Greg, I've added you to the this thread hoping for a little insight into USB drivers and their use of coherent and GFP_ATOMIC. Am I barking up the wrong tree by looking a the drivers? On Mon, Jan 14, 2013 at 12:56:57PM +0100, Soeren Moch wrote: > On 20.11.2012 15:31, Marek Szyprowski wrote: > >dmapool always calls dma_alloc_coherent() with GFP_ATOMIC flag, > >regardless the flags provided by the caller. This causes excessive > >pruning of emergency memory pools without any good reason. Additionaly, > >on ARM architecture any driver which is using dmapools will sooner or > >later trigger the following error: > >"ERROR: 256 KiB atomic DMA coherent pool is too small! > >Please increase it with coherent_pool= kernel parameter!". > >Increasing the coherent pool size usually doesn't help much and only > >delays such error, because all GFP_ATOMIC DMA allocations are always > >served from the special, very limited memory pool. > > > >This patch changes the dmapool code to correctly use gfp flags provided > >by the dmapool caller. > > > >Reported-by: Soeren Moch <smoch@xxxxxx> > >Reported-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> > >Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> > >Tested-by: Andrew Lunn <andrew@xxxxxxx> > >Tested-by: Soeren Moch <smoch@xxxxxx> > > Now I tested linux-3.7.1 (this patch is included there) on my Marvell > Kirkwood system. I still see > > ERROR: 1024 KiB atomic DMA coherent pool is too small! > Please increase it with coherent_pool= kernel parameter! > > after several hours of runtime under heavy load with SATA and > DVB-Sticks (em28xx / drxk and dib0700). Could you try running the system w/o the em28xx stick and see how it goes with v3.7.1? thx, Jason. > As already reported earlier this patch improved the behavior > compared to linux-3.6.x and 3.7.0 (error after several ten minutes > runtime), but > I still see a regression compared to linux-3.5.x. With this kernel the > same system with same workload runs flawlessly. > > Regards, > Soeren > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>