* [PATCH]cputime: make bool type for steal ticks
@ 2012-11-16 9:24 liguang
2013-01-26 0:45 ` Frederic Weisbecker
0 siblings, 1 reply; 5+ messages in thread
From: liguang @ 2012-11-16 9:24 UTC (permalink / raw)
To: mingo, peterz; +Cc: linux-kernel, liguang
Signed-off-by: liguang <lig.fnst@cn.fujitsu.com>
---
kernel/sched/cputime.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 81b763b..d2c24c1 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -282,7 +282,7 @@ static __always_inline bool steal_account_process_tick(void)
this_rq()->prev_steal_time += st * TICK_NSEC;
account_steal_time(st);
- return st;
+ return !!st;
}
#endif
return false;
--
1.7.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH]cputime: make bool type for steal ticks
2012-11-16 9:24 [PATCH]cputime: make bool type for steal ticks liguang
@ 2013-01-26 0:45 ` Frederic Weisbecker
2013-01-26 1:24 ` Joe Perches
0 siblings, 1 reply; 5+ messages in thread
From: Frederic Weisbecker @ 2013-01-26 0:45 UTC (permalink / raw)
To: liguang; +Cc: mingo, peterz, linux-kernel
2012/11/16 liguang <lig.fnst@cn.fujitsu.com>:
> Signed-off-by: liguang <lig.fnst@cn.fujitsu.com>
> ---
> kernel/sched/cputime.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
> index 81b763b..d2c24c1 100644
> --- a/kernel/sched/cputime.c
> +++ b/kernel/sched/cputime.c
> @@ -282,7 +282,7 @@ static __always_inline bool steal_account_process_tick(void)
> this_rq()->prev_steal_time += st * TICK_NSEC;
>
> account_steal_time(st);
> - return st;
> + return !!st;
I would expect gcc to perform the semantic "!!" cast implicitly. I
just did some basic tests locally and it does.
I prefer to be paranoid and not do any assumption though, unless I'm
told gcc always guarantees this correct implicit cast. I'm queuing
this patch and will send it to Ingo.
Thanks!
> }
> #endif
> return false;
> --
> 1.7.1
>
> --
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH]cputime: make bool type for steal ticks
2013-01-26 0:45 ` Frederic Weisbecker
@ 2013-01-26 1:24 ` Joe Perches
2013-01-26 14:38 ` Frederic Weisbecker
0 siblings, 1 reply; 5+ messages in thread
From: Joe Perches @ 2013-01-26 1:24 UTC (permalink / raw)
To: Frederic Weisbecker; +Cc: liguang, mingo, peterz, linux-kernel
On Sat, 2013-01-26 at 01:45 +0100, Frederic Weisbecker wrote:
> > diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
[]
> > @@ -282,7 +282,7 @@ static __always_inline bool steal_account_process_tick(void)
[]
> > - return st;
> > + return !!st;
>
> I would expect gcc to perform the semantic "!!" cast implicitly. I
> just did some basic tests locally and it does.
> I prefer to be paranoid and not do any assumption though, unless I'm
> told gcc always guarantees this correct implicit cast. I'm queuing
> this patch and will send it to Ingo.
It's unnecessary.
6.3.1.2p1:
"When any scalar value is converted to _Bool, the result is 0
if the value compares equal to 0; otherwise, the result is 1."
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH]cputime: make bool type for steal ticks
2013-01-26 1:24 ` Joe Perches
@ 2013-01-26 14:38 ` Frederic Weisbecker
0 siblings, 0 replies; 5+ messages in thread
From: Frederic Weisbecker @ 2013-01-26 14:38 UTC (permalink / raw)
To: Joe Perches; +Cc: liguang, mingo, peterz, linux-kernel
2013/1/26 Joe Perches <joe@perches.com>:
> On Sat, 2013-01-26 at 01:45 +0100, Frederic Weisbecker wrote:
>> > diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
> []
>> > @@ -282,7 +282,7 @@ static __always_inline bool steal_account_process_tick(void)
> []
>> > - return st;
>> > + return !!st;
>>
>> I would expect gcc to perform the semantic "!!" cast implicitly. I
>> just did some basic tests locally and it does.
>> I prefer to be paranoid and not do any assumption though, unless I'm
>> told gcc always guarantees this correct implicit cast. I'm queuing
>> this patch and will send it to Ingo.
>
> It's unnecessary.
>
> 6.3.1.2p1:
>
> "When any scalar value is converted to _Bool, the result is 0
> if the value compares equal to 0; otherwise, the result is 1."
Ok then I'll ignore this patch. If somebody oppose, raise your hand.
Thanks.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH]cputime: make bool type for steal ticks
@ 2012-11-06 7:12 liguang
0 siblings, 0 replies; 5+ messages in thread
From: liguang @ 2012-11-06 7:12 UTC (permalink / raw)
To: mingo, peterz; +Cc: linux-kernel, liguang
Signed-off-by: liguang <lig.fnst@cn.fujitsu.com>
---
kernel/sched/cputime.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 81b763b..d2c24c1 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -282,7 +282,7 @@ static __always_inline bool steal_account_process_tick(void)
this_rq()->prev_steal_time += st * TICK_NSEC;
account_steal_time(st);
- return st;
+ return !!st;
}
#endif
return false;
--
1.7.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
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Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2012-11-16 9:24 [PATCH]cputime: make bool type for steal ticks liguang
2013-01-26 0:45 ` Frederic Weisbecker
2013-01-26 1:24 ` Joe Perches
2013-01-26 14:38 ` Frederic Weisbecker
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2012-11-06 7:12 liguang
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