ldiskfs/kernel_patches/patches/rhel7.6/ext4-preread-gd.patch

   1 commit 85c8f176a6111ecde9c158109989dbd445a0e59a
   2 Author: Andrew Perepechko <andrew.perepechko@seagate.com>
   3 AuthorDate: Sun Apr 30 00:46:35 2017 -0400
   4 Commit: Theodore Ts'o <tytso@mit.edu>
   5 CommitDate: Sun Apr 30 00:46:35 2017 -0400
   6 ext4: preload block group descriptors
   7
   8 With enabled meta_bg option block group descriptors
   9 reading IO is not sequential and requires optimization.
  10
  11 Signed-off-by: Andrew Perepechko <andrew.perepechko@seagate.com>
  12 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  13 Index: fs/ext4/super.c
  14 ===================================================================
  15 --- linux-stage/fs/ext4/super.c.orig
  16 +++ linux-stage.orig/fs/ext4/super.c
  17 @@ -3918,6 +3919,12 @@ static int ext4_fill_super(struct super_
  18
  19         bgl_lock_init(sbi->s_blockgroup_lock);
  20
  21 +       /* Pre-read the descriptors into the buffer cache */
  22 +       for (i = 0; i < db_count; i++) {
  23 +               block = descriptor_loc(sb, logical_sb_block, i);
  24 +               sb_breadahead(sb, block);
  25 +       }
  26 +
  27         for (i = 0; i < db_count; i++) {
  28                 block = descriptor_loc(sb, logical_sb_block, i);
  29                 sbi->s_group_desc[i] = sb_bread(sb, block);