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([2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e]) by smtp.gmail.com with ESMTPSA id n1sm2700678edf.45.2021.11.11.23.55.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 11 Nov 2021 23:55:36 -0800 (PST) Message-ID: <016d5b91-6910-2aca-0db1-a65079449454@redhat.com> Date: Fri, 12 Nov 2021 08:55:31 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH v4 01/17] perf: Protect perf_guest_cbs with RCU To: Peter Zijlstra References: <20211111020738.2512932-1-seanjc@google.com> <20211111020738.2512932-2-seanjc@google.com> From: Paolo Bonzini In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Cc: Wanpeng Li , kvm@vger.kernel.org, Alexander Shishkin , Catalin Marinas , Dave Hansen , Guo Ren , "H. Peter Anvin" , linux-riscv@lists.infradead.org, Vincent Chen , Will Deacon , Boris Ostrovsky , Stefano Stabellini , xen-devel@lists.xenproject.org, Marc Zyngier , Joerg Roedel , x86@kernel.org, Russell King , linux-csky@vger.kernel.org, kvmarm@lists.cs.columbia.edu, Ingo Molnar , Like Xu , Albert Ou , Zhu Lingshan , Jiri Olsa , Arnaldo Carvalho de Melo , Borislav Petkov , Greentime Hu , Paul Walmsley , Namhyung Kim , Thomas Gleixner , Artem Kashkanov , linux-arm-kernel@lists.infradead.org, Jim Mattson , Juergen Gross , Like Xu , Nick Hu , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Palmer Dabbelt , Vitaly Kuznetsov X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On 11/11/21 11:47, Peter Zijlstra wrote: >> This technically could be RCU_INIT_POINTER but it's not worth a respin. >> There are dozens of other occurrences, and if somebody wanted they >> could use Coccinelle to fix all of them. > I've been pushing the other way, trying to get rid of RCU_INIT_POINTER() > since rcu_assign_pointer(, NULL) actualy DTRT per __builtin_constant_p() > etc. Oh, that's pretty cool to know, thanks! Paolo > There's a very few sites where we use RCU_INIT_POINTER() with a !NULL > argument, and those are 'special'. > _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F05B6C433EF for ; Fri, 12 Nov 2021 07:55:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C5EA961029 for ; Fri, 12 Nov 2021 07:55:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234144AbhKLH6b (ORCPT ); Fri, 12 Nov 2021 02:58:31 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:32297 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233717AbhKLH6a (ORCPT ); Fri, 12 Nov 2021 02:58:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636703739; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lF7lzRoeZrlEIt3gHEFyVsRoWpbej1ntDFwYNAiQdJI=; b=OoH/RlDgLrBZ4NE0Egiv2jYH8u01kIkq7gOxapj3QCEpGv+UEvV8YL1k8ZDawXVwBCBY9L S/PngiPfgXjne44ijbUWRyM9MJdCI2gzYe1HdEMfP3KVnjv+4tEjyXNuQeDess5Ff4y0/O eBFVMOdsntqB/H6Yt6IMd0RSpBwt2rg= Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-32-4y0MLnGKOiWxetEawMLkDw-1; Fri, 12 Nov 2021 02:55:38 -0500 X-MC-Unique: 4y0MLnGKOiWxetEawMLkDw-1 Received: by mail-ed1-f69.google.com with SMTP id w12-20020a056402268c00b003e2ab5a3370so7607437edd.0 for ; Thu, 11 Nov 2021 23:55:38 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=lF7lzRoeZrlEIt3gHEFyVsRoWpbej1ntDFwYNAiQdJI=; b=w4EWWye2x7zkM49tYcr035feAE7SDdpWO1/nAcSXStAwnYviBCYiY6dQZNfQaX4jSc AkHHH2PTYQYbseyGfd2Ouc+PSxSP2e6ApjGDG0cVStxqQvv3r3pkh9yxuHcuKHF13qNY l3UzJoRqOuDGgq4WtY3tNbBeE8In6Bqo2GYXQzY6ZUaaHDl9qvxa/ykOhSIhl74Nin00 c4qR5CiB5gz+EfuZEWsYGqOOsQSXdft24h4NYAilHIYqkfZcucbvGvDPt0N18WWfmWdU Nll6BobuIxNoJH+K4andNzIOhnsulE0UX1i1Jw+mqMO8u3PSYr3uHNdEEaOTlxjhy5L2 urbg== X-Gm-Message-State: AOAM5328awEJhheVlbPfyvi4a99tswkUFsiZxxeDJJ/LaYvM8N9uBUj/ zx9bTb0vAn6Uc7GVzyQL0QffjjiMAQWT0E7vZhPXRzU+zc+T9pwiVIven+vZyp+KRDiSuHpfsLk RfA0f4uCJjFCEhurEk0M73w== X-Received: by 2002:a17:907:6e10:: with SMTP id sd16mr17768020ejc.158.1636703737507; Thu, 11 Nov 2021 23:55:37 -0800 (PST) X-Google-Smtp-Source: ABdhPJzVTSyaI9bwf+cK3HRTYkkEGrfXsl4Cvt+Fkmz/7JDyaorMKEA4Mec75P9Nt6V8a8edl3Ld8g== X-Received: by 2002:a17:907:6e10:: with SMTP id sd16mr17767982ejc.158.1636703737318; Thu, 11 Nov 2021 23:55:37 -0800 (PST) Received: from ?IPV6:2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e? ([2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e]) by smtp.gmail.com with ESMTPSA id n1sm2700678edf.45.2021.11.11.23.55.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 11 Nov 2021 23:55:36 -0800 (PST) Message-ID: <016d5b91-6910-2aca-0db1-a65079449454@redhat.com> Date: Fri, 12 Nov 2021 08:55:31 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH v4 01/17] perf: Protect perf_guest_cbs with RCU Content-Language: en-US To: Peter Zijlstra Cc: Sean Christopherson , Ingo Molnar , Arnaldo Carvalho de Melo , Will Deacon , Mark Rutland , Russell King , Marc Zyngier , Catalin Marinas , Guo Ren , Nick Hu , Greentime Hu , Vincent Chen , Paul Walmsley , Palmer Dabbelt , Albert Ou , Thomas Gleixner , Borislav Petkov , Dave Hansen , x86@kernel.org, Boris Ostrovsky , Juergen Gross , Alexander Shishkin , Jiri Olsa , Namhyung Kim , James Morse , Alexandru Elisei , Suzuki K Poulose , "H. Peter Anvin" , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Stefano Stabellini , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-csky@vger.kernel.org, linux-riscv@lists.infradead.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, Artem Kashkanov , Like Xu , Like Xu , Zhu Lingshan References: <20211111020738.2512932-1-seanjc@google.com> <20211111020738.2512932-2-seanjc@google.com> From: Paolo Bonzini In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-csky@vger.kernel.org On 11/11/21 11:47, Peter Zijlstra wrote: >> This technically could be RCU_INIT_POINTER but it's not worth a respin. >> There are dozens of other occurrences, and if somebody wanted they >> could use Coccinelle to fix all of them. > I've been pushing the other way, trying to get rid of RCU_INIT_POINTER() > since rcu_assign_pointer(, NULL) actualy DTRT per __builtin_constant_p() > etc. Oh, that's pretty cool to know, thanks! Paolo > There's a very few sites where we use RCU_INIT_POINTER() with a !NULL > argument, and those are 'special'. > 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 595A6C433EF for ; Fri, 12 Nov 2021 07:56:06 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1074260FE7 for ; Fri, 12 Nov 2021 07:56:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1074260FE7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ddsHN8uGDuL/wn8OQx4oSHxdl8AvFYyBR5HxBEXUXCs=; b=lcX0a+f2fBG2kA FRtwTgu8keiOi8Pk3IdgejoN7xgRNCFNb9ttwWffG9v6OZQgbG/Gp+YT3HSYHXox44BGR637fRbru kf1ur1MZDLVqKWMSGmi6g4ebqT57ZxeTCxtAmKqDPbkprAoz8bg6RpmfNnlyGW4IVpN12gUP4JGEc UxpBljSrVp6X3QcgKKx77aKkLoP5hWN8VgmRmlPYXKjlleXXbQDWFHvKZgz3DR3kgnHbPz+0H8atS qzEemiTPF9FGW2dY1r8/iwUeQJMitZ8/iNZyxO0eireQf27MoORujMAE2FGAuU6Zdpe1w/+oLD2YK JflTQQQrjHsaXZCw92ow==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mlRPd-009dKV-DH; Fri, 12 Nov 2021 07:55:53 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mlRPR-009dI9-1q for linux-riscv@lists.infradead.org; Fri, 12 Nov 2021 07:55:42 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636703740; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lF7lzRoeZrlEIt3gHEFyVsRoWpbej1ntDFwYNAiQdJI=; b=idJU5KzXqQnzThBVK1r8v2xTTYjlvHqFV4WeJikBoUTfau774u9MhOp87uNWVEU5QBN8jy dM+kZBY3rRqNAt5Ay4ARUDnHqtcVTozodtUuighFESarf0v3XFx9ScFUyBx0Dquax9+Qm1 Kevo+XJMoBHrTAgjMUT8TeDMfoepxmE= Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-32-6eylRC9sPea5bHbprWhagw-1; Fri, 12 Nov 2021 02:55:38 -0500 X-MC-Unique: 6eylRC9sPea5bHbprWhagw-1 Received: by mail-ed1-f72.google.com with SMTP id y12-20020a056402270c00b003e28de6e995so7543855edd.11 for ; Thu, 11 Nov 2021 23:55:38 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=lF7lzRoeZrlEIt3gHEFyVsRoWpbej1ntDFwYNAiQdJI=; b=k0yMEfumpHJYoURMJOyWsO91Y/u3djExIvM/RyHUE8yxeSTxmq1ypya2GQnLScgqbg OmPw3C8LLBWqmEPhRBufTCjKEP0EJVSCIOYzeJkML6R+I8be76tk1xEdyaGLDtlwUF6j 6ZKkl34xFAWZEoZxoufWw0OFWk6JgpLPYE3jU4Sn8HcmU49yOejkGZnq1xVoqQQf1cUn xFm6nwvpWsfDaSq+/fRHXfDc8FkYgIJh2OG/dHyMhg+GH+OK45hRJv/jGsMJqPz/ArcR W85P2/wC6ZJI5ECaaJq43sclXs4gwNva+VkLbtn0lv9fL7zJHL5UmIvNAE6wORX+LJix mLLw== X-Gm-Message-State: AOAM530H92dXCOA53zMM6fXV9N94Hmcvlb/e6MqEoXruuQMkkpchE76N dg69/MwpsUJEoqjrKhc5bSYvu6QbUVqru12/ENyRZSmWzrPttqDeTGn+BZfjIhziIpMn+TGQnqW 607kyibBGapKoeJDZisQXudmsU7YC X-Received: by 2002:a17:907:6e10:: with SMTP id sd16mr17768012ejc.158.1636703737498; Thu, 11 Nov 2021 23:55:37 -0800 (PST) X-Google-Smtp-Source: ABdhPJzVTSyaI9bwf+cK3HRTYkkEGrfXsl4Cvt+Fkmz/7JDyaorMKEA4Mec75P9Nt6V8a8edl3Ld8g== X-Received: by 2002:a17:907:6e10:: with SMTP id sd16mr17767982ejc.158.1636703737318; Thu, 11 Nov 2021 23:55:37 -0800 (PST) Received: from ?IPV6:2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e? ([2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e]) by smtp.gmail.com with ESMTPSA id n1sm2700678edf.45.2021.11.11.23.55.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 11 Nov 2021 23:55:36 -0800 (PST) Message-ID: <016d5b91-6910-2aca-0db1-a65079449454@redhat.com> Date: Fri, 12 Nov 2021 08:55:31 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH v4 01/17] perf: Protect perf_guest_cbs with RCU To: Peter Zijlstra Cc: Sean Christopherson , Ingo Molnar , Arnaldo Carvalho de Melo , Will Deacon , Mark Rutland , Russell King , Marc Zyngier , Catalin Marinas , Guo Ren , Nick Hu , Greentime Hu , Vincent Chen , Paul Walmsley , Palmer Dabbelt , Albert Ou , Thomas Gleixner , Borislav Petkov , Dave Hansen , x86@kernel.org, Boris Ostrovsky , Juergen Gross , Alexander Shishkin , Jiri Olsa , Namhyung Kim , James Morse , Alexandru Elisei , Suzuki K Poulose , "H. Peter Anvin" , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Stefano Stabellini , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-csky@vger.kernel.org, linux-riscv@lists.infradead.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, Artem Kashkanov , Like Xu , Like Xu , Zhu Lingshan References: <20211111020738.2512932-1-seanjc@google.com> <20211111020738.2512932-2-seanjc@google.com> From: Paolo Bonzini In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211111_235541_179341_734CBEE9 X-CRM114-Status: GOOD ( 12.43 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On 11/11/21 11:47, Peter Zijlstra wrote: >> This technically could be RCU_INIT_POINTER but it's not worth a respin. >> There are dozens of other occurrences, and if somebody wanted they >> could use Coccinelle to fix all of them. > I've been pushing the other way, trying to get rid of RCU_INIT_POINTER() > since rcu_assign_pointer(, NULL) actualy DTRT per __builtin_constant_p() > etc. Oh, that's pretty cool to know, thanks! Paolo > There's a very few sites where we use RCU_INIT_POINTER() with a !NULL > argument, and those are 'special'. > _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv