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authorWanpeng Li <liwanp@linux.vnet.ibm.com>2013-03-22 15:04:40 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-03-22 16:41:20 -0700
commitd00285884c0892bb1310df96bce6056e9ce9b9d9 (patch)
tree8470057e40c7519cbe1ca140e3ff88730d974f4b /mm/hugetlb.c
parentdc72c32e1fd872a9a4fdfe645283c9dcd68e556d (diff)
mm/hugetlb: fix total hugetlbfs pages count when using memory overcommit accouting
hugetlb_total_pages is used for overcommit calculations but the current implementation considers only the 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 commit a137e1cc6d6e ("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. 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 [akpm@linux-foundation.org: coding-style tweak] Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: <stable@vger.kernel.org> [3.0+] 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.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0a0be33bb199..ca9a7c6d7e97 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2124,8 +2124,12 @@ 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)