5-3-1. Format
5-3-2. Control Knobs
5-4. Per-Controller Changes
- 5-4-1. blkio
+ 5-4-1. io
5-4-2. cpuset
5-4-3. memory
6. Planned Changes
universal, and there are various other knobs which simply aren't
available for tasks.
-The blkio controller implicitly creates a hidden leaf node for each
+The io controller implicitly creates a hidden leaf node for each
cgroup to host the tasks. The hidden leaf has its own copies of all
the knobs with "leaf_" prefixed. While this allows equivalent control
over internal tasks, it's with serious drawbacks. It always adds an
5-4. Per-Controller Changes
-5-4-1. blkio
+5-4-1. io
-- blk-throttle becomes properly hierarchical.
+- blkio is renamed to io. The interface is overhauled anyway. The
+ new name is more in line with the other two major controllers, cpu
+ and memory, and better suited given that it may be used for cgroup
+ writeback without involving block layer.
+
+- Everything including stat is always hierarchical making separate
+ recursive stat files pointless and, as no internal node can have
+ tasks, leaf weights are meaningless. The operation model is
+ simplified and the interface is overhauled accordingly.
+
+ io.stat
+
+ The stat file. The reported stats are from the point where
+ bio's are issued to request_queue. The stats are counted
+ independent of which policies are enabled. Each line in the
+ file follows the following format. More fields may later be
+ added at the end.
+
+ $MAJ:$MIN rbytes=$RBYTES wbytes=$WBYTES rios=$RIOS wrios=$WIOS
+
+ io.weight
+
+ The weight setting, currently only available and effective if
+ cfq-iosched is in use for the target device. The weight is
+ between 10 and 1000 and defaults to 500. The first line
+ always contains the default weight in the following format to
+ use when per-device setting is missing.
+
+ default $WEIGHT
+
+ Subsequent lines list per-device weights of the following
+ format.
+
+ $MAJ:$MIN $WEIGHT
+
+ Writing "$WEIGHT" or "default $WEIGHT" changes the default
+ setting. Writing "$MAJ:$MIN $WEIGHT" sets per-device weight
+ while "$MAJ:$MIN default" clears it.
+
+ This file is available only on non-root cgroups.
+
+ io.max
+
+ The maximum bandwidth and/or iops setting, only available if
+ blk-throttle is enabled. The file is of the following format.
+
+ $MAJ:$MIN rbps=$RBPS wbps=$WBPS riops=$RIOPS wiops=$WIOPS
+
+ ${R|W}BPS are read/write bytes per second and ${R|W}IOPS are
+ read/write IOs per second. "max" indicates no limit. Writing
+ to the file follows the same format but the individual
+ settings may be ommitted or specified in any order.
+
+ This file is available only on non-root cgroups.
5-4-2. cpuset
}
EXPORT_SYMBOL_GPL(blkg_conf_finish);
+static int blkcg_print_stat(struct seq_file *sf, void *v)
+{
+ struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
+ struct blkcg_gq *blkg;
+
+ rcu_read_lock();
+
+ hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
+ const char *dname;
+ struct blkg_rwstat rwstat;
+ u64 rbytes, wbytes, rios, wios;
+
+ dname = blkg_dev_name(blkg);
+ if (!dname)
+ continue;
+
+ spin_lock_irq(blkg->q->queue_lock);
+
+ rwstat = blkg_rwstat_recursive_sum(blkg, NULL,
+ offsetof(struct blkcg_gq, stat_bytes));
+ rbytes = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_READ]);
+ wbytes = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_WRITE]);
+
+ rwstat = blkg_rwstat_recursive_sum(blkg, NULL,
+ offsetof(struct blkcg_gq, stat_ios));
+ rios = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_READ]);
+ wios = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_WRITE]);
+
+ spin_unlock_irq(blkg->q->queue_lock);
+
+ if (rbytes || wbytes || rios || wios)
+ seq_printf(sf, "%s rbytes=%llu wbytes=%llu rios=%llu wios=%llu\n",
+ dname, rbytes, wbytes, rios, wios);
+ }
+
+ rcu_read_unlock();
+ return 0;
+}
+
+struct cftype blkcg_files[] = {
+ {
+ .name = "stat",
+ .seq_show = blkcg_print_stat,
+ },
+ { } /* terminate */
+};
+
struct cftype blkcg_legacy_files[] = {
{
.name = "reset_stats",
.css_offline = blkcg_css_offline,
.css_free = blkcg_css_free,
.can_attach = blkcg_can_attach,
+ .dfl_cftypes = blkcg_files,
.legacy_cftypes = blkcg_legacy_files,
.legacy_name = "blkio",
#ifdef CONFIG_MEMCG
mutex_unlock(&blkcg_pol_mutex);
/* everything is in place, add intf files for the new policy */
+ if (pol->dfl_cftypes)
+ WARN_ON(cgroup_add_dfl_cftypes(&io_cgrp_subsys,
+ pol->dfl_cftypes));
if (pol->legacy_cftypes)
WARN_ON(cgroup_add_legacy_cftypes(&io_cgrp_subsys,
pol->legacy_cftypes));
goto out_unlock;
/* kill the intf files first */
+ if (pol->dfl_cftypes)
+ cgroup_rm_cftypes(pol->dfl_cftypes);
if (pol->legacy_cftypes)
cgroup_rm_cftypes(pol->legacy_cftypes);
{ } /* terminate */
};
+static u64 tg_prfill_max(struct seq_file *sf, struct blkg_policy_data *pd,
+ int off)
+{
+ struct throtl_grp *tg = pd_to_tg(pd);
+ const char *dname = blkg_dev_name(pd->blkg);
+ char bufs[4][21] = { "max", "max", "max", "max" };
+
+ if (!dname)
+ return 0;
+ if (tg->bps[READ] == -1 && tg->bps[WRITE] == -1 &&
+ tg->iops[READ] == -1 && tg->iops[WRITE] == -1)
+ return 0;
+
+ if (tg->bps[READ] != -1)
+ snprintf(bufs[0], sizeof(bufs[0]), "%llu", tg->bps[READ]);
+ if (tg->bps[WRITE] != -1)
+ snprintf(bufs[1], sizeof(bufs[1]), "%llu", tg->bps[WRITE]);
+ if (tg->iops[READ] != -1)
+ snprintf(bufs[2], sizeof(bufs[2]), "%u", tg->iops[READ]);
+ if (tg->iops[WRITE] != -1)
+ snprintf(bufs[3], sizeof(bufs[3]), "%u", tg->iops[WRITE]);
+
+ seq_printf(sf, "%s rbps=%s wbps=%s riops=%s wiops=%s\n",
+ dname, bufs[0], bufs[1], bufs[2], bufs[3]);
+ return 0;
+}
+
+static int tg_print_max(struct seq_file *sf, void *v)
+{
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_max,
+ &blkcg_policy_throtl, seq_cft(sf)->private, false);
+ return 0;
+}
+
+static ssize_t tg_set_max(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct blkcg *blkcg = css_to_blkcg(of_css(of));
+ struct blkg_conf_ctx ctx;
+ struct throtl_grp *tg;
+ u64 v[4];
+ int ret;
+
+ ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx);
+ if (ret)
+ return ret;
+
+ tg = blkg_to_tg(ctx.blkg);
+
+ v[0] = tg->bps[READ];
+ v[1] = tg->bps[WRITE];
+ v[2] = tg->iops[READ];
+ v[3] = tg->iops[WRITE];
+
+ while (true) {
+ char tok[27]; /* wiops=18446744073709551616 */
+ char *p;
+ u64 val = -1;
+ int len;
+
+ if (sscanf(ctx.body, "%26s%n", tok, &len) != 1)
+ break;
+ if (tok[0] == '\0')
+ break;
+ ctx.body += len;
+
+ ret = -EINVAL;
+ p = tok;
+ strsep(&p, "=");
+ if (!p || (sscanf(p, "%llu", &val) != 1 && strcmp(p, "max")))
+ goto out_finish;
+
+ ret = -ERANGE;
+ if (!val)
+ goto out_finish;
+
+ ret = -EINVAL;
+ if (!strcmp(tok, "rbps"))
+ v[0] = val;
+ else if (!strcmp(tok, "wbps"))
+ v[1] = val;
+ else if (!strcmp(tok, "riops"))
+ v[2] = min_t(u64, val, UINT_MAX);
+ else if (!strcmp(tok, "wiops"))
+ v[3] = min_t(u64, val, UINT_MAX);
+ else
+ goto out_finish;
+ }
+
+ tg->bps[READ] = v[0];
+ tg->bps[WRITE] = v[1];
+ tg->iops[READ] = v[2];
+ tg->iops[WRITE] = v[3];
+
+ tg_conf_updated(tg);
+ ret = 0;
+out_finish:
+ blkg_conf_finish(&ctx);
+ return ret ?: nbytes;
+}
+
+static struct cftype throtl_files[] = {
+ {
+ .name = "max",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = tg_print_max,
+ .write = tg_set_max,
+ },
+ { } /* terminate */
+};
+
static void throtl_shutdown_wq(struct request_queue *q)
{
struct throtl_data *td = q->td;
}
static struct blkcg_policy blkcg_policy_throtl = {
+ .dfl_cftypes = throtl_files,
.legacy_cftypes = throtl_legacy_files,
.pd_alloc_fn = throtl_pd_alloc,
static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off,
- bool is_leaf_weight)
+ bool on_dfl, bool is_leaf_weight)
{
struct blkcg *blkcg = css_to_blkcg(of_css(of));
struct blkg_conf_ctx ctx;
if (ret)
return ret;
- ret = -EINVAL;
- if (sscanf(ctx.body, "%llu", &v) != 1)
+ if (sscanf(ctx.body, "%llu", &v) == 1) {
+ /* require "default" on dfl */
+ ret = -ERANGE;
+ if (!v && on_dfl)
+ goto out_finish;
+ } else if (!strcmp(strim(ctx.body), "default")) {
+ v = 0;
+ } else {
+ ret = -EINVAL;
goto out_finish;
+ }
cfqg = blkg_to_cfqg(ctx.blkg);
cfqgd = blkcg_to_cfqgd(blkcg);
static ssize_t cfqg_set_weight_device(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
- return __cfqg_set_weight_device(of, buf, nbytes, off, false);
+ return __cfqg_set_weight_device(of, buf, nbytes, off, false, false);
}
static ssize_t cfqg_set_leaf_weight_device(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
- return __cfqg_set_weight_device(of, buf, nbytes, off, true);
+ return __cfqg_set_weight_device(of, buf, nbytes, off, false, true);
}
static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val,
#endif /* CONFIG_DEBUG_BLK_CGROUP */
{ } /* terminate */
};
+
+static int cfq_print_weight_on_dfl(struct seq_file *sf, void *v)
+{
+ struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
+ struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
+
+ seq_printf(sf, "default %u\n", cgd->weight);
+ blkcg_print_blkgs(sf, blkcg, cfqg_prfill_weight_device,
+ &blkcg_policy_cfq, 0, false);
+ return 0;
+}
+
+static ssize_t cfq_set_weight_on_dfl(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ char *endp;
+ int ret;
+ u64 v;
+
+ buf = strim(buf);
+
+ /* "WEIGHT" or "default WEIGHT" sets the default weight */
+ v = simple_strtoull(buf, &endp, 0);
+ if (*endp == '\0' || sscanf(buf, "default %llu", &v) == 1) {
+ ret = __cfq_set_weight(of_css(of), v, false);
+ return ret ?: nbytes;
+ }
+
+ /* "MAJ:MIN WEIGHT" */
+ return __cfqg_set_weight_device(of, buf, nbytes, off, true, false);
+}
+
+static struct cftype cfq_blkcg_files[] = {
+ {
+ .name = "weight",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = cfq_print_weight_on_dfl,
+ .write = cfq_set_weight_on_dfl,
+ },
+ { } /* terminate */
+};
+
#else /* GROUP_IOSCHED */
static struct cfq_group *cfq_lookup_cfqg(struct cfq_data *cfqd,
struct blkcg *blkcg)
#ifdef CONFIG_CFQ_GROUP_IOSCHED
static struct blkcg_policy blkcg_policy_cfq = {
+ .dfl_cftypes = cfq_blkcg_files,
.legacy_cftypes = cfq_blkcg_legacy_files,
.cpd_alloc_fn = cfq_cpd_alloc,
struct blkcg_policy {
int plid;
/* cgroup files for the policy */
+ struct cftype *dfl_cftypes;
struct cftype *legacy_cftypes;
/* operations */
projects / karo-tx-linux.git / commitdiff