From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Steven Rostedt <srostedt@redhat.com>
Subject: [PATCH 01/16] tracing: fix comments about trace buffer resizing
Date: Thu, 12 Mar 2009 22:37:05 -0400 [thread overview]
Message-ID: <20090313023825.008224270@goodmis.org> (raw)
In-Reply-To: 20090313023704.971438367@goodmis.org
[-- Attachment #1: 0001-tracing-fix-comments-about-trace-buffer-resizing.patch --]
[-- Type: text/plain, Size: 1778 bytes --]
From: Steven Rostedt <srostedt@redhat.com>
Impact: cleanup
Some of the comments about the trace buffer resizing is gobbledygook.
And I wonder why people question if I'm a native English speaker.
This patch makes the comments make a bit more sense.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---
kernel/trace/trace.c | 19 ++++++++++++++++---
1 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c3946a6..c61ee85 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2336,7 +2336,8 @@ static int tracing_resize_ring_buffer(unsigned long size)
/*
* If kernel or user changes the size of the ring buffer
- * it get completed.
+ * we use the size that was given, and we can forget about
+ * expanding it later.
*/
ring_buffer_expanded = 1;
@@ -2351,8 +2352,20 @@ static int tracing_resize_ring_buffer(unsigned long size)
r = ring_buffer_resize(global_trace.buffer,
global_trace.entries);
if (r < 0) {
- /* AARGH! We are left with different
- * size max buffer!!!! */
+ /*
+ * AARGH! We are left with different
+ * size max buffer!!!!
+ * The max buffer is our "snapshot" buffer.
+ * When a tracer needs a snapshot (one of the
+ * latency tracers), it swaps the max buffer
+ * with the saved snap shot. We succeeded to
+ * update the size of the main buffer, but failed to
+ * update the size of the max buffer. But when we tried
+ * to reset the main buffer to the original size, we
+ * failed there too. This is very unlikely to
+ * happen, but if it does, warn and kill all
+ * tracing.
+ */
WARN_ON(1);
tracing_disabled = 1;
}
--
1.6.1.3
--
next prev parent reply other threads:[~2009-03-13 2:39 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-13 2:37 [PATCH 00/16] [GIT PULL] updates for tip/tracing/ftrace Steven Rostedt
2009-03-13 2:37 ` Steven Rostedt [this message]
2009-03-13 2:37 ` [PATCH 02/16] tracing: protect ring_buffer_expanded with trace_types_lock Steven Rostedt
2009-03-13 2:37 ` [PATCH 03/16] ring-buffer: use CONFIG_HOTPLUG_CPU not CONFIG_HOTPLUG Steven Rostedt
2009-03-13 2:37 ` [PATCH 04/16] ring-buffer: remove unneeded get_online_cpus Steven Rostedt
2009-03-13 2:37 ` [PATCH 05/16] tracing: show that buffer size is not expanded Steven Rostedt
2009-03-13 3:05 ` KOSAKI Motohiro
2009-03-13 3:20 ` Steven Rostedt
2009-03-13 3:28 ` KOSAKI Motohiro
2009-03-13 2:37 ` [PATCH 06/16] tracing/core: bring back raw trace_printk for dynamic formats strings Steven Rostedt
2009-03-13 2:37 ` [PATCH 07/16] tracing: make bprint event use the proper event id Steven Rostedt
2009-03-13 2:37 ` [PATCH 08/16] tracing: have event_trace_printk use static tracer Steven Rostedt
2009-03-13 2:49 ` Andrew Morton
2009-03-13 3:08 ` Steven Rostedt
2009-03-13 3:09 ` KOSAKI Motohiro
2009-03-13 3:17 ` Steven Rostedt
2009-03-13 3:28 ` KOSAKI Motohiro
2009-03-13 3:34 ` Steven Rostedt
2009-03-13 5:36 ` [tip:tracing/ftrace] tracing: add comment for use of double __builtin_consant_p Steven Rostedt
2009-03-13 2:37 ` [PATCH 09/16] tracing: export trace formats to user space Steven Rostedt
2009-03-13 15:03 ` Frederic Weisbecker
2009-03-13 2:37 ` [PATCH 10/16] tracing: fix stack tracer header Steven Rostedt
2009-03-13 2:37 ` [PATCH 11/16] tracing: explain why stack tracer is empty Steven Rostedt
2009-03-13 2:37 ` [PATCH 12/16] tracing: tracepoints for softirq entry/exit - add softirq-to-name array Steven Rostedt
2009-03-13 4:12 ` Andrew Morton
2009-03-13 4:22 ` Steven Rostedt
2009-03-13 2:37 ` [PATCH 13/16] tracing: tracepoints for softirq entry/exit - tracepoints Steven Rostedt
2009-03-13 2:37 ` [PATCH 14/16] tracing: Dont use tracing_record_cmdline() in workqueue tracer fix Steven Rostedt
2009-03-13 2:37 ` [PATCH 15/16] tracing: show event name in trace for TRACE_EVENT created events Steven Rostedt
2009-03-13 2:37 ` [PATCH 16/16] ring-buffer: document reader page design Steven Rostedt
2009-03-13 3:35 ` [PATCH 00/16] [GIT PULL] updates for tip/tracing/ftrace Ingo Molnar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20090313023825.008224270@goodmis.org \
--to=rostedt@goodmis.org \
--cc=akpm@linux-foundation.org \
--cc=fweisbec@gmail.com \
--cc=kosaki.motohiro@jp.fujitsu.com \
--cc=laijs@cn.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=peterz@infradead.org \
--cc=srostedt@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox