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, 143 insertions, 4 deletions

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 25cc6962f9..44106e52ea 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -32,6 +32,7 @@
 #include "special.h"
 #include "string-table.h"
 #include "string-util.h"
+#include "stdio-util.h"
 
 #define CGROUP_CPU_QUOTA_PERIOD_USEC ((usec_t) 100 * USEC_PER_MSEC)
 
@@ -47,6 +48,9 @@ void cgroup_context_init(CGroupContext *c) {
 
         c->memory_limit = (uint64_t) -1;
 
+        c->io_weight = CGROUP_WEIGHT_INVALID;
+        c->startup_io_weight = CGROUP_WEIGHT_INVALID;
+
         c->blockio_weight = CGROUP_BLKIO_WEIGHT_INVALID;
         c->startup_blockio_weight = CGROUP_BLKIO_WEIGHT_INVALID;
 
@@ -62,6 +66,24 @@ void cgroup_context_free_device_allow(CGroupContext *c, CGroupDeviceAllow *a) {
         free(a);
 }
 
+void cgroup_context_free_io_device_weight(CGroupContext *c, CGroupIODeviceWeight *w) {
+        assert(c);
+        assert(w);
+
+        LIST_REMOVE(device_weights, c->io_device_weights, w);
+        free(w->path);
+        free(w);
+}
+
+void cgroup_context_free_io_device_limit(CGroupContext *c, CGroupIODeviceLimit *l) {
+        assert(c);
+        assert(l);
+
+        LIST_REMOVE(device_limits, c->io_device_limits, l);
+        free(l->path);
+        free(l);
+}
+
 void cgroup_context_free_blockio_device_weight(CGroupContext *c, CGroupBlockIODeviceWeight *w) {
         assert(c);
         assert(w);
@@ -83,6 +105,12 @@ void cgroup_context_free_blockio_device_bandwidth(CGroupContext *c, CGroupBlockI
 void cgroup_context_done(CGroupContext *c) {
         assert(c);
 
+        while (c->io_device_weights)
+                cgroup_context_free_io_device_weight(c, c->io_device_weights);
+
+        while (c->io_device_limits)
+                cgroup_context_free_io_device_limit(c, c->io_device_limits);
+
         while (c->blockio_device_weights)
                 cgroup_context_free_blockio_device_weight(c, c->blockio_device_weights);
 
@@ -94,6 +122,8 @@ void cgroup_context_done(CGroupContext *c) {
 }
 
 void cgroup_context_dump(CGroupContext *c, FILE* f, const char *prefix) {
+        CGroupIODeviceLimit *il;
+        CGroupIODeviceWeight *iw;
         CGroupBlockIODeviceBandwidth *b;
         CGroupBlockIODeviceWeight *w;
         CGroupDeviceAllow *a;
@@ -106,12 +136,15 @@ void cgroup_context_dump(CGroupContext *c, FILE* f, const char *prefix) {
 
         fprintf(f,
                 "%sCPUAccounting=%s\n"
+                "%sIOAccounting=%s\n"
                 "%sBlockIOAccounting=%s\n"
                 "%sMemoryAccounting=%s\n"
                 "%sTasksAccounting=%s\n"
                 "%sCPUShares=%" PRIu64 "\n"
                 "%sStartupCPUShares=%" PRIu64 "\n"
                 "%sCPUQuotaPerSecSec=%s\n"
+                "%sIOWeight=%" PRIu64 "\n"
+                "%sStartupIOWeight=%" PRIu64 "\n"
                 "%sBlockIOWeight=%" PRIu64 "\n"
                 "%sStartupBlockIOWeight=%" PRIu64 "\n"
                 "%sMemoryLimit=%" PRIu64 "\n"
@@ -119,12 +152,15 @@ void cgroup_context_dump(CGroupContext *c, FILE* f, const char *prefix) {
                 "%sDevicePolicy=%s\n"
                 "%sDelegate=%s\n",
                 prefix, yes_no(c->cpu_accounting),
+                prefix, yes_no(c->io_accounting),
                 prefix, yes_no(c->blockio_accounting),
                 prefix, yes_no(c->memory_accounting),
                 prefix, yes_no(c->tasks_accounting),
                 prefix, c->cpu_shares,
                 prefix, c->startup_cpu_shares,
                 prefix, format_timespan(u, sizeof(u), c->cpu_quota_per_sec_usec, 1),
+                prefix, c->io_weight,
+                prefix, c->startup_io_weight,
                 prefix, c->blockio_weight,
                 prefix, c->startup_blockio_weight,
                 prefix, c->memory_limit,
@@ -139,6 +175,31 @@ void cgroup_context_dump(CGroupContext *c, FILE* f, const char *prefix) {
                         a->path,
                         a->r ? "r" : "", a->w ? "w" : "", a->m ? "m" : "");
 
+        LIST_FOREACH(device_weights, iw, c->io_device_weights)
+                fprintf(f,
+                        "%sIODeviceWeight=%s %" PRIu64,
+                        prefix,
+                        iw->path,
+                        iw->weight);
+
+        LIST_FOREACH(device_limits, il, c->io_device_limits) {
+                char buf[FORMAT_BYTES_MAX];
+
+                if (il->rbps_max != CGROUP_LIMIT_MAX)
+                        fprintf(f,
+                                "%sIOReadBandwidthMax=%s %s\n",
+                                prefix,
+                                il->path,
+                                format_bytes(buf, sizeof(buf), il->rbps_max));
+
+                if (il->wbps_max != CGROUP_LIMIT_MAX)
+                        fprintf(f,
+                                "%sIOWriteBandwidthMax=%s %s\n",
+                                prefix,
+                                il->path,
+                                format_bytes(buf, sizeof(buf), il->wbps_max));
+        }
+
         LIST_FOREACH(device_weights, w, c->blockio_device_weights)
                 fprintf(f,
                         "%sBlockIODeviceWeight=%s %" PRIu64,
@@ -158,7 +219,7 @@ void cgroup_context_dump(CGroupContext *c, FILE* f, const char *prefix) {
         }
 }
 
-static int lookup_blkio_device(const char *p, dev_t *dev) {
+static int lookup_block_device(const char *p, dev_t *dev) {
         struct stat st;
         int r;
 
@@ -343,6 +404,77 @@ void cgroup_context_apply(CGroupContext *c, CGroupMask mask, const char *path, M
                                        "Failed to set cpu.cfs_quota_us on %s: %m", path);
         }
 
+        if (mask & CGROUP_MASK_IO) {
+                CGroupIODeviceWeight *w;
+                CGroupIODeviceLimit *l, *next;
+
+                if (!is_root) {
+                        char buf[MAX(8+DECIMAL_STR_MAX(uint64_t)+1,
+                                     DECIMAL_STR_MAX(dev_t)*2+2+DECIMAL_STR_MAX(uint64_t)+1)];
+                        uint64_t weight = CGROUP_WEIGHT_DEFAULT;
+
+                        if (IN_SET(state, MANAGER_STARTING, MANAGER_INITIALIZING) &&
+                            c->startup_io_weight != CGROUP_WEIGHT_INVALID)
+                                weight = c->startup_io_weight;
+                        else if (c->io_weight != CGROUP_WEIGHT_INVALID)
+                                weight = c->io_weight;
+
+                        xsprintf(buf, "default %" PRIu64 "\n", weight);
+                        r = cg_set_attribute("io", path, "io.weight", buf);
+                        if (r < 0)
+                                log_full_errno(IN_SET(r, -ENOENT, -EROFS, -EACCES) ? LOG_DEBUG : LOG_WARNING, r,
+                                               "Failed to set io.weight on %s: %m", path);
+
+                        /* FIXME: no way to reset this list */
+                        LIST_FOREACH(device_weights, w, c->io_device_weights) {
+                                dev_t dev;
+
+                                r = lookup_block_device(w->path, &dev);
+                                if (r < 0)
+                                        continue;
+
+                                xsprintf(buf, "%u:%u %" PRIu64 "\n", major(dev), minor(dev), w->weight);
+                                r = cg_set_attribute("io", path, "io.weight", buf);
+                                if (r < 0)
+                                        log_full_errno(IN_SET(r, -ENOENT, -EROFS, -EACCES) ? LOG_DEBUG : LOG_WARNING, r,
+                                                       "Failed to set io.weight on %s: %m", path);
+                        }
+                }
+
+                LIST_FOREACH_SAFE(device_limits, l, next, c->io_device_limits) {
+                        char rbps_buf[DECIMAL_STR_MAX(uint64_t)] = "max";
+                        char wbps_buf[DECIMAL_STR_MAX(uint64_t)] = "max";
+                        char buf[DECIMAL_STR_MAX(dev_t)*2+2+(5+DECIMAL_STR_MAX(uint64_t)+1)*2];
+                        dev_t dev;
+                        unsigned n = 0;
+
+                        r = lookup_block_device(l->path, &dev);
+                        if (r < 0)
+                                continue;
+
+                        if (l->rbps_max != CGROUP_LIMIT_MAX) {
+                                xsprintf(rbps_buf, "%" PRIu64, l->rbps_max);
+                                n++;
+                        }
+
+                        if (l->wbps_max != CGROUP_LIMIT_MAX) {
+                                xsprintf(wbps_buf, "%" PRIu64, l->wbps_max);
+                                n++;
+                        }
+
+                        xsprintf(buf, "%u:%u rbps=%s wbps=%s\n", major(dev), minor(dev), rbps_buf, wbps_buf);
+                        r = cg_set_attribute("io", path, "io.max", buf);
+                        if (r < 0)
+                                log_full_errno(IN_SET(r, -ENOENT, -EROFS, -EACCES) ? LOG_DEBUG : LOG_WARNING, r,
+                                               "Failed to set io.max on %s: %m", path);
+
+                        /* If @l contained no config, we just cleared the kernel
+                           counterpart too. No reason to keep @l around. */
+                        if (!n)
+                                cgroup_context_free_io_device_limit(c, l);
+                }
+        }
+
         if (mask & CGROUP_MASK_BLKIO) {
                 char buf[MAX(DECIMAL_STR_MAX(uint64_t)+1,
                              DECIMAL_STR_MAX(dev_t)*2+2+DECIMAL_STR_MAX(uint64_t)+1)];
@@ -362,7 +494,7 @@ void cgroup_context_apply(CGroupContext *c, CGroupMask mask, const char *path, M
                         LIST_FOREACH(device_weights, w, c->blockio_device_weights) {
                                 dev_t dev;
 
-                                r = lookup_blkio_device(w->path, &dev);
+                                r = lookup_block_device(w->path, &dev);
                                 if (r < 0)
                                         continue;
 
@@ -379,7 +511,7 @@ void cgroup_context_apply(CGroupContext *c, CGroupMask mask, const char *path, M
                         const char *a;
                         dev_t dev;
 
-                        r = lookup_blkio_device(b->path, &dev);
+                        r = lookup_block_device(b->path, &dev);
                         if (r < 0)
                                 continue;
 
@@ -506,6 +638,13 @@ CGroupMask cgroup_context_get_mask(CGroupContext *c) {
             c->cpu_quota_per_sec_usec != USEC_INFINITY)
                 mask |= CGROUP_MASK_CPUACCT | CGROUP_MASK_CPU;
 
+        if (c->io_accounting ||
+            c->io_weight != CGROUP_WEIGHT_INVALID ||
+            c->startup_io_weight != CGROUP_WEIGHT_INVALID ||
+            c->io_device_weights ||
+            c->io_device_limits)
+                mask |= CGROUP_MASK_IO;
+
         if (c->blockio_accounting ||
             c->blockio_weight != CGROUP_BLKIO_WEIGHT_INVALID ||
             c->startup_blockio_weight != CGROUP_BLKIO_WEIGHT_INVALID ||
@@ -1608,7 +1747,7 @@ void manager_invalidate_startup_units(Manager *m) {
         assert(m);
 
         SET_FOREACH(u, m->startup_units, i)
-                unit_invalidate_cgroup(u, CGROUP_MASK_CPU|CGROUP_MASK_BLKIO);
+                unit_invalidate_cgroup(u, CGROUP_MASK_CPU|CGROUP_MASK_IO|CGROUP_MASK_BLKIO);
 }
 
 static const char* const cgroup_device_policy_table[_CGROUP_DEVICE_POLICY_MAX] = {