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| author | Hugh Dickins <hugh.dickins@tiscali.co.uk> | 2009-09-21 17:01:59 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 07:17:31 -0700 |
| commit | 21333b2b66b805a360641568588e5a0bb06d9d1f (patch) | |
| tree | c0ce4d31e31ae2d2b1ef975b00c0611a3099c7a3 /include | |
| parent | f8af4da3b4c14e7267c4ffb952079af3912c51c5 (diff) | |
| download | op-kernel-dev-21333b2b66b805a360641568588e5a0bb06d9d1f.zip op-kernel-dev-21333b2b66b805a360641568588e5a0bb06d9d1f.tar.gz | |
ksm: no debug in page_dup_rmap()
page_dup_rmap(), used on each mapped page when forking, was originally
just an inline atomic_inc of mapcount. 2.6.22 added CONFIG_DEBUG_VM
out-of-line checks to it, which would need to be ever-so-slightly
complicated to allow for the PageKsm() we're about to define.
But I think these checks never caught anything. And if it's coding errors
we're worried about, such checks should be in page_remove_rmap() too, not
just when forking; whereas if it's pagetable corruption we're worried
about, then they shouldn't be limited to CONFIG_DEBUG_VM.
Oh, just revert page_dup_rmap() to an inline atomic_inc of mapcount.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/rmap.h | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h index bf116d0..477841d 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -71,14 +71,10 @@ void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned lon void page_add_file_rmap(struct page *); void page_remove_rmap(struct page *); -#ifdef CONFIG_DEBUG_VM -void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address); -#else -static inline void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address) +static inline void page_dup_rmap(struct page *page) { atomic_inc(&page->_mapcount); } -#endif /* * Called from mm/vmscan.c to handle paging out |
