On Mon, Nov 01, 2010 at 01:09:34AM +0000, Dimitrios Apostolou wrote: > Hello, > > On Sun, 31 Oct 2010 09:51:32 +0800, Wu Fengguang wrote: > > It may also help to lower the dirty ratio. > > > > echo 5 > /proc/sys/vm/dirty_ratio > > > > Memory pressure + heavy write can easily hurt responsiveness. > > > > - eats up to 20% (the default value for dirty_ratio) memory with dirty > > pages and hence increase the memory pressure and number of swap IO > > My experience has been different with that. Wouldn't it make more sense > to _increase_ dirty_ratio (to 50 lets say) and at the same time decrease > dirty_background_ratio? That way writing to disk starts early, but the > related apps stall waiting for I/O only when dirty_ratio is reached. 50% dirty ratio may help before the system goes thrashing (writing processes will be throttled less/later). However Aidar is seeing hours of unresponsiveness with heavy IO, in this case large dirty ratio won't help reduce the throttling any more. 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>