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authorNick Piggin <npiggin@suse.de>2008-10-18 20:26:09 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-20 08:50:25 -0700
commit62695a84eb8f2e718bf4dfb21700afaa7a08e0ea (patch)
tree0af7bac599748a7e462bff16d70c702c9e33a2fb /mm/mempolicy.c
parent71088785c6bc68fddb450063d57b1bd1c78e0ea1 (diff)
downloadvexpress-lsk-62695a84eb8f2e718bf4dfb21700afaa7a08e0ea.tar.gz
vmscan: move isolate_lru_page() to vmscan.c
On large memory systems, the VM can spend way too much time scanning through pages that it cannot (or should not) evict from memory. Not only does it use up CPU time, but it also provokes lock contention and can leave large systems under memory presure in a catatonic state. This patch series improves VM scalability by: 1) putting filesystem backed, swap backed and unevictable pages onto their own LRUs, so the system only scans the pages that it can/should evict from memory 2) switching to two handed clock replacement for the anonymous LRUs, so the number of pages that need to be scanned when the system starts swapping is bound to a reasonable number 3) keeping unevictable pages off the LRU completely, so the VM does not waste CPU time scanning them. ramfs, ramdisk, SHM_LOCKED shared memory segments and mlock()ed VMA pages are keept on the unevictable list. This patch: isolate_lru_page logically belongs to be in vmscan.c than migrate.c. It is tough, because we don't need that function without memory migration so there is a valid argument to have it in migrate.c. However a subsequent patch needs to make use of it in the core mm, so we can happily move it to vmscan.c. Also, make the function a little more generic by not requiring that it adds an isolated page to a given list. Callers can do that. Note that we now have '__isolate_lru_page()', that does something quite different, visible outside of vmscan.c for use with memory controller. Methinks we need to rationalize these names/purposes. --lts [akpm@linux-foundation.org: fix mm/memory_hotplug.c build] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mempolicy.c')
-rw-r--r--mm/mempolicy.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 83369058ec1..71b47491487 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -93,6 +93,8 @@
#include <asm/tlbflush.h>
#include <asm/uaccess.h>
+#include "internal.h"
+
/* Internal flags */
#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
@@ -762,8 +764,11 @@ static void migrate_page_add(struct page *page, struct list_head *pagelist,
/*
* Avoid migrating a page that is shared with others.
*/
- if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1)
- isolate_lru_page(page, pagelist);
+ if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
+ if (!isolate_lru_page(page)) {
+ list_add_tail(&page->lru, pagelist);
+ }
+ }
}
static struct page *new_node_page(struct page *page, unsigned long node, int **x)