing a page into the
pool.
This patch adds a new architecture hook, arch_clear_hugepage_flags, so
that architectures which rely on the page flags being in a particular
state for fresh allocations can adjust the flags accordingly when a page
is freed into the pool.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
diff --git a/arch/ia64/include/asm/hugetlb.h b/arch/ia64/include/asm/hugetlb.h
index da55c63728e0e..94eaa5bd5d0c4 100644
--- a/arch/ia64/include/asm/hugetlb.h
+++ b/arch/ia64/include/asm/hugetlb.h
@@ -77,4 +77,8 @@ static inline void arch_release_hugepage(struct page *page)
{
}
+static inline void arch_clear_hugepage_flags(struct page *page)
+{
+}
+
#endif /* _ASM_IA64_HUGETLB_H */
diff --git a/arch/mips/include/asm/hugetlb.h b/arch/mips/include/asm/hugetlb.h
index 58d36889f09b3..bd94946a18f34 100644
--- a/arch/mips/include/asm/hugetlb.h
+++ b/arch/mips/include/asm/hugetlb.h
@@ -112,4 +112,8 @@ static inline void arch_release_hugepage(struct page *page)
{
}
+static inline void arch_clear_hugepage_flags(struct page *page)
+{
+}
+
#endif /* __ASM_HUGETLB_H */
diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h
index dfdb95bc59a50..62e11a32c4c2b 100644
--- a/arch/powerpc/include/asm/hugetlb.h
+++ b/arch/powerpc/include/asm/hugetlb.h
@@ -151,6 +151,10 @@ static inline void arch_release_hugepage(struct page *page)
{
}
+static inline void arch_clear_hugepage_flags(struct page *page)
+{
+}
+
#else /* ! CONFIG_HUGETLB_PAGE */
static inline void flush_hugetlb_page(struct vm_area_struct *vma,
unsigned long vmaddr)
diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
index 2d6e6e3805641..fc322421b1cc1 100644
--- a/arch/s390/include/asm/hugetlb.h
+++ b/arch/s390/include/asm/hugetlb.h
@@ -33,6 +33,7 @@ static inline int prepare_hugepage_range(struct file *file,
}
#define hugetlb_prefault_arch_hook(mm) do { } while (0)
+#define arch_clear_hugepage_flags(page) do { } while (0)
int arch_prepare_hugepage(struct page *page);
void arch_release_hugepage(struct page *page);
diff --git a/arch/sh/include/asm/hugetlb.h b/arch/sh/include/asm/hugetlb.h
index 967068fb79ac4..b3808c7d67b23 100644
--- a/arch/sh/include/asm/hugetlb.h
+++ b/arch/sh/include/asm/hugetlb.h
@@ -1,6 +1,7 @@
#ifndef _ASM_SH_HUGETLB_H
#define _ASM_SH_HUGETLB_H
+#include <asm/cacheflush.h>
#include <asm/page.h>
@@ -89,4 +90,9 @@ static inline void arch_release_hugepage(struct page *page)
{
}
+static inline void arch_clear_hugepage_flags(struct page *page)
+{
+ clear_bit(PG_dcache_clean, &page->flags);
+}
+
#endif /* _ASM_SH_HUGETLB_H */
diff --git a/arch/sparc/include/asm/hugetlb.h b/arch/sparc/include/asm/hugetlb.h
index 177061064ee60..e7927c9758a19 100644
--- a/arch/sparc/include/asm/hugetlb.h
+++ b/arch/sparc/include/asm/hugetlb.h
@@ -82,4 +82,8 @@ static inline void arch_release_hugepage(struct page *page)
{
}
+static inline void arch_clear_hugepage_flags(struct page *page)
+{
+}
+
#endif /* _ASM_SPARC64_HUGETLB_H */
diff --git a/arch/tile/include/asm/hugetlb.h b/arch/tile/include/asm/hugetlb.h
index b2042380a5aab..0f885af2b6215 100644
--- a/arch/tile/include/asm/hugetlb.h
+++ b/arch/tile/include/asm/hugetlb.h
@@ -106,6 +106,10 @@ static inline void arch_release_hugepage(struct page *page)
{
}
+static inline void arch_clear_hugepage_flags(struct page *page)
+{
+}
+
#ifdef CONFIG_HUGETLB_SUPER_PAGES
static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
struct page *page, int writable)
diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h
index 439a9acc132d1..bdd35dbd0605b 100644
--- a/arch/x86/include/asm/hugetlb.h
+++ b/arch/x86/include/asm/hugetlb.h
@@ -90,4 +90,8 @@ static inline void arch_release_hugepage(struct page *page)
{
}
+static inline void arch_clear_hugepage_flags(struct page *page)
+{
+}
+
#endif /* _ASM_X86_HUGETLB_H */
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index bc727122dd44d..f1bb534254f69 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -637,6 +637,7 @@ static void free_huge_page(struct page *page)
h->surplus_huge_pages--;
h->surplus_huge_pages_node[nid]--;
} else {
+ arch_clear_hugepage_flags(page);
enqueue_huge_page(h, page);
}
spin_unlock(&hugetlb_lock);