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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 E612BC10F06 for ; Mon, 11 Mar 2019 14:01:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B4AA020657 for ; Mon, 11 Mar 2019 14:01:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727662AbfCKOBK (ORCPT ); Mon, 11 Mar 2019 10:01:10 -0400 Received: from mail-qt1-f193.google.com ([209.85.160.193]:36704 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726897AbfCKOBK (ORCPT ); Mon, 11 Mar 2019 10:01:10 -0400 Received: by mail-qt1-f193.google.com with SMTP id b3so5104603qtj.3 for ; Mon, 11 Mar 2019 07:01:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=NAVSCLI4bpYkN0vehk8e+9hfFe+zl25LDlWzCtnVJs4=; b=d+yCGpp89+aNOSMnMpgYxHr2+erWT+zo6mImDGtQMIZPy2qbgBaKEG7IsWJqMu/0+Q eU9yrywTLJ3vvP7jfEKkhkWd94nX7yzvk0BpPzg03BWMP8hgrFlCxcFGGAvUOBKUOzz3 /bVcA2wfWgn7S5bhRb9ebqnMcGxyHtP/kBEVswX+3qIvV87ZSL2vdTUprq03mLeIFCOc gYJEkgQ5S/vdLTFt6E2Y5AgUEPenhLRTR7zBGOmjqmqatrRB7U/qT8MaBPAsjWaxKwWl hPKvz1ZeFC2thZgrBJNCW8LY2Z/5AmqcOPPYZ/d6BSXkA5XwWYmmLheNseF4jw2kHNCq OmZA== X-Gm-Message-State: APjAAAUzOgtOUql3SzqjRPOkC6Qy9V6BDqa3Ox+MrfAvqgBl7z375f+g nd+l4xX+hzmr8WUS0YuQmOcOIkIOYfjGUjvtTwo= X-Google-Smtp-Source: APXvYqxsIdm3BSNVGFp9FsU9rosmUSaPmP2VP43e8DD+SIqNd/ILmWEbKSwxunuPwJTx91N1nbWiyX+pBuqhbxBTK2A= X-Received: by 2002:a0c:b501:: with SMTP id d1mr26308451qve.115.1552312869102; Mon, 11 Mar 2019 07:01:09 -0700 (PDT) MIME-Version: 1.0 References: <20190310183051.87303-1-cai@lca.pw> <20190311035815.kq7ftc6vphy6vwen@linux-r8p5> <20190311122100.GF22862@mellanox.com> In-Reply-To: <20190311122100.GF22862@mellanox.com> From: Arnd Bergmann Date: Mon, 11 Mar 2019 15:00:50 +0100 Message-ID: Subject: Re: [PATCH] mm/debug: add a cast to u64 for atomic64_read() To: Jason Gunthorpe Cc: Qian Cai , "akpm@linux-foundation.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 11, 2019 at 1:21 PM Jason Gunthorpe wrote: > On Sun, Mar 10, 2019 at 08:58:15PM -0700, Davidlohr Bueso wrote: > > On Sun, 10 Mar 2019, Qian Cai wrote: > > > > Acked-by: Davidlohr Bueso > > Not saying this patch shouldn't go ahead.. > > But is there a special reason the atomic64*'s on ppc don't use the u64 > type like other archs? Seems like a better thing to fix than adding > casts all over the place. Agreed in principle, but I'd note that it's not just ppc64, but almost all 64-bit architectures. x86-64 and arm64 changed over last year from returning 'long' to 'long long', apparently as an unintended side effect of commits 8bf705d13039 ("locking/atomic/x86: Switch atomic.h to use atomic-instrumented.h") and c0df10812835 ("arm64, locking/atomics: Use instrumented atomics"). It would be nice to just do the instrumented atomics on all 64-bit architectures for consistency, but that would be a lot of work, and would not actually give us additional instrumentation on most of them, since they don't support KASAN (except s390). Arnd 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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 44C83C43381 for ; Mon, 11 Mar 2019 14:01:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0C56A20657 for ; Mon, 11 Mar 2019 14:01:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0C56A20657 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arndb.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AD6888E0005; Mon, 11 Mar 2019 10:01:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A849D8E0002; Mon, 11 Mar 2019 10:01:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9758B8E0005; Mon, 11 Mar 2019 10:01:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-qt1-f199.google.com (mail-qt1-f199.google.com [209.85.160.199]) by kanga.kvack.org (Postfix) with ESMTP id 7101F8E0002 for ; Mon, 11 Mar 2019 10:01:10 -0400 (EDT) Received: by mail-qt1-f199.google.com with SMTP id e31so5253213qtb.22 for ; Mon, 11 Mar 2019 07:01:10 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:mime-version :references:in-reply-to:from:date:message-id:subject:to:cc; bh=NAVSCLI4bpYkN0vehk8e+9hfFe+zl25LDlWzCtnVJs4=; b=aMoU96a39Nlsk6uPkZiC/zkwZksy/lSlGJ2Nft5KhVbjenaPuQ/RtM8+of1aTgwYhi DH3Rx4kILhvK2LOSit53STJqnmNyrIlt0y2fQtku38MWfKgqAPc7Vlff1su0Kcp2Pfn0 meZVH/l6+40nZrTCOVJw8c3D4eeUhrCn3ruh/5Cu7vYs2oiK9JA3vnMAR7Rrb9JYnqz2 CcAbgkOO2Hgxuxy4RiqL2xR09Jk7I6Obg8G4QVMxm8HuR62VvbnlS+21ehOR+V4Ifmnf 2Bfn/bZaOim/LUWW/vhbuD5hYEiTgqAD8444bsMD3VfdpVKEUM1SNvzcCkuWG0hJxqnj REWQ== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of arndbergmann@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=arndbergmann@gmail.com X-Gm-Message-State: APjAAAXxF7UUbZYxOAUq6o8HBsTTjhcSn0a7/3QjS9ZJ0aM8QuvWqmOx pNP3dkRrxrdQlknwiff+0ckpeZLAtJ9W/YvlywESJvYiTJjUgUw8N2sMG0JrHQ3ILTJBMBnZpB/ esBU+BIjUlDMo1i/GwrDvNdO2pjVfiAo7DQyCvMTVhZVDX9rc7IulrMB4hXCUKKCALccY6Cfh5y 6DSsfpf42nTZFpYOPpiI+iMfdSdgdcOwtWbh5Rn/nBw0Pp90ywT/6v9CQMje/80aseFpE65xY3m 0S1ooX/zgv2WyETxe/UYv0ko0h/lrTgFDtp5UliMX4wh7wL3MLdPHK9mzx1f7j2+aKPlZJF9Ea5 yAG5br4iXn4zCSGx3O1vNg/r0LtxbbeOrkognk0CWjJwWhWaKBBE6QlEG4k+HIAxQBpCFo2cFw= = X-Received: by 2002:ae9:c30f:: with SMTP id n15mr1875011qkg.227.1552312870262; Mon, 11 Mar 2019 07:01:10 -0700 (PDT) X-Received: by 2002:ae9:c30f:: with SMTP id n15mr1874942qkg.227.1552312869494; Mon, 11 Mar 2019 07:01:09 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1552312869; cv=none; d=google.com; s=arc-20160816; b=u+2pXRYSECzaFDsghyLsgubZdgugXu93I0ELwaZZQulKqP2HB/kWVQX/7EFRDcug+l NqNIs3rtQya3xQIRVnsfQKahOeFbVRPHNoVjCUdrPn9iFMFLajfHeAsAswV9pbUatKIR RLw+VSBLPkB57m7ZR1GPTtOYgOg834woEbzfX6iUEJjdFmUG+OcZl/IetStHZuB9j+8U wrHKjW4cVhWBH4Ph7tXhZ6oxoBnErY8088CizIIHY4/k9VEnAORTDmEbsKxsODgPtE3S Hk934Mv7YyFB3o1ghupRC7yYiEAsw8oMCrBgpeWnfey2zK1KJL03D5QBzrnTWUq9nbix s4FA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version; bh=NAVSCLI4bpYkN0vehk8e+9hfFe+zl25LDlWzCtnVJs4=; b=nSlM58ix0Ak9tKSEIaebXGrSPyg0e6tvF3tRF7krdTZNWr0kXBNsw6oGDkHgyvBH57 RYvuS9fQV+Z6syiUU0prqVxFQUHtxfq/MrlM+225iN8UhhSyEkohB7kmini6bReK3gf/ fJ1g4mvqP0TlZ415loA/3wooOz8fmLOGJt11ENMsS7cl3l1uGIwdbINdmUJCgFfDsZLm /jY9br14ZBZVUiLMDMI525cIzT3+5y+S6Ne34MnD+c9ASoGBY3DkvhhvHddAfdFtj2mj kpuLm5SIooXTkc96BfuyLqtCX5lRH13Zf3LrqnC6Z95WBlvssc9DVjt44YS3euk3EGSU 0wrQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of arndbergmann@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=arndbergmann@gmail.com Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id z43sor6184828qve.15.2019.03.11.07.01.09 for (Google Transport Security); Mon, 11 Mar 2019 07:01:09 -0700 (PDT) Received-SPF: pass (google.com: domain of arndbergmann@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; spf=pass (google.com: domain of arndbergmann@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=arndbergmann@gmail.com X-Google-Smtp-Source: APXvYqxsIdm3BSNVGFp9FsU9rosmUSaPmP2VP43e8DD+SIqNd/ILmWEbKSwxunuPwJTx91N1nbWiyX+pBuqhbxBTK2A= X-Received: by 2002:a0c:b501:: with SMTP id d1mr26308451qve.115.1552312869102; Mon, 11 Mar 2019 07:01:09 -0700 (PDT) MIME-Version: 1.0 References: <20190310183051.87303-1-cai@lca.pw> <20190311035815.kq7ftc6vphy6vwen@linux-r8p5> <20190311122100.GF22862@mellanox.com> In-Reply-To: <20190311122100.GF22862@mellanox.com> From: Arnd Bergmann Date: Mon, 11 Mar 2019 15:00:50 +0100 Message-ID: Subject: Re: [PATCH] mm/debug: add a cast to u64 for atomic64_read() To: Jason Gunthorpe Cc: Qian Cai , "akpm@linux-foundation.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" 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 Mon, Mar 11, 2019 at 1:21 PM Jason Gunthorpe wrote: > On Sun, Mar 10, 2019 at 08:58:15PM -0700, Davidlohr Bueso wrote: > > On Sun, 10 Mar 2019, Qian Cai wrote: > > > > Acked-by: Davidlohr Bueso > > Not saying this patch shouldn't go ahead.. > > But is there a special reason the atomic64*'s on ppc don't use the u64 > type like other archs? Seems like a better thing to fix than adding > casts all over the place. Agreed in principle, but I'd note that it's not just ppc64, but almost all 64-bit architectures. x86-64 and arm64 changed over last year from returning 'long' to 'long long', apparently as an unintended side effect of commits 8bf705d13039 ("locking/atomic/x86: Switch atomic.h to use atomic-instrumented.h") and c0df10812835 ("arm64, locking/atomics: Use instrumented atomics"). It would be nice to just do the instrumented atomics on all 64-bit architectures for consistency, but that would be a lot of work, and would not actually give us additional instrumentation on most of them, since they don't support KASAN (except s390). Arnd