From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 22 Sep 2002 02:45:14 +0100 (BST) From: Hugh Dickins Subject: Re: overcommit stuff In-Reply-To: <3D8D17B6.D4E1ECAE@digeo.com> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Alan Cox , "linux-mm@kvack.org" List-ID: On Sat, 21 Sep 2002, Andrew Morton wrote: > Hugh Dickins wrote: > > ... > > > It seems very unlikely (impossible?) that those pages will > > > ever become unshared. > > > > I expect it's very unlikely (short of application bugs) that > > those pages would become unshared; but they have been mapped > > in such a way that the process is entitled to unshare them, > > therefore they have been counted. A good example of why > > Linux does not impose strict commit accounting, and why > > you may choose not to use Alan's strict accounting policy. > > OK, thanks. Just checking. > > Is glibc mapping executables with PROT_WRITE? If so, > doesn't that rather devalue the whole overcommit thing? No, it looks like glibc is doing the right thing (mapping the code readonly and the data+bss readwrite). And I was wrong to say it's unlikely those pages would ever become unshared: the four 0.5MB areas look like typical readwrite private anon allocations. Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/