From 53863232ef961778aa414b700ed88a48e8e871e6 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Fri, 15 Aug 2008 15:34:18 -0400 Subject: [PATCH] Btrfs: Lower contention on the csum mutex This takes the csum mutex deeper in the call chain and releases it more often. Signed-off-by: Chris Mason --- fs/btrfs/async-thread.c | 3 ++- fs/btrfs/disk-io.c | 9 ++++++++- fs/btrfs/file-item.c | 16 ++++++++++++---- fs/btrfs/inode.c | 2 -- 4 files changed, 22 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c index 958cd8b5f0d7..2ee301740195 100644 --- a/fs/btrfs/async-thread.c +++ b/fs/btrfs/async-thread.c @@ -48,6 +48,7 @@ struct btrfs_worker_thread { /* number of things on the pending list */ atomic_t num_pending; + unsigned long sequence; /* protects the pending list. */ @@ -242,7 +243,7 @@ static struct btrfs_worker_thread *next_worker(struct btrfs_workers *workers) worker = list_entry(next, struct btrfs_worker_thread, worker_list); atomic_inc(&worker->num_pending); worker->sequence++; - if (worker->sequence % 4 == 0) + if (worker->sequence % workers->idle_thresh == 0) list_move_tail(next, &workers->worker_list); return worker; } diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 1aed1f4616b6..92e14dd9bddb 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1386,7 +1386,14 @@ struct btrfs_root *open_ctree(struct super_block *sb, * devices */ fs_info->submit_workers.idle_thresh = 64; - fs_info->workers.idle_thresh = 32; + + /* fs_info->workers is responsible for checksumming file data + * blocks and metadata. Using a larger idle thresh allows each + * worker thread to operate on things in roughly the order they + * were sent by the writeback daemons, improving overall locality + * of the IO going down the pipe. + */ + fs_info->workers.idle_thresh = 128; btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1); btrfs_init_workers(&fs_info->endio_workers, "endio", diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c index 51aba8cee7ce..9454e0a07c89 100644 --- a/fs/btrfs/file-item.c +++ b/fs/btrfs/file-item.c @@ -321,6 +321,7 @@ again: file_key.offset = offset; btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY); + mutex_lock(&BTRFS_I(inode)->csum_mutex); item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1); if (!IS_ERR(item)) { leaf = path->nodes[0]; @@ -367,7 +368,7 @@ again: ret = btrfs_search_slot(trans, root, &file_key, path, BTRFS_CRC32_SIZE, 1); if (ret < 0) - goto fail; + goto fail_unlock; if (ret == 0) { BUG(); } @@ -411,10 +412,10 @@ insert: ret = btrfs_insert_empty_item(trans, root, path, &file_key, ins_size); if (ret < 0) - goto fail; + goto fail_unlock; if (ret != 0) { WARN_ON(1); - goto fail; + goto fail_unlock; } csum: leaf = path->nodes[0]; @@ -427,6 +428,8 @@ found: item_end = (struct btrfs_csum_item *)((unsigned char *)item_end + btrfs_item_size_nr(leaf, path->slots[0])); eb_token = NULL; + mutex_unlock(&BTRFS_I(inode)->csum_mutex); + cond_resched(); next_sector: if (!eb_token || @@ -467,13 +470,18 @@ next_sector: eb_token = NULL; } btrfs_mark_buffer_dirty(path->nodes[0]); + cond_resched(); if (total_bytes < sums->len) { btrfs_release_path(root, path); goto again; } -fail: +out: btrfs_free_path(path); return ret; + +fail_unlock: + mutex_unlock(&BTRFS_I(inode)->csum_mutex); + goto out; } int btrfs_csum_truncate(struct btrfs_trans_handle *trans, diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 33b990878d84..65107894a5bb 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -415,10 +415,8 @@ static noinline int add_pending_csums(struct btrfs_trans_handle *trans, btrfs_set_trans_block_group(trans, inode); list_for_each(cur, list) { sum = list_entry(cur, struct btrfs_ordered_sum, list); - mutex_lock(&BTRFS_I(inode)->csum_mutex); btrfs_csum_file_blocks(trans, BTRFS_I(inode)->root, inode, sum); - mutex_unlock(&BTRFS_I(inode)->csum_mutex); } return 0; } -- 2.30.2