From: Peter Zijlstra <peterz@infradead.org>
To: kernel test robot <lkp@intel.com>
Cc: Yafang Shao <laoar.shao@gmail.com>,
kbuild-all@lists.01.org, linux-kernel@vger.kernel.org,
linux-toolchains@vger.kernel.org
Subject: Re: [peterz-queue:sched/core 13/19] kernel/sched/fair.c:892:34: warning: variable 'stats' set but not used
Date: Sat, 11 Sep 2021 14:20:49 +0200 [thread overview]
Message-ID: <20210911122049.GW4323@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <202109110214.oh62aoIq-lkp@intel.com>
On Sat, Sep 11, 2021 at 02:21:26AM +0800, kernel test robot wrote:
> compiler: m68k-linux-gcc (GCC) 11.2.0
> kernel/sched/fair.c: In function 'update_curr':
> kernel/sched/fair.c:860:42: warning: unused variable 'stats' [-Wunused-variable]
> 860 | struct sched_statistics *stats = __schedstats_from_se(curr);
> | ^~~~~
OK, compiler guys, this code reads like:
#define schedstats_enabled() (0)
#define __schedstat_set(x, y) do { } while (0)
if (schedstats_enabled()) {
struct sched_statistics *stats = __schedstats_from_se(curr);
__schedstat_set(stats->exec_max,
max(delta_exec, stats->exec_max));
}
So yes, we initialize a variable that then isn't used, but the whole
bloody thing is inside if (0) which will not ever get ran *anyway*.
This is a crap warning if ever I saw one...
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: kbuild-all@lists.01.org
Subject: Re: [peterz-queue:sched/core 13/19] kernel/sched/fair.c:892:34: warning: variable 'stats' set but not used
Date: Sat, 11 Sep 2021 14:20:49 +0200 [thread overview]
Message-ID: <20210911122049.GW4323@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <202109110214.oh62aoIq-lkp@intel.com>
[-- Attachment #1: Type: text/plain, Size: 900 bytes --]
On Sat, Sep 11, 2021 at 02:21:26AM +0800, kernel test robot wrote:
> compiler: m68k-linux-gcc (GCC) 11.2.0
> kernel/sched/fair.c: In function 'update_curr':
> kernel/sched/fair.c:860:42: warning: unused variable 'stats' [-Wunused-variable]
> 860 | struct sched_statistics *stats = __schedstats_from_se(curr);
> | ^~~~~
OK, compiler guys, this code reads like:
#define schedstats_enabled() (0)
#define __schedstat_set(x, y) do { } while (0)
if (schedstats_enabled()) {
struct sched_statistics *stats = __schedstats_from_se(curr);
__schedstat_set(stats->exec_max,
max(delta_exec, stats->exec_max));
}
So yes, we initialize a variable that then isn't used, but the whole
bloody thing is inside if (0) which will not ever get ran *anyway*.
This is a crap warning if ever I saw one...
next prev parent reply other threads:[~2021-09-11 12:21 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-10 18:21 [peterz-queue:sched/core 13/19] kernel/sched/fair.c:892:34: warning: variable 'stats' set but not used kernel test robot
2021-09-10 18:21 ` kernel test robot
2021-09-11 1:46 ` Yafang Shao
2021-09-11 1:46 ` Yafang Shao
2021-09-11 12:20 ` Peter Zijlstra [this message]
2021-09-11 12:20 ` Peter Zijlstra
2021-09-11 21:30 ` Segher Boessenkool
2021-09-11 21:30 ` Segher Boessenkool
2021-09-11 22:33 ` Peter Zijlstra
2021-09-11 22:33 ` Peter Zijlstra
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