From 90d3839b90fe379557dae4a44735a6af78f42885 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 12 Nov 2013 19:42:14 -0800 Subject: [PATCH] block: Use u64_stats_init() to initialize seqcounts Now that seqcounts are lockdep enabled objects, we need to explicitly initialize runtime allocated seqcounts so that lockdep can track them. Without this patch, Fengguang was seeing: [ 4.127282] INFO: trying to register non-static key. [ 4.128027] the code is fine but needs lockdep annotation. [ 4.128027] turning off the locking correctness validator. [ 4.128027] CPU: 0 PID: 96 Comm: kworker/u4:1 Not tainted 3.12.0-next-20131108-10601-gbad570d #2 [ 4.128027] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ ... ] [ 4.128027] Call Trace: [ 4.128027] [<7908e744>] ? console_unlock+0x353/0x380 [ 4.128027] [<79dc7cf2>] dump_stack+0x48/0x60 [ 4.128027] [<7908953e>] __lock_acquire.isra.26+0x7e3/0xceb [ 4.128027] [<7908a1c5>] lock_acquire+0x71/0x9a [ 4.128027] [<794079aa>] ? blk_throtl_bio+0x1c3/0x485 [ 4.128027] [<7940658b>] throtl_update_dispatch_stats+0x7c/0x153 [ 4.128027] [<794079aa>] ? blk_throtl_bio+0x1c3/0x485 [ 4.128027] [<794079aa>] blk_throtl_bio+0x1c3/0x485 ... Use u64_stats_init() for all affected data structures, which initializes the seqcount. Reported-and-Tested-by: Fengguang Wu Cc: Vivek Goyal Cc: Jens Axboe Signed-off-by: Peter Zijlstra [ Folded in another fix from the mailing list as well as a fix to that fix. Tweaked commit message. ] Signed-off-by: John Stultz Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1384314134-6895-1-git-send-email-john.stultz@linaro.org [ So I actually think that the two SOBs from PeterZ are the right depiction of the patch route. ] Signed-off-by: Ingo Molnar --- block/blk-cgroup.h | 10 ++++++++++ block/blk-throttle.c | 10 ++++++++++ block/cfq-iosched.c | 25 +++++++++++++++++++++++++ 3 files changed, 45 insertions(+) diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index ae6969a7ffd4..1610b22edf09 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -402,6 +402,11 @@ struct request_list *__blk_queue_next_rl(struct request_list *rl, #define blk_queue_for_each_rl(rl, q) \ for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q))) +static inline void blkg_stat_init(struct blkg_stat *stat) +{ + u64_stats_init(&stat->syncp); +} + /** * blkg_stat_add - add a value to a blkg_stat * @stat: target blkg_stat @@ -458,6 +463,11 @@ static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from) blkg_stat_add(to, blkg_stat_read(from)); } +static inline void blkg_rwstat_init(struct blkg_rwstat *rwstat) +{ + u64_stats_init(&rwstat->syncp); +} + /** * blkg_rwstat_add - add a value to a blkg_rwstat * @rwstat: target blkg_rwstat diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 8331aba9426f..06534049afba 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -256,6 +256,12 @@ static struct throtl_data *sq_to_td(struct throtl_service_queue *sq) } \ } while (0) +static void tg_stats_init(struct tg_stats_cpu *tg_stats) +{ + blkg_rwstat_init(&tg_stats->service_bytes); + blkg_rwstat_init(&tg_stats->serviced); +} + /* * Worker for allocating per cpu stat for tgs. This is scheduled on the * system_wq once there are some groups on the alloc_list waiting for @@ -269,12 +275,16 @@ static void tg_stats_alloc_fn(struct work_struct *work) alloc_stats: if (!stats_cpu) { + int cpu; + stats_cpu = alloc_percpu(struct tg_stats_cpu); if (!stats_cpu) { /* allocation failed, try again after some time */ schedule_delayed_work(dwork, msecs_to_jiffies(10)); return; } + for_each_possible_cpu(cpu) + tg_stats_init(per_cpu_ptr(stats_cpu, cpu)); } spin_lock_irq(&tg_stats_alloc_lock); diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 434944cbd761..4d5cec1ad80d 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1508,6 +1508,29 @@ static void cfq_init_cfqg_base(struct cfq_group *cfqg) } #ifdef CONFIG_CFQ_GROUP_IOSCHED +static void cfqg_stats_init(struct cfqg_stats *stats) +{ + blkg_rwstat_init(&stats->service_bytes); + blkg_rwstat_init(&stats->serviced); + blkg_rwstat_init(&stats->merged); + blkg_rwstat_init(&stats->service_time); + blkg_rwstat_init(&stats->wait_time); + blkg_rwstat_init(&stats->queued); + + blkg_stat_init(&stats->sectors); + blkg_stat_init(&stats->time); + +#ifdef CONFIG_DEBUG_BLK_CGROUP + blkg_stat_init(&stats->unaccounted_time); + blkg_stat_init(&stats->avg_queue_size_sum); + blkg_stat_init(&stats->avg_queue_size_samples); + blkg_stat_init(&stats->dequeue); + blkg_stat_init(&stats->group_wait_time); + blkg_stat_init(&stats->idle_time); + blkg_stat_init(&stats->empty_time); +#endif +} + static void cfq_pd_init(struct blkcg_gq *blkg) { struct cfq_group *cfqg = blkg_to_cfqg(blkg); @@ -1515,6 +1538,8 @@ static void cfq_pd_init(struct blkcg_gq *blkg) cfq_init_cfqg_base(cfqg); cfqg->weight = blkg->blkcg->cfq_weight; cfqg->leaf_weight = blkg->blkcg->cfq_leaf_weight; + cfqg_stats_init(&cfqg->stats); + cfqg_stats_init(&cfqg->dead_stats); } static void cfq_pd_offline(struct blkcg_gq *blkg) -- 2.34.1