Message-ID: <463F5926.6020401@redhat.com>
Date: Mon, 07 May 2007 12:51:50 -0400
From: Rik van Riel <riel@redhat.com>
Organization: Red Hat, Inc
User-Agent: Thunderbird 1.5.0.7 (X11/20061008)
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To: Ulrich Drepper <drepper@redhat.com>
CC: Nick Piggin <nickpiggin@yahoo.com.au>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       linux-kernel <linux-kernel@vger.kernel.org>,
       linux-mm <linux-mm@kvack.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Jakub Jelinek <jakub@redhat.com>
Subject: Re: [PATCH] MM: implement MADV_FREE lazy freeing of anonymous memory
References: <4632D0EF.9050701@redhat.com> <463B108C.10602@yahoo.com.au> <463B598B.80200@redhat.com> <463BC62C.3060605@yahoo.com.au> <463E5A00.6070708@redhat.com> <463E921D.3070407@redhat.com> <463EB169.8030701@redhat.com> <463EB0C4.6060901@redhat.com>
In-Reply-To: <463EB0C4.6060901@redhat.com>
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Ulrich Drepper wrote:
> Rik van Riel wrote:
>> It's trivial to merge the MADV_FREE #defines into the kernel
>> though, and aliasing MADV_FREE to MADV_DONTNEED for the time
>> being is a one-liner - just an extra constant into the big
>> switch statement in sys_madvise().
> 
> Until the semantics of the implementation is cut into stone by having it 
> in the kernel I'll not start using it.

The current MADV_DONTNEED implementation conforms to the
semantics of MADV_FREE :)

With MADV_FREE you can get back either your old data, or
a freshly zeroed out new page.  Always getting back the
second alternative is conformant :)

-- 
Politics is the struggle between those who want to make their country
the best in the world, and those who believe it already is.  Each group
calls the other unpatriotic.
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