| Message ID | 20170817232311.25948-4-bart.vanassche@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 08/18/2017 01:23 AM, Bart Van Assche wrote: > It is nontrivial to derive from the blk-mq source code when > blk_mq_tags.active_queues is decremented. Hence add a comment that > explains this. > > Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Hannes Reinecke <hare@suse.de> > Cc: Johannes Thumshirn <jthumshirn@suse.de> > --- > block/blk-mq.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index f84d145490bf..b86d2cafc355 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -834,6 +834,10 @@ static void blk_mq_timeout_work(struct work_struct *work) > } else { > struct blk_mq_hw_ctx *hctx; > > + /* > + * All requests finished (latest request timeout) seconds ago, > + * so mark each hctx as idle. > + */ > queue_for_each_hw_ctx(q, hctx, i) { > /* the hctx may be unmapped, so check it here */ > if (blk_mq_hw_queue_mapped(hctx)) > Reviewed-by: Hannes Reinecke <hare@suse.com> Cheers, Hannes
On Thu, Aug 17 2017, Bart Van Assche wrote: > It is nontrivial to derive from the blk-mq source code when > blk_mq_tags.active_queues is decremented. Hence add a comment that > explains this. > > Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Hannes Reinecke <hare@suse.de> > Cc: Johannes Thumshirn <jthumshirn@suse.de> > --- > block/blk-mq.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index f84d145490bf..b86d2cafc355 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -834,6 +834,10 @@ static void blk_mq_timeout_work(struct work_struct *work) > } else { > struct blk_mq_hw_ctx *hctx; > > + /* > + * All requests finished (latest request timeout) seconds ago, > + * so mark each hctx as idle. > + */ > queue_for_each_hw_ctx(q, hctx, i) { I don't think that's a great comment, what does 'latest request timeout' refer to? We hit this case when the device has gone idle, I think a more useful comment would be something about how blk-mq implements timeouts. How about something ala: /* * Request timeouts are handled as a forward rolling timer. If we * end up here, there are no more requests pending, and there hasn't * been for a while. Mark each hctx as idle. */
diff --git a/block/blk-mq.c b/block/blk-mq.c index f84d145490bf..b86d2cafc355 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -834,6 +834,10 @@ static void blk_mq_timeout_work(struct work_struct *work) } else { struct blk_mq_hw_ctx *hctx; + /* + * All requests finished (latest request timeout) seconds ago, + * so mark each hctx as idle. + */ queue_for_each_hw_ctx(q, hctx, i) { /* the hctx may be unmapped, so check it here */ if (blk_mq_hw_queue_mapped(hctx))
It is nontrivial to derive from the blk-mq source code when blk_mq_tags.active_queues is decremented. Hence add a comment that explains this. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> --- block/blk-mq.c | 4 ++++ 1 file changed, 4 insertions(+)