From: Mel Gorman <mgorman@suse.de>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Thierry Reding <thierry.reding@avionic-design.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Michal Nazarewicz <mina86@mina86.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
Mark Brown <broonie@opensource.wolfsonmicro.com>,
Peter Ujfalusi <peter.ujfalusi@ti.com>
Subject: Re: CMA broken in next-20120926
Date: Fri, 28 Sep 2012 08:56:28 +0100 [thread overview]
Message-ID: <20120928075628.GJ3429@suse.de> (raw)
In-Reply-To: <20120928054330.GA27594@bbox>
On Fri, Sep 28, 2012 at 02:43:30PM +0900, Minchan Kim wrote:
> On Thu, Sep 27, 2012 at 03:11:59PM -0700, Andrew Morton wrote:
> > On Thu, 27 Sep 2012 13:29:11 +0200
> > Thierry Reding <thierry.reding@avionic-design.de> wrote:
> >
> > > Hi Marek,
> > >
> > > any idea why CMA might be broken in next-20120926. I see that there
> > > haven't been any major changes to CMA itself, but there's been quite a
> > > bit of restructuring of various memory allocation bits lately. I wasn't
> > > able to track the problem down, though.
> > >
> > > What I see is this during boot (with CMA_DEBUG enabled):
> > >
> > > [ 0.266904] cma: dma_alloc_from_contiguous(cma db474f80, count 64, align 6)
> > > [ 0.284469] cma: dma_alloc_from_contiguous(): memory range at c09d7000 is busy, retrying
> > > [ 0.293648] cma: dma_alloc_from_contiguous(): memory range at c09d7800 is busy, retrying
> > > ...
> > > [ 2.648619] DMA: failed to allocate 256 KiB pool for atomic coherent allocation
> > > ...
> > > [ 4.196193] WARNING: at /home/thierry.reding/src/kernel/linux-ipmp.git/arch/arm/mm/dma-mapping.c:485 __alloc_from_pool+0xdc/0x110()
> > > [ 4.207988] coherent pool not initialised!
> > >
> > > So the pool isn't getting initialized properly because CMA can't get at
> > > the memory. Do you have any hints as to what might be going on? If it's
> > > any help, I started seeing this with next-20120926 and it is in today's
> > > next as well.
> > >
> >
> > Bart and Minchan have made recent changes to CMA. Let us cc them.
>
> Hi all,
>
> I have no time now so I look over the problem during short time
> so I mighte be wrong. Even I should leave the office soon and
> Korea will have long vacation from now on so I will be off by next week.
> So it's hard to reach on me.
>
> I hope this patch fixes the bug. If this patch fixes the problem
> but has some problem about description or someone has better idea,
> feel free to modify and resend to akpm, Please.
>
> Thierry, Could you test below patch?
>
> From 24a547855fa2bd4212a779cc73997837148310b3 Mon Sep 17 00:00:00 2001
> From: Minchan Kim <minchan@kernel.org>
> Date: Fri, 28 Sep 2012 14:28:32 +0900
> Subject: [PATCH] revert mm: compaction: iron out isolate_freepages_block()
> and isolate_freepages_range()
>
> [1] made bug on CMA.
> The nr_scanned should be never equal to total_isolated for successful CMA.
> This patch reverts part of the patch.
>
Why should nr_scanned never be equal to total_isolated for CMA?
Reverting the patch reintroduces Andrew's complaint that this function
was "straggly" and getting a bit out of control so I'd much prefer to
understand why this situation is not true and fix that.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2012-09-28 7:56 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20120927112911.GA25959@avionic-0098.mockup.avionic-design.de>
2012-09-27 22:11 ` CMA broken in next-20120926 Andrew Morton
2012-09-28 5:43 ` Minchan Kim
2012-09-28 6:10 ` Thierry Reding
2012-09-28 7:44 ` Peter Ujfalusi
2012-09-28 7:56 ` Mel Gorman [this message]
2012-09-28 8:09 ` Mel Gorman
2012-09-28 8:37 ` Mel Gorman
2012-09-28 8:48 ` Peter Ujfalusi
2012-09-28 10:27 ` Mel Gorman
2012-09-28 10:32 ` Thierry Reding
2012-09-28 10:38 ` Thierry Reding
2012-09-28 10:51 ` Thierry Reding
2012-09-28 11:07 ` Mel Gorman
2012-09-28 11:39 ` Thierry Reding
2012-09-28 12:43 ` Mel Gorman
2012-10-01 14:24 ` Thierry Reding
2012-10-02 12:48 ` Thierry Reding
2012-10-02 14:41 ` Mel Gorman
2012-10-02 15:03 ` Thierry Reding
2012-10-02 15:12 ` Mel Gorman
2012-10-08 8:06 ` Minchan Kim
2012-10-08 8:48 ` Mel Gorman
2012-10-09 8:40 ` Bartlomiej Zolnierkiewicz
2012-10-09 10:11 ` Mel Gorman
2012-10-09 11:02 ` Thierry Reding
2012-10-09 11:08 ` Bartlomiej Zolnierkiewicz
2012-10-09 11:32 ` Mel Gorman
2012-10-09 11:38 ` Thierry Reding
2012-09-28 10:52 ` Mel Gorman
2012-10-04 14:00 ` [PATCH] mm: compaction: Iron out isolate_freepages_block() and isolate_freepages_range() -fix1 Mel Gorman
2012-10-05 9:59 ` [PATCH] mm: compaction: Iron out isolate_freepages_block() and isolate_freepages_range() -fix2 Mel Gorman
2012-10-08 6:50 ` Minchan Kim
2012-10-08 6:53 ` [PATCH] mm: compaction: Iron out isolate_freepages_block() and isolate_freepages_range() -fix1 Minchan Kim
2012-10-04 14:03 ` [PATCH] mm: compaction: Cache if a pageblock was scanned and no pages were isolated -fix3 Mel Gorman
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