linux-kernel - Re: [PATCH v2] sched: Fix print format for u64

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Date:	Thu, 24 Jan 2013 23:31:11 -0800
From:	Paul Turner <pjt@...gle.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Fabio Estevam <festevam@...il.com>, mingo@...hat.com,
	peterz@...radead.org, linux-kernel@...r.kernel.org,
	Fabio Estevam <fabio.estevam@...escale.com>
Subject: Re: [PATCH v2] sched: Fix print format for u64

On Thu, Jan 24, 2013 at 11:19 PM, Ingo Molnar <mingo@...nel.org> wrote:
>
> * Fabio Estevam <festevam@...il.com> wrote:
>
>> On Thu, Jan 24, 2013 at 12:19 PM, Ingo Molnar <mingo@...nel.org> wrote:
>>
>> > I suppose - is this patch warning-free both on 64-bit and 32-bit
>> > systems?
>>
>> Yes, just confirmed that this patch is warning-free on both 64-bit and
>> 32-bit machines.
>
> Apparently it's not all good, see the warning attached below.

Yeah this patch is broken; this is not properly fixable as is without
#ifdefs (or fixing the insanity that is atomic64_read).

Specifically:

On some architectures (e.g. x86_64) atomic64_read is typed long
On some others (e.g. x86-32) it's typed long long
On yet others (e.g. arm) it's typed u64

I think the easiest way to fix it would be instead to promote the read
into a local u64 and print that.

>
> Thanks,
>
>         Ingo
>
> ----- Forwarded message from kbuild test robot <fengguang.wu@...el.com> -----
>
> Date: Fri, 25 Jan 2013 14:02:05 +0800
> From: kbuild test robot <fengguang.wu@...el.com>
> To: Fabio Estevam <fabio.estevam@...escale.com>
> Cc: Ingo Molnar <mingo@...nel.org>
> Subject: [next:akpm 188/817] kernel/sched/debug.c:225:2: warning: format '%llu' expects argument
>         of type 'long long unsigned int', but argument 4 has type 'long int'
>
> tree:   git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git akpm
> head:   5d2ee7d8b03bfe3b90325d736d8e544d0394efa7
> commit: 2d58000fd2020255af63ee92c8d0ef615f6c4ade [188/817] sched: Fix print format for u64
> config: make ARCH=x86_64 allmodconfig
>
> All warnings:
>
>    kernel/sched/debug.c: In function 'print_cfs_rq':
>>> kernel/sched/debug.c:225:2: warning: format '%llu' expects argument of type 'long long unsigned int', but argument 4 has type 'long int' [-Wformat]
>>> kernel/sched/debug.c:225:2: warning: format '%llu' expects argument of type 'long long unsigned int', but argument 3 has type 'long int' [-Wformat]
>
> vim +225 kernel/sched/debug.c
>
>    209          spread = max_vruntime - MIN_vruntime;
>    210          SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread",
>    211                          SPLIT_NS(spread));
>    212          spread0 = min_vruntime - rq0_min_vruntime;
>    213          SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread0",
>    214                          SPLIT_NS(spread0));
>    215          SEQ_printf(m, "  .%-30s: %d\n", "nr_spread_over",
>    216                          cfs_rq->nr_spread_over);
>    217          SEQ_printf(m, "  .%-30s: %d\n", "nr_running", cfs_rq->nr_running);
>    218          SEQ_printf(m, "  .%-30s: %ld\n", "load", cfs_rq->load.weight);
>    219  #ifdef CONFIG_FAIR_GROUP_SCHED
>    220  #ifdef CONFIG_SMP
>    221          SEQ_printf(m, "  .%-30s: %lld\n", "runnable_load_avg",
>    222                          cfs_rq->runnable_load_avg);
>    223          SEQ_printf(m, "  .%-30s: %lld\n", "blocked_load_avg",
>    224                          cfs_rq->blocked_load_avg);
>  > 225          SEQ_printf(m, "  .%-30s: %llu\n", "tg_load_avg",
>    226                          atomic64_read(&cfs_rq->tg->load_avg));
>    227          SEQ_printf(m, "  .%-30s: %lld\n", "tg_load_contrib",
>    228                          cfs_rq->tg_load_contrib);
>    229          SEQ_printf(m, "  .%-30s: %d\n", "tg_runnable_contrib",
>    230                          cfs_rq->tg_runnable_contrib);
>    231          SEQ_printf(m, "  .%-30s: %d\n", "tg->runnable_avg",
>    232                          atomic_read(&cfs_rq->tg->runnable_avg));
>    233  #endif
>
> ---
> 0-DAY kernel build testing backend              Open Source Technology Center
> http://lists.01.org/mailman/listinfo/kbuild                 Intel Corporation
>
> ----- End forwarded message -----
>
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