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From: Neil Brown <neilb@suse.de>
To: Zan Lynx <zlynx@acm.org>
Date: Mon, 30 Apr 2007 18:55:52 +1000
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Cc: Adrian Bunk <bunk@stusta.de>, Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [-mm patch] i386: enable 4k stacks by default
In-Reply-To: message from Zan Lynx on Saturday April 28
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On Saturday April 28, zlynx@acm.org wrote:
> On Sat, 2007-04-28 at 21:19 +0200, Adrian Bunk wrote:
> > 4k stacks have become a well-tested feature used fore a long time in
> > Fedora and even in RHEL 4.
> 
> So has anyone fixed the bugs involving ext3 and LVM snapshots on top of
> DM mirror?

Well -mm has a patch which makes stacked block devices much less of an
issue, but this hasn't made it -linus yet - I think the dm developer
isn't happy that dm works properly with it.

> 
> Our 32-bit Fedora Core 5 dual Opteron server at work crashed once a week
> while running rdiff-backup off a snapshot.  Installing a 64-bit kernel
> stopped the crashes, and I believe the 64-bit still uses the bigger
> stacks.

I wonder if FC-4 has the generic_make_request patch as well as 4K
stacks.  If does, then there is obviously something else to be fixed.
If it doesn't, then maybe that is all that is needed.

http://www.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.21-rc7/2.6.21-rc7-mm2/broken-out/md-dm-reduce-stack-usage-with-stacked-block-devices.patch

NeilBrown