On Tue 02-09-14 07:31:04, Ted Tso wrote: > > - the very small max readahead size > > For things like the readahead size, that's probably something that we > should autotune, based the time it takes to read N sectors. i.e., > start N relatively small, such as 128k, and then bump it up based on > how long it takes to do a sequential read of N sectors until it hits a > given tunable, which is specified in milliseconds instead of kilobytes. Actually the amount of readahead we do is autotuned (based on hit rate). So I would keep the setting in sysfs as the maximum size adaptive readahead can ever read and we can bump it up. We can possibly add another feedback into the readahead code to tune actualy readahead size depending on device speed but we'd have to research exactly what algorithm would work best. Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- 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>