From: Indan Zupancic <indan@nul.nu>
To: srostedt@redhat.com
Cc: mingo@redhat.com, linux-kernel@vger.kernel.org,
Indan Zupancic <indan@nul.nu>
Subject: [PATCH] Minor cleanups in ring_buffer.c, try 2.
Date: Sun, 11 Jan 2009 19:46:12 +1100 [thread overview]
Message-ID: <1231663572-20452-1-git-send-email-indan@nul.nu> (raw)
In-Reply-To: <1231168176.15476.6.camel@localhost.localdomain>
Signed-off-by: Indan Zupancic <indan@nul.nu>
---
kernel/trace/ring_buffer.c | 37 +++++++++++++------------------------
1 files changed, 13 insertions(+), 24 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 4832ffa..875fdce 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1849,7 +1849,7 @@ static void rb_advance_iter(struct ring_buffer_iter *iter)
}
static struct ring_buffer_event *
-rb_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
+rb_get_event(struct ring_buffer *buffer, int cpu, u64 *ts, int consume)
{
struct ring_buffer_per_cpu *cpu_buffer;
struct ring_buffer_event *event;
@@ -1900,6 +1900,8 @@ rb_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
*ts = cpu_buffer->read_stamp + event->time_delta;
ring_buffer_normalize_time_stamp(cpu_buffer->cpu, ts);
}
+ if (consume)
+ rb_advance_reader(cpu_buffer);
return event;
default:
@@ -1908,10 +1910,9 @@ rb_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
return NULL;
}
-EXPORT_SYMBOL_GPL(ring_buffer_peek);
static struct ring_buffer_event *
-rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
+rb_iter_get(struct ring_buffer_iter *iter, u64 *ts, int consume)
{
struct ring_buffer *buffer;
struct ring_buffer_per_cpu *cpu_buffer;
@@ -1961,6 +1962,8 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
*ts = iter->read_stamp + event->time_delta;
ring_buffer_normalize_time_stamp(cpu_buffer->cpu, ts);
}
+ if (consume)
+ rb_advance_iter(iter);
return event;
default:
@@ -1988,11 +1991,12 @@ ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
unsigned long flags;
spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
- event = rb_buffer_peek(buffer, cpu, ts);
+ event = rb_get_event(buffer, cpu, ts, 0);
spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
return event;
}
+EXPORT_SYMBOL_GPL(ring_buffer_peek);
/**
* ring_buffer_iter_peek - peek at the next event to be read
@@ -2010,7 +2014,7 @@ ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
unsigned long flags;
spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
- event = rb_iter_peek(iter, ts);
+ event = rb_iter_get(iter, ts, 0);
spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
return event;
@@ -2031,18 +2035,8 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts)
struct ring_buffer_event *event;
unsigned long flags;
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return NULL;
-
spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
-
- event = rb_buffer_peek(buffer, cpu, ts);
- if (!event)
- goto out;
-
- rb_advance_reader(cpu_buffer);
-
- out:
+ event = rb_get_event(buffer, cpu, ts, 1);
spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
return event;
@@ -2124,12 +2118,7 @@ ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts)
unsigned long flags;
spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
- event = rb_iter_peek(iter, ts);
- if (!event)
- goto out;
-
- rb_advance_iter(iter);
- out:
+ event = rb_iter_get(iter, ts, 1);
spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
return event;
@@ -2404,10 +2393,10 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
/*
- * rb_buffer_peek will get the next ring buffer if
+ * rb_get_event will get the next ring buffer if
* the current reader page is empty.
*/
- event = rb_buffer_peek(buffer, cpu, NULL);
+ event = rb_get_event(buffer, cpu, NULL, 0);
if (!event)
goto out;
--
1.6.1
next prev parent reply other threads:[~2009-01-11 8:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-29 3:59 [PATCH] Fix race in ring_buffer_consume() Indan Zupancic
2008-12-29 7:34 ` [PATCH] Fix race in ring_buffer_consume(): Replace ring_buffer_consume and ring_buffer_peek with ring_buffer_get_event Indan Zupancic
2008-12-29 12:24 ` Ingo Molnar
2009-01-01 5:10 ` Indan Zupancic
2009-01-02 22:08 ` Ingo Molnar
2009-01-03 23:55 ` Steven Rostedt
2009-01-05 15:09 ` Steven Rostedt
2009-01-11 8:35 ` [PATCH] Minor cleanups in ring_buffer.c Indan Zupancic
2009-01-11 8:46 ` Indan Zupancic [this message]
2009-01-11 9:49 ` [PATCH] Fix race in ring_buffer_consume(): Replace ring_buffer_consume and ring_buffer_peek with ring_buffer_get_event Indan Zupancic
2008-12-29 14:47 ` [PATCH] Fix race in ring_buffer_consume() Steven Rostedt
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