Subject: Re: [PATCH 3.4 098/107] kernel/watchdog.c: touch_nmi_watchdog should
 only touch local cpu not every one
To: Don Zickus <dzickus@redhat.com>, <lizf@kernel.org>
References: <1458115541-5712-1-git-send-email-lizf@kernel.org>
 <1458115601-5762-98-git-send-email-lizf@kernel.org>
 <20160316140946.GR194535@redhat.com>
CC: <stable@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Ben Zhang <benzh@chromium.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Linus Torvalds" <torvalds@linux-foundation.org>
From: Zefan Li <lizefan@huawei.com>
Message-ID: <56EA0658.2080609@huawei.com>
Date: Thu, 17 Mar 2016 09:20:24 +0800
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101
 Thunderbird/38.5.1
MIME-Version: 1.0
In-Reply-To: <20160316140946.GR194535@redhat.com>
Content-Type: text/plain; charset="windows-1252"
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 935
Lines: 34

>> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
>> index 991aa93..7527c8c 100644
>> --- a/kernel/watchdog.c
>> +++ b/kernel/watchdog.c
>> @@ -162,6 +162,14 @@ void touch_nmi_watchdog(void)
>>  				per_cpu(watchdog_nmi_touch, cpu) = true;
>>  		}
>>  	}
> 
> The above for-loop was to be replaced by the non-for-loop below.
> 
> The above for-loop is the problem this patch was solving, so keeping it
> around does not solve anything.  :-)
> 

OOps, my fault. I'll remove this for-loop. Thanks for your review!

> 
>> +	/*
>> +	 * Using __raw here because some code paths have
>> +	 * preemption enabled.  If preemption is enabled
>> +	 * then interrupts should be enabled too, in which
>> +	 * case we shouldn't have to worry about the watchdog
>> +	 * going off.
>> +	 */
>> +	__raw_get_cpu_var(watchdog_nmi_touch) = true;
>>  	touch_softlockup_watchdog();
>>  }
>>  EXPORT_SYMBOL(touch_nmi_watchdog);
> 
> Cheers,
> Don
> .
>