On Tue, Nov 24, 2015 at 03:27:43PM +0800, Aaron Lu wrote: > On 11/24/2015 12:55 PM, Joonsoo Kim wrote: > > On Tue, Nov 24, 2015 at 11:40:28AM +0800, Aaron Lu wrote: > >> BTW, I'm still learning how to do proper ftrace for this case and it may > >> take a while. > > > > You can do it simply with trace-cmd. > > > > sudo trace-cmd record -e compaction & > > run test program > > fg > > Ctrl + c > > > > sudo trace-cmd report > > Thanks for the tip, I just recorded it like this: > trace-cmd record -e compaction ./usemem xxx > > Due to the big size of trace.out(6MB after compress), I've uploaed it: > https://drive.google.com/open?id=0B49uX3igf4K4UkJBOGt3cHhOU00 > > The pagetypeinfo, perf and proc-vmstat is also there. > Thanks. Okay. Output proves the theory. pagetypeinfo shows that there are too many unmovable pageblocks. isolate_freepages() should skip these so it's not easy to meet proper pageblock until need_resched(). Hence, updating cached pfn doesn't happen. (You can see unchanged free_pfn with 'grep compaction_begin tracepoint-output') But, I don't think that updating cached pfn is enough to solve your problem. More complex change would be needed, I guess. Thanks. -- 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>