From: Michal Hocko <mhocko@suse.cz>
To: CAI Qian <caiqian@redhat.com>
Cc: linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Nishanth Aravamudan <nacc@us.ibm.com>
Subject: Re: [RFC] /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_overcommit_hugepages
Date: Wed, 5 Jan 2011 09:43:57 +0100 [thread overview]
Message-ID: <20110105084357.GA21349@tiehlicka.suse.cz> (raw)
In-Reply-To: <907929848.134962.1294203162923.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com>
[Let's CC Andrew to pick up the patch - please see bellow]
On Tue 04-01-11 23:52:42, CAI Qian wrote:
> ----- Original Message -----
> > On Tue 04-01-11 05:21:46, CAI Qian wrote:
> > >
> > > > > 3) overcommit 2gb hugepages.
> > > > > mmap(NULL, 18446744071562067968, PROT_READ|PROT_WRITE,
> > > > > MAP_SHARED,
> > > > > 3, 0) = -1 ENOMEM (Cannot allocate memory)
> > > >
> > > > Hmm, you are trying to reserve/mmap a lot of memory (17179869182
> > > > 1GB
> > > > huge pages).
> > > That is strange - the test code merely did this,
> > > addr = mmap(ADDR, 2<<30, PROTECTION, FLAGS, fd, 0);
> >
> > Didn't you want 1<<30 instead?
> No, it was expecting to use both the allocate + overcommited 1GB pages.
Then you propably wanted 2*1UL<<30 rather than 2<<30 which is something
different than you want, I guess. Anyway this is not related to the
bogus value in nr_overcommit_hugepages after your testcase.
next prev parent reply other threads:[~2011-01-05 8:44 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 ` [RFC] /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_overcommit_hugepages CAI Qian
2011-01-04 9:56 ` 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 [this message]
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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