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authorKir Kolyshkin <kolyshkin@gmail.com>2021-06-10 20:07:37 -0700
committerJens Axboe <axboe@kernel.dk>2021-06-16 11:32:03 -0600
commit828615950b5876e75587fdd5e9d1185be9cabba7 (patch)
tree731b09bab247f7a1f968d96744e15a824aa67453
parent37fe403898b2fa5fc9d3616fcda2ee6629318aab (diff)
docs/cgroup-v1/blkio: update for 5.x kernels
Commit bf382fb0bcef4 ("block: remove legacy IO schedulers", Oct 12 2018) removes the CFQ scheduler, together with blkio.weight and blkio.weight_device described in cgroup v1 documentation. Users are supposed to use the BFQ scheduler, which cgroup file for setting weight is blkio.bfq.weight, but there is no way to set per-device weight. Later, commit 795fe54c2a8 per-device weights for BFQ, meaning that blkio.bfq.weight and blkio.bfq.weight_device can be used in a way similar to the old CFQ cgroup interface. Yet, the cgroup v1 docs were never updated. Fix this: - use the new file names; - fix the range for weight (used to be 10..1000, now 1..1000); - link to BFQ scheduler docs. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--Documentation/admin-guide/cgroup-v1/blkio-controller.rst31
1 files changed, 16 insertions, 15 deletions
diff --git a/Documentation/admin-guide/cgroup-v1/blkio-controller.rst b/Documentation/admin-guide/cgroup-v1/blkio-controller.rst
index 8101dcba381d..16253eda192e 100644
--- a/Documentation/admin-guide/cgroup-v1/blkio-controller.rst
+++ b/Documentation/admin-guide/cgroup-v1/blkio-controller.rst
@@ -97,40 +97,41 @@ Details of cgroup files
Proportional weight policy files
--------------------------------
- blkio.weight
+ blkio.bfq.weight
Specifies per cgroup weight. This is default weight of the group
- on all the devices until and unless overridden by per device rule.
- (See blkio.weight_device).
- Currently allowed range of weights is from 10 to 1000.
+ on all the devices until and unless overridden by per device rule
+ (see `blkio.bfq.weight_device` below).
- blkio.weight_device
- One can specify per cgroup per device rules using this interface.
- These rules override the default value of group weight as specified
- by blkio.weight.
+ Currently allowed range of weights is from 1 to 1000. For more details,
+ see Documentation/block/bfq-iosched.rst.
+
+ blkio.bfq.weight_device
+ Specifes per cgroup per device weights, overriding the default group
+ weight. For more details, see Documentation/block/bfq-iosched.rst.
Following is the format::
- # echo dev_maj:dev_minor weight > blkio.weight_device
+ # echo dev_maj:dev_minor weight > blkio.bfq.weight_device
Configure weight=300 on /dev/sdb (8:16) in this cgroup::
- # echo 8:16 300 > blkio.weight_device
- # cat blkio.weight_device
+ # echo 8:16 300 > blkio.bfq.weight_device
+ # cat blkio.bfq.weight_device
dev weight
8:16 300
Configure weight=500 on /dev/sda (8:0) in this cgroup::
- # echo 8:0 500 > blkio.weight_device
- # cat blkio.weight_device
+ # echo 8:0 500 > blkio.bfq.weight_device
+ # cat blkio.bfq.weight_device
dev weight
8:0 500
8:16 300
Remove specific weight for /dev/sda in this cgroup::
- # echo 8:0 0 > blkio.weight_device
- # cat blkio.weight_device
+ # echo 8:0 0 > blkio.bfq.weight_device
+ # cat blkio.bfq.weight_device
dev weight
8:16 300