Messages in this thread Patch in this message | | | From | Wanpeng Li <> | Subject | [PATCH v3] mm/hugetlb: fix total hugetlbfs pages count when memory overcommit accouting | Date | Thu, 14 Mar 2013 19:30:46 +0800 |
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Changelog: v2 -> v3: * update patch description, spotted by Michal v1 -> v2: * update patch description, spotted by Michal
"hugetlb_total_pages is used for overcommit calculations but the current implementation considers only default hugetlb page size (which is either the first defined hugepage size or the one specified by default_hugepagesz kernel boot parameter).
If the system is configured for more than one hugepage size (which is possible since a137e1cc hugetlbfs: per mount huge page sizes) then the overcommit estimation done by __vm_enough_memory (resp. shown by meminfo_proc_show) is not precise - there is an impression of more available/allowed memory. This can lead to an unexpected ENOMEM/EFAULT resp. SIGSEGV when memory is accounted."
The patch should also push to 2.6.27 stable tree.
Testcase: boot: hugepagesz=1G hugepages=1 the default overcommit ratio is 50 before patch: egrep 'CommitLimit' /proc/meminfo CommitLimit: 55434168 kB after patch: egrep 'CommitLimit' /proc/meminfo CommitLimit: 54909880 kB
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> --- mm/hugetlb.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index cdb64e4..9e25040 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2124,8 +2124,11 @@ int hugetlb_report_node_meminfo(int nid, char *buf) /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ unsigned long hugetlb_total_pages(void) { - struct hstate *h = &default_hstate; - return h->nr_huge_pages * pages_per_huge_page(h); + struct hstate *h; + unsigned long nr_total_pages = 0; + for_each_hstate(h) + nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h); + return nr_total_pages; } static int hugetlb_acct_memory(struct hstate *h, long delta) -- 1.7.11.7
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