diff options
| -rw-r--r-- | include/linux/workqueue.h | 5 | ||||
| -rw-r--r-- | kernel/workqueue.c | 60 |
2 files changed, 59 insertions, 6 deletions
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index d60c5701ab4..b90958a037d 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -26,6 +26,9 @@ enum { WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */ #ifdef CONFIG_DEBUG_OBJECTS_WORK WORK_STRUCT_STATIC_BIT = 1, /* static initializer (debugobjects) */ + WORK_STRUCT_FLAG_BITS = 2, +#else + WORK_STRUCT_FLAG_BITS = 1, #endif WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT, @@ -35,7 +38,7 @@ enum { WORK_STRUCT_STATIC = 0, #endif - WORK_STRUCT_FLAG_MASK = 3UL, + WORK_STRUCT_FLAG_MASK = (1UL << WORK_STRUCT_FLAG_BITS) - 1, WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK, }; diff --git a/kernel/workqueue.c b/kernel/workqueue.c index dc78956ccf0..74a38499b19 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -46,7 +46,9 @@ /* * The per-CPU workqueue (if single thread, we always use the first - * possible cpu). + * possible cpu). The lower WORK_STRUCT_FLAG_BITS of + * work_struct->data are used for flags and thus cwqs need to be + * aligned at two's power of the number of flag bits. */ struct cpu_workqueue_struct { @@ -59,7 +61,7 @@ struct cpu_workqueue_struct { struct workqueue_struct *wq; /* I: the owning workqueue */ struct task_struct *thread; -} ____cacheline_aligned; +}; /* * The externally visible workqueue abstraction is an array of @@ -967,6 +969,53 @@ int current_is_keventd(void) } +static struct cpu_workqueue_struct *alloc_cwqs(void) +{ + /* + * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS. + * Make sure that the alignment isn't lower than that of + * unsigned long long. + */ + const size_t size = sizeof(struct cpu_workqueue_struct); + const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS, + __alignof__(unsigned long long)); + struct cpu_workqueue_struct *cwqs; +#ifndef CONFIG_SMP + void *ptr; + + /* + * On UP, percpu allocator doesn't honor alignment parameter + * and simply uses arch-dependent default. Allocate enough + * room to align cwq and put an extra pointer at the end + * pointing back to the originally allocated pointer which + * will be used for free. + * + * FIXME: This really belongs to UP percpu code. Update UP + * percpu code to honor alignment and remove this ugliness. + */ + ptr = __alloc_percpu(size + align + sizeof(void *), 1); + cwqs = PTR_ALIGN(ptr, align); + *(void **)per_cpu_ptr(cwqs + 1, 0) = ptr; +#else + /* On SMP, percpu allocator can do it itself */ + cwqs = __alloc_percpu(size, align); +#endif + /* just in case, make sure it's actually aligned */ + BUG_ON(!IS_ALIGNED((unsigned long)cwqs, align)); + return cwqs; +} + +static void free_cwqs(struct cpu_workqueue_struct *cwqs) +{ +#ifndef CONFIG_SMP + /* on UP, the pointer to free is stored right after the cwq */ + if (cwqs) + free_percpu(*(void **)per_cpu_ptr(cwqs + 1, 0)); +#else + free_percpu(cwqs); +#endif +} + static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) { struct workqueue_struct *wq = cwq->wq; @@ -1012,7 +1061,7 @@ struct workqueue_struct *__create_workqueue_key(const char *name, if (!wq) goto err; - wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); + wq->cpu_wq = alloc_cwqs(); if (!wq->cpu_wq) goto err; @@ -1031,6 +1080,7 @@ struct workqueue_struct *__create_workqueue_key(const char *name, for_each_possible_cpu(cpu) { struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); + BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK); cwq->wq = wq; cwq->cpu = cpu; spin_lock_init(&cwq->lock); @@ -1059,7 +1109,7 @@ struct workqueue_struct *__create_workqueue_key(const char *name, return wq; err: if (wq) { - free_percpu(wq->cpu_wq); + free_cwqs(wq->cpu_wq); kfree(wq); } return NULL; @@ -1112,7 +1162,7 @@ void destroy_workqueue(struct workqueue_struct *wq) for_each_possible_cpu(cpu) cleanup_workqueue_thread(get_cwq(cpu, wq)); - free_percpu(wq->cpu_wq); + free_cwqs(wq->cpu_wq); kfree(wq); } EXPORT_SYMBOL_GPL(destroy_workqueue); |