On Sun, 28 Aug 2011 15:13:35 +0400 Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx> wrote: > Andrew Morton wrote: > > > > (switched to email. Please respond via emailed reply-to-all, not via the > > bugzilla web interface). > > > > On Thu, 28 Jul 2011 12:41:03 GMT > > bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > > > >> https://bugzilla.kernel.org/show_bug.cgi?id=40262 > > > > Two people are reporting this - there are some additional details in > > bugzilla. > > > > We seem to be going around in circles here. > > > > I'll ask Rafael and Maciej to track this as a regression :( > > > > >> > >> issue occurs in new kernel 3.0. > >> does not occurs in 2.6.39.3/2.6.38.8 > >> > > I guess this can be caused by commit v2.6.39-6846-g246e87a "memcg: fix vmscan count in small memcgs" > (it also tweaked kswapd besides of memcg reclaimer) > it was fixed in v3.0-5361-g4508378 "memcg: fix get_scan_count() for small targets" > > commit 4508378b9523e22a2a0175d8bf64d932fb10a67d > Author: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > Date: Tue Jul 26 16:08:24 2011 -0700 > > memcg: fix vmscan count in small memcgs > > Commit 246e87a93934 ("memcg: fix get_scan_count() for small targets") > fixes the memcg/kswapd behavior against small targets and prevent vmscan > priority too high. > > But the implementation is too naive and adds another problem to small > memcg. It always force scan to 32 pages of file/anon and doesn't handle > swappiness and other rotate_info. It makes vmscan to scan anon LRU > regardless of swappiness and make reclaim bad. This patch fixes it by > adjusting scanning count with regard to swappiness at el. > > At a test "cat 1G file under 300M limit." (swappiness=20) > before patch > scanned_pages_by_limit 360919 > scanned_anon_pages_by_limit 180469 > scanned_file_pages_by_limit 180450 > rotated_pages_by_limit 31 > rotated_anon_pages_by_limit 25 > rotated_file_pages_by_limit 6 > freed_pages_by_limit 180458 > freed_anon_pages_by_limit 19 > freed_file_pages_by_limit 180439 > elapsed_ns_by_limit 429758872 > after patch > scanned_pages_by_limit 180674 > scanned_anon_pages_by_limit 24 > scanned_file_pages_by_limit 180650 > rotated_pages_by_limit 35 > rotated_anon_pages_by_limit 24 > rotated_file_pages_by_limit 11 > freed_pages_by_limit 180634 > freed_anon_pages_by_limit 0 > freed_file_pages_by_limit 180634 > elapsed_ns_by_limit 367119089 > scanned_pages_by_system 0 > > the numbers of scanning anon are decreased(as expected), and elapsed time > reduced. By this patch, small memcgs will work better. > (*) Because the amount of file-cache is much bigger than anon, > recalaim_stat's rotate-scan counter make scanning files more. > Ah, yes. this patch may be able to fix the probelm...could you try ? Thanks, -Kame -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>