On Wed, 21 Nov 2012 09:08:52 +0100 Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote: > Hello, > > On 11/20/2012 8:33 PM, Andrew Morton wrote: > > On Tue, 20 Nov 2012 15:31:45 +0100 > > Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> 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. > > > > > > > Is this problem serious enough to justify merging the patch into 3.7? > > And into -stable kernels? > > I wonder if it is a good idea to merge such change at the end of current > -rc period. I'm not sure what you mean by this. But what we do sometimes if we think a patch needs a bit more real-world testing before backporting is to merge it into -rc1 in the normal merge window, and tag it for -stable backporting. That way it gets a few weeks(?) testing in mainline before getting backported. -- 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>