| Message ID | 20170426183728.10821-4-bart.vanassche@sandisk.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
On 04/26/2017 08:37 PM, Bart Van Assche wrote: > Requeuing a request immediately while path initialization is ongoing > causes high CPU usage, something that is undesired. Hence delay > requeuing while path initialization is in progress. > > Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> > Cc: Hannes Reinecke <hare@suse.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: <stable@vger.kernel.org> > --- > drivers/md/dm-mpath.c | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c > index 6d4333fdddf5..e38c92178746 100644 > --- a/drivers/md/dm-mpath.c > +++ b/drivers/md/dm-mpath.c > @@ -322,13 +322,16 @@ static int __pg_init_all_paths(struct multipath *m) > return atomic_read(&m->pg_init_in_progress); > } > > -static void pg_init_all_paths(struct multipath *m) > +static int pg_init_all_paths(struct multipath *m) > { > unsigned long flags; > + int ret; > > spin_lock_irqsave(&m->lock, flags); > - __pg_init_all_paths(m); > + ret = __pg_init_all_paths(m); > spin_unlock_irqrestore(&m->lock, flags); > + > + return ret; > } > > static void __switch_pg(struct multipath *m, struct priority_group *pg) > @@ -485,7 +488,6 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, > struct request **__clone) > { > struct multipath *m = ti->private; > - int r = DM_MAPIO_REQUEUE; > size_t nr_bytes = blk_rq_bytes(rq); > struct pgpath *pgpath; > struct block_device *bdev; > @@ -504,8 +506,8 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, > return -EIO; /* Failed */ > } else if (test_bit(MPATHF_QUEUE_IO, &m->flags) || > test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { > - pg_init_all_paths(m); > - return r; > + return pg_init_all_paths(m) == 0 ? DM_MAPIO_REQUEUE : > + DM_MAPIO_DELAY_REQUEUE; > } > > memset(mpio, 0, sizeof(*mpio)); > Reviewed-by: Hannes Reinecke <hare@suse.com> Cheers, Hannes
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 6d4333fdddf5..e38c92178746 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -322,13 +322,16 @@ static int __pg_init_all_paths(struct multipath *m) return atomic_read(&m->pg_init_in_progress); } -static void pg_init_all_paths(struct multipath *m) +static int pg_init_all_paths(struct multipath *m) { unsigned long flags; + int ret; spin_lock_irqsave(&m->lock, flags); - __pg_init_all_paths(m); + ret = __pg_init_all_paths(m); spin_unlock_irqrestore(&m->lock, flags); + + return ret; } static void __switch_pg(struct multipath *m, struct priority_group *pg) @@ -485,7 +488,6 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, struct request **__clone) { struct multipath *m = ti->private; - int r = DM_MAPIO_REQUEUE; size_t nr_bytes = blk_rq_bytes(rq); struct pgpath *pgpath; struct block_device *bdev; @@ -504,8 +506,8 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, return -EIO; /* Failed */ } else if (test_bit(MPATHF_QUEUE_IO, &m->flags) || test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { - pg_init_all_paths(m); - return r; + return pg_init_all_paths(m) == 0 ? DM_MAPIO_REQUEUE : + DM_MAPIO_DELAY_REQUEUE; } memset(mpio, 0, sizeof(*mpio));
Requeuing a request immediately while path initialization is ongoing causes high CPU usage, something that is undesired. Hence delay requeuing while path initialization is in progress. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Christoph Hellwig <hch@lst.de> Cc: <stable@vger.kernel.org> --- drivers/md/dm-mpath.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)