On Fri, 2015-12-04 at 18:01 +0100, Phil Sutter wrote: > On Fri, Dec 04, 2015 at 10:39:56PM +0800, Herbert Xu wrote: > > On Thu, Dec 03, 2015 at 08:08:39AM -0800, Eric Dumazet wrote: > > > > > > Anyway, __vmalloc() can be used with GFP_ATOMIC, have you tried this ? > > > > OK I've tried it and I no longer get any ENOMEM errors! > > I can't confirm this, sadly. Using 50 threads, results seem to be stable > and good. But increasing the number of threads I can provoke ENOMEM > condition again. See attached log which shows a failing test run with > 100 threads. > > I tried to extract logs of a test run with as few as possible failing > threads, but wasn't successful. It seems like the error amplifies > itself: While having stable success with less than 70 threads, going > beyond a margin I could not identify exactly, much more threads failed > than expected. For instance, the attached log shows 70 out of 100 > threads failing, while for me every single test with 50 threads was > successful. > > HTH, Phil
But this patch is about GFP_ATOMIC allocations, I doubt your test is using GFP_ATOMIC. Threads (process context) should use GFP_KERNEL allocations. BTW, if 100 threads are simultaneously trying to vmalloc(32 MB), this might not be very wise :( Only one should really do this, while others are waiting. If we really want parallelism (multiple cpus coordinating their effort), it should be done very differently. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
