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authorWanpeng Li <liwanp@linux.vnet.ibm.com>2013-03-22 15:04:40 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-28 12:12:12 -0700
commitbea7cce4319edd8c15d78833f9b5bb752f997662 (patch)
tree96c435437d49f4448158a1ffb5a5e0dff0523bde
parent612dadee15aa0a474309a93f53172920fe93d609 (diff)
mm/hugetlb: fix total hugetlbfs pages count when using memory overcommit accouting
commit d00285884c0892bb1310df96bce6056e9ce9b9d9 upstream. 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--mm/hugetlb.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index c384e0901f9c..e427969ecac0 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2096,8 +2096,12 @@ 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)