Commit 397c9f46 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
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blk-cgroup: move blkcg_{pin,unpin}_online out of line 



Move these two functions out of line as there is no good reason
to inline them.  Also switch to passing a cgroup_subsys_state
instead of doing the conversion in the caller to prepare for making
the blkcg structure private to blk-cgroup.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-7-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 216889aa

block/blk-cgroup.c

+65 −23
Original line number Diff line number Diff line
@@ -155,6 +155,17 @@ static void blkg_async_bio_workfn(struct work_struct *work) 
		blk_finish_plug(&plug);

}



/**

 * blkcg_parent - get the parent of a blkcg

 * @blkcg: blkcg of interest

 *

 * Return the parent blkcg of @blkcg.  Can be called anytime.

 */

static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)

{

	return css_to_blkcg(blkcg->css.parent);

}



/**

 * blkg_alloc - allocate a blkg

 * @blkcg: block cgroup the new blkg is associated with
@@ -1015,25 +1026,6 @@ static struct cftype blkcg_legacy_files[] = { 
 *    This finally frees the blkcg.

 */



/**

 * blkcg_css_offline - cgroup css_offline callback

 * @css: css of interest

 *

 * This function is called when @css is about to go away.  Here the cgwbs are

 * offlined first and only once writeback associated with the blkcg has

 * finished do we start step 2 (see above).

 */

static void blkcg_css_offline(struct cgroup_subsys_state *css)

{

	struct blkcg *blkcg = css_to_blkcg(css);



	/* this prevents anyone from attaching or migrating to this blkcg */

	wb_blkcg_offline(blkcg);



	/* put the base online pin allowing step 2 to be triggered */

	blkcg_unpin_online(blkcg);

}



/**

 * blkcg_destroy_blkgs - responsible for shooting down blkgs

 * @blkcg: blkcg of interest
@@ -1045,7 +1037,7 @@ static void blkcg_css_offline(struct cgroup_subsys_state *css) 
 *

 * This is the blkcg counterpart of ioc_release_fn().

 */

void blkcg_destroy_blkgs(struct blkcg *blkcg)

static void blkcg_destroy_blkgs(struct blkcg *blkcg)

{

	might_sleep();
@@ -1075,6 +1067,57 @@ void blkcg_destroy_blkgs(struct blkcg *blkcg) 
	spin_unlock_irq(&blkcg->lock);

}



/**

 * blkcg_pin_online - pin online state

 * @blkcg_css: blkcg of interest

 *

 * While pinned, a blkcg is kept online.  This is primarily used to

 * impedance-match blkg and cgwb lifetimes so that blkg doesn't go offline

 * while an associated cgwb is still active.

 */

void blkcg_pin_online(struct cgroup_subsys_state *blkcg_css)

{

	refcount_inc(&css_to_blkcg(blkcg_css)->online_pin);

}



/**

 * blkcg_unpin_online - unpin online state

 * @blkcg_css: blkcg of interest

 *

 * This is primarily used to impedance-match blkg and cgwb lifetimes so

 * that blkg doesn't go offline while an associated cgwb is still active.

 * When this count goes to zero, all active cgwbs have finished so the

 * blkcg can continue destruction by calling blkcg_destroy_blkgs().

 */

void blkcg_unpin_online(struct cgroup_subsys_state *blkcg_css)

{

	struct blkcg *blkcg = css_to_blkcg(blkcg_css);



	do {

		if (!refcount_dec_and_test(&blkcg->online_pin))

			break;

		blkcg_destroy_blkgs(blkcg);

		blkcg = blkcg_parent(blkcg);

	} while (blkcg);

}



/**

 * blkcg_css_offline - cgroup css_offline callback

 * @css: css of interest

 *

 * This function is called when @css is about to go away.  Here the cgwbs are

 * offlined first and only once writeback associated with the blkcg has

 * finished do we start step 2 (see above).

 */

static void blkcg_css_offline(struct cgroup_subsys_state *css)

{

	/* this prevents anyone from attaching or migrating to this blkcg */

	wb_blkcg_offline(css_to_blkcg(css));



	/* put the base online pin allowing step 2 to be triggered */

	blkcg_unpin_online(css);

}



static void blkcg_css_free(struct cgroup_subsys_state *css)

{

	struct blkcg *blkcg = css_to_blkcg(css);
@@ -1163,8 +1206,7 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css) 


static int blkcg_css_online(struct cgroup_subsys_state *css)

{

	struct blkcg *blkcg = css_to_blkcg(css);

	struct blkcg *parent = blkcg_parent(blkcg);

	struct blkcg *parent = blkcg_parent(css_to_blkcg(css));



	/*

	 * blkcg_pin_online() is used to delay blkcg offline so that blkgs
@@ -1172,7 +1214,7 @@ static int blkcg_css_online(struct cgroup_subsys_state *css) 
	 * parent so that offline always happens towards the root.

	 */

	if (parent)

		blkcg_pin_online(parent);

		blkcg_pin_online(css);

	return 0;

}

include/linux/blk-cgroup.h

+2 −44
Original line number Diff line number Diff line
@@ -111,7 +111,6 @@ struct blkcg_gq { 


extern struct cgroup_subsys_state * const blkcg_root_css;



void blkcg_destroy_blkgs(struct blkcg *blkcg);

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

void blkcg_maybe_throttle_current(void);
@@ -136,49 +135,8 @@ static inline struct blkcg *bio_blkcg(struct bio *bio) 
}



bool blk_cgroup_congested(void);



/**

 * blkcg_parent - get the parent of a blkcg

 * @blkcg: blkcg of interest

 *

 * Return the parent blkcg of @blkcg.  Can be called anytime.

 */

static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)

{

	return css_to_blkcg(blkcg->css.parent);

}



/**

 * blkcg_pin_online - pin online state

 * @blkcg: blkcg of interest

 *

 * While pinned, a blkcg is kept online.  This is primarily used to

 * impedance-match blkg and cgwb lifetimes so that blkg doesn't go offline

 * while an associated cgwb is still active.

 */

static inline void blkcg_pin_online(struct blkcg *blkcg)

{

	refcount_inc(&blkcg->online_pin);

}



/**

 * blkcg_unpin_online - unpin online state

 * @blkcg: blkcg of interest

 *

 * This is primarily used to impedance-match blkg and cgwb lifetimes so

 * that blkg doesn't go offline while an associated cgwb is still active.

 * When this count goes to zero, all active cgwbs have finished so the

 * blkcg can continue destruction by calling blkcg_destroy_blkgs().

 */

static inline void blkcg_unpin_online(struct blkcg *blkcg)

{

	do {

		if (!refcount_dec_and_test(&blkcg->online_pin))

			break;

		blkcg_destroy_blkgs(blkcg);

		blkcg = blkcg_parent(blkcg);

	} while (blkcg);

}

void blkcg_pin_online(struct cgroup_subsys_state *blkcg_css);

void blkcg_unpin_online(struct cgroup_subsys_state *blkcg_css);



#else	/* CONFIG_BLK_CGROUP */

mm/backing-dev.c

+2 −3
Original line number Diff line number Diff line
@@ -390,7 +390,6 @@ static void cgwb_release_workfn(struct work_struct *work) 
{

	struct bdi_writeback *wb = container_of(work, struct bdi_writeback,

						release_work);

	struct blkcg *blkcg = css_to_blkcg(wb->blkcg_css);

	struct backing_dev_info *bdi = wb->bdi;



	mutex_lock(&wb->bdi->cgwb_release_mutex);
@@ -401,7 +400,7 @@ static void cgwb_release_workfn(struct work_struct *work) 
	mutex_unlock(&wb->bdi->cgwb_release_mutex);



	/* triggers blkg destruction if no online users left */

	blkcg_unpin_online(blkcg);

	blkcg_unpin_online(wb->blkcg_css);



	fprop_local_destroy_percpu(&wb->memcg_completions);
@@ -511,7 +510,7 @@ static int cgwb_create(struct backing_dev_info *bdi, 
			list_add_tail_rcu(&wb->bdi_node, &bdi->wb_list);

			list_add(&wb->memcg_node, memcg_cgwb_list);

			list_add(&wb->blkcg_node, blkcg_cgwb_list);

			blkcg_pin_online(blkcg);

			blkcg_pin_online(blkcg_css);

			css_get(memcg_css);

			css_get(blkcg_css);

		}