[PATCH 05/10] ksm: no debug in page_dup_rmap()
From: Izik Eidus <hidden>
Date: 2009-07-17 17:28:10
Also in:
lkml
Subsystem:
memory management, memory management - core, memory management - rmap (reverse mapping), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Lorenzo Stoakes, Linus Torvalds
From: Hugh Dickins <redacted> 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 <redacted> Signed-off-by: Chris Wright <redacted> Signed-off-by: Izik Eidus <redacted> Cc: Nick Piggin <redacted> --- include/linux/rmap.h | 6 +----- mm/memory.c | 2 +- mm/rmap.c | 21 --------------------- 3 files changed, 2 insertions(+), 27 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
diff --git a/mm/memory.c b/mm/memory.c
index 8159a62..8b1922c 100644
--- a/mm/memory.c
+++ b/mm/memory.c@@ -595,7 +595,7 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, page = vm_normal_page(vma, addr, pte); if (page) { get_page(page); - page_dup_rmap(page, vma, addr); + page_dup_rmap(page); rss[!!PageAnon(page)]++; }
diff --git a/mm/rmap.c b/mm/rmap.c
index 836c6c6..ab84e45 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c@@ -709,27 +709,6 @@ void page_add_file_rmap(struct page *page) } } -#ifdef CONFIG_DEBUG_VM -/** - * page_dup_rmap - duplicate pte mapping to a page - * @page: the page to add the mapping to - * @vma: the vm area being duplicated - * @address: the user virtual address mapped - * - * For copy_page_range only: minimal extract from page_add_file_rmap / - * page_add_anon_rmap, avoiding unnecessary tests (already checked) so it's - * quicker. - * - * The caller needs to hold the pte lock. - */ -void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address) -{ - if (PageAnon(page)) - __page_check_anon_rmap(page, vma, address); - atomic_inc(&page->_mapcount); -} -#endif - /** * page_remove_rmap - take down pte mapping from a page * @page: page to remove mapping from
--
1.5.6.5
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