From a92ce0feffeed8b91f02dac85246d1205e4a64b6 Mon Sep 17 00:00:00 2001 From: Mariusz Tkaczyk Date: Fri, 17 Dec 2021 10:29:55 +0100 Subject: md: drop queue limitation for RAID1 and RAID10 As suggested by Neil Brown[1], this limitation seems to be deprecated. With plugging in use, writes are processed behind the raid thread and conf->pending_count is not increased. This limitation occurs only if caller doesn't use plugs. It can be avoided and often it is (with plugging). There are no reports that queue is growing to enormous size so remove queue limitation for non-plugged IOs too. [1] https://lore.kernel.org/linux-raid/162496301481.7211.18031090130574610495@noble.neil.brown.name Signed-off-by: Mariusz Tkaczyk Signed-off-by: Song Liu --- drivers/md/raid10.c | 7 ------- 1 file changed, 7 deletions(-) (limited to 'drivers/md/raid10.c') diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index dde98f65bd04..c683ba138b58 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1387,12 +1387,6 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio, conf->reshape_safe = mddev->reshape_position; } - if (conf->pending_count >= max_queued_requests) { - md_wakeup_thread(mddev->thread); - raid10_log(mddev, "wait queued"); - wait_event(conf->wait_barrier, - conf->pending_count < max_queued_requests); - } /* first select target devices under rcu_lock and * inc refcount on their rdev. Record them by setting * bios[x] to bio @@ -5243,4 +5237,3 @@ MODULE_ALIAS("md-personality-9"); /* RAID10 */ MODULE_ALIAS("md-raid10"); MODULE_ALIAS("md-level-10"); -module_param(max_queued_requests, int, S_IRUGO|S_IWUSR); -- cgit v1.2.3 From c9aa889b035fca4598ae985a0f0c76ebbb547ad2 Mon Sep 17 00:00:00 2001 From: Vishal Verma Date: Tue, 21 Dec 2021 20:06:21 +0000 Subject: md: raid10 add nowait support This adds nowait support to the RAID10 driver. Very similar to raid1 driver changes. It makes RAID10 driver return with EAGAIN for situations where it could wait for eg: - Waiting for the barrier, - Reshape operation, - Discard operation. wait_barrier() and regular_request_wait() fn are modified to return bool to support error for wait barriers. They returns true in case of wait or if wait is not required and returns false if wait was required but not performed to support nowait. Reviewed-by: Jens Axboe Signed-off-by: Vishal Verma Signed-off-by: Song Liu --- drivers/md/raid10.c | 100 +++++++++++++++++++++++++++++++++++----------------- 1 file changed, 67 insertions(+), 33 deletions(-) (limited to 'drivers/md/raid10.c') diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index c683ba138b58..2b969f70a31f 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -952,8 +952,10 @@ static void lower_barrier(struct r10conf *conf) wake_up(&conf->wait_barrier); } -static void wait_barrier(struct r10conf *conf) +static bool wait_barrier(struct r10conf *conf, bool nowait) { + bool ret = true; + spin_lock_irq(&conf->resync_lock); if (conf->barrier) { struct bio_list *bio_list = current->bio_list; @@ -967,27 +969,35 @@ static void wait_barrier(struct r10conf *conf) * that queue to get the nr_pending * count down. */ - raid10_log(conf->mddev, "wait barrier"); - wait_event_lock_irq(conf->wait_barrier, - !conf->barrier || - (atomic_read(&conf->nr_pending) && - bio_list && - (!bio_list_empty(&bio_list[0]) || - !bio_list_empty(&bio_list[1]))) || - /* move on if recovery thread is - * blocked by us - */ - (conf->mddev->thread->tsk == current && - test_bit(MD_RECOVERY_RUNNING, - &conf->mddev->recovery) && - conf->nr_queued > 0), - conf->resync_lock); + /* Return false when nowait flag is set */ + if (nowait) { + ret = false; + } else { + raid10_log(conf->mddev, "wait barrier"); + wait_event_lock_irq(conf->wait_barrier, + !conf->barrier || + (atomic_read(&conf->nr_pending) && + bio_list && + (!bio_list_empty(&bio_list[0]) || + !bio_list_empty(&bio_list[1]))) || + /* move on if recovery thread is + * blocked by us + */ + (conf->mddev->thread->tsk == current && + test_bit(MD_RECOVERY_RUNNING, + &conf->mddev->recovery) && + conf->nr_queued > 0), + conf->resync_lock); + } conf->nr_waiting--; if (!conf->nr_waiting) wake_up(&conf->wait_barrier); } - atomic_inc(&conf->nr_pending); + /* Only increment nr_pending when we wait */ + if (ret) + atomic_inc(&conf->nr_pending); spin_unlock_irq(&conf->resync_lock); + return ret; } static void allow_barrier(struct r10conf *conf) @@ -1098,21 +1108,30 @@ static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule) * currently. * 2. If IO spans the reshape position. Need to wait for reshape to pass. */ -static void regular_request_wait(struct mddev *mddev, struct r10conf *conf, +static bool regular_request_wait(struct mddev *mddev, struct r10conf *conf, struct bio *bio, sector_t sectors) { - wait_barrier(conf); + /* Bail out if REQ_NOWAIT is set for the bio */ + if (!wait_barrier(conf, bio->bi_opf & REQ_NOWAIT)) { + bio_wouldblock_error(bio); + return false; + } while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) && bio->bi_iter.bi_sector < conf->reshape_progress && bio->bi_iter.bi_sector + sectors > conf->reshape_progress) { - raid10_log(conf->mddev, "wait reshape"); allow_barrier(conf); + if (bio->bi_opf & REQ_NOWAIT) { + bio_wouldblock_error(bio); + return false; + } + raid10_log(conf->mddev, "wait reshape"); wait_event(conf->wait_barrier, conf->reshape_progress <= bio->bi_iter.bi_sector || conf->reshape_progress >= bio->bi_iter.bi_sector + sectors); - wait_barrier(conf); + wait_barrier(conf, false); } + return true; } static void raid10_read_request(struct mddev *mddev, struct bio *bio, @@ -1157,7 +1176,8 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio, rcu_read_unlock(); } - regular_request_wait(mddev, conf, bio, r10_bio->sectors); + if (!regular_request_wait(mddev, conf, bio, r10_bio->sectors)) + return; rdev = read_balance(conf, r10_bio, &max_sectors); if (!rdev) { if (err_rdev) { @@ -1179,7 +1199,7 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio, bio_chain(split, bio); allow_barrier(conf); submit_bio_noacct(bio); - wait_barrier(conf); + wait_barrier(conf, false); bio = split; r10_bio->master_bio = bio; r10_bio->sectors = max_sectors; @@ -1338,7 +1358,7 @@ retry_wait: raid10_log(conf->mddev, "%s wait rdev %d blocked", __func__, blocked_rdev->raid_disk); md_wait_for_blocked_rdev(blocked_rdev, mddev); - wait_barrier(conf); + wait_barrier(conf, false); goto retry_wait; } } @@ -1356,6 +1376,11 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio, bio->bi_iter.bi_sector, bio_end_sector(bio)))) { DEFINE_WAIT(w); + /* Bail out if REQ_NOWAIT is set for the bio */ + if (bio->bi_opf & REQ_NOWAIT) { + bio_wouldblock_error(bio); + return; + } for (;;) { prepare_to_wait(&conf->wait_barrier, &w, TASK_IDLE); @@ -1368,7 +1393,8 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio, } sectors = r10_bio->sectors; - regular_request_wait(mddev, conf, bio, sectors); + if (!regular_request_wait(mddev, conf, bio, sectors)) + return; if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) && (mddev->reshape_backwards ? (bio->bi_iter.bi_sector < conf->reshape_safe && @@ -1380,6 +1406,11 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio, set_mask_bits(&mddev->sb_flags, 0, BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING)); md_wakeup_thread(mddev->thread); + if (bio->bi_opf & REQ_NOWAIT) { + allow_barrier(conf); + bio_wouldblock_error(bio); + return; + } raid10_log(conf->mddev, "wait reshape metadata"); wait_event(mddev->sb_wait, !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)); @@ -1476,7 +1507,7 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio, bio_chain(split, bio); allow_barrier(conf); submit_bio_noacct(bio); - wait_barrier(conf); + wait_barrier(conf, false); bio = split; r10_bio->master_bio = bio; } @@ -1601,7 +1632,11 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio) if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) return -EAGAIN; - wait_barrier(conf); + if (WARN_ON_ONCE(bio->bi_opf & REQ_NOWAIT)) { + bio_wouldblock_error(bio); + return 0; + } + wait_barrier(conf, false); /* * Check reshape again to avoid reshape happens after checking @@ -1643,7 +1678,7 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio) allow_barrier(conf); /* Resend the fist split part */ submit_bio_noacct(split); - wait_barrier(conf); + wait_barrier(conf, false); } div_u64_rem(bio_end, stripe_size, &remainder); if (remainder) { @@ -1654,7 +1689,7 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio) /* Resend the second split part */ submit_bio_noacct(bio); bio = split; - wait_barrier(conf); + wait_barrier(conf, false); } bio_start = bio->bi_iter.bi_sector; @@ -1810,7 +1845,7 @@ retry_discard: end_disk_offset += geo->stride; atomic_inc(&first_r10bio->remaining); raid_end_discard_bio(r10_bio); - wait_barrier(conf); + wait_barrier(conf, false); goto retry_discard; } @@ -2005,7 +2040,7 @@ static void print_conf(struct r10conf *conf) static void close_sync(struct r10conf *conf) { - wait_barrier(conf); + wait_barrier(conf, false); allow_barrier(conf); mempool_exit(&conf->r10buf_pool); @@ -4813,7 +4848,7 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, if (need_flush || time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) { /* Need to update reshape_position in metadata */ - wait_barrier(conf); + wait_barrier(conf, false); mddev->reshape_position = conf->reshape_progress; if (mddev->reshape_backwards) mddev->curr_resync_completed = raid10_size(mddev, 0, 0) @@ -5236,4 +5271,3 @@ MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD"); MODULE_ALIAS("md-personality-9"); /* RAID10 */ MODULE_ALIAS("md-raid10"); MODULE_ALIAS("md-level-10"); - -- cgit v1.2.3