On Sun, Jul 25, 2010 at 08:03:45PM +0800, Minchan Kim wrote: > On Sun, Jul 25, 2010 at 07:43:20PM +0900, KOSAKI Motohiro wrote: > > Hi > > > > sorry for the delay. > > > > > Will you be picking it up or should I? The changelog should be more or less > > > the same as yours and consider it > > > > > > Signed-off-by: Mel Gorman <mel@xxxxxxxxx> > > > > > > It'd be nice if the original tester is still knocking around and willing > > > to confirm the patch resolves his/her problem. I am running this patch on > > > my desktop at the moment and it does feel a little smoother but it might be > > > my imagination. I had trouble with odd stalls that I never pinned down and > > > was attributing to the machine being commonly heavily loaded but I haven't > > > noticed them today. > > > > > > It also needs an Acked-by or Reviewed-by from Kosaki Motohiro as it alters > > > logic he introduced in commit [78dc583: vmscan: low order lumpy reclaim also > > > should use PAGEOUT_IO_SYNC] > > > > My reviewing doesn't found any bug. however I think original thread have too many guess > > and we need to know reproduce way and confirm it. > > > > At least, we need three confirms. > > o original issue is still there? > > o DEF_PRIORITY/3 is best value? > > I agree. Wu, how do you determine DEF_PRIORITY/3 of LRU? > I guess system has 512M and 22M writeback pages. > So you may determine it for skipping max 32M writeback pages. > Is right? For 512M mem, DEF_PRIORITY/3 means 32M dirty _or_ writeback pages. Because shrink_inactive_list() first calls shrink_page_list(PAGEOUT_IO_ASYNC) then optionally shrink_page_list(PAGEOUT_IO_SYNC), so dirty pages will first be converted to writeback pages and then optionally be waited on. The dirty/writeback pages may go up to 512M*20% = 100M. So 32M looks a reasonable value. > And I have a question of your below comment. > > "As the default dirty throttle ratio is 20%, sync write&wait > will hardly be triggered by pure dirty pages" > > I am not sure exactly what you mean but at least DEF_PRIOIRTY/3 seems to be > related to dirty_ratio. It always can be changed by admin. > Then do we have to determine magic value(DEF_PRIORITY/3) proportional to dirty_ratio? Yes DEF_PRIORITY/3 is already proportional to the _default_ dirty_ratio. We could do explicit comparison with dirty_ratio just in case dirty_ratio get changed by user. It's mainly a question of whether deserving to add such overheads and complexity. I'd prefer to keep the current simple form :) Thanks, Fengguang -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>