From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4612CB21.9020005@redhat.com> Date: Tue, 03 Apr 2007 14:46:09 -0700 From: Ulrich Drepper MIME-Version: 1.0 Subject: Re: missing madvise functionality References: <46128051.9000609@redhat.com> <46128CC2.9090809@redhat.com> <20070403172841.GB23689@one.firstfloor.org> <20070403125903.3e8577f4.akpm@linux-foundation.org> <4612B645.7030902@redhat.com> <20070403135154.61e1b5f3.akpm@linux-foundation.org> <4612C059.8070702@redhat.com> <4612C2B6.3010302@cosmosbay.com> In-Reply-To: <4612C2B6.3010302@cosmosbay.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig8B4ABF0E8D079DF4795C119E" Sender: owner-linux-mm@kvack.org Return-Path: To: Eric Dumazet Cc: Rik van Riel , Andrew Morton , Andi Kleen , Linux Kernel , Jakub Jelinek , linux-mm@kvack.org, Hugh Dickins List-ID: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig8B4ABF0E8D079DF4795C119E Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Eric Dumazet wrote: > A page fault is not that expensive. But clearing N*PAGE_SIZE bytes is, > because it potentially evicts a large part of CPU cache. *A* page fault is not that expensive. The problem is that you get a page fault for every single page. For 200k allocated you get 50 page faults. It quickly adds up. --=20 =E2=9E=A7 Ulrich Drepper =E2=9E=A7 Red Hat, Inc. =E2=9E=A7 444 Castro St = =E2=9E=A7 Mountain View, CA =E2=9D=96 --------------enig8B4ABF0E8D079DF4795C119E Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFGEssh2ijCOnn/RHQRAt7qAJ9U+1b0HKgq1LwNoBh/PZUhEr7dtgCfakvE pqzrkxFMAYLB2LW5Xh1W2W4= =oN5m -----END PGP SIGNATURE----- --------------enig8B4ABF0E8D079DF4795C119E-- -- 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/ . Don't email: email@kvack.org