From: Dave Chinner <dchinner@xxxxxxxxxx>
There is no reason we need a thread per filesystem to do the
flushing of the delayed write buffer queue. This can be easily
handled by a global concurrency managed workqueue.
Convert the delayed write buffer handling to use workqueues and
workqueue flushes to implement buffer writeback by embedding a
delayed work structure into the struct xfs_buftarg and using that to
control flushing. This greatly simplifes the process of flushing
and also removes a bunch of duplicated code between buftarg flushing
and delwri buffer writeback.
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
fs/xfs/xfs_buf.c | 165 ++++++++++++++++++++----------------------------
fs/xfs/xfs_buf.h | 5 +-
fs/xfs/xfs_dquot.c | 1 -
fs/xfs/xfs_trans_ail.c | 2 +-
4 files changed, 72 insertions(+), 101 deletions(-)
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 410de9f..b1b8c0c 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -42,9 +42,9 @@
#include "xfs_trace.h"
static kmem_zone_t *xfs_buf_zone;
-STATIC int xfsbufd(void *);
-STATIC void xfs_buf_delwri_queue(xfs_buf_t *, int);
+STATIC void xfs_buf_delwri_queue(xfs_buf_t *bp, int unlock);
+static struct workqueue_struct *xfs_buf_wq;
static struct workqueue_struct *xfslogd_workqueue;
struct workqueue_struct *xfsdatad_workqueue;
struct workqueue_struct *xfsconvertd_workqueue;
@@ -1407,8 +1407,9 @@ xfs_buf_delwri_queue(
}
if (list_empty(dwq)) {
- /* start xfsbufd as it is about to have something to do */
- wake_up_process(bp->b_target->bt_task);
+ /* queue a delayed flush as we are about to queue a buffer */
+ queue_delayed_work(xfs_buf_wq, &bp->b_target->bt_delwrite_work,
+ xfs_buf_timer_centisecs * msecs_to_jiffies(10));
}
bp->b_flags |= _XBF_DELWRI_Q;
@@ -1486,13 +1487,13 @@ STATIC int
xfs_buf_delwri_split(
xfs_buftarg_t *target,
struct list_head *list,
- unsigned long age)
+ unsigned long age,
+ int force)
{
xfs_buf_t *bp, *n;
struct list_head *dwq = &target->bt_delwrite_queue;
spinlock_t *dwlk = &target->bt_delwrite_lock;
int skipped = 0;
- int force;
force = test_and_clear_bit(XBT_FORCE_FLUSH, &target->bt_flags);
INIT_LIST_HEAD(list);
@@ -1543,90 +1544,36 @@ xfs_buf_cmp(
return 0;
}
-STATIC int
-xfsbufd(
- void *data)
-{
- xfs_buftarg_t *target = (xfs_buftarg_t *)data;
-
- current->flags |= PF_MEMALLOC;
-
- set_freezable();
-
- do {
- long age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
- long tout = xfs_buf_timer_centisecs * msecs_to_jiffies(10);
- struct list_head tmp;
- struct blk_plug plug;
-
- if (unlikely(freezing(current))) {
- set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
- refrigerator();
- } else {
- clear_bit(XBT_FORCE_SLEEP, &target->bt_flags);
- }
-
- /* sleep for a long time if there is nothing to do. */
- if (list_empty(&target->bt_delwrite_queue))
- tout = MAX_SCHEDULE_TIMEOUT;
- schedule_timeout_interruptible(tout);
-
- xfs_buf_delwri_split(target, &tmp, age);
- list_sort(NULL, &tmp, xfs_buf_cmp);
-
- blk_start_plug(&plug);
- while (!list_empty(&tmp)) {
- struct xfs_buf *bp;
- bp = list_first_entry(&tmp, struct xfs_buf, b_list);
- list_del_init(&bp->b_list);
- xfs_bdstrat_cb(bp);
- }
- blk_finish_plug(&plug);
- } while (!kthread_should_stop());
-
- return 0;
-}
-
-/*
- * Handling of buffer targets (buftargs).
- */
-
/*
- * Go through all incore buffers, and release buffers if they belong to
- * the given device. This is used in filesystem error handling to
- * preserve the consistency of its metadata.
+ * If we are doing a forced flush, then we need to wait for the IO that we
+ * issue to complete.
*/
-int
-xfs_flush_buftarg(
- xfs_buftarg_t *target,
- int wait)
+static void
+xfs_buf_delwri_work(
+ struct work_struct *work)
{
- xfs_buf_t *bp;
- int pincount = 0;
+ struct xfs_buftarg *btp = container_of(to_delayed_work(work),
+ struct xfs_buftarg, bt_delwrite_work);
+ struct xfs_buf *bp;
+ struct blk_plug plug;
LIST_HEAD(tmp_list);
LIST_HEAD(wait_list);
- struct blk_plug plug;
-
- xfs_buf_runall_queues(xfsconvertd_workqueue);
- xfs_buf_runall_queues(xfsdatad_workqueue);
- xfs_buf_runall_queues(xfslogd_workqueue);
+ long age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
+ int force = 0;
- set_bit(XBT_FORCE_FLUSH, &target->bt_flags);
- pincount = xfs_buf_delwri_split(target, &tmp_list, 0);
+ if (test_and_clear_bit(XBT_FORCE_FLUSH, &btp->bt_flags)) {
+ force = 1;
+ age = 0;
+ }
- /*
- * Dropped the delayed write list lock, now walk the temporary list.
- * All I/O is issued async and then if we need to wait for completion
- * we do that after issuing all the IO.
- */
+ xfs_buf_delwri_split(btp, &tmp_list, age, force);
list_sort(NULL, &tmp_list, xfs_buf_cmp);
blk_start_plug(&plug);
while (!list_empty(&tmp_list)) {
bp = list_first_entry(&tmp_list, struct xfs_buf, b_list);
- ASSERT(target == bp->b_target);
list_del_init(&bp->b_list);
- if (wait) {
+ if (force) {
bp->b_flags &= ~XBF_ASYNC;
list_add(&bp->b_list, &wait_list);
}
@@ -1634,7 +1581,7 @@ xfs_flush_buftarg(
}
blk_finish_plug(&plug);
- if (wait) {
+ if (force) {
/* Wait for IO to complete. */
while (!list_empty(&wait_list)) {
bp = list_first_entry(&wait_list, struct xfs_buf, b_list);
@@ -1645,7 +1592,39 @@ xfs_flush_buftarg(
}
}
- return pincount;
+ if (list_empty(&btp->bt_delwrite_queue))
+ return;
+
+ queue_delayed_work(xfs_buf_wq, &btp->bt_delwrite_work,
+ xfs_buf_timer_centisecs * msecs_to_jiffies(10));
+}
+
+/*
+ * Handling of buffer targets (buftargs).
+ */
+
+/*
+ * Flush all the queued buffer work, then flush any remaining dirty buffers
+ * and wait for them to complete. If there are buffers remaining on the delwri
+ * queue, then they were pinned so couldn't be flushed. Return a value of 1 to
+ * indicate that there were pinned buffers and the caller needs to retry the
+ * flush.
+ */
+int
+xfs_flush_buftarg(
+ xfs_buftarg_t *target,
+ int wait)
+{
+ xfs_buf_runall_queues(xfsconvertd_workqueue);
+ xfs_buf_runall_queues(xfsdatad_workqueue);
+ xfs_buf_runall_queues(xfslogd_workqueue);
+
+ set_bit(XBT_FORCE_FLUSH, &target->bt_flags);
+ flush_delayed_work_sync(&target->bt_delwrite_work);
+
+ if (!list_empty(&target->bt_delwrite_queue))
+ return 1;
+ return 0;
}
/*
@@ -1740,7 +1719,6 @@ xfs_free_buftarg(
if (mp->m_flags & XFS_MOUNT_BARRIER)
xfs_blkdev_issue_flush(btp);
- kthread_stop(btp->bt_task);
kmem_free(btp);
}
@@ -1788,20 +1766,6 @@ xfs_setsize_buftarg(
return xfs_setsize_buftarg_flags(btp, blocksize, sectorsize, 1);
}
-STATIC int
-xfs_alloc_delwrite_queue(
- xfs_buftarg_t *btp,
- const char *fsname)
-{
- INIT_LIST_HEAD(&btp->bt_delwrite_queue);
- spin_lock_init(&btp->bt_delwrite_lock);
- btp->bt_flags = 0;
- btp->bt_task = kthread_run(xfsbufd, btp, "xfsbufd/%s", fsname);
- if (IS_ERR(btp->bt_task))
- return PTR_ERR(btp->bt_task);
- return 0;
-}
-
xfs_buftarg_t *
xfs_alloc_buftarg(
struct xfs_mount *mp,
@@ -1824,8 +1788,11 @@ xfs_alloc_buftarg(
spin_lock_init(&btp->bt_lru_lock);
if (xfs_setsize_buftarg_early(btp, bdev))
goto error;
- if (xfs_alloc_delwrite_queue(btp, fsname))
- goto error;
+
+ INIT_LIST_HEAD(&btp->bt_delwrite_queue);
+ spin_lock_init(&btp->bt_delwrite_lock);
+ INIT_DELAYED_WORK(&btp->bt_delwrite_work, xfs_buf_delwri_work);
+
btp->bt_shrinker.shrink = xfs_buftarg_shrink;
btp->bt_shrinker.seeks = DEFAULT_SEEKS;
register_shrinker(&btp->bt_shrinker);
@@ -1860,8 +1827,13 @@ xfs_buf_init(void)
if (!xfsconvertd_workqueue)
goto out_destroy_xfsdatad_workqueue;
+ xfs_buf_wq = alloc_workqueue("xfsbufd", WQ_MEM_RECLAIM, 8);
+ if (!xfs_buf_wq)
+ goto out_destroy_xfsconvertd_wq;
return 0;
+ out_destroy_xfsconvertd_wq:
+ destroy_workqueue(xfsconvertd_workqueue);
out_destroy_xfsdatad_workqueue:
destroy_workqueue(xfsdatad_workqueue);
out_destroy_xfslogd_workqueue:
@@ -1875,6 +1847,7 @@ xfs_buf_init(void)
void
xfs_buf_terminate(void)
{
+ destroy_workqueue(xfs_buf_wq);
destroy_workqueue(xfsconvertd_workqueue);
destroy_workqueue(xfsdatad_workqueue);
destroy_workqueue(xfslogd_workqueue);
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 620972b..c1aabfd 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -90,8 +90,7 @@ typedef unsigned int xfs_buf_flags_t;
{ _XBF_DELWRI_Q, "DELWRI_Q" }
typedef enum {
- XBT_FORCE_SLEEP = 0,
- XBT_FORCE_FLUSH = 1,
+ XBT_FORCE_FLUSH = 0,
} xfs_buftarg_flags_t;
typedef struct xfs_buftarg {
@@ -104,7 +103,7 @@ typedef struct xfs_buftarg {
size_t bt_smask;
/* per device delwri queue */
- struct task_struct *bt_task;
+ struct delayed_work bt_delwrite_work;
struct list_head bt_delwrite_queue;
spinlock_t bt_delwrite_lock;
unsigned long bt_flags;
diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index db62959..1fb9d93 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -1446,7 +1446,6 @@ xfs_qm_dqflock_pushbuf_wait(
if (xfs_buf_ispinned(bp))
xfs_log_force(mp, 0);
xfs_buf_delwri_promote(bp);
- wake_up_process(bp->b_target->bt_task);
}
xfs_buf_relse(bp);
out_lock:
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
index dd966e0..919a31e 100644
--- a/fs/xfs/xfs_trans_ail.c
+++ b/fs/xfs/xfs_trans_ail.c
@@ -495,7 +495,7 @@ xfs_ail_worker(
if (push_xfsbufd) {
/* we've got delayed write buffers to flush */
- wake_up_process(mp->m_ddev_targp->bt_task);
+ flush_delayed_work(&mp->m_ddev_targp->bt_delwrite_work);
}
/* assume we have more work to do in a short while */
--
1.7.5.4
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