linux-kernel - Re: [PATCH][RFC] 4K stacks default, not a debug thing any more...?

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Message-ID:  <yw1xr6n76hq3.fsf@thrashbarg.mansr.com>
Date:	Tue, 17 Jul 2007 00:39:48 +0100
From:	Måns Rullgård <mans@...sr.com>
To:	linux-kernel@...r.kernel.org
Subject:  Re: [PATCH][RFC] 4K stacks default, not a debug thing any more...?

utz lehmann <lkml123@...4n2c.de> writes:

> On Tue, 2007-07-17 at 00:28 +0200, Rene Herman wrote:
>> Given that as Arjan stated Fedora and even RHEL have been using 4K
>> stacks for some time now, and certainly the latter being a
>> distribution which I would expect to both host a relatively large
>> number of lvm/md/xfs and what stackeaters have you users and to be
>> fairly conservative with respect to the chances of scribbling over
>> kernel memory (I'm a trusting person...) it seems there might at
>> this stage only be very few offenders left.
>
> I have to recompile the fedora kernel rpms (fc6, f7) with 8k stacks on
> my i686 server. It's using NFS -> XFS -> DM -> MD (raid1) -> IDE disks.
> With 4k stacks it crash (hang) within minutes after using NFS.
> With 8k stacks it's rock solid. No crashes within months.

Running either vanilla or Gentoo kernels, I've had no luck at all with
4k stacks.  On SATA+MD(raid1)+LVM+XFS I've had numerous crashes when
doing even light I/O.  One particularly crash-prone scenario is
writing to random locations in sparse files, thus forcing new blocks
to be allocated.

I don't have dedicated testing machines, so I can't afford the time
and potential data loss of testing this regularly.  I have no shortage
on RAM with 8k stacks, so for me the choice is quite simple.

-- 
Måns Rullgård
mans@...sr.com

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