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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
