blk-cgroup: Introduce cgroup changes for throttling policy

o cgroup chagnes for throttle policy.

o Introduces READ and WRITE bytes per second throttling rules.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 7762987..aae8c93 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -128,6 +128,27 @@ blkio_update_group_weight(struct blkio_group *blkg, unsigned int weight)
        }
 }
 
+static inline void blkio_update_group_bps(struct blkio_group *blkg, u64 bps,
+                               int fileid)
+{
+       struct blkio_policy_type *blkiop;
+
+       list_for_each_entry(blkiop, &blkio_list, list) {
+
+               /* If this policy does not own the blkg, do not send updates */
+               if (blkiop->plid != blkg->plid)
+                       continue;
+
+               if (fileid == BLKIO_THROTL_read_bps_device
+                   && blkiop->ops.blkio_update_group_read_bps_fn)
+                       blkiop->ops.blkio_update_group_read_bps_fn(blkg, bps);
+
+               if (fileid == BLKIO_THROTL_write_bps_device
+                   && blkiop->ops.blkio_update_group_write_bps_fn)
+                       blkiop->ops.blkio_update_group_write_bps_fn(blkg, bps);
+       }
+}
+
 /*
  * Add to the appropriate stat variable depending on the request type.
  * This should be called with the blkg->stats_lock held.
@@ -612,6 +633,7 @@ static int blkio_policy_parse_and_set(char *buf,
        unsigned long major, minor, temp;
        int i = 0;
        dev_t dev;
+       u64 bps;
 
        memset(s, 0, sizeof(s));
 
@@ -667,7 +689,16 @@ static int blkio_policy_parse_and_set(char *buf,
 
                newpn->plid = plid;
                newpn->fileid = fileid;
-               newpn->weight = temp;
+               newpn->val.weight = temp;
+               break;
+       case BLKIO_POLICY_THROTL:
+               ret = strict_strtoull(s[1], 10, &bps);
+               if (ret)
+                       return -EINVAL;
+
+               newpn->plid = plid;
+               newpn->fileid = fileid;
+               newpn->val.bps = bps;
                break;
        default:
                BUG();
@@ -684,18 +715,45 @@ unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
        pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_PROP,
                                BLKIO_PROP_weight_device);
        if (pn)
-               return pn->weight;
+               return pn->val.weight;
        else
                return blkcg->weight;
 }
 EXPORT_SYMBOL_GPL(blkcg_get_weight);
 
+uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg, dev_t dev)
+{
+       struct blkio_policy_node *pn;
+
+       pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
+                               BLKIO_THROTL_read_bps_device);
+       if (pn)
+               return pn->val.bps;
+       else
+               return -1;
+}
+
+uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg, dev_t dev)
+{
+       struct blkio_policy_node *pn;
+       pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
+                               BLKIO_THROTL_write_bps_device);
+       if (pn)
+               return pn->val.bps;
+       else
+               return -1;
+}
+
 /* Checks whether user asked for deleting a policy rule */
 static bool blkio_delete_rule_command(struct blkio_policy_node *pn)
 {
        switch(pn->plid) {
        case BLKIO_POLICY_PROP:
-               if (pn->weight == 0)
+               if (pn->val.weight == 0)
+                       return 1;
+               break;
+       case BLKIO_POLICY_THROTL:
+               if (pn->val.bps == 0)
                        return 1;
                break;
        default:
@@ -710,7 +768,10 @@ static void blkio_update_policy_rule(struct blkio_policy_node *oldpn,
 {
        switch(oldpn->plid) {
        case BLKIO_POLICY_PROP:
-               oldpn->weight = newpn->weight;
+               oldpn->val.weight = newpn->val.weight;
+               break;
+       case BLKIO_POLICY_THROTL:
+               oldpn->val.bps = newpn->val.bps;
                break;
        default:
                BUG();
@@ -725,13 +786,23 @@ static void blkio_update_blkg_policy(struct blkio_cgroup *blkcg,
                struct blkio_group *blkg, struct blkio_policy_node *pn)
 {
        unsigned int weight;
+       u64 bps;
 
        switch(pn->plid) {
        case BLKIO_POLICY_PROP:
-               weight = pn->weight ? pn->weight :
+               weight = pn->val.weight ? pn->val.weight :
                                blkcg->weight;
                blkio_update_group_weight(blkg, weight);
                break;
+       case BLKIO_POLICY_THROTL:
+               switch(pn->fileid) {
+               case BLKIO_THROTL_read_bps_device:
+               case BLKIO_THROTL_write_bps_device:
+                       bps = pn->val.bps ? pn->val.bps : (-1);
+                       blkio_update_group_bps(blkg, bps, pn->fileid);
+                       break;
+               }
+               break;
        default:
                BUG();
        }
@@ -826,7 +897,17 @@ blkio_print_policy_node(struct seq_file *m, struct blkio_policy_node *pn)
                case BLKIO_POLICY_PROP:
                        if (pn->fileid == BLKIO_PROP_weight_device)
                                seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
-                                       MINOR(pn->dev), pn->weight);
+                                       MINOR(pn->dev), pn->val.weight);
+                       break;
+               case BLKIO_POLICY_THROTL:
+                       if (pn->fileid == BLKIO_THROTL_read_bps_device)
+                               seq_printf(m, "%u:%u\t%llu\n", MAJOR(pn->dev),
+                                       MINOR(pn->dev), pn->val.bps);
+                       else if (pn->fileid == BLKIO_THROTL_write_bps_device)
+                               seq_printf(m, "%u:%u\t%llu\n", MAJOR(pn->dev),
+                                       MINOR(pn->dev), pn->val.bps);
+                       else
+                               BUG();
                        break;
                default:
                        BUG();
@@ -869,6 +950,16 @@ static int blkiocg_file_read(struct cgroup *cgrp, struct cftype *cft,
                        BUG();
                }
                break;
+       case BLKIO_POLICY_THROTL:
+               switch(name){
+               case BLKIO_THROTL_read_bps_device:
+               case BLKIO_THROTL_write_bps_device:
+                       blkio_read_policy_node_files(cft, blkcg, m);
+                       return 0;
+               default:
+                       BUG();
+               }
+               break;
        default:
                BUG();
        }
@@ -959,7 +1050,18 @@ static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft,
                        BUG();
                }
                break;
-
+       case BLKIO_POLICY_THROTL:
+               switch(name){
+               case BLKIO_THROTL_io_service_bytes:
+                       return blkio_read_blkg_stats(blkcg, cft, cb,
+                                               BLKIO_STAT_SERVICE_BYTES, 1);
+               case BLKIO_THROTL_io_serviced:
+                       return blkio_read_blkg_stats(blkcg, cft, cb,
+                                               BLKIO_STAT_SERVICED, 1);
+               default:
+                       BUG();
+               }
+               break;
        default:
                BUG();
        }
@@ -1053,6 +1155,23 @@ struct cftype blkio_files[] = {
                .write_u64 = blkiocg_file_write_u64,
        },
        {
+               .name = "throttle.read_bps_device",
+               .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
+                               BLKIO_THROTL_read_bps_device),
+               .read_seq_string = blkiocg_file_read,
+               .write_string = blkiocg_file_write,
+               .max_write_len = 256,
+       },
+
+       {
+               .name = "throttle.write_bps_device",
+               .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
+                               BLKIO_THROTL_write_bps_device),
+               .read_seq_string = blkiocg_file_read,
+               .write_string = blkiocg_file_write,
+               .max_write_len = 256,
+       },
+       {
                .name = "time",
                .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
                                BLKIO_PROP_time),
@@ -1071,12 +1190,24 @@ struct cftype blkio_files[] = {
                .read_map = blkiocg_file_read_map,
        },
        {
+               .name = "throttle.io_service_bytes",
+               .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
+                               BLKIO_THROTL_io_service_bytes),
+               .read_map = blkiocg_file_read_map,
+       },
+       {
                .name = "io_serviced",
                .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
                                BLKIO_PROP_io_serviced),
                .read_map = blkiocg_file_read_map,
        },
        {
+               .name = "throttle.io_serviced",
+               .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
+                               BLKIO_THROTL_io_serviced),
+               .read_map = blkiocg_file_read_map,
+       },
+       {
                .name = "io_service_time",
                .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
                                BLKIO_PROP_io_service_time),

diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index c8de259..1b73882 100644 (file)
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -17,6 +17,7 @@
 
 enum blkio_policy_id {
        BLKIO_POLICY_PROP = 0,          /* Proportional Bandwidth division */
+       BLKIO_POLICY_THROTL,            /* Throttling */
 };
 
 #if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
@@ -88,6 +89,14 @@ enum blkcg_file_name_prop {
        BLKIO_PROP_dequeue,
 };
 
+/* cgroup files owned by throttle policy */
+enum blkcg_file_name_throtl {
+       BLKIO_THROTL_read_bps_device,
+       BLKIO_THROTL_write_bps_device,
+       BLKIO_THROTL_io_service_bytes,
+       BLKIO_THROTL_io_serviced,
+};
+
 struct blkio_cgroup {
        struct cgroup_subsys_state css;
        unsigned int weight;
@@ -146,23 +155,42 @@ struct blkio_group {
 struct blkio_policy_node {
        struct list_head node;
        dev_t dev;
-       unsigned int weight;
        /* This node belongs to max bw policy or porportional weight policy */
        enum blkio_policy_id plid;
        /* cgroup file to which this rule belongs to */
        int fileid;
+
+       union {
+               unsigned int weight;
+               /*
+                * Rate read/write in terms of byptes per second
+                * Whether this rate represents read or write is determined
+                * by file type "fileid".
+                */
+               u64 bps;
+       } val;
 };
 
 extern unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
                                     dev_t dev);
+extern uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg,
+                                    dev_t dev);
+extern uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg,
+                                    dev_t dev);
 
 typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
 typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
                                                unsigned int weight);
+typedef void (blkio_update_group_read_bps_fn) (struct blkio_group *blkg,
+                                               u64 read_bps);
+typedef void (blkio_update_group_write_bps_fn) (struct blkio_group *blkg,
+                                               u64 write_bps);
 
 struct blkio_policy_ops {
        blkio_unlink_group_fn *blkio_unlink_group_fn;
        blkio_update_group_weight_fn *blkio_update_group_weight_fn;
+       blkio_update_group_read_bps_fn *blkio_update_group_read_bps_fn;
+       blkio_update_group_write_bps_fn *blkio_update_group_write_bps_fn;
 };
 
 struct blkio_policy_type {