From: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>, Shaohua Li <shli@fb.com>,
linux-mm@kvack.org, linux-kernel <linux-kernel@vger.kernel.org>,
kernel-team@fb.com
Subject: Re: [PATCH] proc: revert /proc/<pid>/maps [stack:TID] annotation
Date: Wed, 20 Jan 2016 08:51:38 +0530 [thread overview]
Message-ID: <CAAHN_R2q23-gN43j52X231k0Xs-D_x5KofEMGq_npdWCWVpuyA@mail.gmail.com> (raw)
In-Reply-To: <20160119233028.GA22867@node.shutemov.name>
On 20 January 2016 at 05:00, Kirill A. Shutemov <kirill@shutemov.name> wrote:
> I doubt it can be very useful as it's unreliable: if two stacks are
> allocated end-to-end (which is not good idea, but still) it can only
> report [stack:XXX] for the first one as they are merged into one VMA.
> Any other anon VMA merged with the stack will be also claimed as stack,
> which is not always correct.
It is quite uncommon because you will always have an intervening guard
page that separates the two stack vmas. To have the vmas merge, you
will have to disable guard pages which is an even worse idea.
A more relevant argument about its unreliability is context changes
due to makecontext/setcontext, which could momentarily show the heap
or some other arbitrary vma as a stack.
Siddhesh
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next prev parent reply other threads:[~2016-01-20 3:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-19 18:02 Johannes Weiner
2016-01-19 22:14 ` Andrew Morton
2016-01-19 23:30 ` Kirill A. Shutemov
2016-01-20 3:21 ` Siddhesh Poyarekar [this message]
2016-01-19 23:38 ` Johannes Weiner
2016-01-20 3:17 ` Siddhesh Poyarekar
2016-01-20 5:27 ` Andrew Morton
2016-01-21 10:49 ` [PATCH] proc: add missing 'mm' variable in nommu is_stack() Arnd Bergmann
2016-01-25 21:30 [PATCH] proc: revert /proc/<pid>/maps [stack:TID] annotation Colin Cross
2016-01-25 23:14 ` Kirill A. Shutemov
2016-01-25 23:53 ` Colin Cross
2016-01-28 10:25 ` Kirill A. Shutemov
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