From 795fe54c2a828099e461e8c36b04210b2df462ed Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Wed, 28 Aug 2019 11:54:53 +0800 Subject: bfq: Add per-device weight This adds to BFQ the missing per-device weight interfaces: blkio.bfq.weight_device on legacy and io.bfq.weight on unified. The implementation pretty closely resembles what we had in CFQ and the parsing code is basically reused. Tests ===== Using two cgroups and three block devices, having weights setup as: Cgroup test1 test2 ============================================ default 100 500 sda 500 100 sdb default default sdc 200 200 cgroup v1 runs -------------- sda.test1.out: READ: bw=913MiB/s sda.test2.out: READ: bw=183MiB/s sdb.test1.out: READ: bw=213MiB/s sdb.test2.out: READ: bw=1054MiB/s sdc.test1.out: READ: bw=650MiB/s sdc.test2.out: READ: bw=650MiB/s cgroup v2 runs -------------- sda.test1.out: READ: bw=915MiB/s sda.test2.out: READ: bw=184MiB/s sdb.test1.out: READ: bw=216MiB/s sdb.test2.out: READ: bw=1069MiB/s sdc.test1.out: READ: bw=621MiB/s sdc.test2.out: READ: bw=622MiB/s Signed-off-by: Fam Zheng Acked-by: Tejun Heo Reviewed-by: Paolo Valente Signed-off-by: Jens Axboe --- block/bfq-cgroup.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++------- block/bfq-iosched.h | 3 ++ 2 files changed, 87 insertions(+), 11 deletions(-) (limited to 'block') diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c index 102bdfd6f72c..86a607cf19a1 100644 --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -905,7 +905,7 @@ void bfq_end_wr_async(struct bfq_data *bfqd) bfq_end_wr_async_queues(bfqd, bfqd->root_group); } -static int bfq_io_show_weight(struct seq_file *sf, void *v) +static int bfq_io_show_weight_legacy(struct seq_file *sf, void *v) { struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg); @@ -919,8 +919,32 @@ static int bfq_io_show_weight(struct seq_file *sf, void *v) return 0; } -static void bfq_group_set_weight(struct bfq_group *bfqg, u64 weight) +static u64 bfqg_prfill_weight_device(struct seq_file *sf, + struct blkg_policy_data *pd, int off) +{ + struct bfq_group *bfqg = pd_to_bfqg(pd); + + if (!bfqg->entity.dev_weight) + return 0; + return __blkg_prfill_u64(sf, pd, bfqg->entity.dev_weight); +} + +static int bfq_io_show_weight(struct seq_file *sf, void *v) +{ + struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); + struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg); + + seq_printf(sf, "default %u\n", bfqgd->weight); + blkcg_print_blkgs(sf, blkcg, bfqg_prfill_weight_device, + &blkcg_policy_bfq, 0, false); + return 0; +} + +static void bfq_group_set_weight(struct bfq_group *bfqg, u64 weight, u64 dev_weight) { + weight = dev_weight ?: weight; + + bfqg->entity.dev_weight = dev_weight; /* * Setting the prio_changed flag of the entity * to 1 with new_weight == weight would re-set @@ -968,28 +992,71 @@ static int bfq_io_set_weight_legacy(struct cgroup_subsys_state *css, struct bfq_group *bfqg = blkg_to_bfqg(blkg); if (bfqg) - bfq_group_set_weight(bfqg, val); + bfq_group_set_weight(bfqg, val, 0); } spin_unlock_irq(&blkcg->lock); return ret; } -static ssize_t bfq_io_set_weight(struct kernfs_open_file *of, - char *buf, size_t nbytes, - loff_t off) +static ssize_t bfq_io_set_device_weight(struct kernfs_open_file *of, + char *buf, size_t nbytes, + loff_t off) { - u64 weight; - /* First unsigned long found in the file is used */ - int ret = kstrtoull(strim(buf), 0, &weight); + int ret; + struct blkg_conf_ctx ctx; + struct blkcg *blkcg = css_to_blkcg(of_css(of)); + struct bfq_group *bfqg; + u64 v; + ret = blkg_conf_prep(blkcg, &blkcg_policy_bfq, buf, &ctx); if (ret) return ret; - ret = bfq_io_set_weight_legacy(of_css(of), NULL, weight); + if (sscanf(ctx.body, "%llu", &v) == 1) { + /* require "default" on dfl */ + ret = -ERANGE; + if (!v) + goto out; + } else if (!strcmp(strim(ctx.body), "default")) { + v = 0; + } else { + ret = -EINVAL; + goto out; + } + + bfqg = blkg_to_bfqg(ctx.blkg); + + ret = -ERANGE; + if (!v || (v >= BFQ_MIN_WEIGHT && v <= BFQ_MAX_WEIGHT)) { + bfq_group_set_weight(bfqg, bfqg->entity.weight, v); + ret = 0; + } +out: + blkg_conf_finish(&ctx); return ret ?: nbytes; } +static ssize_t bfq_io_set_weight(struct kernfs_open_file *of, + char *buf, size_t nbytes, + loff_t off) +{ + char *endp; + int ret; + u64 v; + + buf = strim(buf); + + /* "WEIGHT" or "default WEIGHT" sets the default weight */ + v = simple_strtoull(buf, &endp, 0); + if (*endp == '\0' || sscanf(buf, "default %llu", &v) == 1) { + ret = bfq_io_set_weight_legacy(of_css(of), NULL, v); + return ret ?: nbytes; + } + + return bfq_io_set_device_weight(of, buf, nbytes, off); +} + #ifdef CONFIG_BFQ_CGROUP_DEBUG static int bfqg_print_stat(struct seq_file *sf, void *v) { @@ -1146,9 +1213,15 @@ struct cftype bfq_blkcg_legacy_files[] = { { .name = "bfq.weight", .flags = CFTYPE_NOT_ON_ROOT, - .seq_show = bfq_io_show_weight, + .seq_show = bfq_io_show_weight_legacy, .write_u64 = bfq_io_set_weight_legacy, }, + { + .name = "bfq.weight_device", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = bfq_io_show_weight, + .write = bfq_io_set_weight, + }, /* statistics, covers only the tasks in the bfqg */ { diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h index e80adf822bbe..5d1a519640f6 100644 --- a/block/bfq-iosched.h +++ b/block/bfq-iosched.h @@ -168,6 +168,9 @@ struct bfq_entity { /* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */ int budget; + /* device weight, if non-zero, it overrides the default weight of + * bfq_group_data */ + int dev_weight; /* weight of the queue */ int weight; /* next weight if a change is in progress */ -- cgit