ext4: use bio layer instead of buffer layer in mpage_da_submit_io

Call the block I/O layer directly instad of going through the buffer
layer.  This should give us much better performance and scalability,
as well as lowering our CPU utilization when doing buffered writeback.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 7 insertions, 1 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 8a24e9be7cb0..e13b3c3534d7 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4769,9 +4769,12 @@ static int __init init_ext4_fs(void)
         int err;
 
         ext4_check_flag_values();
-        err = init_ext4_system_zone();
+        err = init_ext4_pageio();
         if (err)
                 return err;
+        err = init_ext4_system_zone();
+        if (err)
+                goto out5;
         ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
         if (!ext4_kset)
                 goto out4;
@@ -4812,6 +4815,8 @@ out3:
         kset_unregister(ext4_kset);
 out4:
         exit_ext4_system_zone();
+out5:
+        exit_ext4_pageio();
         return err;
 }
 
@@ -4827,6 +4832,7 @@ static void __exit exit_ext4_fs(void)
         remove_proc_entry("fs/ext4", NULL);
         kset_unregister(ext4_kset);
         exit_ext4_system_zone();
+        exit_ext4_pageio();
 }
 
 MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");