On Wed 06-01-21 18:02:03, Paolo Valente wrote: > > Il giorno 5 gen 2021, alle ore 17:29, Jens Axboe <axboe@xxxxxxxxx> ha scritto: > > > > On 1/5/21 9:21 AM, Jan Kara wrote: > >> On Thu 10-12-20 10:44:33, Jan Kara wrote: > >>> BFQ computes number of tags it allows to be allocated for each request type > >>> based on tag bitmap. However it uses 1 << bitmap.shift as number of > >>> available tags which is wrong. 'shift' is just an internal bitmap value > >>> containing logarithm of how many bits bitmap uses in each bitmap word. > >>> Thus number of tags allowed for some request types can be far to low. > >>> Use proper bitmap.depth which has the number of tags instead. > >>> > >>> Signed-off-by: Jan Kara <jack@xxxxxxx> > >> > >> Ping Jens? I think it has fallen through the cracks? > > > > More like waiting for Paolo to take a look. Don't mind taking it, and > > I'll do that now, but I do expect him to review any BFQ patches being > > sent out. > > Sorry for the delay Jan. As you know, my priority is currently to > finalize the patches I have developed with your help; and > unfortunately I'm way behind. This is delaying also my review > activity. > > As for your proposal, I remember I found the right parameter rather > empirically. In particular, I seem to remember that the bitmap.depth > parameter did not contain the value I needed, i.e, it did not > contain the total number of tags. But maybe something has changed in > the meantime. At any rate, if bitmap.depth does contain that value, > then your replacement is ok. Yes, bitmap.depth is the total number of tags AFAIK. > If your replacement is ok, then I guess you may want to also fix the > comments above the changes you propose. Oh right, there's one paragraph in the comment that my patch made redundant. I'll send a cleanup. Thanks for noticing. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
