From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1I5kJC-000435-8u for user-mode-linux-devel@lists.sourceforge.net; Tue, 03 Jul 2007 08:28:58 -0700 Received: from smtp003.mail.ukl.yahoo.com ([217.12.11.34]) by mail.sourceforge.net with smtp (Exim 4.44) id 1I5kJ8-0006ok-Cw for user-mode-linux-devel@lists.sourceforge.net; Tue, 03 Jul 2007 08:28:54 -0700 From: Blaisorblade Date: Tue, 3 Jul 2007 17:28:30 +0200 References: <20070614202655.GA9647@c2.user-mode-linux.org> <20070627233701.8e53f3cb.akpm@linux-foundation.org> In-Reply-To: <20070627233701.8e53f3cb.akpm@linux-foundation.org> MIME-Version: 1.0 Message-Id: <200707031728.36472.blaisorblade@yahoo.it> Subject: Re: [uml-devel] [PATCH 4/5] UML - Simplify helper stack handling List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============0984312972==" Sender: user-mode-linux-devel-bounces@lists.sourceforge.net Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net To: user-mode-linux-devel@lists.sourceforge.net Cc: Andrew Morton , Jeff Dike , LKML --===============0984312972== Content-Type: multipart/signed; boundary="nextPart1472843.a5S91qz8GL"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit --nextPart1472843.a5S91qz8GL Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On gioved=EC 28 giugno 2007, Andrew Morton wrote: > So I'm running the generic version of this on i386 with 8k stacks (below), > with a quick LTP run. > > Holy cow, either we use a _lot_ of stack or these numbers are off: > > vmm:/home/akpm> dmesg -s 1000000|grep 'bytes left' > khelper used greatest stack depth: 7176 bytes left > khelper used greatest stack depth: 7064 bytes left > khelper used greatest stack depth: 6840 bytes left > khelper used greatest stack depth: 6812 bytes left > hostname used greatest stack depth: 6636 bytes left > uname used greatest stack depth: 6592 bytes left > uname used greatest stack depth: 6284 bytes left > hotplug used greatest stack depth: 5568 bytes left > rpc.nfsd used greatest stack depth: 5136 bytes left > chown02 used greatest stack depth: 4956 bytes left > fchown01 used greatest stack depth: 4892 bytes left > That's the sum of process stack and interrupt stack, but I doubt if this > little box is using much interrupt stack space. > > No wonder people are still getting stack overflows with 4k stacks... =46irst, those numbers pretend to be _unused_ stack space. Well, UML tends to use more stack space than the rest of kernel. Apart it h= as=20 a bit more layering (even if less than in the past), we must use libc's=20 function too, and they're not written to be executed on an 8k stack. We've reimplemented libc's printf() in terms of kernel sprintf() because it= =20 used 32K of stack. =2D-=20 Inform me of my mistakes, so I can add them to my list! Paolo Giarrusso, aka Blaisorblade http://www.user-mode-linux.org/~blaisorblade --nextPart1472843.a5S91qz8GL Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQBGimskqH9OHC+5NscRAoa3AJ0aoVZAsSCUack5plKhHUgAuIP1cgCfVkUo AYs4QvjRsHgXU75C5JT9SDI= =YpvS -----END PGP SIGNATURE----- --nextPart1472843.a5S91qz8GL-- --===============0984312972== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ --===============0984312972== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel --===============0984312972==--