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authorTejun Heo <tj@kernel.org>2015-08-18 14:55:34 -0700
committerJens Axboe <axboe@fb.com>2015-08-18 15:49:35 -0700
commit2ee867dcfa2eaef1063b686da55c35878b2da4a2 (patch)
tree7f2babb38e525ce07394042d5dc019e61a46f50c /block/cfq-iosched.c
parentdd165eb3bb4ef16bcdb75417add40633f38c52b8 (diff)
downloadlinux-0-day-2ee867dcfa2eaef1063b686da55c35878b2da4a2.tar.gz
blkcg: implement interface for the unified hierarchy
blkcg interface grew to be the biggest of all controllers and unfortunately most inconsistent too. The interface files are inconsistent with a number of cloes duplicates. Some files have recursive variants while others don't. There's distinction between normal and leaf weights which isn't intuitive and there are a lot of stat knobs which don't make much sense outside of debugging and expose too much implementation details to userland. In the unified hierarchy, everything is always hierarchical and internal nodes can't have tasks rendering the two structural issues twisting the current interface. The interface has to be updated in a significant anyway and this is a good chance to revamp it as a whole. This patch implements blkcg interface for the unified hierarchy. * (from a previous patch) blkcg is identified by "io" instead of "blkio" on the unified hierarchy. Given that the whole interface is updated anyway, the rename shouldn't carry noticeable conversion overhead. * The original interface consisted of 27 files is replaced with the following three files. blkio.stat : per-blkcg stats blkio.weight : per-cgroup and per-cgroup-queue weight settings blkio.max : per-cgroup-queue bps and iops max limits Documentation/cgroups/unified-hierarchy.txt updated accordingly. v2: blkcg_policy->dfl_cftypes wasn't removed on blkcg_policy_unregister() corrupting the cftypes list. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/cfq-iosched.c')
-rw-r--r--block/cfq-iosched.c61
1 files changed, 56 insertions, 5 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 7a72301..97da571 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1740,7 +1740,7 @@ static int cfq_print_leaf_weight(struct seq_file *sf, void *v)
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;
@@ -1753,9 +1753,17 @@ static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of,
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);
@@ -1779,13 +1787,13 @@ out_finish:
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,
@@ -2103,6 +2111,48 @@ static struct cftype cfq_blkcg_legacy_files[] = {
#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)
@@ -4659,6 +4709,7 @@ static struct elevator_type iosched_cfq = {
#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,