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Message-Id: <1363713419-17803-16-git-send-email-philipp.reisner@linbit.com>
Date: Tue, 19 Mar 2013 18:16:56 +0100
From: Philipp Reisner <philipp.reisner@...bit.com>
To: linux-kernel@...r.kernel.org
Cc: Jens Axboe <axboe@...nel.dk>, drbd-dev@...ts.linbit.com,
lars.ellenberg@...bit.com
Subject: [PATCH 15/18] drbd: consolidate as many updates as possible into one AL transaction
From: Lars Ellenberg <lars.ellenberg@...bit.com>
Depending on current IO depth, try to consolidate as many updates
as possible into one activity log transaction.
Signed-off-by: Philipp Reisner <philipp.reisner@...bit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@...bit.com>
---
drivers/block/drbd/drbd_actlog.c | 49 ++++++++++++++++++++++++++
drivers/block/drbd/drbd_int.h | 2 ++
drivers/block/drbd/drbd_req.c | 70 ++++++++++++++++++++++++++++++--------
3 files changed, 107 insertions(+), 14 deletions(-)
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index ff03f90..6afe173 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 b7b52dd..f943aac 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 43bc1d0..b923d41 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);
+ }
}
}
--
1.7.9.5
--
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