Mel: we talked about this issue below in SFO, apparently I'm not the only one who noticed :-) Rik: a fix for the problem below is crucial for the refault distance-based page cache sizing. The unequal LRU aging is a problem in itself, but it's compounded when we use the skewed non-resident times to base reclaim decisions on On Sat, May 04, 2013 at 05:01:14PM +0400, Konstantin Khlebnikov wrote: > Hey! I can reproduce this: > > Node 0, zone DMA32 > nr_inactive_anon 1 > nr_active_anon 2368 > nr_inactive_file 373642 > nr_active_file 375462 > nr_dirtied 2887369 > nr_written 2887291 > inactive_ratio: 5 > avg_age_inactive_anon: 64942528 > avg_age_active_anon: 64942528 > avg_age_inactive_file: 389824 > avg_age_active_file: 1330368 > Node 0, zone Normal > nr_inactive_anon 376 > nr_active_anon 17768 > nr_inactive_file 534695 > nr_active_file 533685 > nr_dirtied 12071397 > nr_written 11940007 > inactive_ratio: 6 > avg_age_inactive_anon: 65064192 > avg_age_active_anon: 65064192 > avg_age_inactive_file: 28074 > avg_age_active_file: 1304800 > > I'm just copying huge files from one disk to another by rsync. > > In /proc/vmstat pgsteal_kswapd_normal and pgscan_kswapd_normal are rising rapidly, > other pgscan_* pgsteal_* are standing still. So, bug is somewhere in the kswapd. There is a window where a steady stream of allocations and kswapd cooperate in perfect unison and keep the Normal zone always between the low and high watermarks. Kswapd does not stop until the high watermark is met, the allocator does not go to lower zones until the low watermark is breached. As a result, most allocations happen in the Normal zone. I'm playing around with a round-robin scheme on the page allocator side to spread out file pages more evenly, but I'm torn on whether the fix should actually be on the kswapd side, to enforce reclaim instead of allocation more evenly. Thoughts? -- 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>