From: Hugh Dickins <hugh@veritas.com>
To: Ulrich Drepper <drepper@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>, Jakub Jelinek <jakub@redhat.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>
Subject: Re: [PATCH] lazy freeing of memory through MADV_FREE 2/2
Date: Sat, 21 Apr 2007 08:37:03 +0100 (BST) [thread overview]
Message-ID: <Pine.LNX.4.64.0704210830310.26485@blonde.wat.veritas.com> (raw)
In-Reply-To: <a36005b50704201424q3c07d457m6b2c468ff8a826c7@mail.gmail.com>
On Fri, 20 Apr 2007, Ulrich Drepper wrote:
>
> Just for reference: the MADV_CURRENT behavior is to throw away data in
> the range.
Not exactly. The Linux MADV_DONTNEED never throws away data from a
PROT_WRITE,MAP_SHARED mapping (or shm) - it propagates the dirty bit,
the page will eventually get written out to file, and can be retrieved
later by subsequent access. But the Linux MADV_DONTNEED does throw away
data from a PROT_WRITE,MAP_PRIVATE mapping (or brk or stack) - those
changes are discarded, and a subsequent access will revert to zeroes
or the underlying mapped file. Been like that since before 2.4.0.
> The POSIX_MADV_DONTNEED behavior is to never lose data.
> I.e., file backed data is written back, anon data is at most swapped
> out.
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next prev parent reply other threads:[~2007-04-21 7:37 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-17 7:15 [PATCH] lazy freeing of memory through MADV_FREE Rik van Riel
2007-04-19 21:15 ` [PATCH] lazy freeing of memory through MADV_FREE 2/2 Rik van Riel
2007-04-20 21:03 ` Andrew Morton
2007-04-20 21:24 ` Ulrich Drepper
2007-04-21 7:37 ` Hugh Dickins [this message]
2007-04-21 16:32 ` Ulrich Drepper
2007-04-20 20:57 ` [PATCH] lazy freeing of memory through MADV_FREE Andrew Morton
2007-04-20 21:38 ` Rik van Riel
2007-04-20 22:06 ` Andrew Morton
2007-04-20 23:52 ` Rik van Riel
2007-04-21 0:48 ` Eric Dumazet
2007-04-21 3:58 ` Rik van Riel
2007-04-21 7:12 ` Jakub Jelinek
2007-04-23 4:36 ` Nick Piggin
2007-04-22 2:36 ` Nick Piggin
2007-04-22 2:50 ` Nick Piggin
2007-04-22 6:31 ` Rik van Riel
2007-04-23 0:16 ` Nick Piggin
2007-04-23 3:53 ` Rik van Riel
2007-04-23 3:58 ` Nick Piggin
2007-04-23 10:07 ` Nick Piggin
2007-04-23 10:12 ` Rik van Riel
2007-04-23 3:59 ` Rik van Riel
2007-04-23 9:20 ` Rik van Riel
2007-04-23 10:21 ` Nick Piggin
2007-04-23 10:31 ` Rik van Riel
2007-04-23 10:35 ` Nick Piggin
2007-04-23 10:44 ` Rik van Riel
2007-04-24 1:15 ` Nick Piggin
2007-04-24 1:58 ` Rik van Riel
2007-04-24 2:16 ` Nick Piggin
2007-04-24 4:42 ` Paul Mackerras
2007-04-24 5:13 ` Rik van Riel
2007-04-24 2:53 ` Rik van Riel
2007-04-24 3:08 ` Andrew Morton
2007-04-23 10:44 ` Jakub Jelinek
2007-04-23 11:45 ` Rik van Riel
2007-04-23 4:28 ` Rik van Riel
2007-04-21 7:24 ` Hugh Dickins
2007-04-21 18:06 ` Rik van Riel
2007-04-22 8:18 ` Andrew Morton
2007-04-22 9:16 ` Christoph Hellwig
2007-04-22 16:55 ` Ulrich Drepper
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