From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?C=E9dric?= Villemain Subject: Re: [PATCH v2 2/4] mm: introduce fincore() Date: Fri, 04 Jul 2014 17:15:59 +0200 Message-ID: <5816450.BPnLjGgtl5@obelix> References: <1404424335-30128-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1404424335-30128-3-git-send-email-n-horiguchi@ah.jp.nec.com> <20140704101230.GA24688@infradead.org> Reply-To: cedric@2ndquadrant.com Mime-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart8084549.9xpDVVycgD"; micalg="pgp-sha1"; protocol="application/pgp-signature" Return-path: In-Reply-To: <20140704101230.GA24688@infradead.org> Sender: owner-linux-mm@kvack.org To: Christoph Hellwig Cc: Naoya Horiguchi , Andrew Morton , Konstantin Khlebnikov , Wu Fengguang , Arnaldo Carvalho de Melo , Borislav Petkov , "Kirill A. Shutemov" , Johannes Weiner , Rusty Russell , David Miller , Andres Freund , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave Hansen , Michael Kerrisk , Linux API , Naoya Horiguchi List-Id: linux-api@vger.kernel.org --nextPart8084549.9xpDVVycgD Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="iso-8859-1" Le vendredi 4 juillet 2014 03:12:30 Christoph Hellwig a =E9crit : > On Thu, Jul 03, 2014 at 05:52:13PM -0400, Naoya Horiguchi wrote: > > This patch provides a new system call fincore(2), which provides > > mincore()- like information, i.e. page residency of a given file. > > But unlike mincore(), fincore() has a mode flag which allows us to > > extract detailed information about page cache like pfn and page > > flag. This kind of information is very helpful, for example when > > applications want to know the file cache status to control the IO > > on their own way. >=20 > It's still a nasty multiplexer for multiple different reporting > formats in a single system call. How about your really just do a > fincore that mirrors mincore instead of piggybacking exports of > various internal flags (tags and page flags onto it. The fincore =E0 la mincore got some arguments against it too. It seems = this=20 implementations try (I've not tested nor have a close look yet) to=20 answer both concerns : have details and also possible to have=20 aggregation function not too expansive. =2D-=20 C=E9dric Villemain +33 (0)6 20 30 22 52 http://2ndQuadrant.fr/ PostgreSQL: Support 24x7 - D=E9veloppement, Expertise et Formation --nextPart8084549.9xpDVVycgD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. Content-Transfer-Encoding: 7Bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAABAgAGBQJTtsUyAAoJENsgH0yzVBebWBoIAJhFEeV28nzkW/C4Wi3s8YXZ CgfL6Kpu1jvhMQC/5ni4RquqQoZtRtHU1/qBuW5e1njazdflWhTRxsf3zff3mOMD owZbKbi8s8UT9m/uEB9Yv9vXFmiWhpXL+yqcniQWW5WUNCIP/X3F/fMVzlaydrCb vUQlXvJ1p0sUrtualRry3sQpPk/OxT0Fa1n3HdiC4X9wfv0EX8OSXjekZqtUS0NC OUsXEfnaB/KmbiqRLGBgxoofynMby2089Cgi13+MHFvS32YzRA+x0/dbKUJmpN2I j0FCbJEc982/BIK2vpSPZk+/0ZZkWjYDx5RNHGuwYc1FimvN4UdgR4AHnp9DWo8= =AC/X -----END PGP SIGNATURE----- --nextPart8084549.9xpDVVycgD-- -- 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