Hello, Tetsuo. On Fri, Oct 23, 2015 at 09:25:11PM +0900, Tetsuo Handa wrote: > WQ_MEM_RECLAIM only guarantees that a "struct task_struct" is preallocated > in order to avoid failing to allocate it on demand due to a GFP_KERNEL > allocation? Is this correct? > > WQ_CPU_INTENSIVE only guarantees that work items don't participate in > concurrency management in order to avoid failing to wake up a "struct > task_struct" which will process the work items? Is this correct? CPU_INTENSIVE avoids the tail end of concurrency management. The previous HIGHPRI or the posted IMMEDIATE avoids the head end. > Is Michal's question "does it make sense to use WQ_MEM_RECLAIM without > WQ_CPU_INTENSIVE"? In other words, any "struct task_struct" which calls > rescuer_thread() must imply WQ_CPU_INTENSIVE in order to avoid failing to > wake up due to being participated in concurrency management? If this is an actual problem, a better approach would be something which detects the stall condition and kicks off the next work item but if we do that I think I'd still trigger a warning there. I don't know. Don't go busy waiting in kernel. Thanks. -- tejun -- 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>