]> git.kernelconcepts.de Git - karo-tx-linux.git/blobdiff - block/blk-throttle.c
blk-throttle: add .low interface
[karo-tx-linux.git] / block / blk-throttle.c
index 1da9f30cc3d10363a7fe0fd1a7ffae307423c12e..b7b69ecb6e9679ff7cc35e58f2ecc4c3d4a47ee9 100644 (file)
@@ -84,6 +84,7 @@ enum tg_state_flags {
 #define rb_entry_tg(node)      rb_entry((node), struct throtl_grp, rb_node)
 
 enum {
+       LIMIT_LOW,
        LIMIT_MAX,
        LIMIT_CNT,
 };
@@ -124,11 +125,15 @@ struct throtl_grp {
        /* are there any throtl rules between this group and td? */
        bool has_rules[2];
 
-       /* bytes per second rate limits */
+       /* internally used bytes per second rate limits */
        uint64_t bps[2][LIMIT_CNT];
+       /* user configured bps limits */
+       uint64_t bps_conf[2][LIMIT_CNT];
 
-       /* IOPS limits */
+       /* internally used IOPS limits */
        unsigned int iops[2][LIMIT_CNT];
+       /* user configured IOPS limits */
+       unsigned int iops_conf[2][LIMIT_CNT];
 
        /* Number of bytes disptached in current slice */
        uint64_t bytes_disp[2];
@@ -355,6 +360,11 @@ static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node)
        tg->bps[WRITE][LIMIT_MAX] = U64_MAX;
        tg->iops[READ][LIMIT_MAX] = UINT_MAX;
        tg->iops[WRITE][LIMIT_MAX] = UINT_MAX;
+       tg->bps_conf[READ][LIMIT_MAX] = U64_MAX;
+       tg->bps_conf[WRITE][LIMIT_MAX] = U64_MAX;
+       tg->iops_conf[READ][LIMIT_MAX] = UINT_MAX;
+       tg->iops_conf[WRITE][LIMIT_MAX] = UINT_MAX;
+       /* LIMIT_LOW will have default value 0 */
 
        return &tg->pd;
 }
@@ -412,6 +422,41 @@ static void throtl_pd_online(struct blkg_policy_data *pd)
        tg_update_has_rules(pd_to_tg(pd));
 }
 
+static void blk_throtl_update_limit_valid(struct throtl_data *td)
+{
+       struct cgroup_subsys_state *pos_css;
+       struct blkcg_gq *blkg;
+       bool low_valid = false;
+
+       rcu_read_lock();
+       blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) {
+               struct throtl_grp *tg = blkg_to_tg(blkg);
+
+               if (tg->bps[READ][LIMIT_LOW] || tg->bps[WRITE][LIMIT_LOW] ||
+                   tg->iops[READ][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW])
+                       low_valid = true;
+       }
+       rcu_read_unlock();
+
+       td->limit_valid[LIMIT_LOW] = low_valid;
+}
+
+static void throtl_pd_offline(struct blkg_policy_data *pd)
+{
+       struct throtl_grp *tg = pd_to_tg(pd);
+
+       tg->bps[READ][LIMIT_LOW] = 0;
+       tg->bps[WRITE][LIMIT_LOW] = 0;
+       tg->iops[READ][LIMIT_LOW] = 0;
+       tg->iops[WRITE][LIMIT_LOW] = 0;
+
+       blk_throtl_update_limit_valid(tg->td);
+
+       if (tg->td->limit_index == LIMIT_LOW &&
+           !tg->td->limit_valid[LIMIT_LOW])
+               tg->td->limit_index = LIMIT_MAX;
+}
+
 static void throtl_pd_free(struct blkg_policy_data *pd)
 {
        struct throtl_grp *tg = pd_to_tg(pd);
@@ -1284,48 +1329,58 @@ static struct cftype throtl_legacy_files[] = {
        { }     /* terminate */
 };
 
-static u64 tg_prfill_max(struct seq_file *sf, struct blkg_policy_data *pd,
+static u64 tg_prfill_limit(struct seq_file *sf, struct blkg_policy_data *pd,
                         int off)
 {
        struct throtl_grp *tg = pd_to_tg(pd);
        const char *dname = blkg_dev_name(pd->blkg);
        char bufs[4][21] = { "max", "max", "max", "max" };
+       u64 bps_dft;
+       unsigned int iops_dft;
 
        if (!dname)
                return 0;
 
-       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)
+       if (off == LIMIT_LOW) {
+               bps_dft = 0;
+               iops_dft = 0;
+       } else {
+               bps_dft = U64_MAX;
+               iops_dft = UINT_MAX;
+       }
+
+       if (tg->bps_conf[READ][off] == bps_dft &&
+           tg->bps_conf[WRITE][off] == bps_dft &&
+           tg->iops_conf[READ][off] == iops_dft &&
+           tg->iops_conf[WRITE][off] == iops_dft)
                return 0;
 
-       if (tg->bps[READ][LIMIT_MAX] != U64_MAX)
+       if (tg->bps_conf[READ][off] != bps_dft)
                snprintf(bufs[0], sizeof(bufs[0]), "%llu",
-                       tg->bps[READ][LIMIT_MAX]);
-       if (tg->bps[WRITE][LIMIT_MAX] != U64_MAX)
+                       tg->bps_conf[READ][off]);
+       if (tg->bps_conf[WRITE][off] != bps_dft)
                snprintf(bufs[1], sizeof(bufs[1]), "%llu",
-                       tg->bps[WRITE][LIMIT_MAX]);
-       if (tg->iops[READ][LIMIT_MAX] != UINT_MAX)
+                       tg->bps_conf[WRITE][off]);
+       if (tg->iops_conf[READ][off] != iops_dft)
                snprintf(bufs[2], sizeof(bufs[2]), "%u",
-                       tg->iops[READ][LIMIT_MAX]);
-       if (tg->iops[WRITE][LIMIT_MAX] != UINT_MAX)
+                       tg->iops_conf[READ][off]);
+       if (tg->iops_conf[WRITE][off] != iops_dft)
                snprintf(bufs[3], sizeof(bufs[3]), "%u",
-                       tg->iops[WRITE][LIMIT_MAX]);
+                       tg->iops_conf[WRITE][off]);
 
        seq_printf(sf, "%s rbps=%s wbps=%s riops=%s wiops=%s\n",
                   dname, bufs[0], bufs[1], bufs[2], bufs[3]);
        return 0;
 }
 
-static int tg_print_max(struct seq_file *sf, void *v)
+static int tg_print_limit(struct seq_file *sf, void *v)
 {
-       blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_max,
+       blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_limit,
                          &blkcg_policy_throtl, seq_cft(sf)->private, false);
        return 0;
 }
 
-static ssize_t tg_set_max(struct kernfs_open_file *of,
+static ssize_t tg_set_limit(struct kernfs_open_file *of,
                          char *buf, size_t nbytes, loff_t off)
 {
        struct blkcg *blkcg = css_to_blkcg(of_css(of));
@@ -1333,6 +1388,7 @@ static ssize_t tg_set_max(struct kernfs_open_file *of,
        struct throtl_grp *tg;
        u64 v[4];
        int ret;
+       int index = of_cft(of)->private;
 
        ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx);
        if (ret)
@@ -1340,10 +1396,10 @@ static ssize_t tg_set_max(struct kernfs_open_file *of,
 
        tg = blkg_to_tg(ctx.blkg);
 
-       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];
+       v[0] = tg->bps_conf[READ][index];
+       v[1] = tg->bps_conf[WRITE][index];
+       v[2] = tg->iops_conf[READ][index];
+       v[3] = tg->iops_conf[WRITE][index];
 
        while (true) {
                char tok[27];   /* wiops=18446744073709551616 */
@@ -1380,11 +1436,31 @@ static ssize_t tg_set_max(struct kernfs_open_file *of,
                        goto out_finish;
        }
 
-       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->bps_conf[READ][index] = v[0];
+       tg->bps_conf[WRITE][index] = v[1];
+       tg->iops_conf[READ][index] = v[2];
+       tg->iops_conf[WRITE][index] = v[3];
 
+       if (index == LIMIT_MAX) {
+               tg->bps[READ][index] = v[0];
+               tg->bps[WRITE][index] = v[1];
+               tg->iops[READ][index] = v[2];
+               tg->iops[WRITE][index] = v[3];
+       }
+       tg->bps[READ][LIMIT_LOW] = min(tg->bps_conf[READ][LIMIT_LOW],
+               tg->bps_conf[READ][LIMIT_MAX]);
+       tg->bps[WRITE][LIMIT_LOW] = min(tg->bps_conf[WRITE][LIMIT_LOW],
+               tg->bps_conf[WRITE][LIMIT_MAX]);
+       tg->iops[READ][LIMIT_LOW] = min(tg->iops_conf[READ][LIMIT_LOW],
+               tg->iops_conf[READ][LIMIT_MAX]);
+       tg->iops[WRITE][LIMIT_LOW] = min(tg->iops_conf[WRITE][LIMIT_LOW],
+               tg->iops_conf[WRITE][LIMIT_MAX]);
+
+       if (index == LIMIT_LOW) {
+               blk_throtl_update_limit_valid(tg->td);
+               if (tg->td->limit_valid[LIMIT_LOW])
+                       tg->td->limit_index = LIMIT_LOW;
+       }
        tg_conf_updated(tg);
        ret = 0;
 out_finish:
@@ -1393,11 +1469,21 @@ out_finish:
 }
 
 static struct cftype throtl_files[] = {
+#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
+       {
+               .name = "low",
+               .flags = CFTYPE_NOT_ON_ROOT,
+               .seq_show = tg_print_limit,
+               .write = tg_set_limit,
+               .private = LIMIT_LOW,
+       },
+#endif
        {
                .name = "max",
                .flags = CFTYPE_NOT_ON_ROOT,
-               .seq_show = tg_print_max,
-               .write = tg_set_max,
+               .seq_show = tg_print_limit,
+               .write = tg_set_limit,
+               .private = LIMIT_MAX,
        },
        { }     /* terminate */
 };
@@ -1416,6 +1502,7 @@ static struct blkcg_policy blkcg_policy_throtl = {
        .pd_alloc_fn            = throtl_pd_alloc,
        .pd_init_fn             = throtl_pd_init,
        .pd_online_fn           = throtl_pd_online,
+       .pd_offline_fn          = throtl_pd_offline,
        .pd_free_fn             = throtl_pd_free,
 };
 
@@ -1595,6 +1682,7 @@ int blk_throtl_init(struct request_queue *q)
        td->queue = q;
 
        td->limit_valid[LIMIT_MAX] = true;
+       td->limit_index = LIMIT_MAX;
        /* activate policy */
        ret = blkcg_activate_policy(q, &blkcg_policy_throtl);
        if (ret)