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authorTiezhu Yang <kernelpatch@126.com>2016-06-17 04:40:02 +0300
committerJonathan Corbet <corbet@lwn.net>2016-06-23 17:08:36 +0300
commita37376f32687cb4043e72f5f761df5cc52e08073 (patch)
treefa2779cb363661a8ee5add61862dd98539396d0a /Documentation/md.txt
parentc0b8c9a3447ad379869f21884b86ec97c7b8db7a (diff)
downloadlinux-a37376f32687cb4043e72f5f761df5cc52e08073.tar.xz
Documentation: fix wrong value in md.txt
In the current Documentation/md.txt, the lower limit value of stripe_cache_size is 16 and the default value is 128, but when I update kernel to the latest mainline version and RAID5 array is created by mdadm, then execute the following commands, it shows an error and a difference respectively. 1) set stripe_cache_size to 16 [root@localhost ~]# echo 16 > /sys/block/md0/md/stripe_cache_size bash: echo: write error: Invalid argument 2) read the default value of stripe_cache_size [root@localhost ~]# cat /sys/block/md0/md/stripe_cache_size 256 I read drivers/md/raid5.c and find the following related code: 1) in function 'raid5_set_cache_size': if (size <= 16 || size > 32768) return -EINVAL; 2) #define NR_STRIPES 256 So the lower limit value of stripe_cache_size should be 17 and the default value should be 256. Signed-off-by: Tiezhu Yang <kernelpatch@126.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/md.txt')
-rw-r--r--Documentation/md.txt2
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/md.txt b/Documentation/md.txt
index 1a2ada46aaed..d6e2fcf27337 100644
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -602,7 +602,7 @@ These currently include
stripe_cache_size (currently raid5 only)
number of entries in the stripe cache. This is writable, but
- there are upper and lower limits (32768, 16). Default is 128.
+ there are upper and lower limits (32768, 17). Default is 256.
strip_cache_active (currently raid5 only)
number of active entries in the stripe cache
preread_bypass_threshold (currently raid5 only)