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author | Chris Mason <chris.mason@oracle.com> | 2008-11-10 13:08:31 -0500 |
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committer | Chris Mason <chris.mason@oracle.com> | 2008-11-10 13:08:31 -0500 |
commit | 240d5d482b69415b92ffce4b8dfca10799c9890b (patch) | |
tree | 16320929e2220a7859d187bf4eda3810d2886bf2 /fs/btrfs | |
parent | b47eda8690a10f4fc01eb7b795078fa3fa57149f (diff) | |
download | blackbird-op-linux-240d5d482b69415b92ffce4b8dfca10799c9890b.tar.gz blackbird-op-linux-240d5d482b69415b92ffce4b8dfca10799c9890b.zip |
Btrfs: tune btrfs unplug functions for a small number of devices
When btrfs unplugs, it tries to find the correct device to unplug
via search through the extent_map tree. This avoids unplugging
a device that doesn't need it, but is a waste of time for filesystems
with a small number of devices.
This patch checks the total number of devices before doing the
search.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r-- | fs/btrfs/disk-io.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 8efc123d222b..1bb54d69fbb2 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1201,6 +1201,16 @@ void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) return; inode = mapping->host; + + /* + * don't do the expensive searching for a small number of + * devices + */ + if (BTRFS_I(inode)->root->fs_info->fs_devices->open_devices <= 2) { + __unplug_io_fn(bdi, page); + return; + } + offset = page_offset(page); em_tree = &BTRFS_I(inode)->extent_tree; |