On 1/23/24 09:34, Jens Axboe wrote:
If we're entering request dispatch but someone else is already
dispatching, then just skip this dispatch. We know IO is inflight and
this will trigger another dispatch event for any completion. This will
potentially cause slightly lower queue depth for contended cases, but
those are slowed down anyway and this should not cause an issue.
By itself, this patch doesn't help a whole lot, as the dispatch
lock contention reduction is just eating up by the same dd->lock now
^^^^^^^^
Does this perhaps need to be modified into bfqd->lock?
struct bfq_data {
+ struct {
+ spinlock_t lock;
+ } ____cacheline_aligned_in_smp;
Hmm ... why is the spinlock surrounded with a struct { }? This is not
clear to me. Otherwise this patch looks good to me.
Thanks,
Bart.
