From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 2BD078D0039 for ; Mon, 21 Mar 2011 10:25:52 -0400 (EDT) From: Ben Hutchings In-Reply-To: <20110321140812.GD5719@random.random> References: <1300676431.26693.317.camel@localhost> <20110321124203.GB5719@random.random> <1300713183.26693.343.camel@localhost> <20110321140812.GD5719@random.random> Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-c3uRqJOBC4EAD1sSvLWJ" Date: Mon, 21 Mar 2011 14:25:42 +0000 Message-ID: <1300717542.26693.352.camel@localhost> Mime-Version: 1.0 Subject: Re: sysfs interface to transparent hugepages Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli Cc: linux-mm@kvack.org, Mel Gorman , Johannes Weiner , Rik van Riel , Hugh Dickins --=-c3uRqJOBC4EAD1sSvLWJ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2011-03-21 at 15:08 +0100, Andrea Arcangeli wrote: > On Mon, Mar 21, 2011 at 01:13:03PM +0000, Ben Hutchings wrote: > > You have tristates {never, madvise, always} for various THM features. > > Internally, these are represented as a pair of flags. They are exposed > > through sysfs as tristates, but then they are also exposed as flags. >=20 > They must be bitflags for performance and cacheline saving reasons in > the kernel (1 bitflag not enough in kernel for a userland > tristate). They're more intuitive as tristate in the same file for the > user to set (some combination of these flags is forbidden so exposing > the flags to the user doesn't sound good idea, also considering it's > an internal representation which may change, keeping the two separated > is best, especially if you want your current lib not to break). [...] I understand all that. However when I first looked at this I somehow thought that the tristate values were *also* exposed as flags, but I was mistaken. Sorry to bother you with this non-issue. Ben. --=20 Ben Hutchings Once a job is fouled up, anything done to improve it makes it worse. --=-c3uRqJOBC4EAD1sSvLWJ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIVAwUATYdf4Oe/yOyVhhEJAQoJpA//WpUvIShbVKXUDUdL7S5ZrAplysIw70Mv GfrThf1wjBsPpPU8DTsnihRp4agW3m9nt7/UPks4jAMoz13fNioMBlzI+aVXRU4G 7VpJ7W6uVlWYeGGIG5hFy2axhSmdI6A9uPhyR8cJxSgTfXYxhu0nCv0Pest84n1d IuTmQiYojhhRac/7CZzL2ikarAAN0BWF+xiuHsZyXl9DG6VXVnlshYbeGhYi7h1k 5eJD26rDXxhZMW6A/OqLakxx9A1sECsrCm8Lcb/R8lOD41Xk8vY18VViswURqAH+ BaSSav+ZbJAMfO90QdfbZyAOEl5i/pu7tJ/J8YSKZ/wXhvkkR2izuM1wb/Dt3VDN g9+VoiU+QmdbmeaWo6yluINp+J/lu1IEB+lK5nr5wvOmkerF4MahTtS92bcs35rY k06de9osb0lrFhQCKEbw/ll9NmpkCV8SF6kIYU1qF1uxbwvtKnMzAi0vp6oSyA2E o9S1K/o1KwW3342+VeOk9OgbfAnZiPZcON6/vMdjiZVqpAYZa4Be2NpS37xKzQqS WoZ3HffW2/LBFCbMnGFnYTwOAf4prmRQ/1SlGoCUpNN0Ee1zS0gllrQTOx1N/3SS mh0/VtKH3riKovjeoqw0bVh0KoSqTDvCHZ7gLf7xFSVvox8KCOdCwlEPQhBVgTAU /RPsQ7y8bdo= =hzN1 -----END PGP SIGNATURE----- --=-c3uRqJOBC4EAD1sSvLWJ-- -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org