> 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. If your replacement is ok, then I guess you may want to also fix the comments above the changes you propose. Thanks, Paolo > -- > Jens Axboe >
