From: Andrew Morton <akpm@linux-foundation.org>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: a.p.zijlstra@chello.nl, linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch 2/3] only allow nonlinear vmas for ram backed filesystems
Date: Sun, 25 Mar 2007 16:00:50 -0800 [thread overview]
Message-ID: <20070325160050.fe7cb284.akpm@linux-foundation.org> (raw)
In-Reply-To: <E1HVEQJ-0006gF-00@dorka.pomaz.szeredi.hu>
On Sat, 24 Mar 2007 23:09:19 +0100 Miklos Szeredi <miklos@szeredi.hu> wrote:
> Dirty page accounting/limiting doesn't work for nonlinear mappings,
Doesn't it? iirc the problem is that we don't correctly re-clean the ptes
while starting writeout. And the dirty-page accounting is in fact correct
(it'd darn well better be).
> so
> for non-ram backed filesystems emulate with linear mappings. This
> retains ABI compatibility with previous kernels at minimal code cost.
>
> All known users of nonlinear mappings actually use tmpfs, so this
> shouldn't have any negative effect.
Unless someone is using remap_file_pages() against an ext3 file, in which
case their application stops working?
That would be a problem. These guys:
http://www.technovelty.org/code/linux/fremap.html, for example, will be in
for a little surprise.
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: a.p.zijlstra@chello.nl, linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch 2/3] only allow nonlinear vmas for ram backed filesystems
Date: Sun, 25 Mar 2007 16:00:50 -0800 [thread overview]
Message-ID: <20070325160050.fe7cb284.akpm@linux-foundation.org> (raw)
In-Reply-To: <E1HVEQJ-0006gF-00@dorka.pomaz.szeredi.hu>
On Sat, 24 Mar 2007 23:09:19 +0100 Miklos Szeredi <miklos@szeredi.hu> wrote:
> Dirty page accounting/limiting doesn't work for nonlinear mappings,
Doesn't it? iirc the problem is that we don't correctly re-clean the ptes
while starting writeout. And the dirty-page accounting is in fact correct
(it'd darn well better be).
> so
> for non-ram backed filesystems emulate with linear mappings. This
> retains ABI compatibility with previous kernels at minimal code cost.
>
> All known users of nonlinear mappings actually use tmpfs, so this
> shouldn't have any negative effect.
Unless someone is using remap_file_pages() against an ext3 file, in which
case their application stops working?
That would be a problem. These guys:
http://www.technovelty.org/code/linux/fremap.html, for example, will be in
for a little surprise.
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next prev parent reply other threads:[~2007-03-26 0:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-24 22:07 [patch 1/3] split mmap Miklos Szeredi
2007-03-24 22:07 ` Miklos Szeredi, Miklos Szeredi
2007-03-24 22:09 ` [patch 2/3] only allow nonlinear vmas for ram backed filesystems Miklos Szeredi
2007-03-24 22:09 ` Miklos Szeredi, Miklos Szeredi
2007-03-25 12:12 ` Peter Zijlstra
2007-03-25 12:12 ` Peter Zijlstra
2007-03-25 15:51 ` Matt Mackall
2007-03-25 15:51 ` Matt Mackall
2007-03-27 0:02 ` William Lee Irwin III
2007-03-27 0:02 ` William Lee Irwin III
2007-03-26 0:00 ` Andrew Morton [this message]
2007-03-26 0:00 ` Andrew Morton
2007-03-26 6:57 ` Peter Zijlstra
2007-03-26 6:57 ` Peter Zijlstra
2007-03-24 22:11 ` [patch 3/3] update ctime and mtime for mmaped write Miklos Szeredi
2007-03-24 22:11 ` Miklos Szeredi, Miklos Szeredi
2007-03-25 12:12 ` Peter Zijlstra
2007-03-25 12:12 ` Peter Zijlstra
2007-03-25 21:08 ` Miklos Szeredi
2007-03-25 21:08 ` Miklos Szeredi
2007-03-25 12:12 ` [patch 1/3] split mmap Peter Zijlstra
2007-03-25 12:12 ` Peter Zijlstra
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