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Subject[PATCH 3/8] blk-throttle: use io size and direction as parameters to wait routines
Date
I want to reuse wait routines for task wait also. Hence get rid of
dependency of bio being passed in. Instead pass in direction of IO
and size of IO.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
block/blk-throttle.c | 52 +++++++++++++++++++++++--------------------------
1 files changed, 24 insertions(+), 28 deletions(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 8facd17..885ee4a 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -591,9 +591,8 @@ throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
}

static unsigned long tg_wait_iops_limit(struct throtl_data *td,
- struct throtl_grp *tg, struct bio *bio)
+ struct throtl_grp *tg, bool rw, unsigned int nr_ios)
{
- bool rw = bio_data_dir(bio);
unsigned int io_allowed;
unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd;
u64 tmp;
@@ -621,11 +620,11 @@ static unsigned long tg_wait_iops_limit(struct throtl_data *td,
else
io_allowed = tmp;

- if (tg->io_disp[rw] + 1 <= io_allowed)
+ if (tg->io_disp[rw] + nr_ios <= io_allowed)
return 0;

/* Calc approx time to dispatch */
- jiffy_wait = ((tg->io_disp[rw] + 1) * HZ)/tg->iops[rw] + 1;
+ jiffy_wait = ((tg->io_disp[rw] + nr_ios) * HZ)/tg->iops[rw] + 1;

if (jiffy_wait > jiffy_elapsed)
jiffy_wait = jiffy_wait - jiffy_elapsed;
@@ -640,9 +639,8 @@ static unsigned long tg_wait_iops_limit(struct throtl_data *td,
* to bps limit.
*/
static unsigned long tg_wait_bps_limit(struct throtl_data *td,
- struct throtl_grp *tg, struct bio *bio)
+ struct throtl_grp *tg, bool rw, unsigned int sz)
{
- bool rw = bio_data_dir(bio);
u64 bytes_allowed, extra_bytes, tmp;
unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd;

@@ -658,11 +656,11 @@ static unsigned long tg_wait_bps_limit(struct throtl_data *td,
do_div(tmp, HZ);
bytes_allowed = tmp;

- if (tg->bytes_disp[rw] + bio->bi_size <= bytes_allowed)
+ if (tg->bytes_disp[rw] + sz <= bytes_allowed)
return 0;

/* Calc approx time to dispatch */
- extra_bytes = tg->bytes_disp[rw] + bio->bi_size - bytes_allowed;
+ extra_bytes = tg->bytes_disp[rw] + sz - bytes_allowed;
jiffy_wait = div64_u64(extra_bytes * HZ, tg->bps[rw]);

if (!jiffy_wait)
@@ -690,10 +688,9 @@ static bool tg_no_rule_group(struct throtl_grp *tg, bool rw) {
* Retruns the number of jiffies one needs to wait before IO can be dispatched.
* 0 means, IO can be dispatched now.
*/
-static unsigned long
-tg_wait_dispatch(struct throtl_data *td, struct throtl_grp *tg, struct bio *bio)
+static unsigned long tg_wait_dispatch(struct throtl_data *td,
+ struct throtl_grp *tg, bool rw, unsigned int sz, unsigned int nr_ios)
{
- bool rw = bio_data_dir(bio);
unsigned long bps_wait = 0, iops_wait = 0, max_wait = 0;

/* If tg->bps = -1, then BW is unlimited */
@@ -712,8 +709,8 @@ tg_wait_dispatch(struct throtl_data *td, struct throtl_grp *tg, struct bio *bio)
throtl_extend_slice(td, tg, rw, jiffies + throtl_slice);
}

- bps_wait = tg_wait_bps_limit(td, tg, bio);
- iops_wait = tg_wait_iops_limit(td, tg, bio);
+ bps_wait = tg_wait_bps_limit(td, tg, rw, sz);
+ iops_wait = tg_wait_iops_limit(td, tg, rw, nr_ios);

max_wait = max(bps_wait, iops_wait);

@@ -723,16 +720,14 @@ tg_wait_dispatch(struct throtl_data *td, struct throtl_grp *tg, struct bio *bio)
return max_wait;
}

-static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio)
+static void throtl_charge_io(struct throtl_grp *tg, bool rw, unsigned int sz,
+ unsigned int nr_ios, bool sync)
{
- bool rw = bio_data_dir(bio);
- bool sync = bio->bi_rw & REQ_SYNC;
-
- /* Charge the bio to the group */
- tg->bytes_disp[rw] += bio->bi_size;
- tg->io_disp[rw]++;
+ /* Charge the io to the group */
+ tg->bytes_disp[rw] += sz;
+ tg->io_disp[rw] += nr_ios;

- blkiocg_update_dispatch_stats(&tg->blkg, bio->bi_size, rw, sync);
+ blkiocg_update_dispatch_stats(&tg->blkg, sz, rw, sync);
}

static void throtl_add_bio_tg(struct throtl_data *td, struct throtl_grp *tg,
@@ -754,10 +749,10 @@ static void tg_update_disptime(struct throtl_data *td, struct throtl_grp *tg)
struct bio *bio;

if ((bio = bio_list_peek(&tg->bio_lists[READ])))
- read_wait = tg_wait_dispatch(td, tg, bio);
+ read_wait = tg_wait_dispatch(td, tg, READ, bio->bi_size, 1);

if ((bio = bio_list_peek(&tg->bio_lists[WRITE])))
- write_wait = tg_wait_dispatch(td, tg, bio);
+ write_wait = tg_wait_dispatch(td, tg, WRITE, bio->bi_size, 1);

min_wait = min(read_wait, write_wait);
disptime = jiffies + min_wait;
@@ -781,7 +776,7 @@ static void tg_dispatch_one_bio(struct throtl_data *td, struct throtl_grp *tg,
BUG_ON(td->nr_queued[rw] <= 0);
td->nr_queued[rw]--;

- throtl_charge_bio(tg, bio);
+ throtl_charge_io(tg, rw, bio->bi_size, 1, bio->bi_rw & REQ_SYNC);
bio_list_add(bl, bio);
bio->bi_rw |= REQ_THROTTLED;

@@ -799,7 +794,7 @@ static int throtl_dispatch_tg(struct throtl_data *td, struct throtl_grp *tg,
/* Try to dispatch 75% READS and 25% WRITES */

while ((bio = bio_list_peek(&tg->bio_lists[READ]))
- && !tg_wait_dispatch(td, tg, bio)) {
+ && !tg_wait_dispatch(td, tg, READ, bio->bi_size, 1)) {

tg_dispatch_one_bio(td, tg, bio_data_dir(bio), bl);
nr_reads++;
@@ -809,7 +804,7 @@ static int throtl_dispatch_tg(struct throtl_data *td, struct throtl_grp *tg,
}

while ((bio = bio_list_peek(&tg->bio_lists[WRITE]))
- && !tg_wait_dispatch(td, tg, bio)) {
+ && !tg_wait_dispatch(td, tg, WRITE, bio->bi_size, 1)) {

tg_dispatch_one_bio(td, tg, bio_data_dir(bio), bl);
nr_writes++;
@@ -1165,8 +1160,9 @@ int blk_throtl_bio(struct request_queue *q, struct bio **biop)
}

/* Bio is with-in rate limit of group */
- if (!tg_wait_dispatch(td, tg, bio)) {
- throtl_charge_bio(tg, bio);
+ if (!tg_wait_dispatch(td, tg, rw, bio->bi_size, 1)) {
+ throtl_charge_io(tg, rw, bio->bi_size, 1,
+ bio->bi_rw & REQ_SYNC);

/*
* We need to trim slice even when bios are not being queued
--
1.7.4.4


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