On Thu, Sep 12 2013 at 6:45pm -0400, Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: > I think this is too complicated. > > dm-bufio uses similar approach like this patch - but in dm-bufio the code > path is performance critical, we don't want to recalculate memory size > with each i/o request. > > Here it is not performance critical, so I'd drop the mutex, drop the > latch, drop the function __reserved_request_based_ios_refresh and add only > these lines: > > pool_size = ACCESS_ONCE(reserved_rq_based_ios); > if (!pool_size) pool_size = RESERVED_REQUEST_BASED_IOS; Could be I'm missing something but isn't the locking about correctness rather than performance? Also, using the latch enables the dm_get_reserved_rq_based_ios() interface that is used in patch 5. Mike -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
