On Thu, 28 May 2015 17:33:48 -0700 Shaohua Li <shli@xxxxxx> wrote: > Since we have several stripe hash list, the conf->active_stripes doesn't > determine if there is free stripe in a specific hash list, so delete the > check. After this, the R5_INACTIVE_BLOCKED check is inappropriate. There > is no point not to wakeup a task if there is free stripe. > > Signed-off-by: Shaohua Li <shli@xxxxxx> > --- > drivers/md/raid5.c | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c > index 67626f3..4b5a03c 100644 > --- a/drivers/md/raid5.c > +++ b/drivers/md/raid5.c > @@ -687,11 +687,7 @@ get_active_stripe(struct r5conf *conf, sector_t sector, > &conf->cache_state); > wait_event_lock_irq( > conf->wait_for_stripe, > - !list_empty(conf->inactive_list + hash) && > - (atomic_read(&conf->active_stripes) > - < (conf->max_nr_stripes * 3 / 4) > - || !test_bit(R5_INACTIVE_BLOCKED, > - &conf->cache_state)), > + !list_empty(conf->inactive_list + hash), > *(conf->hash_locks + hash)); > clear_bit(R5_INACTIVE_BLOCKED, > &conf->cache_state); Have you actually tested this? Because I do remember why I put that code in and it made a very real performance improvement. The idea is that once we run out of free stripes, we wait until there a lots available. That improves opportunities for batching. So I would definitely needs some performance numbers with a patch like this. Thanks for the review anyway !! NeilBrown
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