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 CCF6E8D0039 for ; Wed, 23 Feb 2011 10:30:39 -0500 (EST) Received: by vws13 with SMTP id 13so3583840vws.14 for ; Wed, 23 Feb 2011 07:30:37 -0800 (PST) Date: Wed, 23 Feb 2011 10:30:30 -0500 From: Eric B Munson Subject: Re: [PATCH 1/5] pagewalk: only split huge pages when necessary Message-ID: <20110223153030.GA2810@mgebm.net> References: <20110222015338.309727CA@kernel> <20110222015339.0C9A2212@kernel> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="9amGYk9869ThD9tj" Content-Disposition: inline In-Reply-To: <20110222015339.0C9A2212@kernel> Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michael J Wolf , Andrea Arcangeli , akpm@osdl.org, Mel Gorman --9amGYk9869ThD9tj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, 21 Feb 2011, Dave Hansen wrote: >=20 > v2 - rework if() block, and remove now redundant split_huge_page() >=20 > Right now, if a mm_walk has either ->pte_entry or ->pmd_entry > set, it will unconditionally split any transparent huge pages > it runs in to. In practice, that means that anyone doing a >=20 > cat /proc/$pid/smaps >=20 > will unconditionally break down every huge page in the process > and depend on khugepaged to re-collapse it later. This is > fairly suboptimal. >=20 > This patch changes that behavior. It teaches each ->pmd_entry > handler (there are five) that they must break down the THPs > themselves. Also, the _generic_ code will never break down > a THP unless a ->pte_entry handler is actually set. >=20 > This means that the ->pmd_entry handlers can now choose to > deal with THPs without breaking them down. >=20 > Acked-by: Mel Gorman > Signed-off-by: Dave Hansen I have been running this set for serveral hours now and viewing various smaps files is not causing wild shifts in my AnonHugePages: counter. Reviewed-and-tested-by: Eric B Munson --9amGYk9869ThD9tj Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQEcBAEBAgAGBQJNZSgWAAoJEH65iIruGRnNCcsH/2dNeUbCWtqFwt4w9xYj/SOH JcdRS8AMG826/O/8Alp7k2HktNyb50cSB2JgUJuM4xjhR8sskQnEkX6SDrubREhD vuLEYGGqhmVA2hcRj1ao+bkJnegzzq1xpcAXJuptjgkv/+KrM+cMNGJd0RXaMHYw spNMkDSzmIZYnBHMl+MAOnErvhVZYaumAxLJRs1TWBfUNm86FA97zlYi7A1gSRfR 1aximEpHTlI8oky099vQnLeO3CgwbJTco0QhwJkU7qNcZyE9gx6UDqLeUlKbuvRb Uw7UwGnAxgImDbX3NGBduk25eSCsJ2CX8EV7SH2cLuacs9hokxxnSiR5+3jTlOQ= =ePjJ -----END PGP SIGNATURE----- --9amGYk9869ThD9tj-- -- 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