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>

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 0d5d85ba25ea346813408d30136288f98a4af8e8..1da9f30cc3d10363a7fe0fd1a7ffae307423c12e 100644 (file)
--- 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,
+       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)