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| author | Lucas Stach <dev@lynxeye.de> | 2016-12-07 17:36:36 +1100 |
|---|---|---|
| committer | Dave Chinner <david@fromorbit.com> | 2016-12-07 17:36:36 +1100 |
| commit | 6031e73a5b3f85ec45cac08ef90995b2d3f941c7 (patch) | |
| tree | 7ea855c18580f1b227a8ed8de6379a660c17d5f2 /fs/xfs/xfs_mount.c | |
| parent | cae028df53449905c944603df624ac94bc619661 (diff) | |
| download | linux-6031e73a5b3f85ec45cac08ef90995b2d3f941c7.tar.gz | |
xfs: use rhashtable to track buffer cache
On filesystems with a lot of metadata and in metadata intensive workloads xfs_buf_find() is showing up at the top of the CPU cycles trace. Most of the CPU time is spent on CPU cache misses while traversing the rbtree. As the buffer cache does not need any kind of ordering, but fast lookups a hashtable is the natural data structure to use. The rhashtable infrastructure provides a self-scaling hashtable implementation and allows lookups to proceed while the table is going through a resize operation. This reduces the CPU-time spent for the lookups to 1/3 even for small filesystems with a relatively small number of cached buffers, with possibly much larger gains on higher loaded filesystems. [dchinner: reduce minimum hash size to an acceptable size for large filesystems with many AGs with no active use.] [dchinner: remove stale rbtree asserts.] [dchinner: use xfs_buf_map for compare function argument.] [dchinner: make functions static.] [dchinner: remove redundant comments.] Signed-off-by: Lucas Stach <dev@lynxeye.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs/xfs_mount.c')
| -rw-r--r-- | fs/xfs/xfs_mount.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index b341f10cf481..9b9540db17a6 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -157,6 +157,7 @@ xfs_free_perag( spin_unlock(&mp->m_perag_lock); ASSERT(pag); ASSERT(atomic_read(&pag->pag_ref) == 0); + xfs_buf_hash_destroy(pag); call_rcu(&pag->rcu_head, __xfs_free_perag); } } @@ -212,8 +213,8 @@ xfs_initialize_perag( spin_lock_init(&pag->pag_ici_lock); mutex_init(&pag->pag_ici_reclaim_lock); INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC); - spin_lock_init(&pag->pag_buf_lock); - pag->pag_buf_tree = RB_ROOT; + if (xfs_buf_hash_init(pag)) + goto out_unwind; if (radix_tree_preload(GFP_NOFS)) goto out_unwind; @@ -239,9 +240,11 @@ xfs_initialize_perag( return 0; out_unwind: + xfs_buf_hash_destroy(pag); kmem_free(pag); for (; index > first_initialised; index--) { pag = radix_tree_delete(&mp->m_perag_tree, index); + xfs_buf_hash_destroy(pag); kmem_free(pag); } return error; |