Add high limit for cgroup and corresponding cgroup interface.

Signed-off-by: Shaohua Li <[email protected]>
---
 block/blk-throttle.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 69 insertions(+), 5 deletions(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index a462e2f..5736d1b 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -87,8 +87,9 @@ enum tg_state_flags {
 
 enum {
        LIMIT_LOW = 0,
-       LIMIT_MAX = 1,
-       LIMIT_CNT = 2,
+       LIMIT_HIGH = 1,
+       LIMIT_MAX = 2,
+       LIMIT_CNT = 3,
 };
 
 struct throtl_grp {
@@ -240,6 +241,8 @@ static uint64_t tg_bps_limit(struct throtl_grp *tg, int rw)
                /* assign a small default */
                return 64 * 1024;
        }
+       if (ret == -1 && tg->td->limit_index == LIMIT_HIGH)
+               return tg->bps[rw][LIMIT_MAX];
 
        return ret;
 }
@@ -258,6 +261,8 @@ static unsigned int tg_iops_limit(struct throtl_grp *tg, 
int rw)
                /* assign a small default */
                return 16;
        }
+       if (ret == -1 && tg->td->limit_index == LIMIT_HIGH)
+               return tg->iops[rw][LIMIT_MAX];
        return ret;
 }
 
@@ -399,7 +404,7 @@ static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, 
int node)
 
        RB_CLEAR_NODE(&tg->rb_node);
        for (rw = READ; rw <= WRITE; rw++) {
-               for (index = LIMIT_MAX; index < LIMIT_CNT; index++) {
+               for (index = LIMIT_HIGH; index < LIMIT_CNT; index++) {
                        tg->bps[rw][index] = -1;
                        tg->iops[rw][index] = -1;
                }
@@ -466,6 +471,7 @@ static void blk_throtl_update_valid_limit(struct 
throtl_data *td)
        struct cgroup_subsys_state *pos_css;
        struct blkcg_gq *blkg;
        bool low_valid = false;
+       bool high_valid = false;
 
        blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) {
                struct throtl_grp *tg = blkg_to_tg(blkg);
@@ -475,12 +481,21 @@ static void blk_throtl_update_valid_limit(struct 
throtl_data *td)
                    tg->iops[READ][LIMIT_LOW] ||
                    tg->iops[WRITE][LIMIT_LOW])
                        low_valid = true;
+               if (tg->bps[READ][LIMIT_HIGH] != -1 ||
+                   tg->bps[WRITE][LIMIT_HIGH] != -1 ||
+                   tg->iops[READ][LIMIT_HIGH] != -1 ||
+                   tg->iops[WRITE][LIMIT_HIGH] != -1)
+                       high_valid = true;
        }
 
        if (low_valid)
                td->limit_valid[LIMIT_LOW] = true;
        else
                td->limit_valid[LIMIT_LOW] = false;
+       if (high_valid)
+               td->limit_valid[LIMIT_HIGH] = true;
+       else
+               td->limit_valid[LIMIT_HIGH] = false;
 }
 
 static void throtl_upgrade_state(struct throtl_data *td);
@@ -492,6 +507,10 @@ static void throtl_pd_offline(struct blkg_policy_data *pd)
        tg->bps[WRITE][LIMIT_LOW] = 0;
        tg->iops[READ][LIMIT_LOW] = 0;
        tg->iops[WRITE][LIMIT_LOW] = 0;
+       tg->bps[READ][LIMIT_HIGH] = -1;
+       tg->bps[WRITE][LIMIT_HIGH] = -1;
+       tg->iops[READ][LIMIT_HIGH] = -1;
+       tg->iops[WRITE][LIMIT_HIGH] = -1;
 
        blk_throtl_update_valid_limit(tg->td);
 
@@ -1476,7 +1495,15 @@ static ssize_t tg_set_limit(struct kernfs_open_file *of,
                if (v[0] < tg->bps[READ][LIMIT_LOW] ||
                    v[1] < tg->bps[WRITE][LIMIT_LOW] ||
                    v[2] < tg->iops[READ][LIMIT_LOW] ||
-                   v[3] < tg->iops[WRITE][LIMIT_LOW]) {
+                   v[3] < tg->iops[WRITE][LIMIT_LOW] ||
+                   (tg->bps[READ][LIMIT_HIGH] != -1 &&
+                    v[0] < tg->bps[READ][LIMIT_HIGH]) ||
+                   (tg->bps[WRITE][LIMIT_HIGH] != -1 &&
+                    v[1] < tg->bps[WRITE][LIMIT_HIGH]) ||
+                   (tg->iops[READ][LIMIT_HIGH] != -1 &&
+                    v[2] < tg->iops[READ][LIMIT_HIGH]) ||
+                   (tg->iops[WRITE][LIMIT_HIGH] != -1 &&
+                    v[3] < tg->iops[WRITE][LIMIT_HIGH])) {
                        ret = -EINVAL;
                        goto out_finish;
                }
@@ -1484,7 +1511,27 @@ static ssize_t tg_set_limit(struct kernfs_open_file *of,
                if (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[3] > tg->iops[WRITE][LIMIT_MAX] ||
+                   (tg->bps[READ][LIMIT_HIGH] != -1 &&
+                    v[0] > tg->bps[READ][LIMIT_HIGH]) ||
+                   (tg->bps[WRITE][LIMIT_HIGH] != -1 &&
+                    v[1] > tg->bps[WRITE][LIMIT_HIGH]) ||
+                   (tg->iops[READ][LIMIT_HIGH] != -1 &&
+                    v[2] > tg->iops[READ][LIMIT_HIGH]) ||
+                   (tg->iops[WRITE][LIMIT_HIGH] != -1 &&
+                    v[3] > tg->iops[WRITE][LIMIT_HIGH])) {
+                       ret = -EINVAL;
+                       goto out_finish;
+               }
+       } else if (index == LIMIT_HIGH) {
+               if ((v[0] != -1 && (v[0] < tg->bps[READ][LIMIT_LOW] ||
+                                   v[0] > tg->bps[READ][LIMIT_MAX])) ||
+                   (v[1] != -1 && (v[1] < tg->bps[WRITE][LIMIT_LOW] ||
+                                   v[1] > tg->bps[WRITE][LIMIT_MAX])) ||
+                   (v[2] != -1 && (v[2] < tg->iops[READ][LIMIT_LOW] ||
+                                   v[2] > tg->iops[READ][LIMIT_MAX])) ||
+                   (v[3] != -1 && (v[3] < tg->iops[WRITE][LIMIT_LOW] ||
+                                   v[3] > tg->iops[WRITE][LIMIT_MAX]))) {
                        ret = -EINVAL;
                        goto out_finish;
                }
@@ -1499,6 +1546,15 @@ static ssize_t tg_set_limit(struct kernfs_open_file *of,
                if (tg->td->limit_valid[LIMIT_LOW])
                        tg->td->limit_index = LIMIT_LOW;
        }
+       if (index == LIMIT_HIGH) {
+               blk_throtl_update_valid_limit(tg->td);
+               if (tg->td->limit_valid[LIMIT_HIGH] &&
+                   tg->td->limit_index == LIMIT_MAX)
+                       tg->td->limit_index = LIMIT_HIGH;
+       }
+       if (index == LIMIT_MAX && tg->td->limit_index == LIMIT_MAX &&
+           tg->td->limit_valid[LIMIT_HIGH])
+               tg->td->limit_index = LIMIT_HIGH;
        tg_conf_updated(tg);
        ret = 0;
 out_finish:
@@ -1515,6 +1571,13 @@ static struct cftype throtl_files[] = {
                .private = LIMIT_LOW,
        },
        {
+               .name = "high",
+               .flags = CFTYPE_NOT_ON_ROOT,
+               .seq_show = tg_print_limit,
+               .write = tg_set_limit,
+               .private = LIMIT_HIGH,
+       },
+       {
                .name = "max",
                .flags = CFTYPE_NOT_ON_ROOT,
                .seq_show = tg_print_limit,
@@ -1988,6 +2051,7 @@ int blk_throtl_init(struct request_queue *q)
        td->queue = q;
 
        td->limit_valid[LIMIT_LOW] = false;
+       td->limit_valid[LIMIT_HIGH] = false;
        td->limit_valid[LIMIT_MAX] = true;
        td->limit_index = LIMIT_MAX;
        td->low_upgrade_time = jiffies;
-- 
2.8.0.rc2

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