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authorChris Mason <chris.mason@oracle.com>2008-11-10 19:08:31 +0100
committerChris Mason <chris.mason@oracle.com>2008-11-10 19:08:31 +0100
commit240d5d482b69415b92ffce4b8dfca10799c9890b (patch)
tree16320929e2220a7859d187bf4eda3810d2886bf2
parentBtrfs: Turn off extent state leak debugging (diff)
downloadlinux-240d5d482b69415b92ffce4b8dfca10799c9890b.tar.xz
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 '')
-rw-r--r--fs/btrfs/disk-io.c10
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;