From: "H. Peter Anvin" <hpa@zytor.com>
To: linux-kernel@vger.kernel.org
Subject: Re: Interesting VM feature?
Date: 20 Aug 2003 19:24:25 -0700 [thread overview]
Message-ID: <bi1agp$40b$1@cesium.transmeta.com> (raw)
In-Reply-To: 20030815211937.GA20208@mail.jlokier.co.uk
Followup to: <20030815211937.GA20208@mail.jlokier.co.uk>
By author: Jamie Lokier <jamie@shareable.org>
In newsgroup: linux.dev.kernel
>
> Mike Fedyk wrote:
> > On Fri, Aug 15, 2003 at 02:56:02PM -0500, mouschi@wi.rr.com wrote:
> > > Is madvise required to result in zero filled pages
> > > by a standard, or is this just the commonly accepted
> > > behavior?
> >
> > I believe it is the standard for clean pages, though someone else will have
> > to point out where...
>
> That's the answer to a different question.
>
> The unanswered question is: what should madvise(MADV_DONTNEED) do,
> given dirty pages?
>
> man madvise(*) says that it zero-fills anonymous private mappings, and
> restores private file-backed mappings to the original file pages.
>
> That is not surprising, as the CPU-friendly semantic is more
> complicated to implement, needing an extra flag in the page table
> (or rmap structure).
>
Sounds entirely reasonable.
It *would* be nice with a way to be able to say to the kernel "you may
discard this but if so I want SIGSEGV", for things like LPSM and the
like.
-hpa
--
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
If you send me mail in HTML format I will assume it's spam.
"Unix gives you enough rope to shoot yourself in the foot."
Architectures needed: ia64 m68k mips64 ppc ppc64 s390 s390x sh v850 x86-64
next prev parent reply other threads:[~2003-08-21 2:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-15 19:56 Interesting VM feature? mouschi
2003-08-15 20:00 ` Mike Fedyk
2003-08-15 21:19 ` Jamie Lokier
2003-08-21 2:24 ` H. Peter Anvin [this message]
2003-08-21 11:59 ` Jeff Dike
-- strict thread matches above, loose matches on Subject: below --
2003-08-15 2:17 mouschi
2003-08-15 12:37 ` jlnance
2003-08-15 12:57 ` Jamie Lokier
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