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[23.128.96.32]) by mx.google.com with ESMTPS id 65-20020a630044000000b005c21d7ee51asi6023226pga.301.2023.11.20.06.38.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Nov 2023 06:38:42 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) client-ip=23.128.96.32; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=sVsdZb9o; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by agentk.vger.email (Postfix) with ESMTP id 38CBB80B816E; Mon, 20 Nov 2023 06:38:23 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at agentk.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233171AbjKTOiG (ORCPT + 99 others); Mon, 20 Nov 2023 09:38:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230030AbjKTOh6 (ORCPT ); Mon, 20 Nov 2023 09:37:58 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5AB76113 for ; Mon, 20 Nov 2023 06:37:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Subject:Cc:To:From:Date:Message-Id: Sender:Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To:References; bh=AzLMHqY7qEz2pgaGraffiJ/GjZASqgIcYbmgvz0+q3g=; b=sVsdZb9ojcx+HaK8Nh0ZVDZYd2 3iKpWF9JUJLgF6u/tn1cP4OOaqYuEw67l6i7lLveQ0CloAKZKXPsi7uq+As+7+CK1LEr/moi36Df/ dVhPWoCKQdOUtH+ALB2sQyvwa0pXeXn8oHbUH+LEQGf+HM6FK0KFKEvKquXf+76c9WfCF8GNpmMp2 z0NqoXgD+8oeMPvTm4hAWuN8EDe9BKzDV+RFQllZB855uj4sVc2YJxsgCZftgNLyiJh//+yY6NtAW D87pSnyJxWE7wz/cJtzAumTF8nQ6rAbeK1irTNup3okovJX8k12Wf77DlJ/OQWiFjec/qWQU55sQW PtYCvMxA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1r55PM-004dy7-7h; Mon, 20 Nov 2023 14:37:52 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 0) id CE868300419; Mon, 20 Nov 2023 15:37:51 +0100 (CET) Message-Id: <20231120143344.584345121@infradead.org> User-Agent: quilt/0.65 Date: Mon, 20 Nov 2023 15:33:44 +0100 From: Peter Zijlstra To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, peterz@infradead.org Subject: [PATCH 0/2] x86/entry: Trade cycles X-Spam-Status: No, score=-0.9 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on agentk.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (agentk.vger.email [0.0.0.0]); Mon, 20 Nov 2023 06:38:23 -0800 (PST) Hi, Two little patches that trade a little performance. First patch optimizes (although I couldn't get definite numbers showing it makes a difference) the return to user path by avoiding some PTI specifics in the generic path. Second patch then steals some of the won cycles by making a debug check unconditional. This came forth from a discussion with amluto who lamented we only had the debug check conditional on DEBUG_ENTRY.