From: Lars Ellenberg Date: Tue, 19 Mar 2013 17:16:56 +0000 (+0100) Subject: drbd: consolidate as many updates as possible into one AL transaction X-Git-Tag: firefly_0821_release~3680^2~530^2~40 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=08a1ddab6df7d3c7b6341774cb1cf4b21b96a214;p=firefly-linux-kernel-4.4.55.git drbd: consolidate as many updates as possible into one AL transaction Depending on current IO depth, try to consolidate as many updates as possible into one activity log transaction. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe --- diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c index ff03f9053316..6afe173d5c2b 100644 --- a/drivers/block/drbd/drbd_actlog.c +++ b/drivers/block/drbd/drbd_actlog.c @@ -359,6 +359,55 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool dele drbd_al_begin_io_commit(mdev, delegate); } +int drbd_al_begin_io_nonblock(struct drbd_conf *mdev, struct drbd_interval *i) +{ + struct lru_cache *al = mdev->act_log; + /* for bios crossing activity log extent boundaries, + * we may need to activate two extents in one go */ + unsigned first = i->sector >> (AL_EXTENT_SHIFT-9); + unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9); + unsigned nr_al_extents; + unsigned available_update_slots; + unsigned enr; + + D_ASSERT(first <= last); + + nr_al_extents = 1 + last - first; /* worst case: all touched extends are cold. */ + available_update_slots = min(al->nr_elements - al->used, + al->max_pending_changes - al->pending_changes); + + /* We want all necessary updates for a given request within the same transaction + * We could first check how many updates are *actually* needed, + * and use that instead of the worst-case nr_al_extents */ + if (available_update_slots < nr_al_extents) + return -EWOULDBLOCK; + + /* Is resync active in this area? */ + for (enr = first; enr <= last; enr++) { + struct lc_element *tmp; + tmp = lc_find(mdev->resync, enr/AL_EXT_PER_BM_SECT); + if (unlikely(tmp != NULL)) { + struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce); + if (test_bit(BME_NO_WRITES, &bm_ext->flags)) { + if (!test_and_set_bit(BME_PRIORITY, &bm_ext->flags)); + return -EBUSY; + return -EWOULDBLOCK; + } + } + } + + /* Checkout the refcounts. + * Given that we checked for available elements and update slots above, + * this has to be successful. */ + for (enr = first; enr <= last; enr++) { + struct lc_element *al_ext; + al_ext = lc_get_cumulative(mdev->act_log, enr); + if (!al_ext) + dev_info(DEV, "LOGIC BUG for enr=%u\n", enr); + } + return 0; +} + void drbd_al_complete_io(struct drbd_conf *mdev, struct drbd_interval *i) { /* for bios crossing activity log extent boundaries, diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index b7b52dd42325..f943aacfdad8 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -1611,6 +1611,8 @@ extern const char *drbd_conn_str(enum drbd_conns s); extern const char *drbd_role_str(enum drbd_role s); /* drbd_actlog.c */ +extern int drbd_al_begin_io_nonblock(struct drbd_conf *mdev, struct drbd_interval *i); +extern void drbd_al_begin_io_commit(struct drbd_conf *mdev, bool delegate); extern bool drbd_al_begin_io_fastpath(struct drbd_conf *mdev, struct drbd_interval *i); extern void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool delegate); extern void drbd_al_complete_io(struct drbd_conf *mdev, struct drbd_interval *i); diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index 43bc1d064bc7..b923d41678e1 100644 --- a/drivers/block/drbd/drbd_req.c +++ b/drivers/block/drbd/drbd_req.c @@ -1164,32 +1164,74 @@ void __drbd_make_request(struct drbd_conf *mdev, struct bio *bio, unsigned long drbd_send_and_submit(mdev, req); } -void __drbd_make_request_from_worker(struct drbd_conf *mdev, struct drbd_request *req) +static void submit_fast_path(struct drbd_conf *mdev, struct list_head *incoming) { - const int rw = bio_rw(req->master_bio); + 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 && req->private_bio && req->i.size - && !test_bit(AL_SUSPENDED, &mdev->flags)) { - drbd_al_begin_io(mdev, &req->i, false); - req->rq_state |= RQ_IN_ACT_LOG; + 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); } - 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(writes); + LIST_HEAD(incoming); + LIST_HEAD(pending); struct drbd_request *req, *tmp; - spin_lock(&mdev->submit.lock); - list_splice_init(&mdev->submit.writes, &writes); - spin_unlock(&mdev->submit.lock); + for (;;) { + spin_lock(&mdev->submit.lock); + list_splice_tail_init(&mdev->submit.writes, &incoming); + spin_unlock(&mdev->submit.lock); - list_for_each_entry_safe(req, tmp, &writes, tl_requests) { - list_del_init(&req->tl_requests); - __drbd_make_request_from_worker(mdev, req); + submit_fast_path(mdev, &incoming); + if (list_empty(&incoming)) + break; + + wait_event(mdev->al_wait, prepare_al_transaction_nonblock(mdev, &incoming, &pending)); + 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); + } } }