linux-kernel - Re: [V2] android: binder: use VM

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Message-ID: <CADAEsF82UgUu2rvfnq2JYPf71YuMp_eGJk72iumWd-HOxjQj+Q@mail.gmail.com>
Date:   Thu, 9 Feb 2017 17:54:03 +0800
From:   Ganesh Mahendran <opensource.ganesh@...il.com>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     linux-kernel <linux-kernel@...r.kernel.org>,
        devel@...verdev.osuosl.org,
        Arve Hjønnevåg <arve@...roid.com>,
        Riley Andrews <riandrews@...roid.com>
Subject: Re: [V2] android: binder: use VM_ALLOC to get vm area

A gentle ping.

Thanks.

2016-11-15 21:18 GMT+08:00 Ganesh Mahendran <opensource.ganesh@...il.com>:
> Hi, Greg
>
> 2016-11-15 18:18 GMT+08:00 Greg KH <gregkh@...uxfoundation.org>:
>> On Tue, Nov 15, 2016 at 05:55:39PM +0800, Ganesh Mahendran wrote:
>>> VM_IOREMAP is used to access hardware through a mechanism called
>>> I/O mapped memory. Android binder is a IPC machanism which will
>>> not access I/O memory.
>>>
>>> Also VM_IOREMAP has alignment requiement which may not needed in
>>> binder.
>>>     __get_vm_area_node()
>>>     {
>>>     ...
>>>         if (flags & VM_IOREMAP)
>>>             align = 1ul << clamp_t(int, fls_long(size),
>>>                PAGE_SHIFT, IOREMAP_MAX_ORDER);
>>>     ...
>>>     }
>>>
>>> This patch use VM_ALLOC to get vm area.
>>>
>>> Below is the throughput test result:
>>>
>>>   # ./binderThroughputTest -w 100
>>>   I run this command 10 times:
>>>                                before    after
>>>   average iterations per sec:  11199.9   11886.9
>>>
>>> No performance regression found throgh binder test.
>>>
>>> Signed-off-by: Ganesh Mahendran <opensource.ganesh@...il.com>
>>> ---
>>>  drivers/android/binder.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> What changed from v1?
>
> Sorry for missing the change information.
>
> In V2, I run the binder test. And there is no side effect with this
> patch.
>
>>
>> Always list that below the --- line.
>
> Thanks for reminder.
>
>>
>> thanks,
>>
>> greg k-h