From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f69.google.com (mail-it0-f69.google.com [209.85.214.69]) by kanga.kvack.org (Postfix) with ESMTP id DDD5028026B for ; Mon, 26 Sep 2016 21:01:42 -0400 (EDT) Received: by mail-it0-f69.google.com with SMTP id 188so3524051iti.0 for ; Mon, 26 Sep 2016 18:01:42 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id u126si250472iod.223.2016.09.26.18.01.42 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 26 Sep 2016 18:01:42 -0700 (PDT) Message-ID: <1474938096.17726.62.camel@redhat.com> Subject: Re: page_waitqueue() considered harmful From: Rik van Riel Date: Mon, 26 Sep 2016 21:01:36 -0400 In-Reply-To: <20160926231132.GA17069@node.shutemov.name> References: <1474925009.17726.61.camel@redhat.com> <20160926231132.GA17069@node.shutemov.name> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-ujyPCaCXpD6Dcfd1Z7Wg" Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Linus Torvalds , Andrew Morton , "Kirill A. Shutemov" , Johannes Weiner , Jan Kara , Mel Gorman , Peter Zijlstra , linux-mm --=-ujyPCaCXpD6Dcfd1Z7Wg Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2016-09-27 at 02:11 +0300, Kirill A. Shutemov wrote: > On Mon, Sep 26, 2016 at 05:23:29PM -0400, Rik van Riel wrote: > >=20 > > On Mon, 2016-09-26 at 13:58 -0700, Linus Torvalds wrote: > >=20 > > >=20 > > > Is there really any reason for that incredible indirection? Do we > > > really want to make the page_waitqueue() be a per-zone thing at > > > all? > > > Especially since all those wait-queues won't even be *used* > > > unless > > > there is actual IO going on and people are really getting into > > > contention on the page lock.. Why isn't the page_waitqueue() just > > > one > > > statically sized array? > >=20 > > Why are we touching file pages at all during fork()? >=20 > We are not. > Unless the vma has private pages (vma->anon_vma is not NULL). >=20 > See first lines for copy_page_range(). Ahhh, indeed. I thought I remembered an optimization like that. --=20 All Rights Reversed. --=-ujyPCaCXpD6Dcfd1Z7Wg 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 iQEcBAABCAAGBQJX6cTxAAoJEM553pKExN6D2WcH/jt6JL9rw3xMuFsO9pfsBSIo ZRXxXsE3bo0oHSEmGJxN20SzFcpdrHKe6uFOQ3spFV+iIX1bWh7th4PZopNyn/uf rj7Zx+rAl1syFodV/rhFTPpxikIFL5V/TZ6lr7cJ12LhH5MGYk/Pz0A6zBAO/629 BtoamnGFhH9Udk4je/78XxB8w3LBLfCNiarPokIotgAWvlEqQTu1UTeJ756A3VZC gbDARHFaF8KKYLX0zz9au4GuGUt003585yW76rE7FLmpvc3Q6k9+RhcdyaJUDRNL qiRmpzJsxKBP6qaTKhJbE1M97wqlopY0pOcjv9llzOl8DP0KIV74BosssUv0/O0= =e4dC -----END PGP SIGNATURE----- --=-ujyPCaCXpD6Dcfd1Z7Wg-- -- 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