Re: [PATCH] tracing: allow tracing of suspend/resume & hibernation code again

From: Peter Teoh
Date: Mon Nov 24 2008 - 10:47:18 EST

I can confirm it is not working, as I revert back again to my previous
copy, recompile and resume successfully, but the patch currently
proposed failed to resume for me.

What should I do next?

On Sun, Nov 23, 2008 at 11:37 PM, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote:
> Thanks Ingo,
>
> I applied the patch (manually) agains Linus's git:
>
> git describe
> v2.6.28-rc6-7-ged31348
>
> Previously, before the patch, I had no problem resuming - for
> v2.6.28-rc6. Now after s2ram, it cannot resume properly - nothing is
> displayed. And I had not applied any changes to ftrace's
> /debug/tracing files yet.
>
> Let me test it out again. Thanks. (I am on FC7).
>
> On Sun, Nov 23, 2008 at 5:41 PM, Ingo Molnar <mingo@xxxxxxx> wrote:
>>
>> * Rafael J. Wysocki <rjw@xxxxxxx> 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@xxxxxxx>
>> 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@xxxxxxx>
>> ---
>> 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)
>>
>


--
Regards,
Peter Teoh

Ernest Hemingway - "Never mistake motion for action."
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