From: Miao Xie <miaox@cn.fujitsu.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Christoph Lameter <cl@linux.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cpuset: mm: Reduce large amounts of memory barrier related damage v2
Date: Thu, 08 Mar 2012 11:40:39 +0800 [thread overview]
Message-ID: <4F582A37.8060802@cn.fujitsu.com> (raw)
In-Reply-To: <20120307112201.GC17697@suse.de>
On wed, 7 Mar 2012 11:22:01 +0000, Mel Gorman wrote:
>> Beside that, we need deal with fork() carefully, or it is possible that the child
>> task will be set to a wrong nodemask.
>>
>
> Can you clarify this statement please? It's not clear what the old code
> did that protected against problems in fork() versus this patch. fork is
> not calling get_mems_allowed() for example or doing anything special
> around mems_allowed.
>
> Maybe you are talking about an existing problem whereby during fork
> there should be get_mems_allowed/put_mems_allowed and the mems_allowed
> mask gets copied explicitly?
Yes, If someone updates cpuset's nodemask or cpumask before the child task is attached
into the cpuset cgroup, the child task's nodemask and cpumask can not be updated, just
holds the old mask.
We can fix this problem by seqcounter in a new patch.(It seems the freeze subsystem also
has the same problem)
Thanks
Miao
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
prev parent reply other threads:[~2012-03-08 3:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-06 13:27 [PATCH] cpuset: mm: Reduce large amounts of memory barrier related damage v2 Mel Gorman
2012-03-06 20:26 ` Andrew Morton
2012-03-06 22:42 ` Mel Gorman
2012-03-06 22:54 ` Andrew Morton
2012-03-07 9:05 ` Miao Xie
2012-03-07 11:01 ` Mel Gorman
2012-03-07 9:15 ` Miao Xie
2012-03-07 11:22 ` Mel Gorman
2012-03-08 3:40 ` Miao Xie [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4F582A37.8060802@cn.fujitsu.com \
--to=miaox@cn.fujitsu.com \
--cc=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=cl@linux.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=rientjes@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).