From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <461494FE.1040403@redhat.com> Date: Wed, 04 Apr 2007 23:19:42 -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> <20070403202937.GE355@devserv.devel.redhat.com> <20070403144948.fe8eede6.akpm@linux-foundation.org> <4612DCC6.7000504@cosmosbay.com> <46130BC8.9050905@yahoo.com.au> <1175675146.6483.26.camel@twins> <461367F6.10705@yahoo.com.au> <20070404113447.17ccbefa.dada1@cosmosbay.com> <46137882.6050708@yahoo.com.au> <20070404135458.4f1a7059.dada1@cosmosbay.com> <4614585F.1050200@yahoo.com.au> <461492A5.1030905@cosmosbay.com> In-Reply-To: <461492A5.1030905@cosmosbay.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig33B43440A24F4E88EB661303" Sender: owner-linux-mm@kvack.org Return-Path: To: Eric Dumazet Cc: Nick Piggin , Peter Zijlstra , Andrew Morton , Jakub Jelinek , Andi Kleen , Rik van Riel , Linux Kernel , linux-mm@kvack.org, Hugh Dickins List-ID: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig33B43440A24F4E88EB661303 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Eric Dumazet wrote: > Database workload, where the user multi threaded app is constantly > accessing GBytes of data, so L2 cache hit is very small. If you want to= > oprofile it, with say a CPU_CLK_UNHALTED:5000 event, then find_vma() is= > in the top 5. We did have a workload with lots of Java and databases at some point when many VMAs were the issue. I brought this up here one, maybe two years ago and I think Blaisorblade went on and looked into avoiding VMA splits by having mprotect() not split VMAs and instead store the flags in the page table somewhere. I don't remember the details. Nothing came out of this but if this is possible it would be yet another way to avoid mmap_sem locking, right? --=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 --------------enig33B43440A24F4E88EB661303 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 iD8DBQFGFJT+2ijCOnn/RHQRAj1UAKCe5X7q/IB9Yt4t2wfmnC+jdm5UlACfcnia TSpVQxWQnRQCq0PQgwAQiSc= =pgqX -----END PGP SIGNATURE----- --------------enig33B43440A24F4E88EB661303-- -- 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