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blk-throttle: prepare support multiple limits 

We are going to support low/max limit, each cgroup will have 2 limits
after that. This patch prepares for the multiple limits change.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Shaohua Li 2017-03-27 10:51:30 -07:00 committed by Jens Axboe
parent 2ab5492de5
commit 9f626e372a
1 changed files with 70 additions and 40 deletions
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110
block/blk-throttle.c
View File

@ -83,6 +83,11 @@ enum tg_state_flags {
#define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node)
enum {
LIMIT_MAX,
LIMIT_CNT,
};
struct throtl_grp {
/* must be the first member */
struct blkg_policy_data pd;
@ -120,10 +125,10 @@ struct throtl_grp {
bool has_rules[2];
/* bytes per second rate limits */
uint64_t bps[2];
uint64_t bps[2][LIMIT_CNT];
/* IOPS limits */
unsigned int iops[2];
unsigned int iops[2][LIMIT_CNT];
/* Number of bytes disptached in current slice */
uint64_t bytes_disp[2];
@ -147,6 +152,8 @@ struct throtl_data
/* Work for dispatching throttled bios */
struct work_struct dispatch_work;
unsigned int limit_index;
bool limit_valid[LIMIT_CNT];
};
static void throtl_pending_timer_fn(unsigned long arg);
@ -198,6 +205,16 @@ static struct throtl_data *sq_to_td(struct throtl_service_queue *sq)
return container_of(sq, struct throtl_data, service_queue);
}
static uint64_t tg_bps_limit(struct throtl_grp *tg, int rw)
{
return tg->bps[rw][tg->td->limit_index];
}
static unsigned int tg_iops_limit(struct throtl_grp *tg, int rw)
{
return tg->iops[rw][tg->td->limit_index];
}
/**
* throtl_log - log debug message via blktrace
* @sq: the service_queue being reported
@ -334,10 +351,10 @@ static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node)
}
RB_CLEAR_NODE(&tg->rb_node);
tg->bps[READ] = U64_MAX;
tg->bps[WRITE] = U64_MAX;
tg->iops[READ] = UINT_MAX;
tg->iops[WRITE] = UINT_MAX;
tg->bps[READ][LIMIT_MAX] = U64_MAX;
tg->bps[WRITE][LIMIT_MAX] = U64_MAX;
tg->iops[READ][LIMIT_MAX] = UINT_MAX;
tg->iops[WRITE][LIMIT_MAX] = UINT_MAX;
return &tg->pd;
}
@ -376,11 +393,14 @@ static void throtl_pd_init(struct blkg_policy_data *pd)
static void tg_update_has_rules(struct throtl_grp *tg)
{
struct throtl_grp *parent_tg = sq_to_tg(tg->service_queue.parent_sq);
struct throtl_data *td = tg->td;
int rw;
for (rw = READ; rw <= WRITE; rw++)
tg->has_rules[rw] = (parent_tg && parent_tg->has_rules[rw]) ||
(tg->bps[rw] != U64_MAX || tg->iops[rw] != UINT_MAX);
(td->limit_valid[td->limit_index] &&
(tg_bps_limit(tg, rw) != U64_MAX ||
tg_iops_limit(tg, rw) != UINT_MAX));
}
static void throtl_pd_online(struct blkg_policy_data *pd)
@ -632,11 +652,11 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw)
if (!nr_slices)
return;
tmp = tg->bps[rw] * throtl_slice * nr_slices;
tmp = tg_bps_limit(tg, rw) * throtl_slice * nr_slices;
do_div(tmp, HZ);
bytes_trim = tmp;
io_trim = (tg->iops[rw] * throtl_slice * nr_slices)/HZ;
io_trim = (tg_iops_limit(tg, rw) * throtl_slice * nr_slices) / HZ;
if (!bytes_trim && !io_trim)
return;
@ -682,7 +702,7 @@ static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio,
* have been trimmed.
*/
tmp = (u64)tg->iops[rw] * jiffy_elapsed_rnd;
tmp = (u64)tg_iops_limit(tg, rw) * jiffy_elapsed_rnd;
do_div(tmp, HZ);
if (tmp > UINT_MAX)
@ -697,7 +717,7 @@ static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio,
}
/* Calc approx time to dispatch */
jiffy_wait = ((tg->io_disp[rw] + 1) * HZ)/tg->iops[rw] + 1;
jiffy_wait = ((tg->io_disp[rw] + 1) * HZ) / tg_iops_limit(tg, rw) + 1;
if (jiffy_wait > jiffy_elapsed)
jiffy_wait = jiffy_wait - jiffy_elapsed;
@ -724,7 +744,7 @@ static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio,
jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, throtl_slice);
tmp = tg->bps[rw] * jiffy_elapsed_rnd;
tmp = tg_bps_limit(tg, rw) * jiffy_elapsed_rnd;
do_div(tmp, HZ);
bytes_allowed = tmp;
@ -736,7 +756,7 @@ static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio,
/* Calc approx time to dispatch */
extra_bytes = tg->bytes_disp[rw] + bio->bi_iter.bi_size - bytes_allowed;
jiffy_wait = div64_u64(extra_bytes * HZ, tg->bps[rw]);
jiffy_wait = div64_u64(extra_bytes * HZ, tg_bps_limit(tg, rw));
if (!jiffy_wait)
jiffy_wait = 1;
@ -771,7 +791,8 @@ static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio,
bio != throtl_peek_queued(&tg->service_queue.queued[rw]));
/* If tg->bps = -1, then BW is unlimited */
if (tg->bps[rw] == U64_MAX && tg->iops[rw] == UINT_MAX) {
if (tg_bps_limit(tg, rw) == U64_MAX &&
tg_iops_limit(tg, rw) == UINT_MAX) {
if (wait)
*wait = 0;
return true;
@ -1150,8 +1171,8 @@ static void tg_conf_updated(struct throtl_grp *tg)
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]);
tg_bps_limit(tg, READ), tg_bps_limit(tg, WRITE),
tg_iops_limit(tg, READ), tg_iops_limit(tg, WRITE));
/*
* Update has_rules[] flags for the updated tg's subtree. A tg is
@ -1228,25 +1249,25 @@ static ssize_t tg_set_conf_uint(struct kernfs_open_file *of,
static struct cftype throtl_legacy_files[] = {
{
.name = "throttle.read_bps_device",
.private = offsetof(struct throtl_grp, bps[READ]),
.private = offsetof(struct throtl_grp, bps[READ][LIMIT_MAX]),
.seq_show = tg_print_conf_u64,
.write = tg_set_conf_u64,
},
{
.name = "throttle.write_bps_device",
.private = offsetof(struct throtl_grp, bps[WRITE]),
.private = offsetof(struct throtl_grp, bps[WRITE][LIMIT_MAX]),
.seq_show = tg_print_conf_u64,
.write = tg_set_conf_u64,
},
{
.name = "throttle.read_iops_device",
.private = offsetof(struct throtl_grp, iops[READ]),
.private = offsetof(struct throtl_grp, iops[READ][LIMIT_MAX]),
.seq_show = tg_print_conf_uint,
.write = tg_set_conf_uint,
},
{
.name = "throttle.write_iops_device",
.private = offsetof(struct throtl_grp, iops[WRITE]),
.private = offsetof(struct throtl_grp, iops[WRITE][LIMIT_MAX]),
.seq_show = tg_print_conf_uint,
.write = tg_set_conf_uint,
},
@ -1272,18 +1293,25 @@ static u64 tg_prfill_max(struct seq_file *sf, struct blkg_policy_data *pd,
if (!dname)
return 0;
if (tg->bps[READ] == U64_MAX && tg->bps[WRITE] == U64_MAX &&
tg->iops[READ] == UINT_MAX && tg->iops[WRITE] == UINT_MAX)
if (tg->bps[READ][LIMIT_MAX] == U64_MAX &&
tg->bps[WRITE][LIMIT_MAX] == U64_MAX &&
tg->iops[READ][LIMIT_MAX] == UINT_MAX &&
tg->iops[WRITE][LIMIT_MAX] == UINT_MAX)
return 0;
if (tg->bps[READ] != U64_MAX)
snprintf(bufs[0], sizeof(bufs[0]), "%llu", tg->bps[READ]);
if (tg->bps[WRITE] != U64_MAX)
snprintf(bufs[1], sizeof(bufs[1]), "%llu", tg->bps[WRITE]);
if (tg->iops[READ] != UINT_MAX)
snprintf(bufs[2], sizeof(bufs[2]), "%u", tg->iops[READ]);
if (tg->iops[WRITE] != UINT_MAX)
snprintf(bufs[3], sizeof(bufs[3]), "%u", tg->iops[WRITE]);
if (tg->bps[READ][LIMIT_MAX] != U64_MAX)
snprintf(bufs[0], sizeof(bufs[0]), "%llu",
tg->bps[READ][LIMIT_MAX]);
if (tg->bps[WRITE][LIMIT_MAX] != U64_MAX)
snprintf(bufs[1], sizeof(bufs[1]), "%llu",
tg->bps[WRITE][LIMIT_MAX]);
if (tg->iops[READ][LIMIT_MAX] != UINT_MAX)
snprintf(bufs[2], sizeof(bufs[2]), "%u",
tg->iops[READ][LIMIT_MAX]);
if (tg->iops[WRITE][LIMIT_MAX] != UINT_MAX)
snprintf(bufs[3], sizeof(bufs[3]), "%u",
tg->iops[WRITE][LIMIT_MAX]);
seq_printf(sf, "%s rbps=%s wbps=%s riops=%s wiops=%s\n",
dname, bufs[0], bufs[1], bufs[2], bufs[3]);
@ -1312,10 +1340,10 @@ static ssize_t tg_set_max(struct kernfs_open_file *of,
tg = blkg_to_tg(ctx.blkg);
v[0] = tg->bps[READ];
v[1] = tg->bps[WRITE];
v[2] = tg->iops[READ];
v[3] = tg->iops[WRITE];
v[0] = tg->bps[READ][LIMIT_MAX];
v[1] = tg->bps[WRITE][LIMIT_MAX];
v[2] = tg->iops[READ][LIMIT_MAX];
v[3] = tg->iops[WRITE][LIMIT_MAX];
while (true) {
char tok[27]; /* wiops=18446744073709551616 */
@ -1352,10 +1380,10 @@ static ssize_t tg_set_max(struct kernfs_open_file *of,
goto out_finish;
}
tg->bps[READ] = v[0];
tg->bps[WRITE] = v[1];
tg->iops[READ] = v[2];
tg->iops[WRITE] = v[3];
tg->bps[READ][LIMIT_MAX] = v[0];
tg->bps[WRITE][LIMIT_MAX] = v[1];
tg->iops[READ][LIMIT_MAX] = v[2];
tg->iops[WRITE][LIMIT_MAX] = v[3];
tg_conf_updated(tg);
ret = 0;
@ -1453,8 +1481,9 @@ bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
/* out-of-limit, queue to @tg */
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_iter.bi_size, tg->bps[rw],
tg->io_disp[rw], tg->iops[rw],
tg->bytes_disp[rw], bio->bi_iter.bi_size,
tg_bps_limit(tg, rw),
tg->io_disp[rw], tg_iops_limit(tg, rw),
sq->nr_queued[READ], sq->nr_queued[WRITE]);
bio_associate_current(bio);
@ -1565,6 +1594,7 @@ int blk_throtl_init(struct request_queue *q)
q->td = td;
td->queue = q;
td->limit_valid[LIMIT_MAX] = true;
/* activate policy */
ret = blkcg_activate_policy(q, &blkcg_policy_throtl);
if (ret)