diff options
Diffstat (limited to 'kernel/trace/ring_buffer.c')
| -rw-r--r-- | kernel/trace/ring_buffer.c | 73 |
1 files changed, 42 insertions, 31 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index a1ca4956ab5e..8c1b2d290718 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -423,7 +423,7 @@ struct ring_buffer_per_cpu { int cpu; struct ring_buffer *buffer; spinlock_t reader_lock; /* serialize readers */ - raw_spinlock_t lock; + arch_spinlock_t lock; struct lock_class_key lock_key; struct list_head *pages; struct buffer_page *head_page; /* read from head */ @@ -464,6 +464,8 @@ struct ring_buffer_iter { struct ring_buffer_per_cpu *cpu_buffer; unsigned long head; struct buffer_page *head_page; + struct buffer_page *cache_reader_page; + unsigned long cache_read; u64 read_stamp; }; @@ -998,7 +1000,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu) cpu_buffer->buffer = buffer; spin_lock_init(&cpu_buffer->reader_lock); lockdep_set_class(&cpu_buffer->reader_lock, buffer->reader_lock_key); - cpu_buffer->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; + cpu_buffer->lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()), GFP_KERNEL, cpu_to_node(cpu)); @@ -1193,9 +1195,6 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages) struct list_head *p; unsigned i; - atomic_inc(&cpu_buffer->record_disabled); - synchronize_sched(); - spin_lock_irq(&cpu_buffer->reader_lock); rb_head_page_deactivate(cpu_buffer); @@ -1211,12 +1210,9 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages) return; rb_reset_cpu(cpu_buffer); - spin_unlock_irq(&cpu_buffer->reader_lock); - rb_check_pages(cpu_buffer); - atomic_dec(&cpu_buffer->record_disabled); - + spin_unlock_irq(&cpu_buffer->reader_lock); } static void @@ -1227,9 +1223,6 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer, struct list_head *p; unsigned i; - atomic_inc(&cpu_buffer->record_disabled); - synchronize_sched(); - spin_lock_irq(&cpu_buffer->reader_lock); rb_head_page_deactivate(cpu_buffer); @@ -1242,11 +1235,9 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer, list_add_tail(&bpage->list, cpu_buffer->pages); } rb_reset_cpu(cpu_buffer); - spin_unlock_irq(&cpu_buffer->reader_lock); - rb_check_pages(cpu_buffer); - atomic_dec(&cpu_buffer->record_disabled); + spin_unlock_irq(&cpu_buffer->reader_lock); } /** @@ -1254,11 +1245,6 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer, * @buffer: the buffer to resize. * @size: the new size. * - * The tracer is responsible for making sure that the buffer is - * not being used while changing the size. - * Note: We may be able to change the above requirement by using - * RCU synchronizations. - * * Minimum size is 2 * BUF_PAGE_SIZE. * * Returns -1 on failure. @@ -1290,6 +1276,11 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) if (size == buffer_size) return size; + atomic_inc(&buffer->record_disabled); + + /* Make sure all writers are done with this buffer. */ + synchronize_sched(); + mutex_lock(&buffer->mutex); get_online_cpus(); @@ -1352,6 +1343,8 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) put_online_cpus(); mutex_unlock(&buffer->mutex); + atomic_dec(&buffer->record_disabled); + return size; free_pages: @@ -1361,6 +1354,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) } put_online_cpus(); mutex_unlock(&buffer->mutex); + atomic_dec(&buffer->record_disabled); return -ENOMEM; /* @@ -1370,6 +1364,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) out_fail: put_online_cpus(); mutex_unlock(&buffer->mutex); + atomic_dec(&buffer->record_disabled); return -1; } EXPORT_SYMBOL_GPL(ring_buffer_resize); @@ -2723,6 +2718,8 @@ static void rb_iter_reset(struct ring_buffer_iter *iter) iter->read_stamp = cpu_buffer->read_stamp; else iter->read_stamp = iter->head_page->page->time_stamp; + iter->cache_reader_page = cpu_buffer->reader_page; + iter->cache_read = cpu_buffer->read; } /** @@ -2834,7 +2831,7 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) int ret; local_irq_save(flags); - __raw_spin_lock(&cpu_buffer->lock); + arch_spin_lock(&cpu_buffer->lock); again: /* @@ -2876,7 +2873,7 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) * Splice the empty reader page into the list around the head. */ reader = rb_set_head_page(cpu_buffer); - cpu_buffer->reader_page->list.next = reader->list.next; + cpu_buffer->reader_page->list.next = rb_list_head(reader->list.next); cpu_buffer->reader_page->list.prev = reader->list.prev; /* @@ -2913,7 +2910,7 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) * * Now make the new head point back to the reader page. */ - reader->list.next->prev = &cpu_buffer->reader_page->list; + rb_list_head(reader->list.next)->prev = &cpu_buffer->reader_page->list; rb_inc_page(cpu_buffer, &cpu_buffer->head_page); /* Finally update the reader page to the new head */ @@ -2923,7 +2920,7 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) goto again; out: - __raw_spin_unlock(&cpu_buffer->lock); + arch_spin_unlock(&cpu_buffer->lock); local_irq_restore(flags); return reader; @@ -3067,13 +3064,22 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) struct ring_buffer_event *event; int nr_loops = 0; - if (ring_buffer_iter_empty(iter)) - return NULL; - cpu_buffer = iter->cpu_buffer; buffer = cpu_buffer->buffer; + /* + * Check if someone performed a consuming read to + * the buffer. A consuming read invalidates the iterator + * and we need to reset the iterator in this case. + */ + if (unlikely(iter->cache_read != cpu_buffer->read || + iter->cache_reader_page != cpu_buffer->reader_page)) + rb_iter_reset(iter); + again: + if (ring_buffer_iter_empty(iter)) + return NULL; + /* * We repeat when a timestamp is encountered. * We can get multiple timestamps by nested interrupts or also @@ -3088,6 +3094,11 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) if (rb_per_cpu_empty(cpu_buffer)) return NULL; + if (iter->head >= local_read(&iter->head_page->page->commit)) { + rb_inc_iter(iter); + goto again; + } + event = rb_iter_head_event(iter); switch (event->type_len) { @@ -3286,9 +3297,9 @@ ring_buffer_read_start(struct ring_buffer *buffer, int cpu) synchronize_sched(); spin_lock_irqsave(&cpu_buffer->reader_lock, flags); - __raw_spin_lock(&cpu_buffer->lock); + arch_spin_lock(&cpu_buffer->lock); rb_iter_reset(iter); - __raw_spin_unlock(&cpu_buffer->lock); + arch_spin_unlock(&cpu_buffer->lock); spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); return iter; @@ -3408,11 +3419,11 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu) if (RB_WARN_ON(cpu_buffer, local_read(&cpu_buffer->committing))) goto out; - __raw_spin_lock(&cpu_buffer->lock); + arch_spin_lock(&cpu_buffer->lock); rb_reset_cpu(cpu_buffer); - __raw_spin_unlock(&cpu_buffer->lock); + arch_spin_unlock(&cpu_buffer->lock); out: spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); |
