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Message-Id: <20181112095632.69114-13-paolo.valente@linaro.org>
Date: Mon, 12 Nov 2018 10:56:32 +0100
From: Paolo Valente <paolo.valente@...aro.org>
To: Jens Axboe <axboe@...nel.dk>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Tejun Heo <tj@...nel.org>, Li Zefan <lizefan@...wei.com>,
Angelo Ruocco <angeloruocco90@...il.com>,
Dennis Zhou <dennis@...nel.org>,
Josef Bacik <josef@...icpanda.com>,
Liu Bo <bo.liu@...ux.alibaba.com>,
Bart Van Assche <bvanassche@....org>,
Johannes Weiner <hannes@...xchg.org>
Cc: linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
ulf.hansson@...aro.org, linus.walleij@...aro.org,
broonie@...nel.org, bfq-iosched@...glegroups.com,
oleksandr@...alenko.name, cgroups@...r.kernel.org,
linux-doc@...r.kernel.org, Jonathan Corbet <corbet@....net>,
Paolo Valente <paolo.valente@...aro.org>
Subject: [PATCH 12/12] doc, bfq-iosched: make it consistent with the new cgroup interface
BFQ now shares interface files with CFQ, for the proportional-share
policy. Make documentation consistent with that.
Signed-off-by: Paolo Valente <paolo.valente@...aro.org>
---
Documentation/block/bfq-iosched.txt | 25 ++++++++++++-------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/Documentation/block/bfq-iosched.txt b/Documentation/block/bfq-iosched.txt
index 6d7dd5ab8554..b1faf091266e 100644
--- a/Documentation/block/bfq-iosched.txt
+++ b/Documentation/block/bfq-iosched.txt
@@ -508,12 +508,11 @@ process.
To get proportional sharing of bandwidth with BFQ for a given device,
BFQ must of course be the active scheduler for that device.
-Within each group directory, the names of the files associated with
-BFQ-specific cgroup parameters and stats begin with the "bfq."
-prefix. So, with cgroups-v1 or cgroups-v2, the full prefix for
-BFQ-specific files is "blkio.bfq." or "io.bfq." For example, the group
-parameter to set the weight of a group with BFQ is blkio.bfq.weight
-or io.bfq.weight.
+BFQ shares interface files with CFQ. So, if one reads/writes a file
+provided by the proportional share policy for a group, then the
+associated operation is performed by/on BFQ for each device where BFQ
+is the active scheduler, and by/on CFQ for each device where CFQ is
+the active scheduler.
As for cgroups-v1 (blkio controller), the exact set of stat files
created, and kept up-to-date by bfq, depends on whether
@@ -521,13 +520,13 @@ CONFIG_DEBUG_BLK_CGROUP is set. If it is set, then bfq creates all
the stat files documented in
Documentation/cgroup-v1/blkio-controller.txt. If, instead,
CONFIG_DEBUG_BLK_CGROUP is not set, then bfq creates only the files
-blkio.bfq.io_service_bytes
-blkio.bfq.io_service_bytes_recursive
-blkio.bfq.io_serviced
-blkio.bfq.io_serviced_recursive
+blkio.io_service_bytes
+blkio.io_service_bytes_recursive
+blkio.io_serviced
+blkio.io_serviced_recursive
The value of CONFIG_DEBUG_BLK_CGROUP greatly influences the maximum
-throughput sustainable with bfq, because updating the blkio.bfq.*
+throughput sustainable with BFQ, because updating the blkio.*
stats is rather costly, especially for some of the stats enabled by
CONFIG_DEBUG_BLK_CGROUP.
@@ -536,8 +535,8 @@ Parameters to set
For each group, there is only the following parameter to set.
-weight (namely blkio.bfq.weight or io.bfq-weight): the weight of the
-group inside its parent. Available values: 1..10000 (default 100). The
+weight (namely blkio.weight or io.weight): the weight of the group
+inside its parent. Available values: 1..10000 (default 100). The
linear mapping between ioprio and weights, described at the beginning
of the tunable section, is still valid, but all weights higher than
IOPRIO_BE_NR*10 are mapped to ioprio 0.
--
2.16.1
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