ldiskfs/kernel_patches/patches/ext4-mballoc-skip-grps.patch

   1 Index: linux-stage/fs/ext4/mballoc.c
   2 ===================================================================
   3 --- linux-stage.orig/fs/ext4/mballoc.c
   4 +++ linux-stage/fs/ext4/mballoc.c
   5 @@ -2009,9 +2009,13 @@ repeat:
   6                         if (group == EXT4_SB(sb)->s_groups_count)
   7                                 group = 0;
   8
   9 -                       /* quick check to skip empty groups */
  10 +                       /* If there's no chance that this group has a better
  11 +                        * extent, just skip it instead of seeking to read
  12 +                        * block bitmap from disk. Initially ac_b_ex.fe_len = 0,
  13 +                        * so this always skips groups with no free space. */
  14 +
  15                         grp = ext4_get_group_info(sb, group);
  16 -                       if (grp->bb_free == 0)
  17 +                       if (grp->bb_free <= ac->ac_b_ex.fe_len)
  18                                 continue;
  19
  20                         /*
  21 @@ -2780,7 +2784,7 @@ int ext4_mb_init(struct super_block *sb,
  22
  23                 sbi->s_mb_small_req = 256;
  24                 sbi->s_mb_large_req = 1024;
  25 -               sbi->s_mb_group_prealloc = 512;
  26 +               sbi->s_mb_group_prealloc = 256;
  27         } else {
  28                 sbi->s_mb_prealloc_table_size = 3;
  29                 i = sbi->s_mb_prealloc_table_size * sizeof(unsigned long);
  30 @@ -2798,7 +2802,7 @@ int ext4_mb_init(struct super_block *sb,
  31
  32                 sbi->s_mb_small_req = sbi->s_stripe;
  33                 sbi->s_mb_large_req = sbi->s_stripe * 8;
  34 -               sbi->s_mb_group_prealloc = sbi->s_stripe * 4;
  35 +               sbi->s_mb_group_prealloc = sbi->s_stripe;
  36         }
  37
  38         sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);