This Patch added a unique application identifier i.e
app_id knob to blkcg which allows identification of traffic
sources at an individual cgroup based Applications
(ex:virtual machine (VM))level in both host and
fabric infrastructure.
Provided the interface blkcg_get_app_identifier to
grab the app identifier associated with a bio.
Provided the interface blkcg_set_app_identifier to
set the app identifier in a blkcgrp associated with cgroup id
Signed-off-by: Muneendra <muneendra.kumar@xxxxxxxxxxxx>
---
v2:
renamed app_identifier to app_id
removed the sysfs interface blkio.app_identifie under
/sys/fs/cgroup/blkio
Added a new interface blkcg_set_app_identifier
---
block/blk-cgroup.c | 31 +++++++++++++++++++++++++++++++
include/linux/blk-cgroup.h | 22 ++++++++++++++++++++++
2 files changed, 53 insertions(+)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 619a79b51068..672971521010 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -546,6 +546,37 @@ static struct blkcg_gq *blkg_lookup_check(struct blkcg *blkcg,
return __blkg_lookup(blkcg, q, true /* update_hint */);
}
+/*
+ * Sets the app_identifier field associted to blkcg
+ * @buf: application identifier
+ * @id: cgrp id
+ * @len: size of appid
+ */
+int blkcg_set_app_identifier(char *buf, u64 id, size_t len)
+{
+ struct cgroup *cgrp = NULL;
+ struct cgroup_subsys_state *css = NULL;
+ struct blkcg *blkcg = NULL;
+
+ cgrp = cgroup_get_from_kernfs_id(id);
+ if (!cgrp)
+ return -ENOENT;
+
+ css = cgroup_get_e_css(cgrp, &io_cgrp_subsys);
+ if (!css)
+ return -ENOENT;
+
+ blkcg = css_to_blkcg(css);
+ if (!blkcg)
+ return -ENOENT;
+
+ if (len > APPID_LEN)
+ return -EINVAL;
+ strlcpy(blkcg->app_id, buf, len);
+ return 0;
+}
+EXPORT_SYMBOL(blkcg_set_app_identifier);
+
/**
* blkg_conf_prep - parse and prepare for per-blkg config update
* @inputp: input string pointer
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index c8fc9792ac77..5bd3f9f397ac 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -30,6 +30,8 @@
/* Max limits for throttle policy */
#define THROTL_IOPS_MAX UINT_MAX
+#define APPID_LEN 128
+
#ifdef CONFIG_BLK_CGROUP
@@ -55,6 +57,8 @@ struct blkcg {
struct blkcg_policy_data *cpd[BLKCG_MAX_POLS];
struct list_head all_blkcgs_node;
+ char app_id[APPID_LEN];
+
#ifdef CONFIG_CGROUP_WRITEBACK
struct list_head cgwb_list;
#endif
@@ -206,6 +210,24 @@ struct gendisk *blkcg_conf_get_disk(char **inputp);
int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
char *input, struct blkg_conf_ctx *ctx);
void blkg_conf_finish(struct blkg_conf_ctx *ctx);
+int blkcg_set_app_identifier(char *buf, u64 id, size_t len);
+
+/**
+ * blkcg_get_app_identifier - grab the app identifier associated with a bio
+ * @bio: target bio
+ *
+ * This returns the app identifier associated with a bio,
+ * %NULL if not associated.
+ * Callers are expected to either handle %NULL or know association has been
+ * done prior to calling this.
+ */
+static inline char *blkcg_get_app_identifier(struct bio *bio)
+{
+ if (bio && bio->bi_blkg &&
+ strlen(bio->bi_blkg->blkcg->app_id))
+ return bio->bi_blkg->blkcg->app_id;
+ return NULL;
+}
/**
* blkcg_css - find the current css
--
2.26.2
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