From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx157.postini.com [74.125.245.157]) by kanga.kvack.org (Postfix) with SMTP id 343D06B0033 for ; Tue, 16 Jul 2013 04:25:00 -0400 (EDT) Date: Tue, 16 Jul 2013 18:00:26 +1000 From: David Gibson Subject: Re: [PATCH] mm/hugetlb: per-vma instantiation mutexes Message-ID: <20130716080026.GA8925@voom.fritz.box> References: <1373671681.2448.10.camel@buesod1.americas.hpqcorp.net> <1373858204.13826.9.camel@buesod1.americas.hpqcorp.net> <20130715072432.GA28053@voom.fritz.box> <20130715160802.9d0cdc0ee012b5e119317a98@linux-foundation.org> <1373933551.4622.12.camel@buesod1.americas.hpqcorp.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="gKMricLos+KVdGMg" Content-Disposition: inline In-Reply-To: <1373933551.4622.12.camel@buesod1.americas.hpqcorp.net> Sender: owner-linux-mm@kvack.org List-ID: To: Davidlohr Bueso Cc: Andrew Morton , Hugh Dickins , Rik van Riel , Michel Lespinasse , Mel Gorman , Konstantin Khlebnikov , Michal Hocko , "AneeshKumarK.V" , KAMEZAWA Hiroyuki , Hillf Danton , linux-mm@kvack.org, LKML , Anton Blanchard --gKMricLos+KVdGMg Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jul 15, 2013 at 05:12:31PM -0700, Davidlohr Bueso wrote: > On Mon, 2013-07-15 at 16:08 -0700, Andrew Morton wrote: > > On Mon, 15 Jul 2013 17:24:32 +1000 David Gibson wrote: > >=20 > > > I have previously proposed a correct method of improving scalability, > > > although it doesn't eliminate the lock. That's to use a set of hashed > > > mutexes. > >=20 > > Yep - hashing the mutexes is an obvious and nicely localized way of > > improving this. It's a tweak, not a design change. > >=20 > > The changelog should describe the choice of the hash key with great > > precision, please. It's important and is the first thing which > > reviewers and readers will zoom in on. Yeah, that is important. I no longer have much interest in the result of this patch, so I'll leave it to others to do the forward port and cleanup. But I will point out the gotcha here is that the hash key needs to be based on (address_space & file offset) for MAP_SHARED, but (mm & address) for MAP_PRIVATE. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --gKMricLos+KVdGMg Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) iEYEARECAAYFAlHk/ZoACgkQaILKxv3ab8ZXcgCcDZjdB4LY0XfQKHhc02bgJ9kH JQ4AniHdXZ9WUY/R0Jb4gLiJmdFzAAX+ =Unly -----END PGP SIGNATURE----- --gKMricLos+KVdGMg-- -- 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