From: CAI Qian <caiqian@redhat.com>
To: linux-mm <linux-mm@kvack.org>
Subject: [RFC] /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_overcommit_hugepages
Date: Fri, 31 Dec 2010 06:08:21 -0500 (EST) [thread overview]
Message-ID: <617041603.101416.1293793701124.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com> (raw)
In-Reply-To: <1060163918.101411.1293793346203.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com>
Hi,
Problem: nr_overcommit_hugepages for 1gb hugepage went crazy.
Symptom:
1) setup 1gb hugepages.
# cat /proc/cmdline
default_hugepagesz=1g hugepagesz=1g hugepages=1
# cat /proc/meminfo
...
HugePages_Total: 1
HugePages_Free: 1
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 1048576 kB
...
2) set nr_overcommit_hugepages
# echo 1 >/sys/kernel/mm/hugepages/hugepages-1048576kB/nr_overcommit_hugepages
# cat /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_overcommit_hugepages
1
3) overcommit 2gb hugepages.
mmap(NULL, 18446744071562067968, PROT_READ|PROT_WRITE, MAP_SHARED, 3, 0) = -1 ENOMEM (Cannot allocate memory)
# cat /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_overcommit_hugepages
18446744071589420672
As you can see from the above, it did not allow overcommit despite nr_overcommit_hugepages value. Also, nr_overcommit_hugepages was overwritten with such a strange value after overcommit failure. Should we just remove this file from sysfs for simplicity?
Thanks.
CAI Qian
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next parent reply other threads:[~2010-12-31 11:08 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1060163918.101411.1293793346203.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com>
2010-12-31 11:08 ` CAI Qian [this message]
2011-01-04 9:56 ` [RFC] /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_overcommit_hugepages Michal Hocko
2011-01-04 10:21 ` CAI Qian
2011-01-04 10:52 ` Michal Hocko
2011-01-05 4:52 ` CAI Qian
2011-01-05 8:43 ` Michal Hocko
2011-01-05 8:54 ` CAI Qian
2011-01-05 9:51 ` Michal Hocko
2011-01-05 15:36 ` CAI Qian
2011-01-05 15:59 ` Michal Hocko
2011-01-05 16:42 ` CAI Qian
2011-01-05 16:44 ` Michal Hocko
2011-01-05 17:00 ` CAI Qian
2011-01-05 20:59 ` Andrew Morton
2011-01-06 10:04 ` PATCH: hugetlb: handle NODEMASK_ALLOC failure correctly Michal Hocko
2011-01-06 20:38 ` Andrew Morton
2011-01-06 22:23 ` Michal Hocko
2011-01-04 17:21 ` [RFC] /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_overcommit_hugepages Eric B Munson
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