diff options
Diffstat (limited to 'drivers/block/drbd/drbd_req.c')
| -rw-r--r-- | drivers/block/drbd/drbd_req.c | 192 |
1 files changed, 161 insertions, 31 deletions
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index 2b8303ad63c9..c24379ffd4e3 100644 --- a/drivers/block/drbd/drbd_req.c +++ b/drivers/block/drbd/drbd_req.c @@ -34,14 +34,14 @@ static bool drbd_may_do_local_read(struct drbd_conf *mdev, sector_t sector, int size); /* Update disk stats at start of I/O request */ -static void _drbd_start_io_acct(struct drbd_conf *mdev, struct drbd_request *req, struct bio *bio) +static void _drbd_start_io_acct(struct drbd_conf *mdev, struct drbd_request *req) { - const int rw = bio_data_dir(bio); + const int rw = bio_data_dir(req->master_bio); int cpu; cpu = part_stat_lock(); part_round_stats(cpu, &mdev->vdisk->part0); part_stat_inc(cpu, &mdev->vdisk->part0, ios[rw]); - part_stat_add(cpu, &mdev->vdisk->part0, sectors[rw], bio_sectors(bio)); + part_stat_add(cpu, &mdev->vdisk->part0, sectors[rw], req->i.size >> 9); (void) cpu; /* The macro invocations above want the cpu argument, I do not like the compiler warning about cpu only assigned but never used... */ part_inc_in_flight(&mdev->vdisk->part0, rw); @@ -263,8 +263,7 @@ void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m) else root = &mdev->read_requests; drbd_remove_request_interval(root, req); - } else if (!(s & RQ_POSTPONED)) - D_ASSERT((s & (RQ_NET_MASK & ~RQ_NET_DONE)) == 0); + } /* Before we can signal completion to the upper layers, * we may need to close the current transfer log epoch. @@ -755,6 +754,11 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what, D_ASSERT(req->rq_state & RQ_NET_PENDING); mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK|RQ_NET_DONE); break; + + case QUEUE_AS_DRBD_BARRIER: + start_new_tl_epoch(mdev->tconn); + mod_rq_state(req, m, 0, RQ_NET_OK|RQ_NET_DONE); + break; }; return rv; @@ -861,8 +865,10 @@ static void maybe_pull_ahead(struct drbd_conf *mdev) bool congested = false; enum drbd_on_congestion on_congestion; + rcu_read_lock(); nc = rcu_dereference(tconn->net_conf); on_congestion = nc ? nc->on_congestion : OC_BLOCK; + rcu_read_unlock(); if (on_congestion == OC_BLOCK || tconn->agreed_pro_version < 96) return; @@ -956,14 +962,8 @@ static int drbd_process_write_request(struct drbd_request *req) struct drbd_conf *mdev = req->w.mdev; int remote, send_oos; - rcu_read_lock(); remote = drbd_should_do_remote(mdev->state); - if (remote) { - maybe_pull_ahead(mdev); - remote = drbd_should_do_remote(mdev->state); - } send_oos = drbd_should_send_out_of_sync(mdev->state); - rcu_read_unlock(); /* Need to replicate writes. Unless it is an empty flush, * which is better mapped to a DRBD P_BARRIER packet, @@ -975,8 +975,8 @@ static int drbd_process_write_request(struct drbd_request *req) /* The only size==0 bios we expect are empty flushes. */ D_ASSERT(req->master_bio->bi_rw & REQ_FLUSH); if (remote) - start_new_tl_epoch(mdev->tconn); - return 0; + _req_mod(req, QUEUE_AS_DRBD_BARRIER); + return remote; } if (!remote && !send_oos) @@ -1020,12 +1020,24 @@ drbd_submit_req_private_bio(struct drbd_request *req) bio_endio(bio, -EIO); } -void __drbd_make_request(struct drbd_conf *mdev, struct bio *bio, unsigned long start_time) +static void drbd_queue_write(struct drbd_conf *mdev, struct drbd_request *req) { - const int rw = bio_rw(bio); - struct bio_and_error m = { NULL, }; + spin_lock(&mdev->submit.lock); + list_add_tail(&req->tl_requests, &mdev->submit.writes); + spin_unlock(&mdev->submit.lock); + queue_work(mdev->submit.wq, &mdev->submit.worker); +} + +/* returns the new drbd_request pointer, if the caller is expected to + * drbd_send_and_submit() it (to save latency), or NULL if we queued the + * request on the submitter thread. + * Returns ERR_PTR(-ENOMEM) if we cannot allocate a drbd_request. + */ +struct drbd_request * +drbd_request_prepare(struct drbd_conf *mdev, struct bio *bio, unsigned long start_time) +{ + const int rw = bio_data_dir(bio); struct drbd_request *req; - bool no_remote = false; /* allocate outside of all locks; */ req = drbd_req_new(mdev, bio); @@ -1035,7 +1047,7 @@ void __drbd_make_request(struct drbd_conf *mdev, struct bio *bio, unsigned long * if user cannot handle io errors, that's not our business. */ dev_err(DEV, "could not kmalloc() req\n"); bio_endio(bio, -ENOMEM); - return; + return ERR_PTR(-ENOMEM); } req->start_time = start_time; @@ -1044,28 +1056,40 @@ void __drbd_make_request(struct drbd_conf *mdev, struct bio *bio, unsigned long req->private_bio = NULL; } - /* For WRITES going to the local disk, grab a reference on the target - * extent. This waits for any resync activity in the corresponding - * resync extent to finish, and, if necessary, pulls in the target - * extent into the activity log, which involves further disk io because - * of transactional on-disk meta data updates. - * Empty flushes don't need to go into the activity log, they can only - * flush data for pending writes which are already in there. */ + /* Update disk stats */ + _drbd_start_io_acct(mdev, req); + if (rw == WRITE && req->private_bio && req->i.size && !test_bit(AL_SUSPENDED, &mdev->flags)) { + if (!drbd_al_begin_io_fastpath(mdev, &req->i)) { + drbd_queue_write(mdev, req); + return NULL; + } req->rq_state |= RQ_IN_ACT_LOG; - drbd_al_begin_io(mdev, &req->i); } + return req; +} + +static void drbd_send_and_submit(struct drbd_conf *mdev, struct drbd_request *req) +{ + const int rw = bio_rw(req->master_bio); + struct bio_and_error m = { NULL, }; + bool no_remote = false; + spin_lock_irq(&mdev->tconn->req_lock); if (rw == WRITE) { /* This may temporarily give up the req_lock, * but will re-aquire it before it returns here. * Needs to be before the check on drbd_suspended() */ complete_conflicting_writes(req); + /* no more giving up req_lock from now on! */ + + /* check for congestion, and potentially stop sending + * full data updates, but start sending "dirty bits" only. */ + maybe_pull_ahead(mdev); } - /* no more giving up req_lock from now on! */ if (drbd_suspended(mdev)) { /* push back and retry: */ @@ -1078,9 +1102,6 @@ void __drbd_make_request(struct drbd_conf *mdev, struct bio *bio, unsigned long goto out; } - /* Update disk stats */ - _drbd_start_io_acct(mdev, req, bio); - /* We fail READ/READA early, if we can not serve it. * We must do this before req is registered on any lists. * Otherwise, drbd_req_complete() will queue failed READ for retry. */ @@ -1137,7 +1158,116 @@ out: if (m.bio) complete_master_bio(mdev, &m); - return; +} + +void __drbd_make_request(struct drbd_conf *mdev, struct bio *bio, unsigned long start_time) +{ + struct drbd_request *req = drbd_request_prepare(mdev, bio, start_time); + if (IS_ERR_OR_NULL(req)) + return; + drbd_send_and_submit(mdev, req); +} + +static void submit_fast_path(struct drbd_conf *mdev, struct list_head *incoming) +{ + struct drbd_request *req, *tmp; + list_for_each_entry_safe(req, tmp, incoming, tl_requests) { + const int rw = bio_data_dir(req->master_bio); + + if (rw == WRITE /* rw != WRITE should not even end up here! */ + && req->private_bio && req->i.size + && !test_bit(AL_SUSPENDED, &mdev->flags)) { + if (!drbd_al_begin_io_fastpath(mdev, &req->i)) + continue; + + req->rq_state |= RQ_IN_ACT_LOG; + } + + list_del_init(&req->tl_requests); + drbd_send_and_submit(mdev, req); + } +} + +static bool prepare_al_transaction_nonblock(struct drbd_conf *mdev, + struct list_head *incoming, + struct list_head *pending) +{ + struct drbd_request *req, *tmp; + int wake = 0; + int err; + + spin_lock_irq(&mdev->al_lock); + list_for_each_entry_safe(req, tmp, incoming, tl_requests) { + err = drbd_al_begin_io_nonblock(mdev, &req->i); + if (err == -EBUSY) + wake = 1; + if (err) + continue; + req->rq_state |= RQ_IN_ACT_LOG; + list_move_tail(&req->tl_requests, pending); + } + spin_unlock_irq(&mdev->al_lock); + if (wake) + wake_up(&mdev->al_wait); + + return !list_empty(pending); +} + +void do_submit(struct work_struct *ws) +{ + struct drbd_conf *mdev = container_of(ws, struct drbd_conf, submit.worker); + LIST_HEAD(incoming); + LIST_HEAD(pending); + struct drbd_request *req, *tmp; + + for (;;) { + spin_lock(&mdev->submit.lock); + list_splice_tail_init(&mdev->submit.writes, &incoming); + spin_unlock(&mdev->submit.lock); + + submit_fast_path(mdev, &incoming); + if (list_empty(&incoming)) + break; + + wait_event(mdev->al_wait, prepare_al_transaction_nonblock(mdev, &incoming, &pending)); + /* Maybe more was queued, while we prepared the transaction? + * Try to stuff them into this transaction as well. + * Be strictly non-blocking here, no wait_event, we already + * have something to commit. + * Stop if we don't make any more progres. + */ + for (;;) { + LIST_HEAD(more_pending); + LIST_HEAD(more_incoming); + bool made_progress; + + /* It is ok to look outside the lock, + * it's only an optimization anyways */ + if (list_empty(&mdev->submit.writes)) + break; + + spin_lock(&mdev->submit.lock); + list_splice_tail_init(&mdev->submit.writes, &more_incoming); + spin_unlock(&mdev->submit.lock); + + if (list_empty(&more_incoming)) + break; + + made_progress = prepare_al_transaction_nonblock(mdev, &more_incoming, &more_pending); + + list_splice_tail_init(&more_pending, &pending); + list_splice_tail_init(&more_incoming, &incoming); + + if (!made_progress) + break; + } + drbd_al_begin_io_commit(mdev, false); + + list_for_each_entry_safe(req, tmp, &pending, tl_requests) { + list_del_init(&req->tl_requests); + drbd_send_and_submit(mdev, req); + } + } } void drbd_make_request(struct request_queue *q, struct bio *bio) |