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Message-ID: <0f8bd2b0-025b-424e-823e-03e51e99cfcd@intel.com>
Date:   Thu, 2 Nov 2023 15:23:27 -0700
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH v2] x86/resctrl: Fix unused variable warning in
 cache_alloc_hsw_probe()
Content-Language: en-US
To:     "Luck, Tony" <tony.luck@intel.com>,
        "Moger, Babu" <babu.moger@amd.com>
CC:     "Yu, Fenghua" <fenghua.yu@intel.com>,
        Peter Newman <peternewman@google.com>,
        "x86@kernel.org" <x86@kernel.org>,
        Shaopeng Tan <tan.shaopeng@fujitsu.com>,
        James Morse <james.morse@arm.com>,
        Jamie Iles <quic_jiles@quicinc.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "patches@lists.linux.dev" <patches@lists.linux.dev>
References: <20231031220534.37730-1-tony.luck@intel.com>
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From:   Reinette Chatre <reinette.chatre@intel.com>
In-Reply-To: <SJ1PR11MB6083D8F1467F094A5F1993EAFCA6A@SJ1PR11MB6083.namprd11.prod.outlook.com>
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Hi Tony,

On 11/2/2023 3:02 PM, Luck, Tony wrote:
>> This is strange, I am not able to encounter this warning. Is my gcc perhaps
>> too old? I know there were some specific versions needed to reproduce similar
>> warnings with clang (see reference commit 793207bad71c ("x86/resctrl: Fix a silly
>> -Wunused-but-set-variable warning")).
> 
> I'm using the default install from Fedora 38:
> 
> $ gcc --version
> gcc (GCC) 13.2.1 20230728 (Red Hat 13.2.1-1)
> Copyright (C) 2023 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.  There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Thank you for confirming. I tested with the same version. Strange, I see other
instances of this warning but not the resctrl one:

$ grep "set but not used" ~/t/log | wc -l
20
$ grep resctrl ~/t/log
  CC      arch/x86/kernel/cpu/resctrl/core.o
  CC      arch/x86/kernel/cpu/resctrl/rdtgroup.o
  CC      arch/x86/kernel/cpu/resctrl/monitor.o
  CC      arch/x86/kernel/cpu/resctrl/ctrlmondata.o
  CC      arch/x86/kernel/cpu/resctrl/pseudo_lock.o
  AR      arch/x86/kernel/cpu/resctrl/built-in.a

This does seem a valid issue and my Ack remains. I'm just puzzled why I do not
encounter the same warning.

Reinette