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Date: Fri, 24 Feb 2012 23:53:38 +0530
Message-ID: <CAAHN_R1Viv5GpJfbvc71OyNG7CdFWei7-3XPTap47MM2e8uEsg@mail.gmail.com>
Subject: Re: [PATCH] Mark thread stack correctly in proc/<pid>/maps
From: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
To: Mike Frysinger <vapier@gentoo.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        KOSAKI Motohiro <kosaki.motohiro@gmail.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Alexander Viro <viro@zeniv.linux.org.uk>,
        linux-fsdevel@vger.kernel.org, Jamie Lokier <jamie@shareable.org>
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On Fri, Feb 24, 2012 at 9:42 PM, Mike Frysinger <vapier@gentoo.org> wrote:
>> I like the idea of marking all stack vmas with their task ids but it
>> will most likely break procps.
>
> how ?

I don't know yet, since I haven't looked at the procps code. I intend
to do that once the patch is stable. But I imagine it would look for
"[stack]" or something similar in the output. It ought to be easy
enough to change I guess.

>> Besides, I think it could be done within procps with this change rather than
>> having the kernel do it.
>
> how exactly is procps supposed to figure this out ? ?/proc/<pid>/maps shows the
> pid's main stack, as does /proc/<pid>/tid/*/maps.

Since the maps are essentially the same, it would require pmap for
example, to read through the PID/maps as well as TID/maps and
associate them. I understand now that this may be a little racy.

I'll include thread ids and see how procps copes with it.


-- 
Siddhesh Poyarekar
http://siddhesh.in
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