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| author | Hugh Dickins <hugh.dickins@tiscali.co.uk> | 2009-12-15 04:58:57 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-15 19:53:17 +0300 |
| commit | 3ca7b3c5b64d35fe02c35b5d44c2c58b49499fee (patch) | |
| tree | bb6af24d3683788ef658282f8794af19d2232663 /mm | |
| parent | bb3ab596832b920c703d1aea1ce76d69c0f71fb7 (diff) | |
| download | linux-3ca7b3c5b64d35fe02c35b5d44c2c58b49499fee.tar.xz | |
mm: define PAGE_MAPPING_FLAGS
At present we define PageAnon(page) by the low PAGE_MAPPING_ANON bit set
in page->mapping, with the higher bits a pointer to the anon_vma; and have
defined PageKsm(page) as that with NULL anon_vma.
But KSM swapping will need to store a pointer there: so in preparation for
that, now define PAGE_MAPPING_FLAGS as the low two bits, including
PAGE_MAPPING_KSM (always set along with PAGE_MAPPING_ANON, until some
other use for the bit emerges).
Declare page_rmapping(page) to return the pointer part of page->mapping,
and page_anon_vma(page) to return the anon_vma pointer when that's what it
is. Use these in a few appropriate places: notably, unuse_vma() has been
testing page->mapping, but is better to be testing page_anon_vma() (cases
may be added in which flag bits are set without any pointer).
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/migrate.c | 11 | ||||
| -rw-r--r-- | mm/rmap.c | 7 | ||||
| -rw-r--r-- | mm/swapfile.c | 2 |
3 files changed, 8 insertions, 12 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 576c25eeb1ca..367272d04423 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -172,17 +172,14 @@ static void remove_anon_migration_ptes(struct page *old, struct page *new) { struct anon_vma *anon_vma; struct vm_area_struct *vma; - unsigned long mapping; - - mapping = (unsigned long)new->mapping; - - if (!mapping || (mapping & PAGE_MAPPING_ANON) == 0) - return; /* * We hold the mmap_sem lock. So no need to call page_lock_anon_vma. */ - anon_vma = (struct anon_vma *) (mapping - PAGE_MAPPING_ANON); + anon_vma = page_anon_vma(new); + if (!anon_vma) + return; + spin_lock(&anon_vma->lock); list_for_each_entry(vma, &anon_vma->head, anon_vma_node) diff --git a/mm/rmap.c b/mm/rmap.c index 1a0ee6e634c2..f06cee48eca7 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -203,7 +203,7 @@ struct anon_vma *page_lock_anon_vma(struct page *page) rcu_read_lock(); anon_mapping = (unsigned long) page->mapping; - if (!(anon_mapping & PAGE_MAPPING_ANON)) + if ((anon_mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON) goto out; if (!page_mapped(page)) goto out; @@ -248,8 +248,7 @@ vma_address(struct page *page, struct vm_area_struct *vma) unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) { if (PageAnon(page)) { - if ((void *)vma->anon_vma != - (void *)page->mapping - PAGE_MAPPING_ANON) + if (vma->anon_vma != page_anon_vma(page)) return -EFAULT; } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) { if (!vma->vm_file || @@ -513,7 +512,7 @@ int page_referenced(struct page *page, referenced++; *vm_flags = 0; - if (page_mapped(page) && page->mapping) { + if (page_mapped(page) && page_rmapping(page)) { if (PageAnon(page)) referenced += page_referenced_anon(page, mem_cont, vm_flags); diff --git a/mm/swapfile.c b/mm/swapfile.c index d5eb2e85600b..e74112e8e5f4 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -938,7 +938,7 @@ static int unuse_vma(struct vm_area_struct *vma, unsigned long addr, end, next; int ret; - if (page->mapping) { + if (page_anon_vma(page)) { addr = page_address_in_vma(page, vma); if (addr == -EFAULT) return 0; |