diff mbox series

[v4,02/19] blkcg: Added a app identifier support for blkcg

Message ID 1604895845-2587-3-git-send-email-muneendra.kumar@broadcom.com
State New
Headers show
Series [v4,01/19] cgroup: Added cgroup_get_from_kernfs_id | expand

Commit Message

Muneendra Kumar Nov. 9, 2020, 4:23 a.m. UTC
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_fc_appid to
grab the app identifier associated with a bio.

Provided the interface blkcg_set_fc_appid to
set the app identifier in a blkcgrp associated with cgroup id

Added a new config BLK_CGROUP_FC_APPID and moved the changes
under this config

Signed-off-by: Muneendra <muneendra.kumar@broadcom.com>

---
v4:
No change

v3:
Renamed the functions and app_id to more specific

Addressed the reference leaks in blkcg_set_app_identifier

Added a new config BLK_CGROUP_FC_APPID and moved the changes
under this config

Added blkcg_get_fc_appid,blkcg_set_fc_appid as inline functions

v2:
renamed app_identifier to app_id
removed the  sysfs interface blkio.app_identifie under
---
 block/Kconfig              |  9 ++++++
 include/linux/blk-cgroup.h | 65 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+)

Comments

Hannes Reinecke Nov. 16, 2020, 7:31 a.m. UTC | #1
On 11/9/20 5:23 AM, Muneendra wrote:
> 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_fc_appid to

> grab the app identifier associated with a bio.

> 

> Provided the interface blkcg_set_fc_appid to

> set the app identifier in a blkcgrp associated with cgroup id

> 

> Added a new config BLK_CGROUP_FC_APPID and moved the changes

> under this config

> 

> Signed-off-by: Muneendra <muneendra.kumar@broadcom.com>

> 

> ---

> v4:

> No change

> 

> v3:

> Renamed the functions and app_id to more specific

> 

> Addressed the reference leaks in blkcg_set_app_identifier

> 

> Added a new config BLK_CGROUP_FC_APPID and moved the changes

> under this config

> 

> Added blkcg_get_fc_appid,blkcg_set_fc_appid as inline functions

> 

> v2:

> renamed app_identifier to app_id

> removed the  sysfs interface blkio.app_identifie under

> ---

>   block/Kconfig              |  9 ++++++

>   include/linux/blk-cgroup.h | 65 ++++++++++++++++++++++++++++++++++++++

>   2 files changed, 74 insertions(+)

> 

> diff --git a/block/Kconfig b/block/Kconfig

> index bbad5e8bbffe..ed22df654ce5 100644

> --- a/block/Kconfig

> +++ b/block/Kconfig

> @@ -144,6 +144,15 @@ config BLK_CGROUP_IOLATENCY

>   

>   	Note, this is an experimental interface and could be changed someday.

>   

> +config BLK_CGROUP_FC_APPID

> +	bool "Enable support to track FC io Traffic across cgroup applications"

> +	depends on BLK_CGROUP=y

> +	help

> +	Enabling this option enables the support to track FC io traffic across

> +	cgroup applications.It enables the Fabric and the storage targets to

> +	identify, monitor, and handle FC traffic based on vm tags by inserting

> +	application specific identification into the FC frame.

> +


Please replace 'io' with 'I/O'.

>   config BLK_CGROUP_IOCOST

>   	bool "Enable support for cost model based cgroup IO controller"

>   	depends on BLK_CGROUP=y

> diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h

> index c8fc9792ac77..00ea1cfa3420 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 +57,9 @@ struct blkcg {

>   	struct blkcg_policy_data	*cpd[BLKCG_MAX_POLS];

>   

>   	struct list_head		all_blkcgs_node;

> +#ifdef CONFIG_BLK_CGROUP_FC_APPID

> +	char                            fc_app_id[APPID_LEN];

> +#endif

>   #ifdef CONFIG_CGROUP_WRITEBACK

>   	struct list_head		cgwb_list;

>   #endif


If this is an UUID, wouldn't it be better to use 'uuid_t' here?

> @@ -660,4 +665,64 @@ static inline void blk_cgroup_bio_start(struct bio *bio) { }

>   

>   #endif	/* CONFIG_BLOCK */

>   #endif	/* CONFIG_BLK_CGROUP */

> +

> +#ifdef CONFIG_BLK_CGROUP_FC_APPID

> +/*

> + * Sets the fc_app_id field associted to blkcg

> + * @buf: application identifier

> + * @id: cgrp id

> + * @len: size of appid

> + */

> +static inline int blkcg_set_fc_appid(char *buf, u64 id, size_t len)

> +{

> +	struct cgroup *cgrp = NULL;

> +	struct cgroup_subsys_state *css = NULL;

> +	struct blkcg *blkcg = NULL;

> +	int ret  = 0;

> +

> +	cgrp = cgroup_get_from_kernfs_id(id);

> +	if (!cgrp)

> +		return -ENOENT;

> +	css = cgroup_get_e_css(cgrp, &io_cgrp_subsys);

> +	if (!css) {

> +		ret = -ENOENT;

> +		goto out_cgrp_put;

> +	}

> +	blkcg = css_to_blkcg(css);

> +	if (!blkcg) {

> +		ret = -ENOENT;

> +		goto out_put;

> +	}

> +	if (len > APPID_LEN) {

> +		ret = -EINVAL;

> +		goto out_put;

> +	}

> +	strlcpy(blkcg->fc_app_id, buf, len);


String or UUID?
And will it be NULL-terminated?
Wouldn't it be better to use 'memcpy' here?
And it is NULL terminated: what happens if the user sets a 128-byte 
string? IE shouldn't the app_id be 129 bytes long if it's assumed to be 
NULL-terminated?

> +out_put:

> +	css_put(css);

> +out_cgrp_put:

> +	cgroup_put(cgrp);

> +	return ret;

> +}

> +

> +/**

> + * blkcg_get_fc_appid - 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_fc_appid(struct bio *bio)

> +{

> +	if (bio && bio->bi_blkg &&

> +			strlen(bio->bi_blkg->blkcg->fc_app_id))

> +		return bio->bi_blkg->blkcg->fc_app_id;

> +	return NULL;

> +}


Same question as above: Is the string NULL terminated or not?
And if not, how do you specify the length of the 'app_id' variable?

> +#else

> +static inline int blkcg_set_fc_appid(char *buf, u64 id, size_t len) { return -EINVAL; }

> +static inline char *blkcg_get_fc_appid(struct bio *bio) { return NULL; }

> +#endif /*CONFIG_BLK_CGROUP_FC_APPID*/

>   #endif	/* _BLK_CGROUP_H */

> 


Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
Muneendra Kumar Nov. 18, 2020, 9:39 a.m. UTC | #2
Hi Hannes,
Thanks for the review.

> +		ret = -EINVAL;

> +		goto out_put;

> +	}

> +	strlcpy(blkcg->fc_app_id, buf, len);


>String or UUID?

>And will it be NULL-terminated?

>Wouldn't it be better to use 'memcpy' here?

>And it is NULL terminated: what happens if the user sets a 128-byte string?

>IE shouldn't the app_id be 129 bytes long if it's assumed to be

>NULL-terminated?

[Muneendra]It is a string and it is NULL terminated.
Agreed it should be 129 bytes long.

Regards,
Muneendra.
diff mbox series

Patch

diff --git a/block/Kconfig b/block/Kconfig
index bbad5e8bbffe..ed22df654ce5 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -144,6 +144,15 @@  config BLK_CGROUP_IOLATENCY
 
 	Note, this is an experimental interface and could be changed someday.
 
+config BLK_CGROUP_FC_APPID
+	bool "Enable support to track FC io Traffic across cgroup applications"
+	depends on BLK_CGROUP=y
+	help
+	Enabling this option enables the support to track FC io traffic across
+	cgroup applications.It enables the Fabric and the storage targets to
+	identify, monitor, and handle FC traffic based on vm tags by inserting
+	application specific identification into the FC frame.
+
 config BLK_CGROUP_IOCOST
 	bool "Enable support for cost model based cgroup IO controller"
 	depends on BLK_CGROUP=y
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index c8fc9792ac77..00ea1cfa3420 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 +57,9 @@  struct blkcg {
 	struct blkcg_policy_data	*cpd[BLKCG_MAX_POLS];
 
 	struct list_head		all_blkcgs_node;
+#ifdef CONFIG_BLK_CGROUP_FC_APPID
+	char                            fc_app_id[APPID_LEN];
+#endif
 #ifdef CONFIG_CGROUP_WRITEBACK
 	struct list_head		cgwb_list;
 #endif
@@ -660,4 +665,64 @@  static inline void blk_cgroup_bio_start(struct bio *bio) { }
 
 #endif	/* CONFIG_BLOCK */
 #endif	/* CONFIG_BLK_CGROUP */
+
+#ifdef CONFIG_BLK_CGROUP_FC_APPID
+/*
+ * Sets the fc_app_id field associted to blkcg
+ * @buf: application identifier
+ * @id: cgrp id
+ * @len: size of appid
+ */
+static inline int blkcg_set_fc_appid(char *buf, u64 id, size_t len)
+{
+	struct cgroup *cgrp = NULL;
+	struct cgroup_subsys_state *css = NULL;
+	struct blkcg *blkcg = NULL;
+	int ret  = 0;
+
+	cgrp = cgroup_get_from_kernfs_id(id);
+	if (!cgrp)
+		return -ENOENT;
+	css = cgroup_get_e_css(cgrp, &io_cgrp_subsys);
+	if (!css) {
+		ret = -ENOENT;
+		goto out_cgrp_put;
+	}
+	blkcg = css_to_blkcg(css);
+	if (!blkcg) {
+		ret = -ENOENT;
+		goto out_put;
+	}
+	if (len > APPID_LEN) {
+		ret = -EINVAL;
+		goto out_put;
+	}
+	strlcpy(blkcg->fc_app_id, buf, len);
+out_put:
+	css_put(css);
+out_cgrp_put:
+	cgroup_put(cgrp);
+	return ret;
+}
+
+/**
+ * blkcg_get_fc_appid - 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_fc_appid(struct bio *bio)
+{
+	if (bio && bio->bi_blkg &&
+			strlen(bio->bi_blkg->blkcg->fc_app_id))
+		return bio->bi_blkg->blkcg->fc_app_id;
+	return NULL;
+}
+#else
+static inline int blkcg_set_fc_appid(char *buf, u64 id, size_t len) { return -EINVAL; }
+static inline char *blkcg_get_fc_appid(struct bio *bio) { return NULL; }
+#endif /*CONFIG_BLK_CGROUP_FC_APPID*/
 #endif	/* _BLK_CGROUP_H */