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Commit fda6f272 authored by Tejun Heo's avatar Tejun Heo
Browse files

blk-throttle: implement sq_to_tg(), sq_to_td() and throtl_log() 



Now that both throtl_data and throtl_grp embed throtl_service_queue,
we can unify throtl_log() and throtl_log_tg().

* sq_to_tg() is added.  This returns the throtl_grp a service_queue is
  embedded in.  If the service_queue is the top-level one embedded in
  throtl_data, NULL is returned.

* sq_to_td() is added.  A service_queue is always associated with a
  throtl_data.  This function finds the associated td and returns it.

* throtl_log() is updated to take throtl_service_queue instead of
  throtl_data.  If the service_queue is one embedded in throtl_grp, it
  prints the same header as throtl_log_tg() did.  If it's one embedded
  in throtl_data, it behaves the same as before.  This renders
  throtl_log_tg() unnecessary.  Removed.

This change is necessary for hierarchy support as we're gonna be using
the same code paths to dispatch bios to intermediate service_queues
embedded in throtl_grps and the top-level service_queue embedded in
throtl_data.

This patch doesn't make any behavior changes.

v2: throtl_log() didn't print a space after blkg path.  Updated so
    that it prints a space after throtl_grp path.  Spotted by Vivek.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
parent 77216b04

block/blk-throttle.c

+81 −29
Original line number Diff line number Diff line
@@ -151,16 +151,65 @@ static inline struct throtl_grp *td_root_tg(struct throtl_data *td) 
	return blkg_to_tg(td->queue->root_blkg);

}



#define throtl_log_tg(tg, fmt, args...)	do {				\

/**

 * sq_to_tg - return the throl_grp the specified service queue belongs to

 * @sq: the throtl_service_queue of interest

 *

 * Return the throtl_grp @sq belongs to.  If @sq is the top-level one

 * embedded in throtl_data, %NULL is returned.

 */

static struct throtl_grp *sq_to_tg(struct throtl_service_queue *sq)

{

	if (sq && sq->parent_sq)

		return container_of(sq, struct throtl_grp, service_queue);

	else

		return NULL;

}



/**

 * sq_to_td - return throtl_data the specified service queue belongs to

 * @sq: the throtl_service_queue of interest

 *

 * A service_queue can be embeded in either a throtl_grp or throtl_data.

 * Determine the associated throtl_data accordingly and return it.

 */

static struct throtl_data *sq_to_td(struct throtl_service_queue *sq)

{

	struct throtl_grp *tg = sq_to_tg(sq);



	if (tg)

		return tg->td;

	else

		return container_of(sq, struct throtl_data, service_queue);

}



/**

 * throtl_log - log debug message via blktrace

 * @sq: the service_queue being reported

 * @fmt: printf format string

 * @args: printf args

 *

 * The messages are prefixed with "throtl BLKG_NAME" if @sq belongs to a

 * throtl_grp; otherwise, just "throtl".

 *

 * TODO: this should be made a function and name formatting should happen

 * after testing whether blktrace is enabled.

 */

#define throtl_log(sq, fmt, args...)	do {				\

	struct throtl_grp *__tg = sq_to_tg((sq));			\

	struct throtl_data *__td = sq_to_td((sq));			\

									\

	(void)__td;							\

	if ((__tg)) {							\

		char __pbuf[128];					\

									\

	blkg_path(tg_to_blkg(tg), __pbuf, sizeof(__pbuf));		\

	blk_add_trace_msg((tg)->td->queue, "throtl %s " fmt, __pbuf, ##args); \

		blkg_path(tg_to_blkg(__tg), __pbuf, sizeof(__pbuf));	\

		blk_add_trace_msg(__td->queue, "throtl %s " fmt, __pbuf, ##args); \

	} else {							\

		blk_add_trace_msg(__td->queue, "throtl " fmt, ##args);	\

	}								\

} while (0)



#define throtl_log(td, fmt, args...)	\

	blk_add_trace_msg((td)->queue, "throtl " fmt, ##args)



/*

 * Worker for allocating per cpu stat for tgs. This is scheduled on the

 * system_wq once there are some groups on the alloc_list waiting for
@@ -402,9 +451,10 @@ static void throtl_schedule_delayed_work(struct throtl_data *td, 
					 unsigned long delay)

{

	struct delayed_work *dwork = &td->dispatch_work;

	struct throtl_service_queue *sq = &td->service_queue;



	mod_delayed_work(kthrotld_workqueue, dwork, delay);

	throtl_log(td, "schedule work. delay=%lu jiffies=%lu", delay, jiffies);

	throtl_log(sq, "schedule work. delay=%lu jiffies=%lu", delay, jiffies);

}



static void throtl_schedule_next_dispatch(struct throtl_data *td)
@@ -429,7 +479,8 @@ static inline void throtl_start_new_slice(struct throtl_grp *tg, bool rw) 
	tg->io_disp[rw] = 0;

	tg->slice_start[rw] = jiffies;

	tg->slice_end[rw] = jiffies + throtl_slice;

	throtl_log_tg(tg, "[%c] new slice start=%lu end=%lu jiffies=%lu",

	throtl_log(&tg->service_queue,

		   "[%c] new slice start=%lu end=%lu jiffies=%lu",

		   rw == READ ? 'R' : 'W', tg->slice_start[rw],

		   tg->slice_end[rw], jiffies);

}
@@ -444,7 +495,8 @@ static inline void throtl_extend_slice(struct throtl_grp *tg, bool rw, 
				       unsigned long jiffy_end)

{

	tg->slice_end[rw] = roundup(jiffy_end, throtl_slice);

	throtl_log_tg(tg, "[%c] extend slice start=%lu end=%lu jiffies=%lu",

	throtl_log(&tg->service_queue,

		   "[%c] extend slice start=%lu end=%lu jiffies=%lu",

		   rw == READ ? 'R' : 'W', tg->slice_start[rw],

		   tg->slice_end[rw], jiffies);

}
@@ -511,8 +563,8 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) 


	tg->slice_start[rw] += nr_slices * throtl_slice;



	throtl_log_tg(tg, "[%c] trim slice nr=%lu bytes=%llu io=%lu"

			" start=%lu end=%lu jiffies=%lu",

	throtl_log(&tg->service_queue,

		   "[%c] trim slice nr=%lu bytes=%llu io=%lu start=%lu end=%lu jiffies=%lu",

		   rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim,

		   tg->slice_start[rw], tg->slice_end[rw], jiffies);

}
@@ -852,7 +904,7 @@ void blk_throtl_dispatch_work_fn(struct work_struct *work) 


	bio_list_init(&bio_list_on_stack);



	throtl_log(td, "dispatch nr_queued=%u read=%u write=%u",

	throtl_log(sq, "dispatch nr_queued=%u read=%u write=%u",

		   td->nr_queued[READ] + td->nr_queued[WRITE],

		   td->nr_queued[READ], td->nr_queued[WRITE]);
@@ -863,7 +915,7 @@ void blk_throtl_dispatch_work_fn(struct work_struct *work) 
			bio_list_merge(&bio_list_on_stack, &sq->bio_lists[rw]);

			bio_list_init(&sq->bio_lists[rw]);

		}

		throtl_log(td, "bios disp=%u", nr_disp);

		throtl_log(sq, "bios disp=%u", nr_disp);

	}



	throtl_schedule_next_dispatch(td);
@@ -972,7 +1024,8 @@ static int tg_set_conf(struct cgroup *cgrp, struct cftype *cft, const char *buf, 
	else

		*(unsigned int *)((void *)tg + cft->private) = ctx.v;



	throtl_log_tg(tg, "limit change rbps=%llu wbps=%llu riops=%u wiops=%u",

	throtl_log(&tg->service_queue,

		   "limit change rbps=%llu wbps=%llu riops=%u wiops=%u",

		   tg->bps[READ], tg->bps[WRITE],

		   tg->iops[READ], tg->iops[WRITE]);
@@ -1131,8 +1184,7 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio) 
	}



queue_bio:

	throtl_log_tg(tg, "[%c] bio. bdisp=%llu sz=%u bps=%llu"

			" iodisp=%u iops=%u queued=%d/%d",

	throtl_log(sq, "[%c] bio. bdisp=%llu sz=%u bps=%llu iodisp=%u iops=%u queued=%d/%d",

		   rw == READ ? 'R' : 'W',

		   tg->bytes_disp[rw], bio->bi_size, tg->bps[rw],

		   tg->io_disp[rw], tg->iops[rw],