core: add io controller support on the unified hierarchy

On the unified hierarchy, blkio controller is renamed to io and the interface
is changed significantly.

* blkio.weight and blkio.weight_device are consolidated into io.weight which
  uses the standardized weight range [1, 10000] with 100 as the default value.

* blkio.throttle.{read|write}_{bps|iops}_device are consolidated into io.max.
  Expansion of throttling features is being worked on to support
  work-conserving absolute limits (io.low and io.high).

* All stats are consolidated into io.stats.

This patchset adds support for the new interface.  As the interface has been
revamped and new features are expected to be added, it seems best to treat it
as a separate controller rather than trying to expand the blkio settings
although we might add automatic translation if only blkio settings are
specified.

* io.weight handling is mostly identical to blkio.weight[_device] handling
  except that the weight range is different.

* Both read and write bandwidth settings are consolidated into
  CGroupIODeviceLimit which describes all limits applicable to the device.
  This makes it less painful to add new limits.

* "max" can be used to specify the maximum limit which is equivalent to no
  config for max limits and treated as such.  If a given CGroupIODeviceLimit
  doesn't contain any non-default configs, the config struct is discarded once
  the no limit config is applied to cgroup.

* lookup_blkio_device() is renamed to lookup_block_device().

Signed-off-by: Tejun Heo <htejun@fb.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/src/core/cgroup.h b/src/core/cgroup.h
index 360bbca30f..a533923072 100644
--- a/src/core/cgroup.h
+++ b/src/core/cgroup.h
@@ -26,6 +26,8 @@
 
 typedef struct CGroupContext CGroupContext;
 typedef struct CGroupDeviceAllow CGroupDeviceAllow;
+typedef struct CGroupIODeviceWeight CGroupIODeviceWeight;
+typedef struct CGroupIODeviceLimit CGroupIODeviceLimit;
 typedef struct CGroupBlockIODeviceWeight CGroupBlockIODeviceWeight;
 typedef struct CGroupBlockIODeviceBandwidth CGroupBlockIODeviceBandwidth;
 
@@ -53,6 +55,19 @@ struct CGroupDeviceAllow {
         bool m:1;
 };
 
+struct CGroupIODeviceWeight {
+        LIST_FIELDS(CGroupIODeviceWeight, device_weights);
+        char *path;
+        uint64_t weight;
+};
+
+struct CGroupIODeviceLimit {
+        LIST_FIELDS(CGroupIODeviceLimit, device_limits);
+        char *path;
+        uint64_t rbps_max;
+        uint64_t wbps_max;
+};
+
 struct CGroupBlockIODeviceWeight {
         LIST_FIELDS(CGroupBlockIODeviceWeight, device_weights);
         char *path;
@@ -68,10 +83,18 @@ struct CGroupBlockIODeviceBandwidth {
 
 struct CGroupContext {
         bool cpu_accounting;
+        bool io_accounting;
         bool blockio_accounting;
         bool memory_accounting;
         bool tasks_accounting;
 
+        /* For unified hierarchy */
+        uint64_t io_weight;
+        uint64_t startup_io_weight;
+        LIST_HEAD(CGroupIODeviceWeight, io_device_weights);
+        LIST_HEAD(CGroupIODeviceLimit, io_device_limits);
+
+        /* For legacy hierarchies */
         uint64_t cpu_shares;
         uint64_t startup_cpu_shares;
         usec_t cpu_quota_per_sec_usec;
@@ -86,6 +109,7 @@ struct CGroupContext {
         CGroupDevicePolicy device_policy;
         LIST_HEAD(CGroupDeviceAllow, device_allow);
 
+        /* Common */
         uint64_t tasks_max;
 
         bool delegate;
@@ -102,6 +126,8 @@ void cgroup_context_apply(CGroupContext *c, CGroupMask mask, const char *path, M
 CGroupMask cgroup_context_get_mask(CGroupContext *c);
 
 void cgroup_context_free_device_allow(CGroupContext *c, CGroupDeviceAllow *a);
+void cgroup_context_free_io_device_weight(CGroupContext *c, CGroupIODeviceWeight *w);
+void cgroup_context_free_io_device_limit(CGroupContext *c, CGroupIODeviceLimit *l);
 void cgroup_context_free_blockio_device_weight(CGroupContext *c, CGroupBlockIODeviceWeight *w);
 void cgroup_context_free_blockio_device_bandwidth(CGroupContext *c, CGroupBlockIODeviceBandwidth *b);