On 3/15/22 18:27, Ming Lei wrote: > sbitmap has been used in scsi for replacing atomic operations on > sdev->device_busy, so IOPS on some fast scsi storage can be improved. > > However, sdev->device_busy can be changed in fast path, so we have to > allocate the sb->map statically. sdev->device_busy has been capped to 1024, > but some drivers may configure the default depth as < 8, then > cause each sbitmap word to hold only one bit. Finally 1024 * 128( > sizeof(sbitmap_word)) bytes is needed for sb->map, given it is order 5 > allocation, sometimes it may fail. > > Avoid the issue by using kvzalloc_node() for allocating sb->map. > > Cc: Ewan D. Milne <emilne@xxxxxxxxxx> > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> > --- > maybe considering the total size before actual allocation that will not buy us anything ? Looks good. Reviewed-by: Chaitanya Kulkarni <kch@xxxxxxxxxx> -ck
