On Wed, Nov 04, 2009 at 01:18:11AM +0000, Mel Gorman wrote: > > From vmstat for .31.1: > > kswapd_highorder_rewakeup 20 > > kswapd_slept_prematurely_fast 307 > > kswapd_slept_prematurely_slow 105 > > > > This is useful. > > The high premature_fast shows that after kswapd apparently finishes its work, > the high waterwater marks are being breached very quickly (the fast counter > being positive). The "slow" counter is even worse. Your machine is getting > from the high to low watermark quickly without kswapd noticing and processes > depending on the atomics are not waiting long enough. > Sorry, that should have been The premature_fast shows that after kswapd finishes its work, the low waterwater marks are being breached very quickly as kswapd is being rewoken up. The "slow" counter is slightly worse. Just after kswapd sleeps, the high watermark is being breached again. Either counter being positive implies that kswapd is having to do too much work while parallel allocators are chewing up the high-order pages quickly. The effect of the patch should still be to delay the rate high-order pages are consumed but it assumes there are enough high-order requests that can go to sleep. Mentioning sleep, I'm going to get some. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
