LU-12988 ldiskfs: skip non-loaded groups at cr=0/1

[fs/lustre-release.git] / ldiskfs / kernel_patches / patches / rhel8 / ext4-mballoc-skip-uninit-groups-cr0.patch

diff --git a/ldiskfs/kernel_patches/patches/rhel8/ext4-mballoc-skip-uninit-groups-cr0.patch b/ldiskfs/kernel_patches/patches/rhel8/ext4-mballoc-skip-uninit-groups-cr0.patch
new file mode 100644 (file)
index 0000000..38925ac
--- /dev/null
+++ b/ldiskfs/kernel_patches/patches/rhel8/ext4-mballoc-skip-uninit-groups-cr0.patch
@@ -0,0 +1,19 @@
+--- linux-4.18/fs/ext4/mballoc.c       2019-11-28 14:55:26.500545920 +0300
++++ linux-4.18/fs/ext4/mballoc.c       2019-11-28 14:53:18.600086008 +0300
+@@ -2060,7 +2060,15 @@ static int ext4_mb_good_group(struct
+ 
+       /* We only do this if the grp has never been initialized */
+       if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
+-              int ret = ext4_mb_init_group(ac->ac_sb, group, GFP_NOFS);
++              int ret;
++
++              /* cr=0/1 is a very optimistic search to find large
++               * good chunks almost for free. if buddy data is
++               * not ready, then this optimization makes no sense */
++
++              if (cr < 2)
++                      return 0;
++              ret = ext4_mb_init_group(ac->ac_sb, group, GFP_NOFS);
+               if (ret)
+                       return ret;
+       }