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

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

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Herrmann <aherrmann@suse.de>
Link: https://lore.kernel.org/r/20230203150400.3199230-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2023-02-03 16:03:48 +01:00 committed by Jens Axboe
parent 84d7d462b1
commit f05837ed73
4 changed files with 18 additions and 20 deletions
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32
block/blk-cgroup.c
View File

@ -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)

2
include/linux/sched.h
View File

@ -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

2
kernel/fork.c
View File

@ -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

2
mm/swapfile.c
View File

@ -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);