From: Mel Gorman <mgorman@suse.de>
To: Mike Christie <mchristi@redhat.com>
Cc: Ilya Dryomov <idryomov@gmail.com>,
ceph-devel@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
Sage Weil <sage@redhat.com>, NeilBrown <neilb@suse.de>,
netdev@vger.kernel.org
Subject: Re: SOCK_MEMALLOC vs loopback
Date: Thu, 5 Mar 2015 09:50:44 +0000 [thread overview]
Message-ID: <20150305095044.GR3087@suse.de> (raw)
In-Reply-To: <54F7D5A7.1060404@redhat.com>
On Wed, Mar 04, 2015 at 10:03:51PM -0600, Mike Christie wrote:
> On 03/04/2015 02:04 PM, Mel Gorman wrote:
> > other options. If that contract is not met then using it can deadlock the
> > system. It's the same for PF_MEMALLOC -- activating that is a recipe for
> > deadlock due to memory exhaustion.
>
> For rbd and iscsi's SOCK_MEMALLOC/PF_MEMALLOC use, I copied what you did
> for nbd in commit 7f338fe4540b1d0600b02314c7d885fd358e9eca which always
> sets those flags and seems to rely on the network layer to do the right
> thing. Are they all incorrect?
NBD is a poor example and if it comes to that, I would suggest removing it
and let NBD easily deadlock like it used to. NBD has other failure cases
such as the client can get paged out if -swap is not specified. The same
commit notes that NBD may still deadlock and that min_free_kbytes may have
to be increased.
--
Mel Gorman
SUSE Labs
prev parent reply other threads:[~2015-03-05 9:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-04 18:38 SOCK_MEMALLOC vs loopback Ilya Dryomov
2015-03-04 20:04 ` Mel Gorman
2015-03-05 4:03 ` Mike Christie
2015-03-05 4:13 ` Mike Christie
2015-03-05 7:09 ` Ilya Dryomov
2015-03-05 9:50 ` Mel Gorman [this message]
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