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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 DE6F3C33C8C for ; Mon, 6 Jan 2020 15:06:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B19CF2072E for ; Mon, 6 Jan 2020 15:06:17 +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="a7YFIco7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726622AbgAFPGQ (ORCPT ); Mon, 6 Jan 2020 10:06:16 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:35372 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726477AbgAFPGQ (ORCPT ); Mon, 6 Jan 2020 10:06:16 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=1Hy7rL5lKVG+BbappkxvNtg+NY3Qm8VQqVEeiRUmLRI=; b=a7YFIco7xYYRt8i7Yx8+DHdpc +YX/QCBmYhbrIj8ngbtLB2aJy7GndbuuUXpEFjLecmsCR53LdxN9cOqY/gQDFlg/dvXYGMzPetO39 DvPIG1ocIzokp3NgqWiaq1oxWAmkGRXtXnkBVsuQ0Y4+osvl1l6Dsj7rknircJ4BT4mPR6QMcZ3L0 SpHNsk+xgBA0jQFOKUyh6AUSlKjoM4aHOK0HhqD7UHn5wh20JAt6ohWXowSS6q81bjpNyroxSyvHd xqYtAVWYUVq26rI0ZFzQOf8/8jdDmudCi0EHHId7Ukz7yGIYulxnhbEec1X81KQ9CqJ+zQIpbaoFU 7cdBVHCeQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1ioTwy-00014b-PJ; Mon, 06 Jan 2020 15:05:48 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 2E3003007F2; Mon, 6 Jan 2020 16:04:14 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 451D92B284504; Mon, 6 Jan 2020 16:05:46 +0100 (CET) Date: Mon, 6 Jan 2020 16:05:46 +0100 From: Peter Zijlstra To: Frederic Weisbecker Cc: linux-kernel@vger.kernel.org, Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Wanpeng Li , Borislav Petkov , Thomas Gleixner , Sean Christopherson , Ingo Molnar , Jim Mattson , Joerg Roedel , Andy Lutomirski , Vitaly Kuznetsov Subject: Re: [PATCH 0/2] x86/context-tracking: Remove last remaining calls to exception_enter/exception_exit() Message-ID: <20200106150546.GS2810@hirez.programming.kicks-ass.net> References: <20191227163612.10039-1-frederic@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191227163612.10039-1-frederic@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 27, 2019 at 05:36:10PM +0100, Frederic Weisbecker wrote: > Thanks to the cleanups from Andy Lutomirski over the years, those calls > can now be removed. This will allow for nice things in the future for > x86 support on full nohz: > > * Remove TIF_NOHZ and use a per-cpu switch to enable, disable context > tracking. > > * Avoid context tracking on housekeepers. > > * Dynamically enable/disable context tracking on CPU on runtime and > therefore allow runtime enable/disable of nohz_full > > * Make nohz_full a property of cpuset. > > Frederic Weisbecker (2): > x86/context-tracking: Remove exception_enter/exit() from > do_page_fault() > x86/context-tracking: Remove exception_enter/exit() from > KVM_PV_REASON_PAGE_NOT_PRESENT async page fault Thanks, these look good to me. Did I tell you about my 'TODO' item vs text_poke_sync() ? Basically, we can avoid sending the IPI to NOHZ_FULL user CPUs, provided we make their enter_from_user_mode() do the sync_core().