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From: Phil Carmody <ext-phil.2.carmody@nokia.com>
To: ext Tony Luck <tony.luck@intel.com>
Cc: "fenghua.yu@intel.com" <fenghua.yu@intel.com>,
	"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/2] ia64: possible module unwind table optimisation
Date: Fri, 17 Sep 2010 08:44:11 +0000	[thread overview]
Message-ID: <20100917084411.GC20325@esdhcp04044.research.nokia.com> (raw)
In-Reply-To: <AANLkTikgi38O3=MsVNc-X64PnLOFNktC_x9Y3vQ7CbD+@mail.gmail.com>

On 16/09/10 23:56 +0200, ext Tony Luck wrote:
> On Wed, Sep 15, 2010 at 3:22 PM, Phil Carmody
> <ext-phil.2.carmody@nokia.com> wrote:
> > Turn on kmemleak, or anything else which repeatedly runs up the stack just
> > for the fun of gathering backtraces. Kmemleak's what caused us to notice
> > the issue in our ARM-based environment.
> 
> kmemleak needs CONFIG_STACKTRACE - which I haven't got around to putting
> into ia64 yet.  I dug up an earlier attempt at doing so, and turned on kmemleak,
> but it crashes early in boot (before ever getting to my stack tracer)
> in possibly
> the first call to kmem_cache_alloc().  With SLUB the error is an unaligned
> reference to 0xffffffffffffffff, with SLAB I get a NULL deref.
> 
> :-(

This is a shame, but not a real problem in the context of my patch - you can't 
usefully optimise something that's seemingly almost never used. It can be filed
in the cylindrical filing cabinet.

Phil

  reply	other threads:[~2010-09-17  8:44 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-10 10:40 [PATCH 0/2] ia64: possible module unwind table optimisation Phil Carmody
2010-09-10 10:40 ` [PATCH 1/2] ia64: unwind: remove preprocesser noise, and correct comment Phil Carmody
2010-09-10 10:40 ` [PATCH 2/2] ia64: unwind - optimise linked-list searches for modules Phil Carmody
2010-09-14 23:18 ` [PATCH 0/2] ia64: possible module unwind table optimisation Tony Luck
2010-09-15 12:48   ` Phil Carmody
2010-09-15 17:28     ` Tony Luck
2010-09-15 22:22       ` Phil Carmody
2010-09-16 21:56         ` Tony Luck
2010-09-17  8:44           ` Phil Carmody [this message]
2010-09-17 17:44             ` Tony Luck

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