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| author | Zhao Lei <zhaolei@cn.fujitsu.com> | 2016-01-07 18:38:48 +0800 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2016-02-18 10:27:23 +0100 |
| commit | 2fefd5583f8b86171c898f90cadac7c09ccf9d73 (patch) | |
| tree | 6f5c406bc2dc0ba63c36f3fb19e2462c9f42739c /fs/btrfs | |
| parent | 895a11b868347ca8e287f152f7816862ad4b179d (diff) | |
| download | linux-2fefd5583f8b86171c898f90cadac7c09ccf9d73.tar.gz linux-2fefd5583f8b86171c898f90cadac7c09ccf9d73.tar.bz2 linux-2fefd5583f8b86171c898f90cadac7c09ccf9d73.zip | |
btrfs: reada: limit max works count
Reada creates 2 works for each level of tree recursively.
In case of a tree having many levels, the number of created works
is 2^level_of_tree.
Actually we don't need so many works in parallel, this patch limits
max works to BTRFS_MAX_MIRRORS * 2.
The per-fs works_counter will be also used for btrfs_reada_wait() to
check is there are background workers.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/ctree.h | 3 | ||||
| -rw-r--r-- | fs/btrfs/disk-io.c | 1 | ||||
| -rw-r--r-- | fs/btrfs/reada.c | 9 |
3 files changed, 12 insertions, 1 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index e557e05d2318..e43d987e1c99 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1822,6 +1822,9 @@ struct btrfs_fs_info { spinlock_t reada_lock; struct radix_tree_root reada_tree; + /* readahead works cnt */ + atomic_t reada_works_cnt; + /* Extent buffer radix tree */ spinlock_t buffer_lock; struct radix_tree_root buffer_radix; diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 498156ede32c..5e3ec1fc0ac3 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2603,6 +2603,7 @@ int open_ctree(struct super_block *sb, atomic_set(&fs_info->nr_async_bios, 0); atomic_set(&fs_info->defrag_running, 0); atomic_set(&fs_info->qgroup_op_seq, 0); + atomic_set(&fs_info->reada_works_cnt, 0); atomic64_set(&fs_info->tree_mod_seq, 0); fs_info->sb = sb; fs_info->max_inline = BTRFS_DEFAULT_MAX_INLINE; diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c index 9157d789ae86..e97bc8eb01e2 100644 --- a/fs/btrfs/reada.c +++ b/fs/btrfs/reada.c @@ -748,6 +748,8 @@ static void reada_start_machine_worker(struct btrfs_work *work) set_task_ioprio(current, BTRFS_IOPRIO_READA); __reada_start_machine(fs_info); set_task_ioprio(current, old_ioprio); + + atomic_dec(&fs_info->reada_works_cnt); } static void __reada_start_machine(struct btrfs_fs_info *fs_info) @@ -779,8 +781,12 @@ static void __reada_start_machine(struct btrfs_fs_info *fs_info) * enqueue to workers to finish it. This will distribute the load to * the cores. */ - for (i = 0; i < 2; ++i) + for (i = 0; i < 2; ++i) { reada_start_machine(fs_info); + if (atomic_read(&fs_info->reada_works_cnt) > + BTRFS_MAX_MIRRORS * 2) + break; + } } static void reada_start_machine(struct btrfs_fs_info *fs_info) @@ -797,6 +803,7 @@ static void reada_start_machine(struct btrfs_fs_info *fs_info) rmw->fs_info = fs_info; btrfs_queue_work(fs_info->readahead_workers, &rmw->work); + atomic_inc(&fs_info->reada_works_cnt); } #ifdef DEBUG |