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-rw-r--r--kernel/trace/ring_buffer.c70
1 files changed, 69 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index f2f821a..f5b7b5c 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -488,12 +488,14 @@ struct ring_buffer_per_cpu {
struct buffer_page *reader_page;
unsigned long lost_events;
unsigned long last_overrun;
+ local_t entries_bytes;
local_t commit_overrun;
local_t overrun;
local_t entries;
local_t committing;
local_t commits;
unsigned long read;
+ unsigned long read_bytes;
u64 write_stamp;
u64 read_stamp;
};
@@ -1708,6 +1710,7 @@ rb_handle_head_page(struct ring_buffer_per_cpu *cpu_buffer,
* the counters.
*/
local_add(entries, &cpu_buffer->overrun);
+ local_sub(BUF_PAGE_SIZE, &cpu_buffer->entries_bytes);
/*
* The entries will be zeroed out when we move the
@@ -1863,6 +1866,9 @@ rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer,
event = __rb_page_index(tail_page, tail);
kmemcheck_annotate_bitfield(event, bitfield);
+ /* account for padding bytes */
+ local_add(BUF_PAGE_SIZE - tail, &cpu_buffer->entries_bytes);
+
/*
* Save the original length to the meta data.
* This will be used by the reader to add lost event
@@ -2054,6 +2060,9 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
if (!tail)
tail_page->page->time_stamp = ts;
+ /* account for these added bytes */
+ local_add(length, &cpu_buffer->entries_bytes);
+
return event;
}
@@ -2076,6 +2085,7 @@ rb_try_to_discard(struct ring_buffer_per_cpu *cpu_buffer,
if (bpage->page == (void *)addr && rb_page_write(bpage) == old_index) {
unsigned long write_mask =
local_read(&bpage->write) & ~RB_WRITE_MASK;
+ unsigned long event_length = rb_event_length(event);
/*
* This is on the tail page. It is possible that
* a write could come in and move the tail page
@@ -2085,8 +2095,11 @@ rb_try_to_discard(struct ring_buffer_per_cpu *cpu_buffer,
old_index += write_mask;
new_index += write_mask;
index = local_cmpxchg(&bpage->write, old_index, new_index);
- if (index == old_index)
+ if (index == old_index) {
+ /* update counters */
+ local_sub(event_length, &cpu_buffer->entries_bytes);
return 1;
+ }
}
/* could not discard */
@@ -2661,6 +2674,58 @@ rb_num_of_entries(struct ring_buffer_per_cpu *cpu_buffer)
}
/**
+ * ring_buffer_oldest_event_ts - get the oldest event timestamp from the buffer
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to read from.
+ */
+unsigned long ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu)
+{
+ unsigned long flags;
+ struct ring_buffer_per_cpu *cpu_buffer;
+ struct buffer_page *bpage;
+ unsigned long ret;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return 0;
+
+ cpu_buffer = buffer->buffers[cpu];
+ raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ /*
+ * if the tail is on reader_page, oldest time stamp is on the reader
+ * page
+ */
+ if (cpu_buffer->tail_page == cpu_buffer->reader_page)
+ bpage = cpu_buffer->reader_page;
+ else
+ bpage = rb_set_head_page(cpu_buffer);
+ ret = bpage->page->time_stamp;
+ raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_oldest_event_ts);
+
+/**
+ * ring_buffer_bytes_cpu - get the number of bytes consumed in a cpu buffer
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to read from.
+ */
+unsigned long ring_buffer_bytes_cpu(struct ring_buffer *buffer, int cpu)
+{
+ struct ring_buffer_per_cpu *cpu_buffer;
+ unsigned long ret;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return 0;
+
+ cpu_buffer = buffer->buffers[cpu];
+ ret = local_read(&cpu_buffer->entries_bytes) - cpu_buffer->read_bytes;
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_bytes_cpu);
+
+/**
* ring_buffer_entries_cpu - get the number of entries in a cpu buffer
* @buffer: The ring buffer
* @cpu: The per CPU buffer to get the entries from.
@@ -3527,11 +3592,13 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
cpu_buffer->reader_page->read = 0;
local_set(&cpu_buffer->commit_overrun, 0);
+ local_set(&cpu_buffer->entries_bytes, 0);
local_set(&cpu_buffer->overrun, 0);
local_set(&cpu_buffer->entries, 0);
local_set(&cpu_buffer->committing, 0);
local_set(&cpu_buffer->commits, 0);
cpu_buffer->read = 0;
+ cpu_buffer->read_bytes = 0;
cpu_buffer->write_stamp = 0;
cpu_buffer->read_stamp = 0;
@@ -3918,6 +3985,7 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
} else {
/* update the entry counter */
cpu_buffer->read += rb_page_entries(reader);
+ cpu_buffer->read_bytes += BUF_PAGE_SIZE;
/* swap the pages */
rb_init_page(bpage);
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