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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 358FDC433F5 for ; Thu, 25 Nov 2021 15:26:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9340F6B0075; Thu, 25 Nov 2021 10:25:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8E4126B0078; Thu, 25 Nov 2021 10:25:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7AA036B007B; Thu, 25 Nov 2021 10:25:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0242.hostedemail.com [216.40.44.242]) by kanga.kvack.org (Postfix) with ESMTP id 673436B0075 for ; Thu, 25 Nov 2021 10:25:45 -0500 (EST) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 26D9D8DC18 for ; Thu, 25 Nov 2021 15:25:35 +0000 (UTC) X-FDA: 78847826946.17.D6CB442 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by imf23.hostedemail.com (Postfix) with ESMTP id 7B91190000AC for ; Thu, 25 Nov 2021 15:25:29 +0000 (UTC) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1637853933; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=5ScN0yZJ9DZrfZrU9bEQf2Vg3+YysYzBmCXrDw5SbvI=; b=YE/yEWqDEOy+qF2FEZAfhspZGSfX33lbs9F9pxlG3hCFCCziJvGlP47svWrSUyTz5dv56i nEWu9G4BOmeyeAFDSM/tZPqUB0CHip5bP86yHW8gbQoMDfepKtwSDc3MBcXf0/VWXOm/8I 1GT0fitRJpSr6qLFep1PdQo7OEvjMCuCfGEsTiwjQ1ypNuEIeOd512ffqJTrivsv11dRvM Y6PySfjhDOtKDmzXa6raADo8CH/DXi6Bai+5mO6oWzaIs5pnWmpAdJ4TgvZsA9A8ErfXwt JEsWAZCJxTcNP+mdqlpK0FhChwPK99jmlR/lh0CcB6Mpl3SqWXGbfBbvV8gjqQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1637853933; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=5ScN0yZJ9DZrfZrU9bEQf2Vg3+YysYzBmCXrDw5SbvI=; b=PX3lkAHehFpJ5BUzLqbVMbfTtqKYVTSfZgmsEAnqxCRL1EjZfzcsfZW11y6bxaJzOMhAKV t7WAUHINCW/1IRCQ== To: ira.weiny@intel.com, Dave Hansen , Dan Williams Cc: Ira Weiny , Fenghua Yu , Ingo Molnar , Borislav Petkov , Peter Zijlstra , Andy Lutomirski , "H. Peter Anvin" , Rick Edgecombe , x86@kernel.org, linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev, linux-mm@kvack.org Subject: Re: [PATCH V7 07/18] x86/pks: Preserve the PKRS MSR on context switch In-Reply-To: <20210804043231.2655537-8-ira.weiny@intel.com> References: <20210804043231.2655537-1-ira.weiny@intel.com> <20210804043231.2655537-8-ira.weiny@intel.com> Date: Thu, 25 Nov 2021 16:25:32 +0100 Message-ID: <87fsrkl0k3.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: 7B91190000AC X-Stat-Signature: u5mjjw8d8qws8br5bdwtksknnphs5wta Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=linutronix.de header.s=2020 header.b="YE/yEWqD"; dkim=pass header.d=linutronix.de header.s=2020e header.b=PX3lkAHe; dmarc=pass (policy=none) header.from=linutronix.de; spf=pass (imf23.hostedemail.com: domain of tglx@linutronix.de designates 193.142.43.55 as permitted sender) smtp.mailfrom=tglx@linutronix.de X-Rspamd-Server: rspam02 X-HE-Tag: 1637853929-211086 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Aug 03 2021 at 21:32, ira weiny wrote: > @@ -658,6 +659,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) > /* Load the Intel cache allocation PQR MSR. */ > resctrl_sched_in(); > > + pkrs_write_current(); This is invoked from switch_to() and does this extra get/put_cpu_ptr() dance in the write function for no reason. Can you please stop sticking overhead into the hotpath just because? Thanks, tglx