From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f172.google.com (mail-qt1-f172.google.com [209.85.160.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ECCD31C5496 for ; Wed, 18 Jun 2025 05:17:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750223858; cv=none; b=kCmUH6w8Rsg8l2E+69AONGceKOcsSXA6xIPArha2rXpGtS3C2OaO72iIKskqKwLSQqVyZWVXyFumGJr3wSDQ6tLO0TIahr2VWioW+zCvFTudUD493DDxvYtQu25iUetDuwyyzIx/ES14N2qqUr+7/WLfWTbghihh0ZH2eBo6HfE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750223858; c=relaxed/simple; bh=WexBtDk2E9LKCacblwmFztJs1P58mwxrFjwv2qAp77I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GhfYqxUvZiJXLvMZX+UgVDgoNMiiUX3QofI0kpajb3RqALpchc5YITQZooBvW2RZMVwcUffxoQBHHbeTRiTS2bbsVNn3FW8wL8zVMefyV5LV/At07s3u9X40Yrt0vY5CujxEYEeDkJkIqW5YUIob4V4ucWkI5OwosCsCf8HnQ6o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=UsiC4fJC; arc=none smtp.client-ip=209.85.160.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UsiC4fJC" Received: by mail-qt1-f172.google.com with SMTP id d75a77b69052e-4a44b3526e6so85689361cf.0 for ; Tue, 17 Jun 2025 22:17:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1750223856; x=1750828656; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:feedback-id:from:to:cc:subject:date :message-id:reply-to; bh=uZS0GU7imY1C4qrYwHoQAIT1W20r16a6TjrlPEOgXYU=; b=UsiC4fJCfeVLCnArzIBYSLHwIgFyf4d2X0KnxqLG+OeHRAoyStS1U0aBdQvKwU8r6A LIozT2SGaHYBlLg35UnVDnLQpJSzrBQrU6cu5NTNT0dCTTZvI3BleF4oNOs1Y12W4wlL Dc+55KWD38tmZSJ/CLtrQ0BZaozV/FQL0iT0D35nh94zVsBSOfiCKTwc2+De6NPJ4JAy cDxEk9kKFeOppOQpVvsRH5k7aV8+BAZs6AYd1IMnjD6Xam4VjgX5zhSQUpJHaffPwjdr 926uIBdyoXDpiUdiZUwUNjEIHhHpbmcC/FCxo4KnjdTaKLD9GdnL80nVloB8/VHM22AK HwxQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1750223856; x=1750828656; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:feedback-id:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=uZS0GU7imY1C4qrYwHoQAIT1W20r16a6TjrlPEOgXYU=; b=Q8+Cik9rS3oDp+2r8PXFUFNUqepQY55UApGczbVOUDuWS1W+HajzBBiT+vdCfl9Gkq DjmZ7s374aKhu0R/MeME+OqZSkcbFGFT1N4gifzxJddHQsDOGNtgSLPhz5K9sphhnpBn P5ZHbtc7NQNS0EIb3Co9wSqxtV67HyBNnWDXZp55FQDRWdQGuIydVitLtGpEB8IQJ41/ 34LnDzNX9V1PnCvijV5Ox9h3psp2gbrBFR9wKSKuIAMT8MLvgQiOGG0CHjjkvQxK01+9 t+wJrmLKgtf1mvMYNWqz6s4eJTryqkIJ3ovwlJLATnuBwOyvKnTyMQ8gHrmZdOCOonoI E2sw== X-Forwarded-Encrypted: i=1; AJvYcCXhXuJmXbl3SIvrTzxGbHMTVpy5t2s8e+ZcP3+j0BvwzGOC5zsUmDaygx/gGdDi2vCdj3V1RaWwHm1uW6g=@vger.kernel.org X-Gm-Message-State: AOJu0YxpK3ToY48TevYGPoW4tJlrCzJUF1qy1QdmDJ1sOubqo5NJp6cA 7w2uR5vz/2crMl8jvjH0tbRZCCghNUfs1Lvv9xyHxwwMbHxzCMJsv+50 X-Gm-Gg: ASbGncszsMrRPZDTeuH2L1JudIEMzcHdS5Y6t1Rh5lk1NaRjW9GndE6qpNUqPA6nWKm Pfzi6ulcnkggqbYscouEmes0CCmQjkhazMCQBvZ1E39hitfM8Touh2Dv/udAk02i9M4pgSRd90+ HvHui4/Le4qrFVqEzr+gkiBXe+uxfM4Ese/gW42vUl37Y8mqgKMf1GwSjQxZFKceOx86Oj635X1 j5qrCh/vMyfeGMvM+2vNykjPckGHu5yTT82f8080Y4zVoMVrdinGkVt/9q82tLzRC6nctjJR5uD AzlPVgR7B7pYvhUn8hKYxkBQOPURfHgTva6XeDht/xZVkLQvtygJsbW/Nz8ThP4CAyBMV5HRb42 ARyo0LBO/Gfoq424NVcO2bH36Bt3kP1q6aWxaUTJd7mK156f25mSK X-Google-Smtp-Source: AGHT+IFQ4YD0qeScvPjSCrO4CwY/Hgqethao3wAwOto+pCfvumm509Bf6OSurwwYn1HLYC7oOT7Mlw== X-Received: by 2002:a05:6214:5707:b0:6ec:edf9:4658 with SMTP id 6a1803df08f44-6fb477262e5mr291009876d6.18.1750223855822; Tue, 17 Jun 2025 22:17:35 -0700 (PDT) Received: from fauth-a1-smtp.messagingengine.com (fauth-a1-smtp.messagingengine.com. [103.168.172.200]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6fb58e7687dsm22210186d6.115.2025.06.17.22.17.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Jun 2025 22:17:35 -0700 (PDT) Received: from phl-compute-02.internal (phl-compute-02.phl.internal [10.202.2.42]) by mailfauth.phl.internal (Postfix) with ESMTP id C5A1E1200043; Wed, 18 Jun 2025 01:17:34 -0400 (EDT) Received: from phl-mailfrontend-01 ([10.202.2.162]) by phl-compute-02.internal (MEProxy); Wed, 18 Jun 2025 01:17:34 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtddvgddvtdduucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdggtfgfnhhsuhgsshgtrhhisggvpdfu rfetoffkrfgpnffqhgenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnh htshculddquddttddmnecujfgurhepfffhvfevuffkfhggtggujgesthdtredttddtvden ucfhrhhomhepuehoqhhunhcuhfgvnhhguceosghoqhhunhdrfhgvnhhgsehgmhgrihhlrd gtohhmqeenucggtffrrghtthgvrhhnpeehudfgudffffetuedtvdehueevledvhfelleei vedtgeeuhfegueevieduffeivdenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmh epmhgrihhlfhhrohhmpegsohhquhhnodhmvghsmhhtphgruhhthhhpvghrshhonhgrlhhi thihqdeiledvgeehtdeigedqudejjeekheehhedvqdgsohhquhhnrdhfvghngheppehgmh grihhlrdgtohhmsehfihigmhgvrdhnrghmvgdpnhgspghrtghpthhtohepudehpdhmohgu vgepshhmthhpohhuthdprhgtphhtthhopegrrhhnugeskhgvrhhnvghlrdhorhhgpdhrtg hpthhtohepphgvthgvrhiisehinhhfrhgruggvrggurdhorhhgpdhrtghpthhtohepmhhi nhhgohesrhgvughhrghtrdgtohhmpdhrtghpthhtohepfihilhhlsehkvghrnhgvlhdroh hrghdprhgtphhtthhopehnrghthhgrnheskhgvrhhnvghlrdhorhhgpdhrtghpthhtohep rghrnhgusegrrhhnuggsrdguvgdprhgtphhtthhopehlohhnghhmrghnsehrvgguhhgrth drtghomhdprhgtphhtthhopehnihgtkhdruggvshgruhhlnhhivghrshdolhhkmhhlsehg mhgrihhlrdgtohhmpdhrtghpthhtohepmhhorhgsohesghhoohhglhgvrdgtohhm X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Wed, 18 Jun 2025 01:17:34 -0400 (EDT) Date: Tue, 17 Jun 2025 22:17:32 -0700 From: Boqun Feng To: Arnd Bergmann Cc: Peter Zijlstra , Ingo Molnar , Will Deacon , Nathan Chancellor , Arnd Bergmann , Waiman Long , Nick Desaulniers , Bill Wendling , Justin Stitt , Kent Overstreet , Andy Shevchenko , linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: Re: [PATCH] lockdep: avoid struct return in lock_stats() Message-ID: References: <20250610092941.2642847-1-arnd@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250610092941.2642847-1-arnd@kernel.org> On Tue, Jun 10, 2025 at 11:29:21AM +0200, Arnd Bergmann wrote: > From: Arnd Bergmann > > Returning a large structure from the lock_stats() function causes clang > to have multiple copies of it on the stack and copy between them, which > can end up exceeding the frame size warning limit: > > kernel/locking/lockdep.c:300:25: error: stack frame size (1464) exceeds limit (1280) in 'lock_stats' [-Werror,-Wframe-larger-than] > 300 | struct lock_class_stats lock_stats(struct lock_class *class) > > Change the calling conventions to directly operate on the caller's copy, > which apparently is what gcc does already. > > Signed-off-by: Arnd Bergmann Queued for more tests and reviews, thanks! Regards, Boqun