From: vinayak <vinayakm.list@gmail.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, rientjes@google.com
Subject: Re: [PATCH] mm: add an option to disable bounce
Date: Mon, 22 Apr 2013 23:48:51 +0530 [thread overview]
Message-ID: <51757F0B.1090104@gmail.com> (raw)
In-Reply-To: <20130422174712.GS14496@n2100.arm.linux.org.uk>
On Monday 22 April 2013 11:17 PM, Russell King - ARM Linux wrote:
> On Mon, Apr 22, 2013 at 08:53:00PM +0530, vinayakm.list@gmail.com wrote:
>> From: Vinayak Menon <vinayakm.list@gmail.com>
>>
>> There are times when HIGHMEM is enabled, but
>> we don't prefer CONFIG_BOUNCE to be enabled.
>> CONFIG_BOUNCE can reduce the block device
>> throughput, and this is not ideal for machines
>> where we don't gain much by enabling it. So
>> provide an option to deselect CONFIG_BOUNCE. The
>> observation was made while measuring eMMC throughput
>> using iozone on an ARM device with 1GB RAM.
>>
>> Signed-off-by: Vinayak Menon <vinayakm.list@gmail.com>
>> ---
>> mm/Kconfig | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/mm/Kconfig b/mm/Kconfig
>> index 3bea74f..29f9736 100644
>> --- a/mm/Kconfig
>> +++ b/mm/Kconfig
>> @@ -263,8 +263,14 @@ config ZONE_DMA_FLAG
>> default "1"
>>
>> config BOUNCE
>> + bool "Enable bounce buffers"
>> def_bool y
>> depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
>
> I don't think this is correct. You shouldn't use "bool" with "def_bool".
> Sure, add the "bool", but also change "def_bool" to "default".
Yes. I will change it to "default" and this looks to be correct
even from the definition in kconfig-language.txt. But I see other
instances in mm/Kconfig, where bool and def_bool are used together. When
I had tested this patch with def_bool, it worked as expected.
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next prev parent reply other threads:[~2013-04-22 18:19 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-22 15:23 [PATCH] mm: add an option to disable bounce vinayakm.list
2013-04-22 16:58 ` Randy Dunlap
2013-04-22 17:37 ` vinayak
2013-04-22 17:47 ` Russell King - ARM Linux
2013-04-22 18:18 ` vinayak [this message]
2013-04-29 20:46 ` KOSAKI Motohiro
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