[PATCH V2 01/11] block-throttle: prepare support multiple limits

From: Shaohua Li
Date: Thu Sep 15 2016 - 12:24:31 EST

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

Signed-off-by: Shaohua Li <shli@xxxxxx>
---
block/blk-throttle.c | 109 ++++++++++++++++++++++++++++++++-------------------
1 file changed, 68 insertions(+), 41 deletions(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index f1aba26..71ecee7 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -83,6 +83,11 @@ enum tg_state_flags {

#define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node)

+enum {
+ LIMIT_MAX = 0,
+ LIMIT_CNT = 1,
+};
+
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
@@ -320,7 +337,7 @@ static void throtl_service_queue_init(struct throtl_service_queue *sq)
static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node)
{
struct throtl_grp *tg;
- int rw;
+ int rw, index;

tg = kzalloc_node(sizeof(*tg), gfp, node);
if (!tg)
@@ -334,10 +351,12 @@ static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node)
}

RB_CLEAR_NODE(&tg->rb_node);
- tg->bps[READ] = -1;
- tg->bps[WRITE] = -1;
- tg->iops[READ] = -1;
- tg->iops[WRITE] = -1;
+ for (rw = READ; rw <= WRITE; rw++) {
+ for (index = LIMIT_MAX; index < LIMIT_CNT; index++) {
+ tg->bps[rw][index] = -1;
+ tg->iops[rw][index] = -1;
+ }
+ }

return &tg->pd;
}
@@ -376,11 +395,14 @@ 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] != -1 || tg->iops[rw] != -1);
+ (td->limit_valid[td->limit_index] &&
+ (tg_bps_limit(tg, rw) != -1 ||
+ tg_iops_limit(tg, rw) != -1));
}

static void throtl_pd_online(struct blkg_policy_data *pd)
@@ -632,11 +654,11 @@ 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 +704,7 @@ 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 +719,7 @@ 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 +746,7 @@ 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 +758,7 @@ 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 +793,7 @@ 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] == -1 && tg->iops[rw] == -1) {
+ if (tg_bps_limit(tg, rw) == -1 && tg_iops_limit(tg, rw) == -1) {
if (wait)
*wait = 0;
return true;
@@ -1146,8 +1168,8 @@ 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
@@ -1224,25 +1246,25 @@ 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,
},
@@ -1268,18 +1290,22 @@ static u64 tg_prfill_max(struct seq_file *sf, struct blkg_policy_data *pd,

if (!dname)
return 0;
- if (tg->bps[READ] == -1 && tg->bps[WRITE] == -1 &&
- tg->iops[READ] == -1 && tg->iops[WRITE] == -1)
+ if (tg->bps[READ][LIMIT_MAX] == -1 && tg->bps[WRITE][LIMIT_MAX] == -1 &&
+ tg->iops[READ][LIMIT_MAX] == -1 && tg->iops[WRITE][LIMIT_MAX] == -1)
return 0;

- if (tg->bps[READ] != -1)
- snprintf(bufs[0], sizeof(bufs[0]), "%llu", tg->bps[READ]);
- if (tg->bps[WRITE] != -1)
- snprintf(bufs[1], sizeof(bufs[1]), "%llu", tg->bps[WRITE]);
- if (tg->iops[READ] != -1)
- snprintf(bufs[2], sizeof(bufs[2]), "%u", tg->iops[READ]);
- if (tg->iops[WRITE] != -1)
- snprintf(bufs[3], sizeof(bufs[3]), "%u", tg->iops[WRITE]);
+ if (tg->bps[READ][LIMIT_MAX] != -1)
+ snprintf(bufs[0], sizeof(bufs[0]), "%llu",
+ tg->bps[READ][LIMIT_MAX]);
+ if (tg->bps[WRITE][LIMIT_MAX] != -1)
+ snprintf(bufs[1], sizeof(bufs[1]), "%llu",
+ tg->bps[WRITE][LIMIT_MAX]);
+ if (tg->iops[READ][LIMIT_MAX] != -1)
+ snprintf(bufs[2], sizeof(bufs[2]), "%u",
+ tg->iops[READ][LIMIT_MAX]);
+ if (tg->iops[WRITE][LIMIT_MAX] != -1)
+ 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]);
@@ -1308,10 +1334,10 @@ 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 */
@@ -1348,10 +1374,10 @@ 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;
@@ -1449,8 +1475,8 @@ 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);
@@ -1561,6 +1587,7 @@ 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)
--
2.8.0.rc2

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