From e4a9bde9589fdc51283755cdd75d47b27ca7c6fb Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 18 Aug 2015 14:55:16 -0700 Subject: [PATCH] blkcg: replace blkcg_policy->cpd_size with ->cpd_alloc/free_fn() methods Each active policy has a cpd (blkcg_policy_data) on each blkcg. The cpd's were allocated by blkcg core and each policy could request to allocate extra space at the end by setting blkcg_policy->cpd_size larger than the size of cpd. This is a bit unusual but blkg (blkcg_gq) policy data used to be handled this way too so it made sense to be consistent; however, blkg policy data switched to alloc/free callbacks. This patch makes similar changes to cpd handling. blkcg_policy->cpd_alloc/free_fn() are added to replace ->cpd_size. As cpd allocation is now done from policy side, it can simply allocate a larger area which embeds cpd at the beginning. As ->cpd_alloc_fn() may be able to perform all necessary initializations, this patch makes ->cpd_init_fn() optional. Signed-off-by: Tejun Heo Cc: Vivek Goyal Cc: Arianna Avanzini Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 39 +++++++++++++++++++++++--------------- block/cfq-iosched.c | 19 ++++++++++++++++++- include/linux/blk-cgroup.h | 17 ++++++++++------- 3 files changed, 52 insertions(+), 23 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 247c42c8c83b..2b4354b6b5de 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -817,11 +817,15 @@ static void blkcg_css_free(struct cgroup_subsys_state *css) int i; mutex_lock(&blkcg_pol_mutex); + list_del(&blkcg->all_blkcgs_node); - mutex_unlock(&blkcg_pol_mutex); for (i = 0; i < BLKCG_MAX_POLS; i++) - kfree(blkcg->cpd[i]); + if (blkcg->cpd[i]) + blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]); + + mutex_unlock(&blkcg_pol_mutex); + kfree(blkcg); } @@ -854,11 +858,10 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css) * check if the policy requires any specific per-cgroup * data: if it does, allocate and initialize it. */ - if (!pol || !pol->cpd_size) + if (!pol || !pol->cpd_alloc_fn) continue; - BUG_ON(blkcg->cpd[i]); - cpd = kzalloc(pol->cpd_size, GFP_KERNEL); + cpd = pol->cpd_alloc_fn(GFP_KERNEL); if (!cpd) { ret = ERR_PTR(-ENOMEM); goto free_pd_blkcg; @@ -866,7 +869,8 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css) blkcg->cpd[i] = cpd; cpd->blkcg = blkcg; cpd->plid = i; - pol->cpd_init_fn(cpd); + if (pol->cpd_init_fn) + pol->cpd_init_fn(cpd); } spin_lock_init(&blkcg->lock); @@ -882,7 +886,8 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css) free_pd_blkcg: for (i--; i >= 0; i--) - kfree(blkcg->cpd[i]); + if (blkcg->cpd[i]) + blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]); free_blkcg: kfree(blkcg); mutex_unlock(&blkcg_pol_mutex); @@ -1159,11 +1164,11 @@ int blkcg_policy_register(struct blkcg_policy *pol) blkcg_policy[pol->plid] = pol; /* allocate and install cpd's */ - if (pol->cpd_size) { + if (pol->cpd_alloc_fn) { list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) { struct blkcg_policy_data *cpd; - cpd = kzalloc(pol->cpd_size, GFP_KERNEL); + cpd = pol->cpd_alloc_fn(GFP_KERNEL); if (!cpd) { mutex_unlock(&blkcg_pol_mutex); goto err_free_cpds; @@ -1186,10 +1191,12 @@ int blkcg_policy_register(struct blkcg_policy *pol) return 0; err_free_cpds: - if (pol->cpd_size) { + if (pol->cpd_alloc_fn) { list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) { - kfree(blkcg->cpd[pol->plid]); - blkcg->cpd[pol->plid] = NULL; + if (blkcg->cpd[pol->plid]) { + pol->cpd_free_fn(blkcg->cpd[pol->plid]); + blkcg->cpd[pol->plid] = NULL; + } } } blkcg_policy[pol->plid] = NULL; @@ -1222,10 +1229,12 @@ void blkcg_policy_unregister(struct blkcg_policy *pol) /* remove cpds and unregister */ mutex_lock(&blkcg_pol_mutex); - if (pol->cpd_size) { + if (pol->cpd_alloc_fn) { list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) { - kfree(blkcg->cpd[pol->plid]); - blkcg->cpd[pol->plid] = NULL; + if (blkcg->cpd[pol->plid]) { + pol->cpd_free_fn(blkcg->cpd[pol->plid]); + blkcg->cpd[pol->plid] = NULL; + } } } blkcg_policy[pol->plid] = NULL; diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index dd6ea9ee6245..a4429b366820 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1568,6 +1568,16 @@ static void cfqg_stats_init(struct cfqg_stats *stats) #endif } +static struct blkcg_policy_data *cfq_cpd_alloc(gfp_t gfp) +{ + struct cfq_group_data *cgd; + + cgd = kzalloc(sizeof(*cgd), GFP_KERNEL); + if (!cgd) + return NULL; + return &cgd->cpd; +} + static void cfq_cpd_init(struct blkcg_policy_data *cpd) { struct cfq_group_data *cgd = cpd_to_cfqgd(cpd); @@ -1581,6 +1591,11 @@ static void cfq_cpd_init(struct blkcg_policy_data *cpd) } } +static void cfq_cpd_free(struct blkcg_policy_data *cpd) +{ + kfree(cpd_to_cfqgd(cpd)); +} + static struct blkg_policy_data *cfq_pd_alloc(gfp_t gfp, int node) { struct cfq_group *cfqg; @@ -4649,10 +4664,12 @@ static struct elevator_type iosched_cfq = { #ifdef CONFIG_CFQ_GROUP_IOSCHED static struct blkcg_policy blkcg_policy_cfq = { - .cpd_size = sizeof(struct cfq_group_data), .cftypes = cfq_blkcg_files, + .cpd_alloc_fn = cfq_cpd_alloc, .cpd_init_fn = cfq_cpd_init, + .cpd_free_fn = cfq_cpd_free, + .pd_alloc_fn = cfq_pd_alloc, .pd_init_fn = cfq_pd_init, .pd_offline_fn = cfq_pd_offline, diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 7988d4749fff..15f2382bc723 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -81,11 +81,11 @@ struct blkg_policy_data { }; /* - * Policies that need to keep per-blkcg data which is independent - * from any request_queue associated to it must specify its size - * with the cpd_size field of the blkcg_policy structure and - * embed a blkcg_policy_data in it. cpd_init() is invoked to let - * each policy handle per-blkcg data. + * Policies that need to keep per-blkcg data which is independent from any + * request_queue associated to it should implement cpd_alloc/free_fn() + * methods. A policy can allocate private data area by allocating larger + * data structure which embeds blkcg_policy_data at the beginning. + * cpd_init() is invoked to let each policy handle per-blkcg data. */ struct blkcg_policy_data { /* the blkcg and policy id this per-policy data belongs to */ @@ -124,7 +124,9 @@ struct blkcg_gq { struct rcu_head rcu_head; }; +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 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); @@ -134,13 +136,14 @@ typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd); struct blkcg_policy { int plid; - /* policy specific per-blkcg data size */ - size_t cpd_size; /* cgroup files for the policy */ struct cftype *cftypes; /* operations */ + 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_alloc_pd_fn *pd_alloc_fn; blkcg_pol_init_pd_fn *pd_init_fn; blkcg_pol_online_pd_fn *pd_online_fn;