From ac06a0cf8a5c5bd58bfa022408361e982f100bcb Mon Sep 17 00:00:00 2001
From: Tejun Heo <htejun@fb.com>
Date: Wed, 18 May 2016 13:50:56 -0700
Subject: core: add support for IOReadIOPSMax and IOWriteIOPSMax

cgroup IO controller supports maximum limits for both bandwidth and IOPS but
systemd resource control currently only supports bandwidth limits.  This patch
adds support for IOReadIOPSMax and IOWriteIOPSMax when unified cgroup hierarchy
is in use.

It isn't difficult to also add BlockIOReadIOPS and BlockIOWriteIOPS for legacy
hierarchies but IO control on legacy hierarchies is half-broken anyway, so
let's leave it alone for now.
---
 man/systemd.resource-control.xml | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

(limited to 'man')

diff --git a/man/systemd.resource-control.xml b/man/systemd.resource-control.xml
index 313a49a959..8a95e1196b 100644
--- a/man/systemd.resource-control.xml
+++ b/man/systemd.resource-control.xml
@@ -336,6 +336,30 @@
         </listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>IOReadIOPSMax=<replaceable>device</replaceable> <replaceable>IOPS</replaceable></varname></term>
+        <term><varname>IOWriteIOPSMax=<replaceable>device</replaceable> <replaceable>IOPS</replaceable></varname></term>
+
+        <listitem>
+          <para>Set the per-device overall block I/O IOs-Per-Second maximum limit for the executed processes, if the
+          unified control group hierarchy is used on the system. This limit is not work-conserving and the executed
+          processes are not allowed to use more even if the device has idle capacity.  Takes a space-separated pair of
+          a file path and an IOPS value to specify the device specific IOPS. The file path may be a path to a block
+          device node, or as any other file in which case the backing block device of the file system of the file is
+          used. If the IOPS is suffixed with K, M, G, or T, the specified IOPS is parsed as KiloIOPS, MegaIOPS,
+          GigaIOPS, or TeraIOPS, respectively, to the base of 1000. (Example:
+          "/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 1K"). This controls the <literal>io.max</literal> control
+          group attributes. Use this option multiple times to set IOPS limits for multiple devices. For details about
+          this control group attribute, see <ulink
+          url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.
+          </para>
+
+          <para>Implies <literal>IOAccounting=true</literal>.</para>
+
+          <para>This setting is supported only if the unified control group hierarchy is used.</para>
+        </listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><varname>BlockIOAccounting=</varname></term>
 
-- 
cgit v1.2.3-54-g00ecf