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author | NeilBrown <neilb@suse.de> | 2011-04-18 18:25:43 +1000 |
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committer | NeilBrown <neilb@suse.de> | 2011-04-18 18:25:43 +1000 |
commit | 7c13edc87510f665da3094174e1fd633e06649f4 (patch) | |
tree | c0c50ab6ac43e9c762199bfd94c787f43a8e0896 /drivers/md | |
parent | 97658cdd3af7d01461874c93b89afa4a2465e7c6 (diff) | |
download | kernel_samsung_smdk4412-7c13edc87510f665da3094174e1fd633e06649f4.tar.gz kernel_samsung_smdk4412-7c13edc87510f665da3094174e1fd633e06649f4.tar.bz2 kernel_samsung_smdk4412-7c13edc87510f665da3094174e1fd633e06649f4.zip |
md: incorporate new plugging into raid5.
In raid5 plugging is used for 2 things:
1/ collecting writes that require a bitmap update
2/ collecting writes in the hope that we can create full
stripes - or at least more-full.
We now release these different sets of stripes when plug_cnt
is zero.
Also in make_request, we call mddev_check_plug to hopefully increase
plug_cnt, and wake up the thread at the end if plugging wasn't
achieved for some reason.
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md')
-rw-r--r-- | drivers/md/raid5.c | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index a1755a6a3e5..f301e6ae220 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -27,12 +27,12 @@ * * We group bitmap updates into batches. Each batch has a number. * We may write out several batches at once, but that isn't very important. - * conf->bm_write is the number of the last batch successfully written. - * conf->bm_flush is the number of the last batch that was closed to + * conf->seq_write is the number of the last batch successfully written. + * conf->seq_flush is the number of the last batch that was closed to * new additions. * When we discover that we will need to write to any block in a stripe * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq - * the number of the batch it will be in. This is bm_flush+1. + * the number of the batch it will be in. This is seq_flush+1. * When we are ready to do a write, if that batch hasn't been written yet, * we plug the array and queue the stripe for later. * When an unplug happens, we increment bm_flush, thus closing the current @@ -459,7 +459,7 @@ get_active_stripe(raid5_conf_t *conf, sector_t sector, < (conf->max_nr_stripes *3/4) || !conf->inactive_blocked), conf->device_lock, - md_wakeup_thread(conf->mddev->thread)); + ); conf->inactive_blocked = 0; } else init_stripe(sh, sector, previous); @@ -3927,6 +3927,7 @@ static int make_request(mddev_t *mddev, struct bio * bi) struct stripe_head *sh; const int rw = bio_data_dir(bi); int remaining; + int plugged; if (unlikely(bi->bi_rw & REQ_FLUSH)) { md_flush_request(mddev, bi); @@ -3945,6 +3946,7 @@ static int make_request(mddev_t *mddev, struct bio * bi) bi->bi_next = NULL; bi->bi_phys_segments = 1; /* over-loaded to count active stripes */ + plugged = mddev_check_plugged(mddev); for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) { DEFINE_WAIT(w); int disks, data_disks; @@ -4059,6 +4061,9 @@ static int make_request(mddev_t *mddev, struct bio * bi) } } + if (!plugged) + md_wakeup_thread(mddev->thread); + spin_lock_irq(&conf->device_lock); remaining = raid5_dec_bi_phys_segments(bi); spin_unlock_irq(&conf->device_lock); @@ -4472,14 +4477,18 @@ static void raid5d(mddev_t *mddev) while (1) { struct bio *bio; - if (conf->seq_flush != conf->seq_write) { - int seq = conf->seq_flush; + if (atomic_read(&mddev->plug_cnt) == 0 && + !list_empty(&conf->bitmap_list)) { + /* Now is a good time to flush some bitmap updates */ + conf->seq_flush++; spin_unlock_irq(&conf->device_lock); bitmap_unplug(mddev->bitmap); spin_lock_irq(&conf->device_lock); - conf->seq_write = seq; + conf->seq_write = conf->seq_flush; activate_bit_delay(conf); } + if (atomic_read(&mddev->plug_cnt) == 0) + raid5_activate_delayed(conf); while ((bio = remove_bio_from_retry(conf))) { int ok; |