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=-5.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 98C39C433DF for ; Tue, 13 Oct 2020 21:00:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F673208D5 for ; Tue, 13 Oct 2020 21:00:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="HeWN9uPQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726878AbgJMVA7 (ORCPT ); Tue, 13 Oct 2020 17:00:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726186AbgJMVA6 (ORCPT ); Tue, 13 Oct 2020 17:00:58 -0400 Received: from mail-pj1-x1044.google.com (mail-pj1-x1044.google.com [IPv6:2607:f8b0:4864:20::1044]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD054C061755 for ; Tue, 13 Oct 2020 14:00:58 -0700 (PDT) Received: by mail-pj1-x1044.google.com with SMTP id a17so134707pju.1 for ; Tue, 13 Oct 2020 14:00:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=35KdctzIrSBX2mg6IoDLEL1qwd4y1P4GeBRmVWUjxAk=; b=HeWN9uPQx7edJWlSQV4WI0zrWQ/4+cArpAu3sGJzpjcHnYQ0RnSUocrK3ge2ZhP+JZ pLdBt+dUNJnbCEL69MledzokOcmLYb/1KxvXSF0vIQVM6auH0A93k8npU/x5A/70Wgdc kRz36KHAFHQfQ3LGJQvkx9Kf2CWbZ6Buq6FDeE410jyTdKtKhIxm5DpSI/3nkNqC4Oy9 RJwWPbTbI568Rnxj0eSOZBz2K3C00UBe8bj41TjbemrjlgZXYj49soVw+vhFPFSBqG7c nxbyRNrltQ/AhA9qQuwFJoE5MtmukSIXVwZ38A91olrtAAhztZSxG3QKdUWpMbLKz7qh pnrA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=35KdctzIrSBX2mg6IoDLEL1qwd4y1P4GeBRmVWUjxAk=; b=BRfr7CV+Mp/TEDZKznWlf9X0CxKCQzTLBxPeQcA/7v9QO5zRImUeL5GEGSTyA5RGcR DovAoqW50FMYpYl+7pM9b07C4vT+I5vvwHkHXfQ+DnGsS80WRFngNh1QZaVijOGUVSQt Ltsuh0BXrlmrFDrwDxFlPxZlDmazvDoghWSUXAptIUhTvXRsNSeQu9aIMfpMrCkfRZVm 2+PeccarjXHYp8geEQeSD5DaCxIT4sZAunuY8pMGBDHaRWdcu5/I5MKpsmRxh0SynY86 oWKJd5sH4WlwjHV7bx7wZzfbTthcmFjdqZRFYttJLCp7KeidsZjpEhqrX7EB4xb0fF0o wf+g== X-Gm-Message-State: AOAM532f62gwdpov3E+sogPaSu6Ow4d7BIz5CxIVwQt6uACFDeQqshCX SnCasmM9RdWOTSyp8fsBx6wKyw== X-Google-Smtp-Source: ABdhPJzEkiDHxZwinBbb70w4edrvZ5KbQj6DFDmXtrUEZVKUuoLWH+/LYYGiHOx3TfcYkg9gL17jTA== X-Received: by 2002:a17:902:c313:b029:d4:b6ac:7b5a with SMTP id k19-20020a170902c313b02900d4b6ac7b5amr1523992plx.39.1602622858128; Tue, 13 Oct 2020 14:00:58 -0700 (PDT) Received: from [192.168.1.134] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id l18sm548332pfd.210.2020.10.13.14.00.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 13 Oct 2020 14:00:57 -0700 (PDT) Subject: Re: [GIT PULL] io_uring updates for 5.10-rc1 To: Rasmus Villemoes , Linus Torvalds Cc: io-uring , "linux-kernel@vger.kernel.org" References: <36a6706d-73e1-64e7-f1f8-8f5ef246d3ea@kernel.dk> <3e37f236-c0ce-abb0-fa89-2118dd18d042@rasmusvillemoes.dk> From: Jens Axboe Message-ID: <7f2c7699-b8f4-3b50-d1c9-beeb429e32e4@kernel.dk> Date: Tue, 13 Oct 2020 15:00:56 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <3e37f236-c0ce-abb0-fa89-2118dd18d042@rasmusvillemoes.dk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 10/13/20 2:49 PM, Rasmus Villemoes wrote: > On 13/10/2020 21.49, Jens Axboe wrote: >> On 10/13/20 1:46 PM, Linus Torvalds wrote: >>> On Mon, Oct 12, 2020 at 6:46 AM Jens Axboe wrote: >>>> >>>> Here are the io_uring updates for 5.10. >>> >>> Very strange. My clang build gives a warning I've never seen before: >>> >>> /tmp/io_uring-dd40c4.s:26476: Warning: ignoring changed section >>> attributes for .data..read_mostly >>> >>> and looking at what clang generates for the *.s file, it seems to be >>> the "section" line in: >>> >>> .type io_op_defs,@object # @io_op_defs >>> .section .data..read_mostly,"a",@progbits >>> .p2align 4 >>> >>> I think it's the combination of "const" and "__read_mostly". >>> >>> I think the warning is sensible: how can a piece of data be both >>> "const" and "__read_mostly"? If it's "const", then it's not "mostly" >>> read - it had better be _always_ read. >>> >>> I'm letting it go, and I've pulled this (gcc doesn't complain), but >>> please have a look. >> >> Huh weird, I'll take a look. FWIW, the construct isn't unique across >> the kernel. > > Citation needed. There's lots of "pointer to const foo" stuff declared > as __read_mostly, but I can't find any objects that are themselves both > const and __read_mostly. Other than that io_op_defs and io_uring_fops now. You are right, they are all pointers, so not the same. I'll just revert the patch. -- Jens Axboe