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authorLee Schermerhorn <Lee.Schermerhorn@hp.com>2008-10-18 23:26:43 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-20 11:50:26 -0400
commit89e004ea55abe201b29e2d6e35124101f1288ef7 (patch)
tree272a8f453106fd33d66fd7153f44696648dbe8b6 /include/linux/swap.h
parentba9ddf49391645e6bb93219131a40446538a5e76 (diff)
SHM_LOCKED pages are unevictable
Shmem segments locked into memory via shmctl(SHM_LOCKED) should not be kept on the normal LRU, since scanning them is a waste of time and might throw off kswapd's balancing algorithms. Place them on the unevictable LRU list instead. Use the AS_UNEVICTABLE flag to mark address_space of SHM_LOCKed shared memory regions as unevictable. Then these pages will be culled off the normal LRU lists during vmscan. Add new wrapper function to clear the mapping's unevictable state when/if shared memory segment is munlocked. Add 'scan_mapping_unevictable_page()' to mm/vmscan.c to scan all pages in the shmem segment's mapping [struct address_space] for evictability now that they're no longer locked. If so, move them to the appropriate zone lru list. Changes depend on [CONFIG_]UNEVICTABLE_LRU. [kosaki.motohiro@jp.fujitsu.com: revert shm change] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Kosaki Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/swap.h')
-rw-r--r--include/linux/swap.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index a2113044d20a..7edb4cbc29f9 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -232,12 +232,16 @@ static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
232 232
233#ifdef CONFIG_UNEVICTABLE_LRU 233#ifdef CONFIG_UNEVICTABLE_LRU
234extern int page_evictable(struct page *page, struct vm_area_struct *vma); 234extern int page_evictable(struct page *page, struct vm_area_struct *vma);
235extern void scan_mapping_unevictable_pages(struct address_space *);
235#else 236#else
236static inline int page_evictable(struct page *page, 237static inline int page_evictable(struct page *page,
237 struct vm_area_struct *vma) 238 struct vm_area_struct *vma)
238{ 239{
239 return 1; 240 return 1;
240} 241}
242static inline void scan_mapping_unevictable_pages(struct address_space *mapping)
243{
244}
241#endif 245#endif
242 246
243extern int kswapd_run(int nid); 247extern int kswapd_run(int nid);