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Message-ID: <20081123094124.GO30453@elte.hu>
Date: Sun, 23 Nov 2008 10:41:24 +0100
From: Ingo Molnar <mingo@...e.hu>
To: "Rafael J. Wysocki" <rjw@...k.pl>
Cc: Peter Teoh <htmldeveloper@...il.com>,
Steven Rostedt <srostedt@...hat.com>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] tracing: allow tracing of suspend/resume & hibernation
code again
* Rafael J. Wysocki <rjw@...k.pl> wrote:
> > Q2: how to ftrace s2ram and resume? I attempted to do it, but the
> > trace output is always filled with "resume" related functions when
> > it started up, which is only logical.
>
> The tracing is disabled during suspend/resume, so you can't.
i think we could lift this restriction now that dftrace is gone for
good - which was causing most of the trouble.
41108eb10142e0552f2de1e4c0675b108c5f018f
f42ac38c59e0a03d6da0c24a63fb211393f484b0
Completely untested patch below. Peter, does it work for you?
Ingo
------------------->
>From 3134c953216111a35d17f77b784e5d1fa2ba36d5 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@...e.hu>
Date: Sun, 23 Nov 2008 10:37:12 +0100
Subject: [PATCH] tracing: allow tracing of suspend/resume & hibernation code again:
Now that the ftrace kernel thread is gone, we can allow tracing
during suspend/resume again.
So revert these two commits:
f42ac38c5 "ftrace: disable tracing for suspend to ram"
41108eb10 "ftrace: disable tracing for hibernation"
This should be tested very carefully, as it could interact with
altneratives instruction patching, etc.
Not-Yet-Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
kernel/power/disk.c | 13 +++----------
kernel/power/main.c | 5 +----
2 files changed, 4 insertions(+), 14 deletions(-)
diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index c9d7408..f77d381 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -22,7 +22,6 @@
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/freezer.h>
-#include <linux/ftrace.h>
#include "power.h"
@@ -257,7 +256,7 @@ static int create_image(int platform_mode)
int hibernation_snapshot(int platform_mode)
{
- int error, ftrace_save;
+ int error;
/* Free memory before shutting down devices. */
error = swsusp_shrink_memory();
@@ -269,7 +268,6 @@ int hibernation_snapshot(int platform_mode)
goto Close;
suspend_console();
- ftrace_save = __ftrace_enabled_save();
error = device_suspend(PMSG_FREEZE);
if (error)
goto Recover_platform;
@@ -299,7 +297,6 @@ int hibernation_snapshot(int platform_mode)
Resume_devices:
device_resume(in_suspend ?
(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
- __ftrace_enabled_restore(ftrace_save);
resume_console();
Close:
platform_end(platform_mode);
@@ -370,11 +367,10 @@ static int resume_target_kernel(void)
int hibernation_restore(int platform_mode)
{
- int error, ftrace_save;
+ int error;
pm_prepare_console();
suspend_console();
- ftrace_save = __ftrace_enabled_save();
error = device_suspend(PMSG_QUIESCE);
if (error)
goto Finish;
@@ -389,7 +385,6 @@ int hibernation_restore(int platform_mode)
platform_restore_cleanup(platform_mode);
device_resume(PMSG_RECOVER);
Finish:
- __ftrace_enabled_restore(ftrace_save);
resume_console();
pm_restore_console();
return error;
@@ -402,7 +397,7 @@ int hibernation_restore(int platform_mode)
int hibernation_platform_enter(void)
{
- int error, ftrace_save;
+ int error;
if (!hibernation_ops)
return -ENOSYS;
@@ -417,7 +412,6 @@ int hibernation_platform_enter(void)
goto Close;
suspend_console();
- ftrace_save = __ftrace_enabled_save();
error = device_suspend(PMSG_HIBERNATE);
if (error) {
if (hibernation_ops->recover)
@@ -452,7 +446,6 @@ int hibernation_platform_enter(void)
hibernation_ops->finish();
Resume_devices:
device_resume(PMSG_RESTORE);
- __ftrace_enabled_restore(ftrace_save);
resume_console();
Close:
hibernation_ops->end();
diff --git a/kernel/power/main.c b/kernel/power/main.c
index eaa122b..142e005 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -22,7 +22,6 @@
#include <linux/freezer.h>
#include <linux/vmstat.h>
#include <linux/syscalls.h>
-#include <linux/ftrace.h>
#include "power.h"
@@ -321,7 +320,7 @@ static int suspend_enter(suspend_state_t state)
*/
int suspend_devices_and_enter(suspend_state_t state)
{
- int error, ftrace_save;
+ int error;
if (!suspend_ops)
return -ENOSYS;
@@ -332,7 +331,6 @@ int suspend_devices_and_enter(suspend_state_t state)
goto Close;
}
suspend_console();
- ftrace_save = __ftrace_enabled_save();
suspend_test_start();
error = device_suspend(PMSG_SUSPEND);
if (error) {
@@ -364,7 +362,6 @@ int suspend_devices_and_enter(suspend_state_t state)
suspend_test_start();
device_resume(PMSG_RESUME);
suspend_test_finish("resume devices");
- __ftrace_enabled_restore(ftrace_save);
resume_console();
Close:
if (suspend_ops->end)
--
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