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=-8.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 104A6C4363D for ; Thu, 24 Sep 2020 14:00:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B633E20B1F for ; Thu, 24 Sep 2020 14:00:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="FWvDvV70" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728057AbgIXOAb (ORCPT ); Thu, 24 Sep 2020 10:00:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728032AbgIXOAb (ORCPT ); Thu, 24 Sep 2020 10:00:31 -0400 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E3852C0613CE; Thu, 24 Sep 2020 07:00:30 -0700 (PDT) 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; bh=qIgj7Hl/mK3z08IlAa0KO02ef5f7Ktvw+3PqNseFblg=; b=FWvDvV70XJ5TuIqo2IUFpsddid 4bpADJ7rTnH62tcaWl9Sq1nKrU4IyHE+KamW32gcBG4U1bzjOm5PtJySQLChaW8M6gY0LPSZ0coze LM8z4wCOv8Zpa8kvOxn1wyatKvQIhtPRU/Hs/NVZEUFjJJAFBuHUhGS5qawq1Mczd1ftu3YW+tFeL 864SUTdfJvJxMMEpGydt5PyuVqcKJrHbgH14qXZByDkv8OO5fNrYni6b3K9R/ee4jMHnkkzXQQV9/ BRWBg4IMjdDnVRLswoFywsUZ67wWYEw3e8p0FgYYSgFQZ7Vdbv5Uwu9sd+jK1xsAmMGJgWdEn9nM/ 1agEj31w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kLRnN-0002LE-D2; Thu, 24 Sep 2020 14:00:25 +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 C89D13003E5; Thu, 24 Sep 2020 16:00:23 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id B53EE2023C925; Thu, 24 Sep 2020 16:00:23 +0200 (CEST) Date: Thu, 24 Sep 2020 16:00:23 +0200 From: Peter Zijlstra To: Mathieu Desnoyers Cc: Peter Oskolkov , paulmck , Boqun Feng , linux-kernel , Paul Turner , Chris Kennelly , Peter Oskolkov , shuah , linux-kselftest Subject: Re: [PATCH v8 1/3] rseq/membarrier: add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ Message-ID: <20200924140023.GO2628@hirez.programming.kicks-ass.net> References: <20200923233618.2572849-1-posk@google.com> <1693241031.67909.1600955503870.JavaMail.zimbra@efficios.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1693241031.67909.1600955503870.JavaMail.zimbra@efficios.com> Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Thu, Sep 24, 2020 at 09:51:43AM -0400, Mathieu Desnoyers wrote: > > > ----- On Sep 23, 2020, at 7:36 PM, Peter Oskolkov posk@google.com wrote: > > > This patchset is based on Google-internal RSEQ > > work done by Paul Turner and Andrew Hunter. > > > > When working with per-CPU RSEQ-based memory allocations, > > it is sometimes important to make sure that a global > > memory location is no longer accessed from RSEQ critical > > sections. For example, there can be two per-CPU lists, > > one is "active" and accessed per-CPU, while another one > > is inactive and worked on asynchronously "off CPU" (e.g. > > garbage collection is performed). Then at some point > > the two lists are swapped, and a fast RCU-like mechanism > > is required to make sure that the previously active > > list is no longer accessed. > > > > This patch introduces such a mechanism: in short, > > membarrier() syscall issues an IPI to a CPU, restarting > > a potentially active RSEQ critical section on the CPU. > > > > Acked-by: Mathieu Desnoyers Thanks!, I've queued them in: git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/core please double check the Subject/Changelog edits I made. Once all the robots are green, I'll push out the lot to -tip.