On 05/23/2012 10:41 PM, Satoru Moriya wrote: > Hi Andrew, > > This patch has been reviewed for couple of months. > > This patch *only* improves the behavior when the kernel has > enough filebacked pages. It means that it does not change > the behavior when kernel has small number of filebacked pages. > > Kosaki-san pointed out that the threshold which we use > to decide whether filebacked page is enough or not is not > appropriate(*). > > (*) http://www.spinics.net/lists/linux-mm/msg32380.html > > As I described in (**), I believe that threshold discussion > should be done in other thread because it affects not only > swappiness=0 case and the kernel behave the same way with > or without this patch below the threshold. > > (**) http://www.spinics.net/lists/linux-mm/msg34317.html > > The patch may not be perfect but, at least, we can improve > the kernel behavior in the enough filebacked memory case > with this patch. I believe it's better than nothing. > > Do you have any comments about it? > > NOTE: I updated the patch with Acked-by tags > > --- > Sometimes we'd like to avoid swapping out anonymous memory > in particular, avoid swapping out pages of important process or > process groups while there is a reasonable amount of pagecache > on RAM so that we can satisfy our customers' requirements. > > OTOH, we can control how aggressive the kernel will swap memory pages > with /proc/sys/vm/swappiness for global and > /sys/fs/cgroup/memory/memory.swappiness for each memcg. > > But with current reclaim implementation, the kernel may swap out > even if we set swappiness==0 and there is pagecache on RAM. > > This patch changes the behavior with swappiness==0. If we set > swappiness==0, the kernel does not swap out completely > (for global reclaim until the amount of free pages and filebacked > pages in a zone has been reduced to something very very small > (nr_free + nr_filebacked < high watermark)). > > Any comments are welcome. > > Regards, > Satoru Moriya > > Signed-off-by: Satoru Moriya <satoru.moriya@xxxxxxx> > Acked-by: Minchan Kim <minchan@xxxxxxxxxx> > Acked-by: Rik van Riel <riel@xxxxxxxxxx> > Acked-by: Jerome Marchand <jmarchan@xxxxxxxxxx> -- 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>