From: "David S. Miller" <davem@redhat.com>
To: Matthew Wilcox <willy@debian.org>
Cc: James.Bottomley@SteelEye.com, linux-kernel@vger.kernel.org,
parisc-linux@lists.parisc-linux.org, drepper@redhat.com
Subject: Re: [parisc-linux] Re: Problems with kernel mmap (failing tst-mmap-eofsync in glibc on parisc)
Date: Fri, 22 Aug 2003 09:39:00 -0700 [thread overview]
Message-ID: <20030822093900.4468c012.davem@redhat.com> (raw)
In-Reply-To: <20030822163429.GH18834@parcelfarce.linux.theplanet.co.uk>
On Fri, 22 Aug 2003 17:34:29 +0100
Matthew Wilcox <willy@debian.org> wrote:
> On Fri, Aug 22, 2003 at 09:14:47AM -0700, David S. Miller wrote:
> > On 22 Aug 2003 09:40:37 -0500
> > flush_dcache_page() checks both the shared and non-shared mmap lists,
> > so if it is on _either_ list it is flushed. It does not check only
> > the shared list.
>
> Gah, that's going to get really inefficient. I still think we want to
> split flush_dcache_page() into two operations -- flush_dcache_user() and
> flush_dcache_kernel(). flush_dcache_user() would flush this specific
> user mapping back to ram and flush_dcache_kernel() would flush the
> kernel mapping. Obviously we'd still want to have flush_dcache_page()
> as there are instances when you want to flush all user mappings and the
> kernel mapping back to ram.
flush_dcache_page() works only on kernel pages.
It is defined to execute when the kernel executes store instructions
into a page.
Therefore splitting it into a "user" part makes absolutely no
sense.
> > The VM_SHARED change you are proposing is definitely wrong.
>
> Why is it wrong? Why should whether-or-not a mapping is read-only affect
> whether it's mapped shared? I can't see anything in SuS v3 that suggests
> we should do this.
MAP_SHARED has no meaning if the mapping isn't writable.
next prev parent reply other threads:[~2003-08-22 16:46 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-22 14:40 Problems with kernel mmap (failing tst-mmap-eofsync in glibc on parisc) James Bottomley
2003-08-22 16:14 ` David S. Miller
2003-08-22 16:34 ` [parisc-linux] " Matthew Wilcox
2003-08-22 16:39 ` David S. Miller [this message]
2003-08-22 17:41 ` Matthew Wilcox
2003-08-22 17:36 ` David S. Miller
2003-08-22 18:01 ` David S. Miller
2003-08-22 18:34 ` Hugh Dickins
2003-08-22 18:31 ` David S. Miller
2003-08-22 18:56 ` James Bottomley
2003-08-22 19:19 ` David S. Miller
2003-08-22 22:27 ` James Bottomley
2003-08-22 22:41 ` David S. Miller
2003-08-23 1:09 ` James Bottomley
2003-08-23 7:22 ` Hugh Dickins
2003-08-23 15:59 ` James Bottomley
2003-08-23 21:44 ` David S. Miller
2003-08-23 21:43 ` David S. Miller
2003-08-23 22:21 ` James Bottomley
2003-08-23 22:51 ` David S. Miller
2003-08-23 23:01 ` James Bottomley
2003-08-23 22:53 ` David S. Miller
2003-08-23 23:11 ` James Bottomley
2003-08-24 0:22 ` David S. Miller
[not found] ` <1061702282.1992.1153.camel@mulgrave>
[not found] ` <20030823222300.4695a0c4.davem@redhat.com>
2003-08-24 16:54 ` James Bottomley
2003-08-22 18:41 ` James Bottomley
2003-08-22 19:02 ` Hugh Dickins
2003-08-22 19:09 ` Randolph Chung
2003-08-22 16:42 ` Russell King
2003-08-22 16:39 ` David S. Miller
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