Add interface for per-cgroup target latency. This latency is for 4k
request.
Signed-off-by: Shaohua Li <shli@xxxxxx>
---
block/blk-throttle.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 67 insertions(+)
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index a05d351..ac4d9ea 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -147,6 +147,8 @@ struct throtl_grp {
unsigned long last_check_time;
int upgrade_check_batch;
+
+ u64 latency_target;
/* When did we start a new slice */
unsigned long slice_start[2];
unsigned long slice_end[2];
@@ -463,6 +465,7 @@ static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node)
tg->iops[rw][index] = -1;
}
}
+ /* target latency default 0, eg, always not meet */
return &tg->pd;
}
@@ -1572,6 +1575,64 @@ static ssize_t tg_set_limit(struct kernfs_open_file *of,
return ret ?: nbytes;
}
+static u64 tg_prfill_latency_target(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);
+
+ if (!dname)
+ return 0;
+ if (tg->latency_target == 0)
+ return 0;
+
+ seq_printf(sf, "%s 4k_lat=%llu\n", dname, tg->latency_target);
+ return 0;
+}
+
+static int tg_print_latency_target(struct seq_file *sf, void *v)
+{
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
+ tg_prfill_latency_target, &blkcg_policy_throtl,
+ seq_cft(sf)->private, false);
+ return 0;
+}
+
+static ssize_t tg_set_latency_target(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;
+ int ret = -EINVAL;
+ char tok[27];
+ char *p;
+ u64 val;
+
+ ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx);
+ if (ret)
+ return ret;
+
+ tg = blkg_to_tg(ctx.blkg);
+
+ if (sscanf(ctx.body, "%26s", tok) != 1)
+ goto out_finish;
+
+ p = tok;
+ strsep(&p, "=");
+ if (!p || kstrtou64(p, 10, &val))
+ goto out_finish;
+
+ if (strcmp(tok, "4k_lat"))
+ goto out_finish;
+
+ tg->latency_target = val;
+ ret = 0;
+out_finish:
+ blkg_conf_finish(&ctx);
+ return ret ?: nbytes;
+}
+
static struct cftype throtl_files[] = {
{
.name = "high",
@@ -1587,6 +1648,12 @@ static struct cftype throtl_files[] = {
.write = tg_set_limit,
.private = LIMIT_MAX,
},
+ {
+ .name = "latency_target",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = tg_print_latency_target,
+ .write = tg_set_latency_target,
+ },
{ } /* terminate */
};
--
2.9.3
--
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