Re: [PATCH] mm: Use WQ_HIGHPRI for mm_percpu_wq.
From: Michal Hocko <mhocko@kernel.org>
Date: 2017-08-31 15:25:27
On Thu 31-08-17 23:52:57, Tetsuo Handa wrote: [...]
So, this pending state seems to be caused by many concurrent allocations by !PF_WQ_WORKER threads consuming too much CPU time (because they only yield CPU time by many cond_resched() and one schedule_timeout_uninterruptible(1)) enough to keep schedule_timeout_uninterruptible(1) by PF_WQ_WORKER threads away for order of minutes. A sort of memory allocation dependency observable in the form of CPU time starvation for the worker to wake up.
I do not understand this. Why is cond_resched from the user context insufficient to let runable kworkers to run? -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>