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, 193 insertions, 0 deletions

diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index 1a8c03904c..9d7329e924 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -2904,6 +2904,196 @@ int config_parse_device_allow(
         return 0;
 }
 
+int config_parse_io_weight(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        uint64_t *weight = data;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+
+        r = cg_weight_parse(rvalue, weight);
+        if (r < 0) {
+                log_syntax(unit, LOG_ERR, filename, line, r, "IO weight '%s' invalid. Ignoring.", rvalue);
+                return 0;
+        }
+
+        return 0;
+}
+
+int config_parse_io_device_weight(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        _cleanup_free_ char *path = NULL;
+        CGroupIODeviceWeight *w;
+        CGroupContext *c = data;
+        const char *weight;
+        uint64_t u;
+        size_t n;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+
+        if (isempty(rvalue)) {
+                while (c->io_device_weights)
+                        cgroup_context_free_io_device_weight(c, c->io_device_weights);
+
+                return 0;
+        }
+
+        n = strcspn(rvalue, WHITESPACE);
+        weight = rvalue + n;
+        weight += strspn(weight, WHITESPACE);
+
+        if (isempty(weight)) {
+                log_syntax(unit, LOG_ERR, filename, line, 0, "Expected block device and device weight. Ignoring.");
+                return 0;
+        }
+
+        path = strndup(rvalue, n);
+        if (!path)
+                return log_oom();
+
+        if (!path_startswith(path, "/dev")) {
+                log_syntax(unit, LOG_ERR, filename, line, 0, "Invalid device node path '%s'. Ignoring.", path);
+                return 0;
+        }
+
+        r = cg_weight_parse(weight, &u);
+        if (r < 0) {
+                log_syntax(unit, LOG_ERR, filename, line, r, "IO weight '%s' invalid. Ignoring.", weight);
+                return 0;
+        }
+
+        assert(u != CGROUP_WEIGHT_INVALID);
+
+        w = new0(CGroupIODeviceWeight, 1);
+        if (!w)
+                return log_oom();
+
+        w->path = path;
+        path = NULL;
+
+        w->weight = u;
+
+        LIST_PREPEND(device_weights, c->io_device_weights, w);
+        return 0;
+}
+
+int config_parse_io_limit(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        _cleanup_free_ char *path = NULL;
+        CGroupIODeviceLimit *l = NULL, *t;
+        CGroupContext *c = data;
+        const char *limit;
+        uint64_t num;
+        bool read;
+        size_t n;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+
+        read = streq("IOReadBandwidthMax", lvalue);
+
+        if (isempty(rvalue)) {
+                LIST_FOREACH(device_limits, l, c->io_device_limits)
+                        if (read)
+                                l->rbps_max = CGROUP_LIMIT_MAX;
+                        else
+                                l->wbps_max = CGROUP_LIMIT_MAX;
+                return 0;
+        }
+
+        n = strcspn(rvalue, WHITESPACE);
+        limit = rvalue + n;
+        limit += strspn(limit, WHITESPACE);
+
+        if (!*limit) {
+                log_syntax(unit, LOG_ERR, filename, line, 0, "Expected space separated pair of device node and bandwidth. Ignoring.");
+                return 0;
+        }
+
+        path = strndup(rvalue, n);
+        if (!path)
+                return log_oom();
+
+        if (!path_startswith(path, "/dev")) {
+                log_syntax(unit, LOG_ERR, filename, line, 0, "Invalid device node path '%s'. Ignoring.", path);
+                return 0;
+        }
+
+        if (streq("max", limit)) {
+                num = CGROUP_LIMIT_MAX;
+        } else {
+                r = parse_size(limit, 1000, &num);
+                if (r < 0 || num <= 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "IO Limit '%s' invalid. Ignoring.", rvalue);
+                        return 0;
+                }
+        }
+
+        LIST_FOREACH(device_limits, t, c->io_device_limits) {
+                if (path_equal(path, t->path)) {
+                        l = t;
+                        break;
+                }
+        }
+
+        if (!l) {
+                l = new0(CGroupIODeviceLimit, 1);
+                if (!l)
+                        return log_oom();
+
+                l->path = path;
+                path = NULL;
+                l->rbps_max = CGROUP_LIMIT_MAX;
+                l->wbps_max = CGROUP_LIMIT_MAX;
+
+                LIST_PREPEND(device_limits, c->io_device_limits, l);
+        }
+
+        if (read)
+                l->rbps_max = num;
+        else
+                l->wbps_max = num;
+
+        return 0;
+}
+
 int config_parse_blockio_weight(
                 const char *unit,
                 const char *filename,
@@ -3824,6 +4014,9 @@ void unit_dump_config_items(FILE *f) {
                 { config_parse_memory_limit,          "LIMIT" },
                 { config_parse_device_allow,          "DEVICE" },
                 { config_parse_device_policy,         "POLICY" },
+                { config_parse_io_limit,              "LIMIT" },
+                { config_parse_io_weight,             "WEIGHT" },
+                { config_parse_io_device_weight,      "DEVICEWEIGHT" },
                 { config_parse_blockio_bandwidth,     "BANDWIDTH" },
                 { config_parse_blockio_weight,        "WEIGHT" },
                 { config_parse_blockio_device_weight, "DEVICEWEIGHT" },