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authorNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>2010-05-28 09:29:16 +0900
committerAndi Kleen <ak@linux.intel.com>2010-08-11 09:21:15 +0200
commit0fe6e20b9c4c53b3e97096ee73a0857f60aad43f (patch)
tree3014636f2ed66fdebecb6f6bab338b39c3543a07 /include/linux/poison.h
parent8edf344c66a3f214d709dad1421c29d678915b3f (diff)
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hugetlb, rmap: add reverse mapping for hugepage
This patch adds reverse mapping feature for hugepage by introducing mapcount for shared/private-mapped hugepage and anon_vma for private-mapped hugepage. While hugepage is not currently swappable, reverse mapping can be useful for memory error handler. Without this patch, memory error handler cannot identify processes using the bad hugepage nor unmap it from them. That is: - for shared hugepage: we can collect processes using a hugepage through pagecache, but can not unmap the hugepage because of the lack of mapcount. - for privately mapped hugepage: we can neither collect processes nor unmap the hugepage. This patch solves these problems. This patch include the bug fix given by commit 23be7468e8, so reverts it. Dependency: "hugetlb: move definition of is_vm_hugetlb_page() to hugepage_inline.h" ChangeLog since May 24. - create hugetlb_inline.h and move is_vm_hugetlb_index() in it. - move functions setting up anon_vma for hugepage into mm/rmap.c. ChangeLog since May 13. - rebased to 2.6.34 - fix logic error (in case that private mapping and shared mapping coexist) - move is_vm_hugetlb_page() into include/linux/mm.h to use this function from linear_page_index() - define and use linear_hugepage_index() instead of compound_order() - use page_move_anon_rmap() in hugetlb_cow() - copy exclusive switch of __set_page_anon_rmap() into hugepage counterpart. - revert commit 24be7468 completely Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Acked-by: Fengguang Wu <fengguang.wu@intel.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andi Kleen <ak@linux.intel.com>
Diffstat (limited to 'include/linux/poison.h')
-rw-r--r--include/linux/poison.h9
1 files changed, 0 insertions, 9 deletions
diff --git a/include/linux/poison.h b/include/linux/poison.h
index 34066ffd893d..2110a81c5e2a 100644
--- a/include/linux/poison.h
+++ b/include/linux/poison.h
@@ -48,15 +48,6 @@
#define POISON_FREE 0x6b /* for use-after-free poisoning */
#define POISON_END 0xa5 /* end-byte of poisoning */
-/********** mm/hugetlb.c **********/
-/*
- * Private mappings of hugetlb pages use this poisoned value for
- * page->mapping. The core VM should not be doing anything with this mapping
- * but futex requires the existence of some page->mapping value even though it
- * is unused if PAGE_MAPPING_ANON is set.
- */
-#define HUGETLB_POISON ((void *)(0x00300300 + POISON_POINTER_DELTA + PAGE_MAPPING_ANON))
-
/********** arch/$ARCH/mm/init.c **********/
#define POISON_FREE_INITMEM 0xcc