From: Markos Chandras <Markos.Chandras@imgtec.com>
To: James Hogan <james.hogan@imgtec.com>, <linux-mips@linux-mips.org>
Cc: <stable@vger.kernel.org>
Subject: Re: [PATCH 2/3] MIPS: HTW: Prevent accidental HTW start due to nested htw_{start,stop}
Date: Mon, 26 Jan 2015 12:04:16 +0000 [thread overview]
Message-ID: <54C62D40.3040906@imgtec.com> (raw)
In-Reply-To: <54C62D26.80907@imgtec.com>
On 01/26/2015 12:03 PM, James Hogan wrote:
> On 26/01/15 11:47, Markos Chandras wrote:
>> On 01/26/2015 11:36 AM, James Hogan wrote:
>>
>>>
>>>> + raw_current_cpu_data.htw_seq++; \
>>>
>>> not "if (!raw_current_cpu_data.htw_seq++)) {"?
>> Why?
>>
>> on _stop() calls you just increment it. The _start() will do the right
>> thing then.
>>
>> I think what you suggest it to move the if() condition from the _start()
>> to _stop().
>
> I just mean you only need to disable htw the first time its called. I
> guess the extra branch every time could be worse than the extra disable
> and ehb when nesting does occur, so its probably premature optimisation.
>
> Up to you.
>
> Cheers
> James
>
good idea i will change it.
--
markos
WARNING: multiple messages have this Message-ID (diff)
From: Markos Chandras <Markos.Chandras@imgtec.com>
To: James Hogan <james.hogan@imgtec.com>, linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Subject: Re: [PATCH 2/3] MIPS: HTW: Prevent accidental HTW start due to nested htw_{start,stop}
Date: Mon, 26 Jan 2015 12:04:16 +0000 [thread overview]
Message-ID: <54C62D40.3040906@imgtec.com> (raw)
Message-ID: <20150126120416.stl2a_tDlWSeG2yWVAUUd7tSvHI_tnUs4LgrC_cc-S0@z> (raw)
In-Reply-To: <54C62D26.80907@imgtec.com>
On 01/26/2015 12:03 PM, James Hogan wrote:
> On 26/01/15 11:47, Markos Chandras wrote:
>> On 01/26/2015 11:36 AM, James Hogan wrote:
>>
>>>
>>>> + raw_current_cpu_data.htw_seq++; \
>>>
>>> not "if (!raw_current_cpu_data.htw_seq++)) {"?
>> Why?
>>
>> on _stop() calls you just increment it. The _start() will do the right
>> thing then.
>>
>> I think what you suggest it to move the if() condition from the _start()
>> to _stop().
>
> I just mean you only need to disable htw the first time its called. I
> guess the extra branch every time could be worse than the extra disable
> and ehb when nesting does occur, so its probably premature optimisation.
>
> Up to you.
>
> Cheers
> James
>
good idea i will change it.
--
markos
next prev parent reply other threads:[~2015-01-26 12:04 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-26 9:40 [PATCH 0/3 3.19] HTW fixes Markos Chandras
2015-01-26 9:40 ` Markos Chandras
2015-01-26 9:40 ` [PATCH 1/3] MIPS: asm: pgtable: Add c0 hazards on HTW start/stop sequences Markos Chandras
2015-01-26 9:40 ` Markos Chandras
2015-01-26 9:40 ` [PATCH 2/3] MIPS: HTW: Prevent accidental HTW start due to nested htw_{start,stop} Markos Chandras
2015-01-26 9:40 ` Markos Chandras
2015-01-26 11:36 ` James Hogan
2015-01-26 11:36 ` James Hogan
2015-01-26 11:38 ` James Hogan
2015-01-26 11:38 ` James Hogan
2015-01-26 11:47 ` Markos Chandras
2015-01-26 11:47 ` Markos Chandras
2015-01-26 12:03 ` Markos Chandras
2015-01-26 12:03 ` Markos Chandras
2015-01-26 12:03 ` James Hogan
2015-01-26 12:03 ` James Hogan
2015-01-26 12:04 ` Markos Chandras [this message]
2015-01-26 12:04 ` Markos Chandras
2015-01-26 13:04 ` [PATCH v2 " Markos Chandras
2015-01-26 13:04 ` Markos Chandras
2015-01-26 9:40 ` [PATCH 3/3] MIPS: asm: pgtable: Prevent HTW race when updating PTEs Markos Chandras
2015-01-26 9:40 ` Markos Chandras
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