Commit bbb1ebe7 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

blk-cgroup: replace bio_blkcg with bio_blkcg_css 



All callers of bio_blkcg actually want the CSS, so replace it with an
interface that does return the CSS.  This now allows to move
struct blkcg_gq to block/blk-cgroup.h instead of exposing it in a
public header.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-10-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f4a6a61c

block/blk-cgroup.c

+17 −1
Original line number Diff line number Diff line
@@ -155,6 +155,22 @@ static void blkg_async_bio_workfn(struct work_struct *work) 
		blk_finish_plug(&plug);

}



/**

 * bio_blkcg_css - return the blkcg CSS associated with a bio

 * @bio: target bio

 *

 * This returns the CSS for the blkcg associated with a bio, or %NULL if not

 * associated. Callers are expected to either handle %NULL or know association

 * has been done prior to calling this.

 */

struct cgroup_subsys_state *bio_blkcg_css(struct bio *bio)

{

	if (!bio || !bio->bi_blkg)

		return NULL;

	return &bio->bi_blkg->blkcg->css;

}

EXPORT_SYMBOL_GPL(bio_blkcg_css);



/**

 * blkcg_parent - get the parent of a blkcg

 * @blkcg: blkcg of interest
@@ -1938,7 +1954,7 @@ void bio_associate_blkg(struct bio *bio) 
	rcu_read_lock();



	if (bio->bi_blkg)

		css = &bio_blkcg(bio)->css;

		css = bio_blkcg_css(bio);

	else

		css = blkcg_css();

block/blk-cgroup.h

+64 −3
Original line number Diff line number Diff line
@@ -25,6 +25,64 @@ struct blkg_policy_data; 
#define BLKG_STAT_CPU_BATCH	(INT_MAX / 2)



#ifdef CONFIG_BLK_CGROUP



enum blkg_iostat_type {

	BLKG_IOSTAT_READ,

	BLKG_IOSTAT_WRITE,

	BLKG_IOSTAT_DISCARD,



	BLKG_IOSTAT_NR,

};



struct blkg_iostat {

	u64				bytes[BLKG_IOSTAT_NR];

	u64				ios[BLKG_IOSTAT_NR];

};



struct blkg_iostat_set {

	struct u64_stats_sync		sync;

	struct blkg_iostat		cur;

	struct blkg_iostat		last;

};



/* association between a blk cgroup and a request queue */

struct blkcg_gq {

	/* Pointer to the associated request_queue */

	struct request_queue		*q;

	struct list_head		q_node;

	struct hlist_node		blkcg_node;

	struct blkcg			*blkcg;



	/* all non-root blkcg_gq's are guaranteed to have access to parent */

	struct blkcg_gq			*parent;



	/* reference count */

	struct percpu_ref		refcnt;



	/* is this blkg online? protected by both blkcg and q locks */

	bool				online;



	struct blkg_iostat_set __percpu	*iostat_cpu;

	struct blkg_iostat_set		iostat;



	struct blkg_policy_data		*pd[BLKCG_MAX_POLS];



	spinlock_t			async_bio_lock;

	struct bio_list			async_bios;

	union {

		struct work_struct	async_bio_work;

		struct work_struct	free_work;

	};



	atomic_t			use_delay;

	atomic64_t			delay_nsec;

	atomic64_t			delay_start;

	u64				last_delay;

	int				last_use;



	struct rcu_head			rcu_head;

};



struct blkcg {

	struct cgroup_subsys_state	css;

	spinlock_t			lock;
@@ -173,9 +231,9 @@ static inline struct cgroup_subsys_state *blkcg_css(void) 
 *

 * In order to avoid priority inversions we sometimes need to issue a bio as if

 * it were attached to the root blkg, and then backcharge to the actual owning

 * blkg.  The idea is we do bio_blkcg() to look up the actual context for the

 * bio and attach the appropriate blkg to the bio.  Then we call this helper and

 * if it is true run with the root blkg for that queue and then do any

 * blkg.  The idea is we do bio_blkcg_css() to look up the actual context for

 * the bio and attach the appropriate blkg to the bio.  Then we call this helper

 * and if it is true run with the root blkg for that queue and then do any

 * backcharging to the originating cgroup once the io is complete.

 */

static inline bool bio_issue_as_root_blkg(struct bio *bio)
@@ -464,6 +522,9 @@ struct blkcg_policy_data { 
struct blkcg_policy {

};



struct blkcg {

};



#ifdef CONFIG_BLOCK



static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }

drivers/block/loop.c

+7 −5
Original line number Diff line number Diff line
@@ -1829,12 +1829,14 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, 
	cmd->blkcg_css = NULL;

	cmd->memcg_css = NULL;

#ifdef CONFIG_BLK_CGROUP

	if (rq->bio && rq->bio->bi_blkg) {

		cmd->blkcg_css = &bio_blkcg(rq->bio)->css;

	if (rq->bio) {

		cmd->blkcg_css = bio_blkcg_css(rq->bio);

#ifdef CONFIG_MEMCG

		if (cmd->blkcg_css) {

			cmd->memcg_css =

				cgroup_get_e_css(cmd->blkcg_css->cgroup,

						&memory_cgrp_subsys);

		}

#endif

	}

#endif

include/linux/blk-cgroup.h

+5 −78
Original line number Diff line number Diff line
@@ -28,94 +28,18 @@ 
#define FC_APPID_LEN              129



#ifdef CONFIG_BLK_CGROUP



enum blkg_iostat_type {

	BLKG_IOSTAT_READ,

	BLKG_IOSTAT_WRITE,

	BLKG_IOSTAT_DISCARD,



	BLKG_IOSTAT_NR,

};



struct blkg_iostat {

	u64				bytes[BLKG_IOSTAT_NR];

	u64				ios[BLKG_IOSTAT_NR];

};



struct blkg_iostat_set {

	struct u64_stats_sync		sync;

	struct blkg_iostat		cur;

	struct blkg_iostat		last;

};



/* association between a blk cgroup and a request queue */

struct blkcg_gq {

	/* Pointer to the associated request_queue */

	struct request_queue		*q;

	struct list_head		q_node;

	struct hlist_node		blkcg_node;

	struct blkcg			*blkcg;



	/* all non-root blkcg_gq's are guaranteed to have access to parent */

	struct blkcg_gq			*parent;



	/* reference count */

	struct percpu_ref		refcnt;



	/* is this blkg online? protected by both blkcg and q locks */

	bool				online;



	struct blkg_iostat_set __percpu	*iostat_cpu;

	struct blkg_iostat_set		iostat;



	struct blkg_policy_data		*pd[BLKCG_MAX_POLS];



	spinlock_t			async_bio_lock;

	struct bio_list			async_bios;

	union {

		struct work_struct	async_bio_work;

		struct work_struct	free_work;

	};



	atomic_t			use_delay;

	atomic64_t			delay_nsec;

	atomic64_t			delay_start;

	u64				last_delay;

	int				last_use;



	struct rcu_head			rcu_head;

};



extern struct cgroup_subsys_state * const blkcg_root_css;



void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay);

void blkcg_maybe_throttle_current(void);



/**

 * bio_blkcg - grab the blkcg associated with a bio

 * @bio: target bio

 *

 * This returns the blkcg 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 struct blkcg *bio_blkcg(struct bio *bio)

{

	if (bio && bio->bi_blkg)

		return bio->bi_blkg->blkcg;

	return NULL;

}



bool blk_cgroup_congested(void);

void blkcg_pin_online(struct cgroup_subsys_state *blkcg_css);

void blkcg_unpin_online(struct cgroup_subsys_state *blkcg_css);

struct list_head *blkcg_get_cgwb_list(struct cgroup_subsys_state *css);

struct cgroup_subsys_state *bio_blkcg_css(struct bio *bio);



#else	/* CONFIG_BLK_CGROUP */



struct blkcg_gq {

};



#define blkcg_root_css	((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))



static inline void blkcg_maybe_throttle_current(void) { }
@@ -123,7 +47,10 @@ static inline bool blk_cgroup_congested(void) { return false; } 


#ifdef CONFIG_BLOCK

static inline void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay) { }

static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }

static inline struct cgroup_subsys_state *bio_blkcg_css(struct bio *bio)

{

	return NULL;

}

#endif /* CONFIG_BLOCK */



#endif	/* CONFIG_BLK_CGROUP */

kernel/trace/blktrace.c

+4 −2
Original line number Diff line number Diff line
@@ -783,6 +783,7 @@ void blk_trace_shutdown(struct request_queue *q) 
#ifdef CONFIG_BLK_CGROUP

static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)

{

	struct cgroup_subsys_state *blkcg_css;

	struct blk_trace *bt;



	/* We don't use the 'bt' value here except as an optimization... */
@@ -790,9 +791,10 @@ static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) 
	if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))

		return 0;



	if (!bio->bi_blkg)

	blkcg_css = bio_blkcg_css(bio);

	if (!blkcg_css)

		return 0;

	return cgroup_id(bio_blkcg(bio)->css.cgroup);

	return cgroup_id(blkcg_css->cgroup);

}

#else

static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)