On Tue, Jun 26, 2012 at 5:37 PM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=43811 > > lru_add_drain_all() uses schedule_on_each_cpu(). But > schedule_on_each_cpu() hangs if a realtime thread is spinning, pinned > to a CPU. There's no intention to change the scheduler behaviour, so I > think we should remove schedule_on_each_cpu() from the kernel. > > The biggest user of schedule_on_each_cpu() is lru_add_drain_all(). > > Does anyone have any thoughts on how we can do this? The obvious > approach is to declare these: > > static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs); > static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs); > static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs); > > to be irq-safe and use on_each_cpu(). lru_rotate_pvecs is already > irq-safe and converting lru_add_pvecs and lru_deactivate_pvecs looks > pretty simple. > > Thoughts? I agree. But i hope more. In these days, we have plenty lru_add_drain_all() callsite. So, i think we should remove struct pagevec and should aim migration aware new batch mechanism. maybe. This also improve compaction success rate. -- 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