diff options
| author | Nikolay Borisov <nborisov@suse.com> | 2019-01-03 10:50:05 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2019-02-25 14:13:20 +0100 |
| commit | 420829d8ea13976e084be8cc2531b52f81e6dd02 (patch) | |
| tree | fb1727588149aaece64b5e17b5bca32e6aba11d0 /fs/btrfs/extent-tree.c | |
| parent | 4546d178745d5d5f78352a275cf50caa47528436 (diff) | |
btrfs: Refactor shrink_delalloc
Add a couple of comments regarding the logic flow in shrink_delalloc.
Then, cease using max_reclaim as a temporary variable when calculating
nr_pages. Finally give max_reclaim a more becoming name, which
uneqivocally shows at what this variable really holds. No functional
changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/extent-tree.c')
| -rw-r--r-- | fs/btrfs/extent-tree.c | 33 |
1 files changed, 22 insertions, 11 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index d81035b7ea7d..0225659f2f42 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4741,7 +4741,7 @@ static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim, struct btrfs_space_info *space_info; struct btrfs_trans_handle *trans; u64 delalloc_bytes; - u64 max_reclaim; + u64 async_pages; u64 items; long time_left; unsigned long nr_pages; @@ -4766,25 +4766,36 @@ static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim, loops = 0; while (delalloc_bytes && loops < 3) { - max_reclaim = min(delalloc_bytes, to_reclaim); - nr_pages = max_reclaim >> PAGE_SHIFT; + nr_pages = min(delalloc_bytes, to_reclaim) >> PAGE_SHIFT; + + /* + * Triggers inode writeback for up to nr_pages. This will invoke + * ->writepages callback and trigger delalloc filling + * (btrfs_run_delalloc_range()). + */ btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items); + /* - * We need to wait for the async pages to actually start before - * we do anything. + * We need to wait for the compressed pages to start before + * we continue. */ - max_reclaim = atomic_read(&fs_info->async_delalloc_pages); - if (!max_reclaim) + async_pages = atomic_read(&fs_info->async_delalloc_pages); + if (!async_pages) goto skip_async; - if (max_reclaim <= nr_pages) - max_reclaim = 0; + /* + * Calculate how many compressed pages we want to be written + * before we continue. I.e if there are more async pages than we + * require wait_event will wait until nr_pages are written. + */ + if (async_pages <= nr_pages) + async_pages = 0; else - max_reclaim -= nr_pages; + async_pages -= nr_pages; wait_event(fs_info->async_submit_wait, atomic_read(&fs_info->async_delalloc_pages) <= - (int)max_reclaim); + (int)async_pages); skip_async: spin_lock(&space_info->lock); if (list_empty(&space_info->tickets) && |