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 E551CC47DB3 for ; Wed, 31 Jan 2024 20:42:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 46DE16B0075; Wed, 31 Jan 2024 15:42:55 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 41E1F6B0078; Wed, 31 Jan 2024 15:42:55 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2BDBB6B007B; Wed, 31 Jan 2024 15:42:55 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 17AB26B0075 for ; Wed, 31 Jan 2024 15:42:55 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id DBF921406CE for ; Wed, 31 Jan 2024 20:42:54 +0000 (UTC) X-FDA: 81740780268.19.3B8708F Received: from mail-pj1-f53.google.com (mail-pj1-f53.google.com [209.85.216.53]) by imf18.hostedemail.com (Postfix) with ESMTP id EBF961C0017 for ; Wed, 31 Jan 2024 20:42:52 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=fromorbit-com.20230601.gappssmtp.com header.s=20230601 header.b=l4ybiVAF; spf=pass (imf18.hostedemail.com: domain of david@fromorbit.com designates 209.85.216.53 as permitted sender) smtp.mailfrom=david@fromorbit.com; dmarc=pass (policy=quarantine) header.from=fromorbit.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1706733773; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=4HikurBEOhu9euC7gl0ui3GG6XowXvyoYxK7m1zGW+s=; b=zPW3uolWl6gQSRBu7BPgJVgW9izHVk2AKf/Uma1fFlRggQn3zkqJp/M7jfGXAbc3gDspJD JhHdtdGv+ftq6p8Zes80wYl3d+7PWppyEddvCTlYthzIS6toENNtbiAwiRLJJoMMl5dRWb Gys7DBP/HNAmTihXVCCrdiiGVb0mvuc= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1706733773; a=rsa-sha256; cv=none; b=a1aVT3U2Pc4mMsy8DL4PUWIWbQ6tPQ0iqWvg3N79icUl2uxpU9mo6DMnCAtNzNk2tn+HsG L7rOqRquqnPZBo5DjwRBTp5bOFFOLOMa+MaZeIPnjDSF08MCQ7eKSpsL8YONRovJrX5f0t UDy+tBmVp2gBTVQyjs/Ww8DCnl+8ICE= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=fromorbit-com.20230601.gappssmtp.com header.s=20230601 header.b=l4ybiVAF; spf=pass (imf18.hostedemail.com: domain of david@fromorbit.com designates 209.85.216.53 as permitted sender) smtp.mailfrom=david@fromorbit.com; dmarc=pass (policy=quarantine) header.from=fromorbit.com Received: by mail-pj1-f53.google.com with SMTP id 98e67ed59e1d1-2906855ac5fso104146a91.3 for ; Wed, 31 Jan 2024 12:42:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fromorbit-com.20230601.gappssmtp.com; s=20230601; t=1706733772; x=1707338572; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=4HikurBEOhu9euC7gl0ui3GG6XowXvyoYxK7m1zGW+s=; b=l4ybiVAF0cVjsnIEKX1Yx9NQdQTeXSnmBoj/cCqu6YGanQ94VSwP4qUeNvz9GmCd2a nwWPJIrDDn5idZ/4zPjKG6jtM+5TZnYZ1VW+Aaiq4Y/9c1iq/Syj4J13J/wgCYiLZbDw evL3H9AeEYjyALx6tC2X/H12qc6M4DCv2B2fee9zrpEtUqpneuA7OoODjRVWV33837IR DuEMgHp3ToBT6QJCuB5UWijU06HiZllzqPR3xk4hIlw0BZzHgTpr4gYzKMMlDyOpMOc5 Wg4KrakdNUZeDa2HemU5IEgiIkgXRxa7CiC3pCeXPrcFiMLYNpnrW4uYMTa9rj1MJZaF IjiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706733772; x=1707338572; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=4HikurBEOhu9euC7gl0ui3GG6XowXvyoYxK7m1zGW+s=; b=fVoXx4PMYOfaSPvgGWRItdIEbxabhmp+rckAp1zbWYa2uYp3P5MNVDUp/TtdKcmBv/ 7AYgAQRNMhR3cV5NfuCidClgbL0247nYQ58zxrn49NiP27njAjA+US/QwU8ubBBcIhNy 0921hk6iOQnauYFNvo7nR7CrGk6fxqxKa6iOQq+vW268ABb4LD099fLW4d/LLJap0mNQ jYMXXF4pM55xtA68J3KQC48fQjpHJ/8hliH69Mjq3jxNnEtOvFail5wLGnTMzqxqWD/3 cC2oi76h9ly8C/PXIrSvVow4oyRqraWH0pDb7EHGUGRlWWZJb/CSrWEAtxpeqj1Sa1Bu TkIQ== X-Gm-Message-State: AOJu0YzXD2kC5GQBCrKtDt9ZMTaugckePmpkpOVZLyCytP/1j4Kln+Lt rRQtyl7rYlqTFL3fkiyHOiB00y42OBGhXe/yzrToqxJNsRGeLP1ee2xrl5ptSJs= X-Google-Smtp-Source: AGHT+IFKgnjyHOHXjb8FWpmberef1nwD4qkIyOp+/vPJjvOfE+QEc5Mj2C0M+Fe+UDPDMwl9iwoIbw== X-Received: by 2002:a17:90b:2406:b0:295:cf9f:a1de with SMTP id nr6-20020a17090b240600b00295cf9fa1demr2928435pjb.12.1706733771727; Wed, 31 Jan 2024 12:42:51 -0800 (PST) Received: from dread.disaster.area (pa49-181-38-249.pa.nsw.optusnet.com.au. [49.181.38.249]) by smtp.gmail.com with ESMTPSA id db16-20020a17090ad65000b0029608793122sm225215pjb.20.2024.01.31.12.42.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 31 Jan 2024 12:42:51 -0800 (PST) Received: from dave by dread.disaster.area with local (Exim 4.96) (envelope-from ) id 1rVHPz-000JNE-2o; Thu, 01 Feb 2024 07:42:47 +1100 Date: Thu, 1 Feb 2024 07:42:47 +1100 From: Dave Chinner To: Mathieu Desnoyers Cc: Dan Williams , Vishal Verma , Dave Jiang , linux-kernel@vger.kernel.org, Andrew Morton , Linus Torvalds , linux-mm@kvack.org, linux-arch@vger.kernel.org, Matthew Wilcox , Arnd Bergmann , Russell King , linux-cxl@vger.kernel.org, nvdimm@lists.linux.dev, linux-xfs@vger.kernel.org Subject: Re: [RFC PATCH v2 7/8] Introduce dcache_is_aliasing() across all architectures Message-ID: References: <20240130165255.212591-1-mathieu.desnoyers@efficios.com> <20240130165255.212591-8-mathieu.desnoyers@efficios.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: 53owacoz9ya5o18yqsqous1nutmgjebo X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: EBF961C0017 X-Rspam-User: X-HE-Tag: 1706733772-26872 X-HE-Meta: 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 DWVu8/nX 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 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: List-Subscribe: List-Unsubscribe: On Wed, Jan 31, 2024 at 09:58:21AM -0500, Mathieu Desnoyers wrote: > On 2024-01-30 21:48, Dave Chinner wrote: > > On Tue, Jan 30, 2024 at 11:52:54AM -0500, Mathieu Desnoyers wrote: > > > Introduce a generic way to query whether the dcache is virtually aliased > > > on all architectures. Its purpose is to ensure that subsystems which > > > are incompatible with virtually aliased data caches (e.g. FS_DAX) can > > > reliably query this. > > > > > > For dcache aliasing, there are three scenarios dependending on the > > > architecture. Here is a breakdown based on my understanding: > > > > > > A) The dcache is always aliasing: > > > > > > * arc > > > * csky > > > * m68k (note: shared memory mappings are incoherent ? SHMLBA is missing there.) > > > * sh > > > * parisc > > > > /me wonders why the dentry cache aliasing has problems on these > > systems. > > > > Oh, dcache != fs/dcache.c (the VFS dentry cache). > > > > Can you please rename this function appropriately so us dumb > > filesystem people don't confuse cpu data cache configurations with > > the VFS dentry cache aliasing when we read this code? Something like > > cpu_dcache_is_aliased(), perhaps? > > Good point, will do. I'm planning go rename as follows for v3 to > eliminate confusion with dentry cache (and with "page cache" in > general): > > ARCH_HAS_CACHE_ALIASING -> ARCH_HAS_CPU_CACHE_ALIASING > dcache_is_aliasing() -> cpu_dcache_is_aliasing() > > I noticed that you suggested "aliased" rather than "aliasing", > but I followed what arm64 did for icache_is_aliasing(). Do you > have a strong preference one way or another ? Not really. -Dave. -- Dave Chinner david@fromorbit.com