From: Jamie Lokier <jamie@shareable.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: anfei <anfei.zhou@gmail.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux@arm.linux.org.uk
Subject: Re: cache alias in mmap + write
Date: Thu, 21 Jan 2010 01:32:05 +0000 [thread overview]
Message-ID: <20100121013205.GA29808@shareable.org> (raw)
In-Reply-To: <20100121094733.3778.A69D9226@jp.fujitsu.com>
KOSAKI Motohiro wrote:
> 2. Add some commnet. almost developer only have x86 machine. so, arm
> specific trick need additional explicit explanation. otherwise anybody
> might break this code in the future.
That's Documentation/cachetlb.txt.
What's being discussed here is not ARM-specific, although it appears
maintainers of different architecture (ARM and MIPS for a start) may
have different ideas about what they are guaranteeing to userspace.
It sounds like MIPS expects userspace to use msync() sometimes (even
though Linux msync(MS_INVALIDATE) is quite broken), and ARM expects to
to keep mappings coherent automatically (which is sometimes slower
than necessary, but usually very helpful).
> 3. Resend the patch. original mail isn't good patch format. please
> consider to reduce akpm suffer.
This type of change in generic code would need review from a number of
architecture maintainers, I'd expect.
-- Jamie
WARNING: multiple messages have this Message-ID (diff)
From: Jamie Lokier <jamie@shareable.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: anfei <anfei.zhou@gmail.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux@arm.linux.org.uk
Subject: Re: cache alias in mmap + write
Date: Thu, 21 Jan 2010 01:32:05 +0000 [thread overview]
Message-ID: <20100121013205.GA29808@shareable.org> (raw)
In-Reply-To: <20100121094733.3778.A69D9226@jp.fujitsu.com>
KOSAKI Motohiro wrote:
> 2. Add some commnet. almost developer only have x86 machine. so, arm
> specific trick need additional explicit explanation. otherwise anybody
> might break this code in the future.
That's Documentation/cachetlb.txt.
What's being discussed here is not ARM-specific, although it appears
maintainers of different architecture (ARM and MIPS for a start) may
have different ideas about what they are guaranteeing to userspace.
It sounds like MIPS expects userspace to use msync() sometimes (even
though Linux msync(MS_INVALIDATE) is quite broken), and ARM expects to
to keep mappings coherent automatically (which is sometimes slower
than necessary, but usually very helpful).
> 3. Resend the patch. original mail isn't good patch format. please
> consider to reduce akpm suffer.
This type of change in generic code would need review from a number of
architecture maintainers, I'd expect.
-- Jamie
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next prev parent reply other threads:[~2010-01-21 1:32 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-20 8:26 cache alias in mmap + write anfei
2010-01-20 8:26 ` anfei
2010-01-20 9:10 ` KOSAKI Motohiro
2010-01-20 9:10 ` KOSAKI Motohiro
2010-01-20 9:52 ` anfei
2010-01-20 9:52 ` anfei
2010-01-21 1:10 ` KOSAKI Motohiro
2010-01-21 1:10 ` KOSAKI Motohiro
2010-01-21 1:32 ` Jamie Lokier [this message]
2010-01-21 1:32 ` Jamie Lokier
2010-01-21 3:06 ` anfei zhou
2010-01-21 3:06 ` anfei zhou
2010-01-21 2:39 ` anfei zhou
2010-01-21 2:39 ` anfei zhou
2010-01-21 4:59 ` anfei zhou
2010-01-21 4:59 ` anfei zhou
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