On Fri, Sep 28, 2012 at 08:56:28AM +0100, Mel Gorman wrote: > 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.red...@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 <minc...@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? >
Ah crap, never mind. It's so obvious that you probably heard the face slap all the way in Korea. Am putting together an alternative fix to a revert that I'll post shortly. -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
