From e80dfa19976b884db1ac2bc5d7d6ca0a4027bd1c Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Wed, 28 Aug 2013 10:18:05 +1000 Subject: [PATCH] xfs: convert buftarg LRU to generic code MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Convert the buftarg LRU to use the new generic LRU list and take advantage of the functionality it supplies to make the buffer cache shrinker node aware. Signed-off-by: Glauber Costa Signed-off-by: Dave Chinner Cc: "Theodore Ts'o" Cc: Adrian Hunter Cc: Al Viro Cc: Artem Bityutskiy Cc: Arve Hjønnevåg Cc: Carlos Maiolino Cc: Christoph Hellwig Cc: Chuck Lever Cc: Daniel Vetter Cc: David Rientjes Cc: Gleb Natapov Cc: Greg Thelen Cc: J. Bruce Fields Cc: Jan Kara Cc: Jerome Glisse Cc: John Stultz Cc: KAMEZAWA Hiroyuki Cc: Kent Overstreet Cc: Kirill A. Shutemov Cc: Marcelo Tosatti Cc: Mel Gorman Cc: Steven Whitehouse Cc: Thomas Hellstrom Cc: Trond Myklebust Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- fs/xfs/xfs_buf.c | 170 ++++++++++++++++++++++------------------------- fs/xfs/xfs_buf.h | 5 +- 2 files changed, 82 insertions(+), 93 deletions(-) diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index c06823fe10d3..665ff792d665 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -86,20 +86,14 @@ xfs_buf_vmap_len( * The LRU takes a new reference to the buffer so that it will only be freed * once the shrinker takes the buffer off the LRU. */ -STATIC void +static void xfs_buf_lru_add( struct xfs_buf *bp) { - struct xfs_buftarg *btp = bp->b_target; - - spin_lock(&btp->bt_lru_lock); - if (list_empty(&bp->b_lru)) { - atomic_inc(&bp->b_hold); - list_add_tail(&bp->b_lru, &btp->bt_lru); - btp->bt_lru_nr++; + if (list_lru_add(&bp->b_target->bt_lru, &bp->b_lru)) { bp->b_lru_flags &= ~_XBF_LRU_DISPOSE; + atomic_inc(&bp->b_hold); } - spin_unlock(&btp->bt_lru_lock); } /* @@ -108,24 +102,13 @@ xfs_buf_lru_add( * The unlocked check is safe here because it only occurs when there are not * b_lru_ref counts left on the inode under the pag->pag_buf_lock. it is there * to optimise the shrinker removing the buffer from the LRU and calling - * xfs_buf_free(). i.e. it removes an unnecessary round trip on the - * bt_lru_lock. + * xfs_buf_free(). */ -STATIC void +static void xfs_buf_lru_del( struct xfs_buf *bp) { - struct xfs_buftarg *btp = bp->b_target; - - if (list_empty(&bp->b_lru)) - return; - - spin_lock(&btp->bt_lru_lock); - if (!list_empty(&bp->b_lru)) { - list_del_init(&bp->b_lru); - btp->bt_lru_nr--; - } - spin_unlock(&btp->bt_lru_lock); + list_lru_del(&bp->b_target->bt_lru, &bp->b_lru); } /* @@ -152,18 +135,10 @@ xfs_buf_stale( bp->b_flags &= ~_XBF_DELWRI_Q; atomic_set(&(bp)->b_lru_ref, 0); - if (!list_empty(&bp->b_lru)) { - struct xfs_buftarg *btp = bp->b_target; - - spin_lock(&btp->bt_lru_lock); - if (!list_empty(&bp->b_lru) && - !(bp->b_lru_flags & _XBF_LRU_DISPOSE)) { - list_del_init(&bp->b_lru); - btp->bt_lru_nr--; - atomic_dec(&bp->b_hold); - } - spin_unlock(&btp->bt_lru_lock); - } + if (!(bp->b_lru_flags & _XBF_LRU_DISPOSE) && + (list_lru_del(&bp->b_target->bt_lru, &bp->b_lru))) + atomic_dec(&bp->b_hold); + ASSERT(atomic_read(&bp->b_hold) >= 1); } @@ -1502,83 +1477,97 @@ xfs_buf_iomove( * returned. These buffers will have an elevated hold count, so wait on those * while freeing all the buffers only held by the LRU. */ -void -xfs_wait_buftarg( - struct xfs_buftarg *btp) +static enum lru_status +xfs_buftarg_wait_rele( + struct list_head *item, + spinlock_t *lru_lock, + void *arg) + { - struct xfs_buf *bp; + struct xfs_buf *bp = container_of(item, struct xfs_buf, b_lru); -restart: - spin_lock(&btp->bt_lru_lock); - while (!list_empty(&btp->bt_lru)) { - bp = list_first_entry(&btp->bt_lru, struct xfs_buf, b_lru); - if (atomic_read(&bp->b_hold) > 1) { - trace_xfs_buf_wait_buftarg(bp, _RET_IP_); - list_move_tail(&bp->b_lru, &btp->bt_lru); - spin_unlock(&btp->bt_lru_lock); - delay(100); - goto restart; - } + if (atomic_read(&bp->b_hold) > 1) { + /* need to wait */ + trace_xfs_buf_wait_buftarg(bp, _RET_IP_); + spin_unlock(lru_lock); + delay(100); + } else { /* * clear the LRU reference count so the buffer doesn't get * ignored in xfs_buf_rele(). */ atomic_set(&bp->b_lru_ref, 0); - spin_unlock(&btp->bt_lru_lock); + spin_unlock(lru_lock); xfs_buf_rele(bp); - spin_lock(&btp->bt_lru_lock); } - spin_unlock(&btp->bt_lru_lock); + + spin_lock(lru_lock); + return LRU_RETRY; } -int -xfs_buftarg_shrink( +void +xfs_wait_buftarg( + struct xfs_buftarg *btp) +{ + while (list_lru_count(&btp->bt_lru)) + list_lru_walk(&btp->bt_lru, xfs_buftarg_wait_rele, + NULL, LONG_MAX); +} + +static enum lru_status +xfs_buftarg_isolate( + struct list_head *item, + spinlock_t *lru_lock, + void *arg) +{ + struct xfs_buf *bp = container_of(item, struct xfs_buf, b_lru); + struct list_head *dispose = arg; + + /* + * Decrement the b_lru_ref count unless the value is already + * zero. If the value is already zero, we need to reclaim the + * buffer, otherwise it gets another trip through the LRU. + */ + if (!atomic_add_unless(&bp->b_lru_ref, -1, 0)) + return LRU_ROTATE; + + bp->b_lru_flags |= _XBF_LRU_DISPOSE; + list_move(item, dispose); + return LRU_REMOVED; +} + +static long +xfs_buftarg_shrink_scan( struct shrinker *shrink, struct shrink_control *sc) { struct xfs_buftarg *btp = container_of(shrink, struct xfs_buftarg, bt_shrinker); - struct xfs_buf *bp; - int nr_to_scan = sc->nr_to_scan; LIST_HEAD(dispose); + long freed; + unsigned long nr_to_scan = sc->nr_to_scan; - if (!nr_to_scan) - return btp->bt_lru_nr; - - spin_lock(&btp->bt_lru_lock); - while (!list_empty(&btp->bt_lru)) { - if (nr_to_scan-- <= 0) - break; - - bp = list_first_entry(&btp->bt_lru, struct xfs_buf, b_lru); - - /* - * Decrement the b_lru_ref count unless the value is already - * zero. If the value is already zero, we need to reclaim the - * buffer, otherwise it gets another trip through the LRU. - */ - if (!atomic_add_unless(&bp->b_lru_ref, -1, 0)) { - list_move_tail(&bp->b_lru, &btp->bt_lru); - continue; - } - - /* - * remove the buffer from the LRU now to avoid needing another - * lock round trip inside xfs_buf_rele(). - */ - list_move(&bp->b_lru, &dispose); - btp->bt_lru_nr--; - bp->b_lru_flags |= _XBF_LRU_DISPOSE; - } - spin_unlock(&btp->bt_lru_lock); + freed = list_lru_walk_node(&btp->bt_lru, sc->nid, xfs_buftarg_isolate, + &dispose, &nr_to_scan); while (!list_empty(&dispose)) { + struct xfs_buf *bp; bp = list_first_entry(&dispose, struct xfs_buf, b_lru); list_del_init(&bp->b_lru); xfs_buf_rele(bp); } - return btp->bt_lru_nr; + return freed; +} + +static long +xfs_buftarg_shrink_count( + struct shrinker *shrink, + struct shrink_control *sc) +{ + struct xfs_buftarg *btp = container_of(shrink, + struct xfs_buftarg, bt_shrinker); + return list_lru_count_node(&btp->bt_lru, sc->nid); } void @@ -1660,12 +1649,13 @@ xfs_alloc_buftarg( if (!btp->bt_bdi) goto error; - INIT_LIST_HEAD(&btp->bt_lru); - spin_lock_init(&btp->bt_lru_lock); + list_lru_init(&btp->bt_lru); if (xfs_setsize_buftarg_early(btp, bdev)) goto error; - btp->bt_shrinker.shrink = xfs_buftarg_shrink; + btp->bt_shrinker.count_objects = xfs_buftarg_shrink_count; + btp->bt_shrinker.scan_objects = xfs_buftarg_shrink_scan; btp->bt_shrinker.seeks = DEFAULT_SEEKS; + btp->bt_shrinker.flags = SHRINKER_NUMA_AWARE; register_shrinker(&btp->bt_shrinker); return btp; diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h index 433a12ed7b17..5ec7d35a77ea 100644 --- a/fs/xfs/xfs_buf.h +++ b/fs/xfs/xfs_buf.h @@ -25,6 +25,7 @@ #include #include #include +#include /* * Base types @@ -92,9 +93,7 @@ typedef struct xfs_buftarg { /* LRU control structures */ struct shrinker bt_shrinker; - struct list_head bt_lru; - spinlock_t bt_lru_lock; - unsigned int bt_lru_nr; + struct list_lru bt_lru; } xfs_buftarg_t; struct xfs_buf; -- 2.20.1