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authorNick Piggin <npiggin@suse.de>2008-10-19 03:26:09 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-20 15:50:25 (GMT)
commit62695a84eb8f2e718bf4dfb21700afaa7a08e0ea (patch)
tree0af7bac599748a7e462bff16d70c702c9e33a2fb /mm/memory_hotplug.c
parent71088785c6bc68fddb450063d57b1bd1c78e0ea1 (diff)
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/memory_hotplug.c')
-rw-r--r--mm/memory_hotplug.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index c299d08..3b49758 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -658,8 +658,9 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
* We can skip free pages. And we can only deal with pages on
* LRU.
*/
- ret = isolate_lru_page(page, &source);
+ ret = isolate_lru_page(page);
if (!ret) { /* Success */
+ list_add_tail(&page->lru, &source);
move_pages--;
} else {
/* Becasue we don't have big zone->lock. we should

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