On 23 May 2014 07:49, Kevin Hilman <khilman@xxxxxxxxxx> wrote: > On Fri, May 16, 2014 at 2:47 AM, Vlastimil Babka <vbabka@xxxxxxx> wrote: >> Compaction uses compact_checklock_irqsave() function to periodically check for >> lock contention and need_resched() to either abort async compaction, or to >> free the lock, schedule and retake the lock. When aborting, cc->contended is >> set to signal the contended state to the caller. Two problems have been >> identified in this mechanism. > > This patch (or later version) has hit next-20140522 (in the form > commit 645ceea9331bfd851bc21eea456dda27862a10f4) and according to my > bisect, appears to be the culprit of several boot failures on ARM > platforms. On i.MX6 where CMA is enabled, the commit causes the drivers calling dma_alloc_coherent() fail to probe. Tracing it a little bit, it seems dma_alloc_from_contiguous() always return page as NULL after this commit. Shawn -- 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>