diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/tick-sched.c | 19 | ||||
| -rw-r--r-- | kernel/trace/ring_buffer.c | 6 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 13 |
3 files changed, 26 insertions, 12 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 333f627a3a3b..6579be96e041 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -589,6 +589,11 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now) tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1); } +static inline bool local_timer_softirq_pending(void) +{ + return local_softirq_pending() & TIMER_SOFTIRQ; +} + static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, ktime_t now, int cpu) { @@ -605,8 +610,18 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, } while (read_seqretry(&jiffies_lock, seq)); ts->last_jiffies = basejiff; - if (rcu_needs_cpu(basemono, &next_rcu) || - arch_needs_cpu() || irq_work_needs_cpu()) { + /* + * Keep the periodic tick, when RCU, architecture or irq_work + * requests it. + * Aside of that check whether the local timer softirq is + * pending. If so its a bad idea to call get_next_timer_interrupt() + * because there is an already expired timer, so it will request + * immeditate expiry, which rearms the hardware timer with a + * minimal delta which brings us back to this place + * immediately. Lather, rinse and repeat... + */ + if (rcu_needs_cpu(basemono, &next_rcu) || arch_needs_cpu() || + irq_work_needs_cpu() || local_timer_softirq_pending()) { next_tick = basemono + TICK_NSEC; } else { /* diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 1275175b0946..d9cd6191760b 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -280,6 +280,8 @@ EXPORT_SYMBOL_GPL(ring_buffer_event_data); /* Missed count stored at end */ #define RB_MISSED_STORED (1 << 30) +#define RB_MISSED_FLAGS (RB_MISSED_EVENTS|RB_MISSED_STORED) + struct buffer_data_page { u64 time_stamp; /* page time stamp */ local_t commit; /* write committed index */ @@ -331,7 +333,9 @@ static void rb_init_page(struct buffer_data_page *bpage) */ size_t ring_buffer_page_len(void *page) { - return local_read(&((struct buffer_data_page *)page)->commit) + struct buffer_data_page *bpage = page; + + return (local_read(&bpage->commit) & ~RB_MISSED_FLAGS) + BUF_PAGE_HDR_SIZE; } diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 581650a1640e..9510d540b48e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5914,7 +5914,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, .spd_release = buffer_spd_release, }; struct buffer_ref *ref; - int entries, size, i; + int entries, i; ssize_t ret = 0; #ifdef CONFIG_TRACER_MAX_TRACE @@ -5965,14 +5965,6 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, break; } - /* - * zero out any left over data, this is going to - * user land. - */ - size = ring_buffer_page_len(ref->page); - if (size < PAGE_SIZE) - memset(ref->page + size, 0, PAGE_SIZE - size); - page = virt_to_page(ref->page); spd.pages[i] = page; @@ -6699,6 +6691,7 @@ allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size buf->data = alloc_percpu(struct trace_array_cpu); if (!buf->data) { ring_buffer_free(buf->buffer); + buf->buffer = NULL; return -ENOMEM; } @@ -6722,7 +6715,9 @@ static int allocate_trace_buffers(struct trace_array *tr, int size) allocate_snapshot ? size : 1); if (WARN_ON(ret)) { ring_buffer_free(tr->trace_buffer.buffer); + tr->trace_buffer.buffer = NULL; free_percpu(tr->trace_buffer.data); + tr->trace_buffer.data = NULL; return -ENOMEM; } tr->allocated_snapshot = allocate_snapshot; |