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authorNishanth Aravamudan <nacc@us.ibm.com>2008-04-29 03:58:26 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 11:05:58 -0400
commit551883ae8c9c31460e796e7b1b8aa9069de268b4 (patch)
tree2f2aaef8024656b3b5e1cf9e599608e54d2e483e
parenta41f24ea9fd6169b147c53c2392e2887cc1d9247 (diff)
page allocator: explicitly retry hugepage allocations
Add __GFP_REPEAT to hugepage allocations. Do so to not necessitate userspace putting pressure on the VM by repeated echo's into /proc/sys/vm/nr_hugepages to grow the pool. With the previous patch to allow for large-order __GFP_REPEAT attempts to loop for a bit (as opposed to indefinitely), this increases the likelihood of getting hugepages when the system experiences (or recently experienced) load. Mel tested the patchset on an x86_32 laptop. With the patches, it was easier to use the proc interface to grow the hugepage pool. The following is the output of a script that grows the pool as much as possible running on 2.6.25-rc9. Allocating hugepages test ------------------------- Disabling OOM Killer for current test process Starting page count: 0 Attempt 1: 57 pages Progress made with 57 pages Attempt 2: 73 pages Progress made with 16 pages Attempt 3: 74 pages Progress made with 1 pages Attempt 4: 75 pages Progress made with 1 pages Attempt 5: 77 pages Progress made with 2 pages 77 pages was the most it allocated but it took 5 attempts from userspace to get it. With the 3 patches in this series applied, Allocating hugepages test ------------------------- Disabling OOM Killer for current test process Starting page count: 0 Attempt 1: 75 pages Progress made with 75 pages Attempt 2: 76 pages Progress made with 1 pages Attempt 3: 79 pages Progress made with 3 pages And 79 pages was the most it got. Your patches were able to allocate the bulk of possible pages on the first attempt. Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Tested-by: Mel Gorman <mel@csn.ul.ie> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/hugetlb.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 2c37c67ed8c9..bbf953eeb58b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -199,7 +199,8 @@ static struct page *alloc_fresh_huge_page_node(int nid)
199 struct page *page; 199 struct page *page;
200 200
201 page = alloc_pages_node(nid, 201 page = alloc_pages_node(nid,
202 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN, 202 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
203 __GFP_REPEAT|__GFP_NOWARN,
203 HUGETLB_PAGE_ORDER); 204 HUGETLB_PAGE_ORDER);
204 if (page) { 205 if (page) {
205 if (arch_prepare_hugepage(page)) { 206 if (arch_prepare_hugepage(page)) {
@@ -294,7 +295,8 @@ static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma,
294 } 295 }
295 spin_unlock(&hugetlb_lock); 296 spin_unlock(&hugetlb_lock);
296 297
297 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN, 298 page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
299 __GFP_REPEAT|__GFP_NOWARN,
298 HUGETLB_PAGE_ORDER); 300 HUGETLB_PAGE_ORDER);
299 301
300 spin_lock(&hugetlb_lock); 302 spin_lock(&hugetlb_lock);