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authorHugh Dickins <hugh.dickins@tiscali.co.uk>2009-12-14 20:58:57 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-15 11:53:17 -0500
commit3ca7b3c5b64d35fe02c35b5d44c2c58b49499fee (patch)
treebb6af24d3683788ef658282f8794af19d2232663 /mm
parentbb3ab596832b920c703d1aea1ce76d69c0f71fb7 (diff)
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.c11
-rw-r--r--mm/rmap.c7
-rw-r--r--mm/swapfile.c2
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)
172{ 172{
173 struct anon_vma *anon_vma; 173 struct anon_vma *anon_vma;
174 struct vm_area_struct *vma; 174 struct vm_area_struct *vma;
175 unsigned long mapping;
176
177 mapping = (unsigned long)new->mapping;
178
179 if (!mapping || (mapping & PAGE_MAPPING_ANON) == 0)
180 return;
181 175
182 /* 176 /*
183 * We hold the mmap_sem lock. So no need to call page_lock_anon_vma. 177 * We hold the mmap_sem lock. So no need to call page_lock_anon_vma.
184 */ 178 */
185 anon_vma = (struct anon_vma *) (mapping - PAGE_MAPPING_ANON); 179 anon_vma = page_anon_vma(new);
180 if (!anon_vma)
181 return;
182
186 spin_lock(&anon_vma->lock); 183 spin_lock(&anon_vma->lock);
187 184
188 list_for_each_entry(vma, &anon_vma->head, anon_vma_node) 185 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)
203 203
204 rcu_read_lock(); 204 rcu_read_lock();
205 anon_mapping = (unsigned long) page->mapping; 205 anon_mapping = (unsigned long) page->mapping;
206 if (!(anon_mapping & PAGE_MAPPING_ANON)) 206 if ((anon_mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
207 goto out; 207 goto out;
208 if (!page_mapped(page)) 208 if (!page_mapped(page))
209 goto out; 209 goto out;
@@ -248,8 +248,7 @@ vma_address(struct page *page, struct vm_area_struct *vma)
248unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) 248unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
249{ 249{
250 if (PageAnon(page)) { 250 if (PageAnon(page)) {
251 if ((void *)vma->anon_vma != 251 if (vma->anon_vma != page_anon_vma(page))
252 (void *)page->mapping - PAGE_MAPPING_ANON)
253 return -EFAULT; 252 return -EFAULT;
254 } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) { 253 } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
255 if (!vma->vm_file || 254 if (!vma->vm_file ||
@@ -513,7 +512,7 @@ int page_referenced(struct page *page,
513 referenced++; 512 referenced++;
514 513
515 *vm_flags = 0; 514 *vm_flags = 0;
516 if (page_mapped(page) && page->mapping) { 515 if (page_mapped(page) && page_rmapping(page)) {
517 if (PageAnon(page)) 516 if (PageAnon(page))
518 referenced += page_referenced_anon(page, mem_cont, 517 referenced += page_referenced_anon(page, mem_cont,
519 vm_flags); 518 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,
938 unsigned long addr, end, next; 938 unsigned long addr, end, next;
939 int ret; 939 int ret;
940 940
941 if (page->mapping) { 941 if (page_anon_vma(page)) {
942 addr = page_address_in_vma(page, vma); 942 addr = page_address_in_vma(page, vma);
943 if (addr == -EFAULT) 943 if (addr == -EFAULT)
944 return 0; 944 return 0;