From 69d7fde5909b614114343974cfc52cb8ff30b544 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 18 Aug 2015 14:55:36 -0700 Subject: [PATCH] blkcg: use CGROUP_WEIGHT_* scale for io.weight on the unified hierarchy cgroup is trying to make interface consistent across different controllers. For weight based resource control, the knob should have the range [1, 10000] and default to 100. This patch updates cfq-iosched so that the weight range conforms. The internal calculations have enough range and the widening of the weight range shouldn't cause any problem. * blkcg_policy->cpd_bind_fn() is added. If present, this is invoked when blkcg is attached to a hierarchy. * cfq_cpd_init() is updated to use the new default value on the unified hierarchy. * cfq_cpd_bind() callback is implemented to clear per-blkg configs and apply the default config matching the hierarchy type. * cfqd->root_group->[leaf_]weight initialization in cfq_init_queue() is moved into !CONFIG_CFQ_GROUP_IOSCHED block. cfq_cpd_bind() is now responsible for initializing the initial weights when blkcg is enabled. Signed-off-by: Tejun Heo Cc: Vivek Goyal Cc: Arianna Avanzini Signed-off-by: Jens Axboe --- Documentation/cgroups/unified-hierarchy.txt | 2 +- block/blk-cgroup.c | 21 ++++++++ block/cfq-iosched.c | 55 +++++++++++++++------ include/linux/blk-cgroup.h | 2 + 4 files changed, 64 insertions(+), 16 deletions(-) diff --git a/Documentation/cgroups/unified-hierarchy.txt b/Documentation/cgroups/unified-hierarchy.txt index bd1ce15d5178..e0975c2cf03d 100644 --- a/Documentation/cgroups/unified-hierarchy.txt +++ b/Documentation/cgroups/unified-hierarchy.txt @@ -464,7 +464,7 @@ may be specified in any order and not all pairs have to be specified. The weight setting, currently only available and effective if cfq-iosched is in use for the target device. The weight is - between 10 and 1000 and defaults to 500. The first line + between 1 and 10000 and defaults to 100. The first line always contains the default weight in the following format to use when per-device setting is missing. diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 88bdb73bd5e0..ac8370cb2515 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1143,11 +1143,32 @@ static int blkcg_can_attach(struct cgroup_subsys_state *css, return ret; } +static void blkcg_bind(struct cgroup_subsys_state *root_css) +{ + int i; + + mutex_lock(&blkcg_pol_mutex); + + for (i = 0; i < BLKCG_MAX_POLS; i++) { + struct blkcg_policy *pol = blkcg_policy[i]; + struct blkcg *blkcg; + + if (!pol || !pol->cpd_bind_fn) + continue; + + list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) + if (blkcg->cpd[pol->plid]) + pol->cpd_bind_fn(blkcg->cpd[pol->plid]); + } + mutex_unlock(&blkcg_pol_mutex); +} + struct cgroup_subsys io_cgrp_subsys = { .css_alloc = blkcg_css_alloc, .css_offline = blkcg_css_offline, .css_free = blkcg_css_free, .can_attach = blkcg_can_attach, + .bind = blkcg_bind, .dfl_cftypes = blkcg_files, .legacy_cftypes = blkcg_legacy_files, .legacy_name = "blkio", diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 0fe721eaff28..04de88463a98 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1522,6 +1522,9 @@ static void cfq_init_cfqg_base(struct cfq_group *cfqg) } #ifdef CONFIG_CFQ_GROUP_IOSCHED +static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val, + bool on_dfl, bool reset_dev, bool is_leaf_weight); + static void cfqg_stats_exit(struct cfqg_stats *stats) { blkg_rwstat_exit(&stats->merged); @@ -1578,14 +1581,14 @@ static struct blkcg_policy_data *cfq_cpd_alloc(gfp_t gfp) static void cfq_cpd_init(struct blkcg_policy_data *cpd) { struct cfq_group_data *cgd = cpd_to_cfqgd(cpd); + unsigned int weight = cgroup_on_dfl(blkcg_root.css.cgroup) ? + CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL; - if (cpd_to_blkcg(cpd) == &blkcg_root) { - cgd->weight = 2 * CFQ_WEIGHT_LEGACY_DFL; - cgd->leaf_weight = 2 * CFQ_WEIGHT_LEGACY_DFL; - } else { - cgd->weight = CFQ_WEIGHT_LEGACY_DFL; - cgd->leaf_weight = CFQ_WEIGHT_LEGACY_DFL; - } + if (cpd_to_blkcg(cpd) == &blkcg_root) + weight *= 2; + + cgd->weight = weight; + cgd->leaf_weight = weight; } static void cfq_cpd_free(struct blkcg_policy_data *cpd) @@ -1593,6 +1596,19 @@ static void cfq_cpd_free(struct blkcg_policy_data *cpd) kfree(cpd_to_cfqgd(cpd)); } +static void cfq_cpd_bind(struct blkcg_policy_data *cpd) +{ + struct blkcg *blkcg = cpd_to_blkcg(cpd); + bool on_dfl = cgroup_on_dfl(blkcg_root.css.cgroup); + unsigned int weight = on_dfl ? CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL; + + if (blkcg == &blkcg_root) + weight *= 2; + + WARN_ON_ONCE(__cfq_set_weight(&blkcg->css, weight, on_dfl, true, false)); + WARN_ON_ONCE(__cfq_set_weight(&blkcg->css, weight, on_dfl, true, true)); +} + static struct blkg_policy_data *cfq_pd_alloc(gfp_t gfp, int node) { struct cfq_group *cfqg; @@ -1742,6 +1758,8 @@ static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off, bool on_dfl, bool is_leaf_weight) { + unsigned int min = on_dfl ? CGROUP_WEIGHT_MIN : CFQ_WEIGHT_LEGACY_MIN; + unsigned int max = on_dfl ? CGROUP_WEIGHT_MAX : CFQ_WEIGHT_LEGACY_MAX; struct blkcg *blkcg = css_to_blkcg(of_css(of)); struct blkg_conf_ctx ctx; struct cfq_group *cfqg; @@ -1769,7 +1787,7 @@ static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of, cfqgd = blkcg_to_cfqgd(blkcg); ret = -ERANGE; - if (!v || (v >= CFQ_WEIGHT_LEGACY_MIN && v <= CFQ_WEIGHT_LEGACY_MAX)) { + if (!v || (v >= min && v <= max)) { if (!is_leaf_weight) { cfqg->dev_weight = v; cfqg->new_weight = v ?: cfqgd->weight; @@ -1797,15 +1815,17 @@ static ssize_t cfqg_set_leaf_weight_device(struct kernfs_open_file *of, } static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val, - bool is_leaf_weight) + bool on_dfl, bool reset_dev, bool is_leaf_weight) { + unsigned int min = on_dfl ? CGROUP_WEIGHT_MIN : CFQ_WEIGHT_LEGACY_MIN; + unsigned int max = on_dfl ? CGROUP_WEIGHT_MAX : CFQ_WEIGHT_LEGACY_MAX; struct blkcg *blkcg = css_to_blkcg(css); struct blkcg_gq *blkg; struct cfq_group_data *cfqgd; int ret = 0; - if (val < CFQ_WEIGHT_LEGACY_MIN || val > CFQ_WEIGHT_LEGACY_MAX) - return -EINVAL; + if (val < min || val > max) + return -ERANGE; spin_lock_irq(&blkcg->lock); cfqgd = blkcg_to_cfqgd(blkcg); @@ -1826,9 +1846,13 @@ static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val, continue; if (!is_leaf_weight) { + if (reset_dev) + cfqg->dev_weight = 0; if (!cfqg->dev_weight) cfqg->new_weight = cfqgd->weight; } else { + if (reset_dev) + cfqg->dev_leaf_weight = 0; if (!cfqg->dev_leaf_weight) cfqg->new_leaf_weight = cfqgd->leaf_weight; } @@ -1842,13 +1866,13 @@ static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val, static int cfq_set_weight(struct cgroup_subsys_state *css, struct cftype *cft, u64 val) { - return __cfq_set_weight(css, val, false); + return __cfq_set_weight(css, val, false, false, false); } static int cfq_set_leaf_weight(struct cgroup_subsys_state *css, struct cftype *cft, u64 val) { - return __cfq_set_weight(css, val, true); + return __cfq_set_weight(css, val, false, false, true); } static int cfqg_print_stat(struct seq_file *sf, void *v) @@ -2135,7 +2159,7 @@ static ssize_t cfq_set_weight_on_dfl(struct kernfs_open_file *of, /* "WEIGHT" or "default WEIGHT" sets the default weight */ v = simple_strtoull(buf, &endp, 0); if (*endp == '\0' || sscanf(buf, "default %llu", &v) == 1) { - ret = __cfq_set_weight(of_css(of), v, false); + ret = __cfq_set_weight(of_css(of), v, true, false, false); return ret ?: nbytes; } @@ -4512,9 +4536,9 @@ static int cfq_init_queue(struct request_queue *q, struct elevator_type *e) goto out_free; cfq_init_cfqg_base(cfqd->root_group); -#endif cfqd->root_group->weight = 2 * CFQ_WEIGHT_LEGACY_DFL; cfqd->root_group->leaf_weight = 2 * CFQ_WEIGHT_LEGACY_DFL; +#endif /* * Not strictly needed (since RB_ROOT just clears the node and we @@ -4715,6 +4739,7 @@ static struct blkcg_policy blkcg_policy_cfq = { .cpd_alloc_fn = cfq_cpd_alloc, .cpd_init_fn = cfq_cpd_init, .cpd_free_fn = cfq_cpd_free, + .cpd_bind_fn = cfq_cpd_bind, .pd_alloc_fn = cfq_pd_alloc, .pd_init_fn = cfq_pd_init, diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 9a7c4bd45fff..0a5cc7a1109b 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -138,6 +138,7 @@ struct blkcg_gq { typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp); typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd); typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd); +typedef void (blkcg_pol_bind_cpd_fn)(struct blkcg_policy_data *cpd); typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp, int node); typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd); typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd); @@ -155,6 +156,7 @@ struct blkcg_policy { blkcg_pol_alloc_cpd_fn *cpd_alloc_fn; blkcg_pol_init_cpd_fn *cpd_init_fn; blkcg_pol_free_cpd_fn *cpd_free_fn; + blkcg_pol_bind_cpd_fn *cpd_bind_fn; blkcg_pol_alloc_pd_fn *pd_alloc_fn; blkcg_pol_init_pd_fn *pd_init_fn;