Commit f05837ed authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

blk-cgroup: store a gendisk to throttle in struct task_struct 



Switch from a request_queue pointer and reference to a gendisk once
for the throttle information in struct task_struct.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarAndreas Herrmann <aherrmann@suse.de>
Link: https://lore.kernel.org/r/20230203150400.3199230-8-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 84d7d462

block/blk-cgroup.c

+15 −17
Original line number Diff line number Diff line
@@ -1362,9 +1362,9 @@ static void blkcg_bind(struct cgroup_subsys_state *root_css) 


static void blkcg_exit(struct task_struct *tsk)

{

	if (tsk->throttle_queue)

		blk_put_queue(tsk->throttle_queue);

	tsk->throttle_queue = NULL;

	if (tsk->throttle_disk)

		put_disk(tsk->throttle_disk);

	tsk->throttle_disk = NULL;

}



struct cgroup_subsys io_cgrp_subsys = {
@@ -1815,29 +1815,29 @@ static void blkcg_maybe_throttle_blkg(struct blkcg_gq *blkg, bool use_memdelay) 
 *

 * This is only called if we've been marked with set_notify_resume().  Obviously

 * we can be set_notify_resume() for reasons other than blkcg throttling, so we

 * check to see if current->throttle_queue is set and if not this doesn't do

 * check to see if current->throttle_disk is set and if not this doesn't do

 * anything.  This should only ever be called by the resume code, it's not meant

 * to be called by people willy-nilly as it will actually do the work to

 * throttle the task if it is setup for throttling.

 */

void blkcg_maybe_throttle_current(void)

{

	struct request_queue *q = current->throttle_queue;

	struct gendisk *disk = current->throttle_disk;

	struct blkcg *blkcg;

	struct blkcg_gq *blkg;

	bool use_memdelay = current->use_memdelay;



	if (!q)

	if (!disk)

		return;



	current->throttle_queue = NULL;

	current->throttle_disk = NULL;

	current->use_memdelay = false;



	rcu_read_lock();

	blkcg = css_to_blkcg(blkcg_css());

	if (!blkcg)

		goto out;

	blkg = blkg_lookup(blkcg, q);

	blkg = blkg_lookup(blkcg, disk->queue);

	if (!blkg)

		goto out;

	if (!blkg_tryget(blkg))
@@ -1846,11 +1846,10 @@ void blkcg_maybe_throttle_current(void) 


	blkcg_maybe_throttle_blkg(blkg, use_memdelay);

	blkg_put(blkg);

	blk_put_queue(q);

	put_disk(disk);

	return;

out:

	rcu_read_unlock();

	blk_put_queue(q);

}



/**
@@ -1872,18 +1871,17 @@ void blkcg_maybe_throttle_current(void) 
 */

void blkcg_schedule_throttle(struct gendisk *disk, bool use_memdelay)

{

	struct request_queue *q = disk->queue;



	if (unlikely(current->flags & PF_KTHREAD))

		return;



	if (current->throttle_queue != q) {

		if (!blk_get_queue(q))

	if (current->throttle_disk != disk) {

		if (test_bit(GD_DEAD, &disk->state))

			return;

		get_device(disk_to_dev(disk));



		if (current->throttle_queue)

			blk_put_queue(current->throttle_queue);

		current->throttle_queue = q;

		if (current->throttle_disk)

			put_disk(current->throttle_disk);

		current->throttle_disk = disk;

	}



	if (use_memdelay)

include/linux/sched.h

+1 −1
Original line number Diff line number Diff line
@@ -1436,7 +1436,7 @@ struct task_struct { 
#endif



#ifdef CONFIG_BLK_CGROUP

	struct request_queue		*throttle_queue;

	struct gendisk			*throttle_disk;

#endif



#ifdef CONFIG_UPROBES

kernel/fork.c

+1 −1
Original line number Diff line number Diff line
@@ -1044,7 +1044,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) 
#endif



#ifdef CONFIG_BLK_CGROUP

	tsk->throttle_queue = NULL;

	tsk->throttle_disk = NULL;

	tsk->use_memdelay = 0;

#endif

mm/swapfile.c

+1 −1
Original line number Diff line number Diff line
@@ -3642,7 +3642,7 @@ void __cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask) 
	 * We've already scheduled a throttle, avoid taking the global swap

	 * lock.

	 */

	if (current->throttle_queue)

	if (current->throttle_disk)

		return;



	spin_lock(&swap_avail_lock);