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authorMiao Xie <miaox@cn.fujitsu.com>2010-05-24 17:32:08 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-25 11:06:57 -0400
commitc0ff7453bb5c7c98e0885fb94279f2571946f280 (patch)
tree8bb2b169a5145f0496575dbd2f48bb4b1c83f819 /mm/hugetlb.c
parent708c1bbc9d0c3e57f40501794d9b0eed29d10fce (diff)
cpuset,mm: fix no node to alloc memory when changing cpuset's mems
Before applying this patch, cpuset updates task->mems_allowed and mempolicy by setting all new bits in the nodemask first, and clearing all old unallowed bits later. But in the way, the allocator may find that there is no node to alloc memory. The reason is that cpuset rebinds the task's mempolicy, it cleans the nodes which the allocater can alloc pages on, for example: (mpol: mempolicy) task1 task1's mpol task2 alloc page 1 alloc on node0? NO 1 1 change mems from 1 to 0 1 rebind task1's mpol 0-1 set new bits 0 clear disallowed bits alloc on node1? NO 0 ... can't alloc page goto oom This patch fixes this problem by expanding the nodes range first(set newly allowed bits) and shrink it lazily(clear newly disallowed bits). So we use a variable to tell the write-side task that read-side task is reading nodemask, and the write-side task clears newly disallowed nodes after read-side task ends the current memory allocation. [akpm@linux-foundation.org: fix spello] Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Paul Menage <menage@google.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Ravikiran Thirumalai <kiran@scalex86.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 4c9e6bbf377..54d42b009db 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -465,11 +465,13 @@ static struct page *dequeue_huge_page_vma(struct hstate *h,
465 struct page *page = NULL; 465 struct page *page = NULL;
466 struct mempolicy *mpol; 466 struct mempolicy *mpol;
467 nodemask_t *nodemask; 467 nodemask_t *nodemask;
468 struct zonelist *zonelist = huge_zonelist(vma, address, 468 struct zonelist *zonelist;
469 htlb_alloc_mask, &mpol, &nodemask);
470 struct zone *zone; 469 struct zone *zone;
471 struct zoneref *z; 470 struct zoneref *z;
472 471
472 get_mems_allowed();
473 zonelist = huge_zonelist(vma, address,
474 htlb_alloc_mask, &mpol, &nodemask);
473 /* 475 /*
474 * A child process with MAP_PRIVATE mappings created by their parent 476 * A child process with MAP_PRIVATE mappings created by their parent
475 * have no page reserves. This check ensures that reservations are 477 * have no page reserves. This check ensures that reservations are
@@ -477,11 +479,11 @@ static struct page *dequeue_huge_page_vma(struct hstate *h,
477 */ 479 */
478 if (!vma_has_reserves(vma) && 480 if (!vma_has_reserves(vma) &&
479 h->free_huge_pages - h->resv_huge_pages == 0) 481 h->free_huge_pages - h->resv_huge_pages == 0)
480 return NULL; 482 goto err;
481 483
482 /* If reserves cannot be used, ensure enough pages are in the pool */ 484 /* If reserves cannot be used, ensure enough pages are in the pool */
483 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) 485 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
484 return NULL; 486 goto err;;
485 487
486 for_each_zone_zonelist_nodemask(zone, z, zonelist, 488 for_each_zone_zonelist_nodemask(zone, z, zonelist,
487 MAX_NR_ZONES - 1, nodemask) { 489 MAX_NR_ZONES - 1, nodemask) {
@@ -500,7 +502,9 @@ static struct page *dequeue_huge_page_vma(struct hstate *h,
500 break; 502 break;
501 } 503 }
502 } 504 }
505err:
503 mpol_cond_put(mpol); 506 mpol_cond_put(mpol);
507 put_mems_allowed();
504 return page; 508 return page;
505} 509}
506 510