On 12/06/2016 08:31 AM, Gabriel Krisman Bertazi wrote: > While stressing memory and IO at the same time we changed SMT settings, > we were able to consistently trigger deadlocks in the mm system, which > froze the entire machine. > > I think that under memory stress conditions, the large allocations > performed by blk_mq_init_rq_map may trigger a reclaim, which stalls > waiting on the block layer remmaping completion, thus deadlocking the > system. The trace below was collected after the machine stalled, > waiting for the hotplug event completion. > > The simplest fix for this is to make allocations in this path > non-reclaimable, with GFP_NOIO. With this patch, We couldn't hit the > issue anymore. This looks fine. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
