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authorNeilBrown <neilb@suse.de>2011-04-18 18:25:43 +1000
committerNeilBrown <neilb@suse.de>2011-04-18 18:25:43 +1000
commit7c13edc87510f665da3094174e1fd633e06649f4 (patch)
treec0c50ab6ac43e9c762199bfd94c787f43a8e0896 /drivers
parent97658cdd3af7d01461874c93b89afa4a2465e7c6 (diff)
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')
-rw-r--r--drivers/md/raid5.c23
1 files changed, 16 insertions, 7 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index a1755a6a3e5f..f301e6ae220c 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;

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