diff options
| -rw-r--r-- | mm/page_alloc.c | 40 |
1 files changed, 22 insertions, 18 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 46c30fa..41985aa 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -92,6 +92,10 @@ EXPORT_PER_CPU_SYMBOL(_numa_mem_); int _node_numa_mem_[MAX_NUMNODES]; #endif +/* work_structs for global per-cpu drains */ +DEFINE_MUTEX(pcpu_drain_mutex); +DEFINE_PER_CPU(struct work_struct, pcpu_drain); + #ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY volatile unsigned long latent_entropy __latent_entropy; EXPORT_SYMBOL(latent_entropy); @@ -2360,7 +2364,6 @@ static void drain_local_pages_wq(struct work_struct *work) */ void drain_all_pages(struct zone *zone) { - struct work_struct __percpu *works; int cpu; /* @@ -2373,7 +2376,16 @@ void drain_all_pages(struct zone *zone) if (current->flags & PF_WQ_WORKER) return; - works = alloc_percpu_gfp(struct work_struct, GFP_ATOMIC); + /* + * Do not drain if one is already in progress unless it's specific to + * a zone. Such callers are primarily CMA and memory hotplug and need + * the drain to be complete when the call returns. + */ + if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) { + if (!zone) + return; + mutex_lock(&pcpu_drain_mutex); + } /* * We don't care about racing with CPU hotplug event @@ -2406,23 +2418,15 @@ void drain_all_pages(struct zone *zone) cpumask_clear_cpu(cpu, &cpus_with_pcps); } - if (works) { - for_each_cpu(cpu, &cpus_with_pcps) { - struct work_struct *work = per_cpu_ptr(works, cpu); - INIT_WORK(work, drain_local_pages_wq); - schedule_work_on(cpu, work); - } - for_each_cpu(cpu, &cpus_with_pcps) - flush_work(per_cpu_ptr(works, cpu)); - } else { - for_each_cpu(cpu, &cpus_with_pcps) { - struct work_struct work; - - INIT_WORK(&work, drain_local_pages_wq); - schedule_work_on(cpu, &work); - flush_work(&work); - } + for_each_cpu(cpu, &cpus_with_pcps) { + struct work_struct *work = per_cpu_ptr(&pcpu_drain, cpu); + INIT_WORK(work, drain_local_pages_wq); + schedule_work_on(cpu, work); } + for_each_cpu(cpu, &cpus_with_pcps) + flush_work(per_cpu_ptr(&pcpu_drain, cpu)); + + mutex_unlock(&pcpu_drain_mutex); } #ifdef CONFIG_HIBERNATION |
