Hello, On Tuesday, October 11, 2011 1:26 PM Maxime Coquelin wrote: > On 10/11/2011 12:50 PM, Marek Szyprowski wrote: > > Hello, > > > > On Tuesday, October 11, 2011 9:30 AM Maxime Coquelin wrote: > > > >> On 10/11/2011 09:17 AM, Marek Szyprowski wrote: > >>> On Monday, October 10, 2011 2:08 PM Maxime Coquelin wrote: > >>> > >>> During our stress tests, we encountered some problems : > >>> > >>> 1) Contiguous allocation lockup: > >>> When system RAM is full of Anon pages, if we try to allocate a > >>> contiguous buffer greater than the min_free value, we face a > >>> dma_alloc_from_contiguous lockup. > >>> The expected result would be dma_alloc_from_contiguous() to fail. > >>> The problem is reproduced systematically on our side. > >>> Thanks for the report. Do you use Android's lowmemorykiller? I haven't > >>> tested CMA on Android kernel yet. I have no idea how it will interfere > >>> with Android patches. > >>> > >> The software used for this test (v16) is a generic 3.0 Kernel and a > >> minimal filesystem using Busybox. > > I'm really surprised. Could you elaborate a bit how to trigger this issue? > > At system startup, I drop caches (sync && echo 3 > > /proc/sys/vm/drop_caches) and check how much memory is free. > For example, in my case, only 15MB is used on the 270MB available on the > system, so I got 255MB of free memory. Note that the min_free is 4MB in > my case. > In userspace, I allocate 230MB using malloc(), the free memory is now 25MB. > Finaly, I ask for a contiguous allocation of 64MB using CMA, the result > is a lockup in dma_alloc_from_contiguous(). Thanks for hint. I've managed to reproduce this issue. I will post fix asap. > > I've did several tests and I never get a lockup. Allocation failed from time > > to time though. > When it succeed, what is the behaviour on your side? Is the OOM triggered? OOM was never triggered. Best regards -- Marek Szyprowski Samsung Poland R&D Center -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
