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=-2.4 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham 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 1EA3CC43142 for ; Tue, 31 Jul 2018 09:13:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE792208A4 for ; Tue, 31 Jul 2018 09:13:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="0fDCauQh" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE792208A4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731210AbeGaKwi (ORCPT ); Tue, 31 Jul 2018 06:52:38 -0400 Received: from merlin.infradead.org ([205.233.59.134]:53566 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729485AbeGaKwi (ORCPT ); Tue, 31 Jul 2018 06:52:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=5UZwBIW7S3NpZ8DmRAnDwkmVrQbw4ELPeSjCQikn/JI=; b=0fDCauQhdJBhQFOtLJA+0GUxs UjSJ9DZyrnqdG1CeKEqOFEyrNrCaeiUl+4YtjbvWIfmwIXbjXK50I6Ab4HQk9MvjK8Hyq8U1AJP/T DTRPA3zRbJ8uxjdSevY2KvUkbfmONdXeYqAVjglRzE0BUVpq9YA9blVVYurtm4ik4K729OzdjY1Tf Pb93ZQ5XNuy+szE19qlGLPLOq+LGbx0XUZYiUDEfIfoZxBwsNYgImTQePyRgolnW2FUcOkZ0ayK1s M2Ben5/wmMxhha1jEhqwEEKf4XExCGNQlzIpzdX7CB9mb/Dw+1Y8dNXhlWftNWHjo/FN5KzwGSaSH 8PCsFrqeg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fkQi3-0004pP-6c; Tue, 31 Jul 2018 09:12:51 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id B82C62027585B; Tue, 31 Jul 2018 11:12:48 +0200 (CEST) Date: Tue, 31 Jul 2018 11:12:48 +0200 From: Peter Zijlstra To: Rik van Riel Cc: Andy Lutomirski , LKML , kernel-team , X86 ML , Vitaly Kuznetsov , Ingo Molnar , Mike Galbraith , Dave Hansen , Catalin Marinas , Benjamin Herrenschmidt Subject: Re: [PATCH v2 11/11] mm,sched: conditionally skip lazy TLB mm refcounting Message-ID: <20180731091248.GS2494@hirez.programming.kicks-ass.net> References: <20180728215357.3249-1-riel@surriel.com> <20180728215357.3249-11-riel@surriel.com> <20180729155452.37eddc11@imladris.surriel.com> <20180730095502.GG2494@hirez.programming.kicks-ass.net> <1532961011.28585.30.camel@surriel.com> <20180730162653.GM2494@hirez.programming.kicks-ass.net> <1532999155.28585.56.camel@surriel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="nbjgUHX6eyHhY7pW" Content-Disposition: inline In-Reply-To: <1532999155.28585.56.camel@surriel.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --nbjgUHX6eyHhY7pW Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jul 30, 2018 at 09:05:55PM -0400, Rik van Riel wrote: > On Mon, 2018-07-30 at 18:26 +0200, Peter Zijlstra wrote: > >=20 > > So for ARCH_NO_ACTIVE_MM we never touch ->active_mm and therefore > > ->active_mm =3D=3D ->mm. >=20 > Close, but not true for kernel threads, which have a=20 > NULL ->mm, but a non-null ->active_mm that gets passed > to enter_lazy_tlb(). I'm confused on the need for this. We mark the CPU lazy, why do we still care about this? --nbjgUHX6eyHhY7pW Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEv3OU3/byMaA0LqWJdkfhpEvA5LoFAltgKBAACgkQdkfhpEvA 5LpkOA/9HofxxAGk4yCPZieMG6ZtvJtm03yMFVawa69JXBQjBPODAXoeU0tWK4vt JmutdWiY+mOzjTxUpYXHDl2b1ZLolfOPRorFRYbSa9mEVbeYDBJjqNKqmOhnJon5 bylGhZKMENE7WoRO8uHXuN7sItUnLEH0c9HB2oo6ko2RnhmWleyMnO21TMmRa1Ru QTQexQaWm1wyUc47Ja6qnhEzfcwfvcZkJ34Ng5WJMPjbc9QREuwJ5E3BDTEt+rNd Mk0EWyoUXIIAT4gvrJtGREwNc8IctUzkWIu4p9vwtzlpPUdbVyi/6AQJZKKyxmKb x+tHKtUaYD9PxUZVwj8KceG8IXyQzyZZrkxGSdIdm5HppUGiBwryUhOvnI9ohaY2 83XIoSmZDr9PBJxhOgwXBA3DUwBucKxkUhvSjUSXSkJQJsx8+t/cgMsLsrJtf4x+ nXpYBm6PgfWJpEDnqcpLk64ZzC67jZ4OyvAb6ChM1k5pYbtEZtTBu0T2u9vwdApv JVpLRf4NM9B+ecESLs3Qa/QlmrQtMdDuEdElq5842jao/pZV7SHB3efDUrfiGcfF b4etfMvtUCbmiTtyCLcWRzo+8fwskdsdpiNGqkfKwx8BnpiX2r3FvHNuaaV/DVqW /5ZHjIESpZicSamhEx3wIxjRoi/54Tu5U8z5KSBeduP6OHjDE2g= =3wx1 -----END PGP SIGNATURE----- --nbjgUHX6eyHhY7pW--