From a6867a6815fa0241848d4620f2dbd2954f4405d7 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Wed, 11 Jan 2006 15:37:58 +1100 Subject: [PATCH] [XFS] Introduce per-filesystem delwri pagebuf flushing to reduce contention between filesystems and prevent deadlocks between filesystems when a flush dependency exists between them. SGI-PV: 947098 SGI-Modid: xfs-linux-melb:xfs-kern:24844a Signed-off-by: David Chinner Signed-off-by: Nathan Scott --- fs/xfs/linux-2.6/xfs_buf.c | 136 +++++++++++++++++++++++++------------ fs/xfs/linux-2.6/xfs_buf.h | 9 +++ 2 files changed, 101 insertions(+), 44 deletions(-) diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c index 6fe21d2b8847..2a8acd38fa1e 100644 --- a/fs/xfs/linux-2.6/xfs_buf.c +++ b/fs/xfs/linux-2.6/xfs_buf.c @@ -33,6 +33,7 @@ STATIC kmem_cache_t *pagebuf_zone; STATIC kmem_shaker_t pagebuf_shake; +STATIC int xfsbufd(void *); STATIC int xfsbufd_wakeup(int, gfp_t); STATIC void pagebuf_delwri_queue(xfs_buf_t *, int); @@ -1492,6 +1493,30 @@ xfs_free_bufhash( btp->bt_hash = NULL; } +/* + * buftarg list for delwrite queue processing + */ +STATIC LIST_HEAD(xfs_buftarg_list); +STATIC DEFINE_SPINLOCK(xfs_buftarg_lock); + +STATIC void +xfs_register_buftarg( + xfs_buftarg_t *btp) +{ + spin_lock(&xfs_buftarg_lock); + list_add(&btp->bt_list, &xfs_buftarg_list); + spin_unlock(&xfs_buftarg_lock); +} + +STATIC void +xfs_unregister_buftarg( + xfs_buftarg_t *btp) +{ + spin_lock(&xfs_buftarg_lock); + list_del(&btp->bt_list); + spin_unlock(&xfs_buftarg_lock); +} + void xfs_free_buftarg( xfs_buftarg_t *btp, @@ -1502,6 +1527,12 @@ xfs_free_buftarg( xfs_blkdev_put(btp->pbr_bdev); xfs_free_bufhash(btp); iput(btp->pbr_mapping->host); + + /* unregister the buftarg first so that we don't get a + * wakeup finding a non-existent task */ + xfs_unregister_buftarg(btp); + kthread_stop(btp->bt_task); + kmem_free(btp, sizeof(*btp)); } @@ -1591,6 +1622,26 @@ xfs_mapping_buftarg( return 0; } +STATIC int +xfs_alloc_delwrite_queue( + xfs_buftarg_t *btp) +{ + int error = 0; + + INIT_LIST_HEAD(&btp->bt_list); + INIT_LIST_HEAD(&btp->bt_delwrite_queue); + spinlock_init(&btp->bt_delwrite_lock, "delwri_lock"); + btp->bt_flags = 0; + btp->bt_task = kthread_run(xfsbufd, btp, "xfsbufd"); + if (IS_ERR(btp->bt_task)) { + error = PTR_ERR(btp->bt_task); + goto out_error; + } + xfs_register_buftarg(btp); +out_error: + return error; +} + xfs_buftarg_t * xfs_alloc_buftarg( struct block_device *bdev, @@ -1606,6 +1657,8 @@ xfs_alloc_buftarg( goto error; if (xfs_mapping_buftarg(btp, bdev)) goto error; + if (xfs_alloc_delwrite_queue(btp)) + goto error; xfs_alloc_bufhash(btp, external); return btp; @@ -1618,20 +1671,19 @@ error: /* * Pagebuf delayed write buffer handling */ - -STATIC LIST_HEAD(pbd_delwrite_queue); -STATIC DEFINE_SPINLOCK(pbd_delwrite_lock); - STATIC void pagebuf_delwri_queue( xfs_buf_t *pb, int unlock) { + struct list_head *dwq = &pb->pb_target->bt_delwrite_queue; + spinlock_t *dwlk = &pb->pb_target->bt_delwrite_lock; + PB_TRACE(pb, "delwri_q", (long)unlock); ASSERT((pb->pb_flags & (PBF_DELWRI|PBF_ASYNC)) == (PBF_DELWRI|PBF_ASYNC)); - spin_lock(&pbd_delwrite_lock); + spin_lock(dwlk); /* If already in the queue, dequeue and place at tail */ if (!list_empty(&pb->pb_list)) { ASSERT(pb->pb_flags & _PBF_DELWRI_Q); @@ -1642,9 +1694,9 @@ pagebuf_delwri_queue( } pb->pb_flags |= _PBF_DELWRI_Q; - list_add_tail(&pb->pb_list, &pbd_delwrite_queue); + list_add_tail(&pb->pb_list, dwq); pb->pb_queuetime = jiffies; - spin_unlock(&pbd_delwrite_lock); + spin_unlock(dwlk); if (unlock) pagebuf_unlock(pb); @@ -1654,16 +1706,17 @@ void pagebuf_delwri_dequeue( xfs_buf_t *pb) { + spinlock_t *dwlk = &pb->pb_target->bt_delwrite_lock; int dequeued = 0; - spin_lock(&pbd_delwrite_lock); + spin_lock(dwlk); if ((pb->pb_flags & PBF_DELWRI) && !list_empty(&pb->pb_list)) { ASSERT(pb->pb_flags & _PBF_DELWRI_Q); list_del_init(&pb->pb_list); dequeued = 1; } pb->pb_flags &= ~(PBF_DELWRI|_PBF_DELWRI_Q); - spin_unlock(&pbd_delwrite_lock); + spin_unlock(dwlk); if (dequeued) pagebuf_rele(pb); @@ -1678,21 +1731,22 @@ pagebuf_runall_queues( flush_workqueue(queue); } -/* Defines for pagebuf daemon */ -STATIC struct task_struct *xfsbufd_task; -STATIC int xfsbufd_force_flush; -STATIC int xfsbufd_force_sleep; - STATIC int xfsbufd_wakeup( int priority, gfp_t mask) { - if (xfsbufd_force_sleep) - return 0; - xfsbufd_force_flush = 1; - barrier(); - wake_up_process(xfsbufd_task); + xfs_buftarg_t *btp, *n; + + spin_lock(&xfs_buftarg_lock); + list_for_each_entry_safe(btp, n, &xfs_buftarg_list, bt_list) { + if (test_bit(BT_FORCE_SLEEP, &btp->bt_flags)) + continue; + set_bit(BT_FORCE_FLUSH, &btp->bt_flags); + barrier(); + wake_up_process(btp->bt_task); + } + spin_unlock(&xfs_buftarg_lock); return 0; } @@ -1702,31 +1756,34 @@ xfsbufd( { struct list_head tmp; unsigned long age; - xfs_buftarg_t *target; + xfs_buftarg_t *target = (xfs_buftarg_t *)data; xfs_buf_t *pb, *n; + struct list_head *dwq = &target->bt_delwrite_queue; + spinlock_t *dwlk = &target->bt_delwrite_lock; current->flags |= PF_MEMALLOC; INIT_LIST_HEAD(&tmp); do { if (unlikely(freezing(current))) { - xfsbufd_force_sleep = 1; + set_bit(BT_FORCE_SLEEP, &target->bt_flags); refrigerator(); } else { - xfsbufd_force_sleep = 0; + clear_bit(BT_FORCE_SLEEP, &target->bt_flags); } schedule_timeout_interruptible( xfs_buf_timer_centisecs * msecs_to_jiffies(10)); age = xfs_buf_age_centisecs * msecs_to_jiffies(10); - spin_lock(&pbd_delwrite_lock); - list_for_each_entry_safe(pb, n, &pbd_delwrite_queue, pb_list) { + spin_lock(dwlk); + list_for_each_entry_safe(pb, n, dwq, pb_list) { PB_TRACE(pb, "walkq1", (long)pagebuf_ispin(pb)); ASSERT(pb->pb_flags & PBF_DELWRI); if (!pagebuf_ispin(pb) && !pagebuf_cond_lock(pb)) { - if (!xfsbufd_force_flush && + if (!test_bit(BT_FORCE_FLUSH, + &target->bt_flags) && time_before(jiffies, pb->pb_queuetime + age)) { pagebuf_unlock(pb); @@ -1738,11 +1795,11 @@ xfsbufd( list_move(&pb->pb_list, &tmp); } } - spin_unlock(&pbd_delwrite_lock); + spin_unlock(dwlk); while (!list_empty(&tmp)) { pb = list_entry(tmp.next, xfs_buf_t, pb_list); - target = pb->pb_target; + ASSERT(target == pb->pb_target); list_del_init(&pb->pb_list); pagebuf_iostrategy(pb); @@ -1753,7 +1810,7 @@ xfsbufd( if (as_list_len > 0) purge_addresses(); - xfsbufd_force_flush = 0; + clear_bit(BT_FORCE_FLUSH, &target->bt_flags); } while (!kthread_should_stop()); return 0; @@ -1772,17 +1829,17 @@ xfs_flush_buftarg( struct list_head tmp; xfs_buf_t *pb, *n; int pincount = 0; + struct list_head *dwq = &target->bt_delwrite_queue; + spinlock_t *dwlk = &target->bt_delwrite_lock; pagebuf_runall_queues(xfsdatad_workqueue); pagebuf_runall_queues(xfslogd_workqueue); INIT_LIST_HEAD(&tmp); - spin_lock(&pbd_delwrite_lock); - list_for_each_entry_safe(pb, n, &pbd_delwrite_queue, pb_list) { - - if (pb->pb_target != target) - continue; + spin_lock(dwlk); + list_for_each_entry_safe(pb, n, dwq, pb_list) { + ASSERT(pb->pb_target == target); ASSERT(pb->pb_flags & (PBF_DELWRI|_PBF_DELWRI_Q)); PB_TRACE(pb, "walkq2", (long)pagebuf_ispin(pb)); if (pagebuf_ispin(pb)) { @@ -1792,7 +1849,7 @@ xfs_flush_buftarg( list_move(&pb->pb_list, &tmp); } - spin_unlock(&pbd_delwrite_lock); + spin_unlock(dwlk); /* * Dropped the delayed write list lock, now walk the temporary list @@ -1847,20 +1904,12 @@ pagebuf_init(void) if (!xfsdatad_workqueue) goto out_destroy_xfslogd_workqueue; - xfsbufd_task = kthread_run(xfsbufd, NULL, "xfsbufd"); - if (IS_ERR(xfsbufd_task)) { - error = PTR_ERR(xfsbufd_task); - goto out_destroy_xfsdatad_workqueue; - } - pagebuf_shake = kmem_shake_register(xfsbufd_wakeup); if (!pagebuf_shake) - goto out_stop_xfsbufd; + goto out_destroy_xfsdatad_workqueue; return 0; - out_stop_xfsbufd: - kthread_stop(xfsbufd_task); out_destroy_xfsdatad_workqueue: destroy_workqueue(xfsdatad_workqueue); out_destroy_xfslogd_workqueue: @@ -1878,7 +1927,6 @@ void pagebuf_terminate(void) { kmem_shake_deregister(pagebuf_shake); - kthread_stop(xfsbufd_task); destroy_workqueue(xfsdatad_workqueue); destroy_workqueue(xfslogd_workqueue); kmem_zone_destroy(pagebuf_zone); diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h index 237a35b915d1..f721d47ad4cc 100644 --- a/fs/xfs/linux-2.6/xfs_buf.h +++ b/fs/xfs/linux-2.6/xfs_buf.h @@ -88,6 +88,15 @@ typedef struct xfs_buftarg { uint bt_hashmask; uint bt_hashshift; xfs_bufhash_t *bt_hash; + + /* per device delwri queue */ + struct task_struct *bt_task; + struct list_head bt_list; + struct list_head bt_delwrite_queue; + spinlock_t bt_delwrite_lock; + uint bt_flags; +#define BT_FORCE_SLEEP 1 +#define BT_FORCE_FLUSH 2 } xfs_buftarg_t; /* -- 2.34.1