From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from flow-b8-smtp.messagingengine.com (flow-b8-smtp.messagingengine.com [202.12.124.143]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 970412FF16F; Tue, 20 Jan 2026 16:45:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.12.124.143 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768927507; cv=none; b=h6gmqj/G5Vm3fpVJEM/9g33/XHZxMciIu2yAhP+bcTHTnbQn5nfQfZ2izqC2y5+nzIPhK4JSXfo7atXaj53VCe5Qh+T4VtcmXm3AQV0jEKGZKBsnEGIe/9BnDnCbYglLNWNr9/6rwL2uNqQIWnrrV8o9bplPAFfwnldkREvHoMY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768927507; c=relaxed/simple; bh=kZcp2PHuxyss+VI4RFZDelap38d4uiw9WboOiWNBp1g=; h=MIME-Version:Date:From:To:Cc:Message-Id:In-Reply-To:References: Subject:Content-Type; b=oeg1Q0hMG+V5ki2Y6eB7XKGtNlp+Lng1GjjasG8ujNxeaPhn+RT4SRjFwrSGpUKDj5eo2NScoHK6ZQpAYmYVDUUJRTiivd897vVxTf1voxwaOaaPvzuHT9BA79ef4F3H/d2UBkbze5bOs/1jofX65xx3MPmzdxvHYDPakoY85Ms= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arndb.de; spf=pass smtp.mailfrom=arndb.de; dkim=pass (2048-bit key) header.d=arndb.de header.i=@arndb.de header.b=fhnYraYl; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=qWIXbyzO; arc=none smtp.client-ip=202.12.124.143 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arndb.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arndb.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=arndb.de header.i=@arndb.de header.b="fhnYraYl"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="qWIXbyzO" Received: from phl-compute-04.internal (phl-compute-04.internal [10.202.2.44]) by mailflow.stl.internal (Postfix) with ESMTP id BC47F130057C; Tue, 20 Jan 2026 11:45:02 -0500 (EST) Received: from phl-imap-02 ([10.202.2.81]) by phl-compute-04.internal (MEProxy); Tue, 20 Jan 2026 11:45:04 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arndb.de; h=cc :cc:content-transfer-encoding:content-type:content-type:date :date:from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to; s=fm2; t=1768927502; x=1768934702; bh=nxbkJAISpw9hnpQ7/ITBBIUz+TKq+iocNACRaG8UpNs=; b= fhnYraYlrrq+RP9vqomjRQwsQ9mvhXiuGoV4zAKoX+FhTObAWpIa/drZeA1aUcS0 bGSjbl2pphX0I3WOvR7J1T5RQu306RrAZx1yxTQAzDYh+wjMAb2zsJ/Ru211VkD0 FFJ6j0oPV0gG3GS8DlU5g6mtmb2W4aXnwusi1bMFGWZzFtU2B+qpeOy/FH2ODMq0 vzYckmbQQCcqlugFQrAP8w49E3LWH4xUcJI/9pt685VYzTEzbryK3io8dNxcRsRU EhDDmJvfexMY7ImJBBzrfKPqM5G7SS+YxvYcjwUWwySEYGHSbyvMjvAYz8htDnrB YqpzDhH0ItWDCgYrVxYVug== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding :content-type:content-type:date:date:feedback-id:feedback-id :from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm2; t=1768927502; x= 1768934702; bh=nxbkJAISpw9hnpQ7/ITBBIUz+TKq+iocNACRaG8UpNs=; b=q WIXbyzOT6bq7HDqgS8ADTf9ZTfFpXm4Lk/scmRmwwLIqRtX4iWxKYlSw5YxYH6Jp /dNbZVMVciC6c0ld15ThSY0vdpLcNdHNHO+A/EJnGIbQNONcPZhp0To5VUqLk0Z6 ZUZvoiQlGdbj5hePd+k9+rmMo18oFTujr6iQ+uVJWIQjwvKq5z3VTMhRyFyHmMtl AsSyfsdcA8dTLYuwsyX/Nvn6HAZUNUI4puT89ClU7s0KSSEAUu2rbe6jtLpK1t0j 9uaHOe0inhxcQXuaVqU+R6SwOxCUKcnjtqIoRiAzP6V+iuafRLGaofHkcXXhBmC8 LHmEkyUOUc8uVEftPQ5LA== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefgedrtddtgddugedtledvucetufdoteggodetrf dotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfurfetoffkrfgpnffqhgenuceu rghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujf gurhepofggfffhvfevkfgjfhfutgfgsehtjeertdertddtnecuhfhrohhmpedftehrnhgu uceuvghrghhmrghnnhdfuceorghrnhgusegrrhhnuggsrdguvgeqnecuggftrfgrthhtvg hrnhephfdthfdvtdefhedukeetgefggffhjeeggeetfefggfevudegudevledvkefhvdei necuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomheprghrnh gusegrrhhnuggsrdguvgdpnhgspghrtghpthhtohepgeefpdhmohguvgepshhmthhpohhu thdprhgtphhtthhopehjrghnihdrnhhikhhulhgrsehlihhnuhigrdhinhhtvghlrdgtoh hmpdhrtghpthhtohepjhhoohhnrghsrdhlrghhthhinhgvnheslhhinhhugidrihhnthgv lhdrtghomhdprhgtphhtthhopehmrggrrhhtvghnrdhlrghnkhhhohhrshhtsehlihhnuh igrdhinhhtvghlrdgtohhmpdhrtghpthhtohepghhrvghgkhhhsehlihhnuhigfhhouhhn uggrthhiohhnrdhorhhgpdhrtghpthhtohepughrihdquggvvhgvlheslhhishhtshdrfh hrvggvuggvshhkthhophdrohhrghdprhgtphhtthhopehinhhtvghlqdhgfhigsehlihhs thhsrdhfrhgvvgguvghskhhtohhprdhorhhgpdhrtghpthhtohepnhhtfhhsfeeslhhish htshdrlhhinhhugidruggvvhdprhgtphhtthhopehnvhguihhmmheslhhishhtshdrlhhi nhhugidruggvvhdprhgtphhtthhopeguvghvvghlsehlihhsthhsrdhorhgrnhhgvghfsh drohhrgh X-ME-Proxy: Feedback-ID: i56a14606:Fastmail Received: by mailuser.phl.internal (Postfix, from userid 501) id 13CA1700069; Tue, 20 Jan 2026 11:45:01 -0500 (EST) X-Mailer: MessagingEngine.com Webmail Interface Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ThreadId: AWSx1lsrOtaB Date: Tue, 20 Jan 2026 17:44:29 +0100 From: "Arnd Bergmann" To: "Lorenzo Stoakes" Cc: "Jason Gunthorpe" , "Andrew Morton" , "Jarkko Sakkinen" , "Dave Hansen" , "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , x86@kernel.org, "H. Peter Anvin" , "Greg Kroah-Hartman" , "Dan Williams" , "Vishal Verma" , "Dave Jiang" , "Maarten Lankhorst" , "Maxime Ripard" , "Thomas Zimmermann" , "Dave Airlie" , "Simona Vetter" , "Jani Nikula" , "Joonas Lahtinen" , "Rodrigo Vivi" , "Tvrtko Ursulin" , =?UTF-8?Q?Christian_K=C3=B6nig?= , "Huang Rui" , "Matthew Auld" , "Matthew Brost" , "Alexander Viro" , "Christian Brauner" , "Jan Kara" , "Benjamin LaHaise" , "Gao Xiang" , "Chao Yu" , "Yue Hu" , "Jeffle Xu" , "Sandeep Dhavale" , "Hongbo Li" , "Chunhai Guo" , "Theodore Ts'o" , "Andreas Dilger" , "Muchun Song" , "Oscar Salvador" , "David Hildenbrand (Red Hat)" , "Konstantin Komarov" , "Mike Marshall" , "Martin Brandenburg" , "Tony Luck" , "Reinette Chatre" , "Dave Martin" , "James Morse" , "Babu Moger" , "Carlos Maiolino" , "Damien Le Moal" , "Naohiro Aota" , "Johannes Thumshirn" , "Matthew Wilcox" , "Liam R. Howlett" , "Vlastimil Babka" , "Mike Rapoport" , "Suren Baghdasaryan" , "Michal Hocko" , "Hugh Dickins" , "Baolin Wang" , "Zi Yan" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Barry Song" , "Lance Yang" , "Jann Horn" , "Pedro Falcato" , "David Howells" , "Paul Moore" , "James Morris" , "Serge E. Hallyn" , "Yury Norov" , "Rasmus Villemoes" , linux-sgx@vger.kernel.org, linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-mm@kvack.org, ntfs3@lists.linux.dev, devel@lists.orangefs.org, linux-xfs@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Message-Id: <9ff58468-a72d-4984-95f4-d0a60554705d@app.fastmail.com> In-Reply-To: <44461883-a75c-466b-a278-97c4ab46b461@lucifer.local> References: <20260119231403.GS1134360@nvidia.com> <36abc616-471b-4c7b-82f5-db87f324d708@lucifer.local> <20260120133619.GZ1134360@nvidia.com> <488a0fd8-5d64-4907-873b-60cefee96979@lucifer.local> <1617ac60-6261-483d-aeb5-13aba5f477af@app.fastmail.com> <44461883-a75c-466b-a278-97c4ab46b461@lucifer.local> Subject: Re: [PATCH RESEND 09/12] mm: make vm_area_desc utilise vma_flags_t only Content-Type: text/plain Content-Transfer-Encoding: 7bit On Tue, Jan 20, 2026, at 17:22, Lorenzo Stoakes wrote: > On Tue, Jan 20, 2026 at 05:00:28PM +0100, Arnd Bergmann wrote: >> On Tue, Jan 20, 2026, at 16:10, Lorenzo Stoakes wrote: >> > >> > It strikes me that the key optimisation here is the inlining, now if the issue >> > is that ye olde compiler might choose not to inline very small functions (seems >> > unlikely) we could always throw in an __always_inline? >> >> I can think of three specific things going wrong with structures passed >> by value: > > I mean now you seem to be talking about it _in general_ which, _in theory_, > kills the whole concept of bitmap VMA flags _altogether_ really, or at > least any workable version of them. No, what I'm saying is "understand what the pitfalls are", not "don't do it". I think that is what Jason was also getting at. Arnd