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Message-Id: <1363713419-17803-12-git-send-email-philipp.reisner@linbit.com>
Date: Tue, 19 Mar 2013 18:16:52 +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 11/18] drbd: split drbd_al_begin_io into fastpath, prepare, and commit
From: Lars Ellenberg <lars.ellenberg@...bit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@...bit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@...bit.com>
---
drivers/block/drbd/drbd_actlog.c | 104 ++++++++++++++++++++++++++------------
drivers/block/drbd/drbd_int.h | 1 +
2 files changed, 72 insertions(+), 33 deletions(-)
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 1d7244d..e4f1231 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -104,7 +104,6 @@ struct update_al_work {
int err;
};
-static int al_write_transaction(struct drbd_conf *mdev, bool delegate);
void *drbd_md_get_buffer(struct drbd_conf *mdev)
{
@@ -246,30 +245,37 @@ static struct lc_element *_al_get(struct drbd_conf *mdev, unsigned int enr)
return al_ext;
}
-/*
- * @delegate: delegate activity log I/O to the worker thread
- */
-void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool delegate)
+bool drbd_al_begin_io_fastpath(struct drbd_conf *mdev, struct drbd_interval *i)
{
/* 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 enr;
- bool need_transaction = false;
- bool locked = false;
+ bool fastpath_ok = true;
- /* When called through generic_make_request(), we must delegate
- * activity log I/O to the worker thread: a further request
- * submitted via generic_make_request() within the same task
- * would be queued on current->bio_list, and would only start
- * after this function returns (see generic_make_request()).
- *
- * However, if we *are* the worker, we must not delegate to ourselves.
- */
+ D_ASSERT((unsigned)(last - first) <= 1);
+ D_ASSERT(atomic_read(&mdev->local_cnt) > 0);
+
+ /* FIXME figure out a fast path for bios crossing AL extent boundaries */
+ if (first != last)
+ return false;
+
+ spin_lock_irq(&mdev->al_lock);
+ fastpath_ok =
+ lc_find(mdev->resync, first/AL_EXT_PER_BM_SECT) == NULL &&
+ lc_try_get(mdev->act_log, first) != NULL;
+ spin_unlock_irq(&mdev->al_lock);
+ return fastpath_ok;
+}
- if (delegate)
- BUG_ON(current == mdev->tconn->worker.task);
+bool drbd_al_begin_io_prepare(struct drbd_conf *mdev, struct drbd_interval *i)
+{
+ /* 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 enr;
+ bool need_transaction = false;
D_ASSERT(first <= last);
D_ASSERT(atomic_read(&mdev->local_cnt) > 0);
@@ -280,11 +286,28 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool dele
if (al_ext->lc_number != enr)
need_transaction = true;
}
+ return need_transaction;
+}
- /* If *this* request was to an already active extent,
- * we're done, even if there are pending changes. */
- if (!need_transaction)
- return;
+static int al_write_transaction(struct drbd_conf *mdev, bool delegate);
+
+/* When called through generic_make_request(), we must delegate
+ * activity log I/O to the worker thread: a further request
+ * submitted via generic_make_request() within the same task
+ * would be queued on current->bio_list, and would only start
+ * after this function returns (see generic_make_request()).
+ *
+ * However, if we *are* the worker, we must not delegate to ourselves.
+ */
+
+/*
+ * @delegate: delegate activity log I/O to the worker thread
+ */
+void drbd_al_begin_io_commit(struct drbd_conf *mdev, bool delegate)
+{
+ bool locked = false;
+
+ BUG_ON(delegate && current == mdev->tconn->worker.task);
/* Serialize multiple transactions.
* This uses test_and_set_bit, memory barrier is implicit.
@@ -303,11 +326,8 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool dele
write_al_updates = rcu_dereference(mdev->ldev->disk_conf)->al_updates;
rcu_read_unlock();
- if (write_al_updates) {
+ if (write_al_updates)
al_write_transaction(mdev, delegate);
- mdev->al_writ_cnt++;
- }
-
spin_lock_irq(&mdev->al_lock);
/* FIXME
if (err)
@@ -321,6 +341,17 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool dele
}
}
+/*
+ * @delegate: delegate activity log I/O to the worker thread
+ */
+void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool delegate)
+{
+ BUG_ON(delegate && current == mdev->tconn->worker.task);
+
+ if (drbd_al_begin_io_prepare(mdev, i))
+ drbd_al_begin_io_commit(mdev, delegate);
+}
+
void drbd_al_complete_io(struct drbd_conf *mdev, struct drbd_interval *i)
{
/* for bios crossing activity log extent boundaries,
@@ -478,15 +509,22 @@ _al_write_transaction(struct drbd_conf *mdev)
crc = crc32c(0, buffer, 4096);
buffer->crc32c = cpu_to_be32(crc);
- /* normal execution path goes through all three branches */
if (drbd_bm_write_hinted(mdev))
err = -EIO;
- /* drbd_chk_io_error done already */
- else if (drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {
- err = -EIO;
- drbd_chk_io_error(mdev, 1, DRBD_META_IO_ERROR);
- } else {
- mdev->al_tr_number++;
+ else {
+ bool write_al_updates;
+ rcu_read_lock();
+ write_al_updates = rcu_dereference(mdev->ldev->disk_conf)->al_updates;
+ rcu_read_unlock();
+ if (write_al_updates) {
+ if (drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {
+ err = -EIO;
+ drbd_chk_io_error(mdev, 1, DRBD_META_IO_ERROR);
+ } else {
+ mdev->al_tr_number++;
+ mdev->al_writ_cnt++;
+ }
+ }
}
drbd_md_put_buffer(mdev);
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index a6b71b6..b7b52dd 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1611,6 +1611,7 @@ extern const char *drbd_conn_str(enum drbd_conns s);
extern const char *drbd_role_str(enum drbd_role s);
/* drbd_actlog.c */
+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);
extern void drbd_rs_complete_io(struct drbd_conf *mdev, sector_t sector);
--
1.7.9.5
--
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