Commit e8368b57 authored by Yu Kuai's avatar Yu Kuai Committed by Jens Axboe
Browse files

blk-throttle: use calculate_io/bytes_allowed() for throtl_trim_slice() 



There are no functional changes, just make the code cleaner.

Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230816012708.1193747-4-yukuai1@huaweicloud.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent bb8d5587

block/blk-throttle.c

+41 −45
Original line number Diff line number Diff line
@@ -697,11 +697,40 @@ static bool throtl_slice_used(struct throtl_grp *tg, bool rw) 
	return true;

}



static unsigned int calculate_io_allowed(u32 iops_limit,

					 unsigned long jiffy_elapsed)

{

	unsigned int io_allowed;

	u64 tmp;



	/*

	 * jiffy_elapsed should not be a big value as minimum iops can be

	 * 1 then at max jiffy elapsed should be equivalent of 1 second as we

	 * will allow dispatch after 1 second and after that slice should

	 * have been trimmed.

	 */



	tmp = (u64)iops_limit * jiffy_elapsed;

	do_div(tmp, HZ);



	if (tmp > UINT_MAX)

		io_allowed = UINT_MAX;

	else

		io_allowed = tmp;



	return io_allowed;

}



static u64 calculate_bytes_allowed(u64 bps_limit, unsigned long jiffy_elapsed)

{

	return mul_u64_u64_div_u64(bps_limit, (u64)jiffy_elapsed, (u64)HZ);

}



/* Trim the used slices and adjust slice start accordingly */

static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw)

{

	unsigned long nr_slices, time_elapsed, io_trim;

	u64 bytes_trim, tmp;

	unsigned long time_elapsed, io_trim;

	u64 bytes_trim;



	BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw]));
@@ -723,19 +752,14 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) 


	throtl_set_slice_end(tg, rw, jiffies + tg->td->throtl_slice);



	time_elapsed = jiffies - tg->slice_start[rw];



	nr_slices = time_elapsed / tg->td->throtl_slice;



	if (!nr_slices)

	time_elapsed = rounddown(jiffies - tg->slice_start[rw],

				 tg->td->throtl_slice);

	if (!time_elapsed)

		return;

	tmp = tg_bps_limit(tg, rw) * tg->td->throtl_slice * nr_slices;

	do_div(tmp, HZ);

	bytes_trim = tmp;



	io_trim = (tg_iops_limit(tg, rw) * tg->td->throtl_slice * nr_slices) /

		HZ;



	bytes_trim = calculate_bytes_allowed(tg_bps_limit(tg, rw),

					     time_elapsed);

	io_trim = calculate_io_allowed(tg_iops_limit(tg, rw), time_elapsed);

	if (!bytes_trim && !io_trim)

		return;
@@ -749,41 +773,13 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) 
	else

		tg->io_disp[rw] = 0;



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

	tg->slice_start[rw] += time_elapsed;



	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);

}



static unsigned int calculate_io_allowed(u32 iops_limit,

					 unsigned long jiffy_elapsed)

{

	unsigned int io_allowed;

	u64 tmp;



	/*

	 * jiffy_elapsed should not be a big value as minimum iops can be

	 * 1 then at max jiffy elapsed should be equivalent of 1 second as we

	 * will allow dispatch after 1 second and after that slice should

	 * have been trimmed.

	 */



	tmp = (u64)iops_limit * jiffy_elapsed;

	do_div(tmp, HZ);



	if (tmp > UINT_MAX)

		io_allowed = UINT_MAX;

	else

		io_allowed = tmp;



	return io_allowed;

}



static u64 calculate_bytes_allowed(u64 bps_limit, unsigned long jiffy_elapsed)

{

	return mul_u64_u64_div_u64(bps_limit, (u64)jiffy_elapsed, (u64)HZ);

		   rw == READ ? 'R' : 'W', time_elapsed / tg->td->throtl_slice,

		   bytes_trim, io_trim, tg->slice_start[rw], tg->slice_end[rw],

		   jiffies);

}



static void __tg_update_carryover(struct throtl_grp *tg, bool rw)