From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5223CC433FF for ; Mon, 29 Jul 2019 16:10:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2F7AE2067D for ; Mon, 29 Jul 2019 16:10:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728537AbfG2QKP (ORCPT ); Mon, 29 Jul 2019 12:10:15 -0400 Received: from shelob.surriel.com ([96.67.55.147]:33160 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727038AbfG2QKO (ORCPT ); Mon, 29 Jul 2019 12:10:14 -0400 Received: from imladris.surriel.com ([96.67.55.152]) by shelob.surriel.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92) (envelope-from ) id 1hs8E0-0006Sx-QS; Mon, 29 Jul 2019 12:10:12 -0400 Message-ID: Subject: Re: [PATCH v2] sched/core: Don't use dying mm as active_mm of kthreads From: Rik van Riel To: Peter Zijlstra Cc: Waiman Long , Ingo Molnar , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Phil Auld , Andy Lutomirski Date: Mon, 29 Jul 2019 12:10:12 -0400 In-Reply-To: <20190729154419.GJ31398@hirez.programming.kicks-ass.net> References: <20190727171047.31610-1-longman@redhat.com> <20190729085235.GT31381@hirez.programming.kicks-ass.net> <4cd17c3a-428c-37a0-b3a2-04e6195a61d5@redhat.com> <20190729150338.GF31398@hirez.programming.kicks-ass.net> <25cd74fcee33dfd0b9604a8d1612187734037394.camel@surriel.com> <20190729154419.GJ31398@hirez.programming.kicks-ass.net> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-Wc6jN0+BMJTfEPLvJuKE" User-Agent: Evolution 3.30.5 (3.30.5-1.fc29) MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-Wc6jN0+BMJTfEPLvJuKE Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2019-07-29 at 17:44 +0200, Peter Zijlstra wrote: > On Mon, Jul 29, 2019 at 11:28:04AM -0400, Rik van Riel wrote: > > On Mon, 2019-07-29 at 17:03 +0200, Peter Zijlstra wrote: > >=20 > > > The 'sad' part is that x86 already switches to init_mm on idle > > > and we > > > only keep the active_mm around for 'stupid'. > >=20 > > Wait, where do we do that? >=20 > drivers/idle/intel_idle.c: leave_mm(cpu); > drivers/acpi/processor_idle.c: acpi_unlazy_tlb(smp_processor_id()); This is only done for deeper c-states, isn't it? > > > Rik and Andy were working on getting that 'fixed' a while ago, > > > not > > > sure > > > where that went. > >=20 > > My lazy TLB stuff got merged last year.=20 >=20 > Yes, but we never got around to getting rid of active_mm for x86, > right? True, we still use active_mm. Getting rid of the active_mm refcounting alltogether did not look entirely worthwhile the hassle. --=20 All Rights Reversed. --=-Wc6jN0+BMJTfEPLvJuKE Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEKR73pCCtJ5Xj3yADznnekoTE3oMFAl0/GmQACgkQznnekoTE 3oN1Mwf+M8ilckJKazPB0sap6Gw+VcoPa1Ij8YnYtR0OIXGLktOKIWlJY9b3hYfY Gn4yYJDoz1z8seaj6Ww+spOBzCxlS9qJlRxSqbijqR9zS4pC19y22l6OUfVPX0AO zXirw8e+2OSbVcb26eAe4pzamJtW0kmf9YQgxJ545nZo4xV4uJ1FyJGKxL9OyJdR /0JS1Vdi9Nlisa7YQw61k2USbGyFROvO3igHf5ii/2M2Rk1JictO4cYSfQrMYBy+ B3R3zlc0v5bNVl9MnBw6AjQs/sseEY/912Vzrsss05OyLI6zgmgsxBF+xsiEGsQW nVdkkuBHbSQwKIQGKfM+JzF/F+ltrw== =TidT -----END PGP SIGNATURE----- --=-Wc6jN0+BMJTfEPLvJuKE--