On 2/2/21 5:28 AM, Jan Kara wrote: > Hello! > > On Fri 29-01-21 19:18:08, Lin Feng wrote: >> This reverts commit 6d4d273588378c65915acaf7b2ee74e9dd9c130a. >> >> bfq.limit_depth passes word_depths[] as shallow_depth down to sbitmap core >> sbitmap_get_shallow, which uses just the number to limit the scan depth of >> each bitmap word, formula: >> scan_percentage_for_each_word = shallow_depth / (1 << sbimap->shift) * 100% > > Looking at sbitmap_get_shallow() again more carefully, I agree that I > misunderstood how shallow_depth argument gets used and the original code > was correct and I broke it. Thanks for spotting this! > > What I didn't notice is that shallow_depth indeed gets used for each bitmap > word separately and not for bitmap as a whole. I'd say this could use some > more documentation but that's unrelated to your revert. So feel free to add: > > Reviewed-by: Jan Kara <jack@xxxxxxx> I don't have the original patch (neither directly nor in the archive), so I had to hand-apply it. In any case, applied for 5.11, thanks. -- Jens Axboe
