On Thu 31-10-13 14:26:12, Karl Kiniger wrote: > On Tue 131029, Jan Kara wrote: > > On Fri 25-10-13 11:15:55, Karl Kiniger wrote: > > > On Fri 131025, Linus Torvalds wrote: > .... > > > Is it currently possible to somehow set above values per block device? > > Yes, to some extent. You can set /sys/block/<device>/bdi/max_ratio to > > the maximum proportion the device's dirty data can take from the total > > amount. The caveat currently is that this setting only takes effect after > > we have more than (dirty_background_ratio + dirty_ratio)/2 dirty data in > > total because that is an amount of dirty data when we start to throttle > > processes. So if the device you'd like to limit is the only one which is > > currently written to, the limiting doesn't have a big effect. > > Thanks for the info - thats was I am looking for. > > You are right that the limiting doesn't have a big effect right now: > > on my 4x speed DVD+RW on /dev/sr0, x86_64, 4GB, > Fedora19: > > max_ratio set to 100 - about 500MB buffered, sync time 2:10 min. > max_ratio set to 1 - about 330MB buffered, sync time 1:23 min. > > ... way too much buffering.
"strictlimit" feature must fit your and Artem's needs quite well. The feature enforces per-BDI dirty limits even if the global dirty limit is not reached yet. I'll send a patch adding knob to turn it on/off. Thanks, Maxim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
