From: Stan Hoeppner <stan@hardwarefreak.com>
To: xfs@oss.sgi.com
Subject: Re: block sizes > 4K ?? possible w/large page support?
Date: Mon, 11 Jun 2012 09:54:57 -0500 [thread overview]
Message-ID: <4FD606C1.1070103@hardwarefreak.com> (raw)
In-Reply-To: <20120611132932.GA18432@andromeda.usersys.redhat.com>
On 6/11/2012 8:29 AM, Carlos Maiolino wrote:
> The maximum block size of a XFS filesystem is 64kiB. But in linux it's limited
> to the PAGE_SIZE value.
Correct.
> so, on x86 architectures, the maximum block size is
> 4kiB.
Not entirely correct. Since ~1996, 16 years ago, PPro and higher 32bit
CPUs with PSE/PSE36 support pages of 4MB, or 2MB with PAE enabled.
x86-64 CPUs in long mode also support a 2MB page size. But the problem
of internal fragmentation may outweigh the TLB and other benefits of
these very large pages. I'm not an MM dev so I can't elaborate further.
There may be other issues.
> although it could benefit from a 16kiB page size, you'll need to be running an
> operating system which supports this page size value.
And AFAIK the kernel MM team doesn't have x86 2MB pages on their radar.
Or do they?
--
Stan
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next prev parent reply other threads:[~2012-06-11 14:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-11 3:21 block sizes > 4K ?? possible w/large page support? Linda A. Walsh
2012-06-11 13:13 ` Stan Hoeppner
2012-06-11 13:29 ` Carlos Maiolino
2012-06-11 14:54 ` Stan Hoeppner [this message]
2012-06-11 16:21 ` Carlos Maiolino
2012-06-11 21:25 ` Stefan Ring
2012-06-11 23:56 ` Dave Chinner
2012-06-12 0:08 ` Dave Chinner
2012-06-12 2:32 ` Eric Sandeen
2012-06-12 17:37 ` Linda A. Walsh
2012-06-12 18:55 ` Eric Sandeen
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