From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 4E7A72DC331; Thu, 21 Aug 2025 10:43:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755773005; cv=none; b=i+hL7VER3zPrMNnacymLRxuPefrfa1USNpm+HcfHg2KL6up+S0HE74gmIw7bK2uO6glqnGw6qLpU4dUgGXoHGN50pjsgLZnttbps0vIOUhAefKHKx9YXAfy6y2alODumf398WyEYtTlEV386EGf/mhM5lWidx9wy3HChl79LIF4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755773005; c=relaxed/simple; bh=xA5z4QGiRT8EMnfJu0zYHYDYsBX5hfHAvWyffpSGsoI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oqHqmGNEnjF3qcNDRq5/8lJjgHQMzMGtidevi+/QYi1yt2LbcYwbdfOzmZLjNcptUeHtMcW3yfvudilBbXKIw+884kGhjsVEHiYBbfZ9WZuO/7n1RngeK5V9R5zBUHlVgNmXxuwP0JYhlAcppXwCSjR1vna1ONkszuGGMwh03As= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 51F9D152B; Thu, 21 Aug 2025 03:43:14 -0700 (PDT) Received: from [10.57.91.188] (unknown [10.57.91.188]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 298EB3F63F; Thu, 21 Aug 2025 03:43:14 -0700 (PDT) Message-ID: <88ea592c-c6ff-4a19-a366-eadeca66b039@arm.com> Date: Thu, 21 Aug 2025 12:43:12 +0200 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/8] selftests/mm: Add -Wunused family of flags To: Muhammad Usama Anjum , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jason Gunthorpe , John Hubbard , Peter Xu , Leon Romanovsky , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, Shuah Khan Cc: kernel@collabora.com References: <20250731160132.1795351-1-usama.anjum@collabora.com> <20250731160132.1795351-5-usama.anjum@collabora.com> <57c816d6-a9ba-47c9-8f40-3978580b7f67@arm.com> <8e9d7c59-46b4-4e1b-8a55-1898302f5080@collabora.com> Content-Language: en-GB From: Kevin Brodsky In-Reply-To: <8e9d7c59-46b4-4e1b-8a55-1898302f5080@collabora.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 21/08/2025 08:28, Muhammad Usama Anjum wrote: >> As to -Wunused-parameter I am frankly not convinced it's worth the >> hassle. We're getting 90 lines changed in patch 6-8 just to mark >> parameters as unused, in other words noise to keep the compiler happy. >> It is not enabled by default in the kernel proper precisely because it >> is so noisy when callbacks are involved. >> >> Patch 5 is clearly an improvement, but I'd rather take it without >> actually enabling -Wunused-parameter. The rest of this patch isn't that >> useful either IMHO. > Patch 5 removes genuinely unused parameters flagged by the compiler. If we > drop the -Wunused-parameter option, however, new unused parameters will > continue to creep in with future patches. The goal of enabling this warning > is to surface such issues early so developers can address them during > development, rather than later during review or debugging. > > Long term, I’d like us to rely more on compiler and static analysis just like > kernel to catch these kinds of problems proactively, instead of waiting until > they’re reported or someone fixes them later. While it may feel like noise > initially, this is largely a one-time cleanup—once done, developers will > simply fix warnings as they arise, keeping the codebase cleaner going forward. Agreed on the general principle, but I think the hassle is just too big for what we're getting in return here (see also Andrew's reply). New code may also introduce a bunch of unused parameters for legitimate reasons and it's easy to imagine contributors ignoring such seemingly harmless/irrelevant warnings instead of sprinkling __unused all over. My feeling is that unused parameters are expected to be allowed in the kernel and it isn't helpful to go against that expectation in just a small subset of kselftests. - Kevin 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 50B87CA0EF8 for ; Thu, 21 Aug 2025 13:20:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=qwJVdbKGkRv9iq61etK0rfEK4ftvjgvlSq1k14bvMro=; b=PfOaqw2X9X45uI W629Jflpf1fZ0PDFQ4xyx0YKdQMNQB4fsx5zXIa+/XR4ySpDBk+M9Zl2IYdtAAw6FK5ON+Om9vfJ2 OXMami33Jw+dgGepCwaQ88jMLCM76SpkVQC50cPAYsJKpGT3oiTsviATIvDzUBi6ZzPTlNylE5w0h Rng3gNOZZa1+O73KoGNVY8BWLOdJcZ7uapfIUD8H1lIbsR+nuk+tx9TrSByHJMzF7aA1lMvNQe4i+ CiRVyMaZ4SWWM8TfOVU7va9HtHyWsX3q2CixGLWak3zoO8EB8a/VE3GT1TFCHA76MGVb73maA4qmt gD1wD+/3MdzOqiM4J4PA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1up5Cw-0000000H26Y-3dmb; Thu, 21 Aug 2025 13:19:58 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1up2lP-0000000Ge7Z-1kBn for linux-riscv@lists.infradead.org; Thu, 21 Aug 2025 10:43:24 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 51F9D152B; Thu, 21 Aug 2025 03:43:14 -0700 (PDT) Received: from [10.57.91.188] (unknown [10.57.91.188]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 298EB3F63F; Thu, 21 Aug 2025 03:43:14 -0700 (PDT) Message-ID: <88ea592c-c6ff-4a19-a366-eadeca66b039@arm.com> Date: Thu, 21 Aug 2025 12:43:12 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/8] selftests/mm: Add -Wunused family of flags To: Muhammad Usama Anjum , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jason Gunthorpe , John Hubbard , Peter Xu , Leon Romanovsky , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, Shuah Khan Cc: kernel@collabora.com References: <20250731160132.1795351-1-usama.anjum@collabora.com> <20250731160132.1795351-5-usama.anjum@collabora.com> <57c816d6-a9ba-47c9-8f40-3978580b7f67@arm.com> <8e9d7c59-46b4-4e1b-8a55-1898302f5080@collabora.com> Content-Language: en-GB From: Kevin Brodsky In-Reply-To: <8e9d7c59-46b4-4e1b-8a55-1898302f5080@collabora.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250821_034323_496946_429D4FDB X-CRM114-Status: GOOD ( 13.14 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org T24gMjEvMDgvMjAyNSAwODoyOCwgTXVoYW1tYWQgVXNhbWEgQW5qdW0gd3JvdGU6Cj4+IEFzIHRv IC1XdW51c2VkLXBhcmFtZXRlciBJIGFtIGZyYW5rbHkgbm90IGNvbnZpbmNlZCBpdCdzIHdvcnRo IHRoZQo+PiBoYXNzbGUuIFdlJ3JlIGdldHRpbmcgOTAgbGluZXMgY2hhbmdlZCBpbiBwYXRjaCA2 LTgganVzdCB0byBtYXJrCj4+IHBhcmFtZXRlcnMgYXMgdW51c2VkLCBpbiBvdGhlciB3b3JkcyBu b2lzZSB0byBrZWVwIHRoZSBjb21waWxlciBoYXBweS4KPj4gSXQgaXMgbm90IGVuYWJsZWQgYnkg ZGVmYXVsdCBpbiB0aGUga2VybmVsIHByb3BlciBwcmVjaXNlbHkgYmVjYXVzZSBpdAo+PiBpcyBz byBub2lzeSB3aGVuIGNhbGxiYWNrcyBhcmUgaW52b2x2ZWQuCj4+Cj4+IFBhdGNoIDUgaXMgY2xl YXJseSBhbiBpbXByb3ZlbWVudCwgYnV0IEknZCByYXRoZXIgdGFrZSBpdCB3aXRob3V0Cj4+IGFj dHVhbGx5IGVuYWJsaW5nIC1XdW51c2VkLXBhcmFtZXRlci4gVGhlIHJlc3Qgb2YgdGhpcyBwYXRj aCBpc24ndCB0aGF0Cj4+IHVzZWZ1bCBlaXRoZXIgSU1ITy4KPiBQYXRjaCA1IHJlbW92ZXMgZ2Vu dWluZWx5IHVudXNlZCBwYXJhbWV0ZXJzIGZsYWdnZWQgYnkgdGhlIGNvbXBpbGVyLiBJZiB3ZQo+ IGRyb3AgdGhlIC1XdW51c2VkLXBhcmFtZXRlciBvcHRpb24sIGhvd2V2ZXIsIG5ldyB1bnVzZWQg cGFyYW1ldGVycyB3aWxsCj4gY29udGludWUgdG8gY3JlZXAgaW4gd2l0aCBmdXR1cmUgcGF0Y2hl cy4gVGhlIGdvYWwgb2YgZW5hYmxpbmcgdGhpcyB3YXJuaW5nCj4gaXMgdG8gc3VyZmFjZSBzdWNo IGlzc3VlcyBlYXJseSBzbyBkZXZlbG9wZXJzIGNhbiBhZGRyZXNzIHRoZW0gZHVyaW5nCj4gZGV2 ZWxvcG1lbnQsIHJhdGhlciB0aGFuIGxhdGVyIGR1cmluZyByZXZpZXcgb3IgZGVidWdnaW5nLgo+ Cj4gTG9uZyB0ZXJtLCBJ4oCZZCBsaWtlIHVzIHRvIHJlbHkgbW9yZSBvbiBjb21waWxlciBhbmQg c3RhdGljIGFuYWx5c2lzIGp1c3QgbGlrZQo+IGtlcm5lbCB0byBjYXRjaCB0aGVzZSBraW5kcyBv ZiBwcm9ibGVtcyBwcm9hY3RpdmVseSwgaW5zdGVhZCBvZiB3YWl0aW5nIHVudGlsCj4gdGhleeKA mXJlIHJlcG9ydGVkIG9yIHNvbWVvbmUgZml4ZXMgdGhlbSBsYXRlci4gV2hpbGUgaXQgbWF5IGZl ZWwgbGlrZSBub2lzZQo+IGluaXRpYWxseSwgdGhpcyBpcyBsYXJnZWx5IGEgb25lLXRpbWUgY2xl YW51cOKAlG9uY2UgZG9uZSwgZGV2ZWxvcGVycyB3aWxsCj4gc2ltcGx5IGZpeCB3YXJuaW5ncyBh cyB0aGV5IGFyaXNlLCBrZWVwaW5nIHRoZSBjb2RlYmFzZSBjbGVhbmVyIGdvaW5nIGZvcndhcmQu CgpBZ3JlZWQgb24gdGhlIGdlbmVyYWwgcHJpbmNpcGxlLCBidXQgSSB0aGluayB0aGUgaGFzc2xl IGlzIGp1c3QgdG9vIGJpZwpmb3Igd2hhdCB3ZSdyZSBnZXR0aW5nIGluIHJldHVybiBoZXJlIChz ZWUgYWxzbyBBbmRyZXcncyByZXBseSkuIE5ldwpjb2RlIG1heSBhbHNvIGludHJvZHVjZSBhIGJ1 bmNoIG9mIHVudXNlZCBwYXJhbWV0ZXJzIGZvciBsZWdpdGltYXRlCnJlYXNvbnMgYW5kIGl0J3Mg ZWFzeSB0byBpbWFnaW5lIGNvbnRyaWJ1dG9ycyBpZ25vcmluZyBzdWNoIHNlZW1pbmdseQpoYXJt bGVzcy9pcnJlbGV2YW50IHdhcm5pbmdzIGluc3RlYWQgb2Ygc3ByaW5rbGluZyBfX3VudXNlZCBh bGwgb3Zlci4gTXkKZmVlbGluZyBpcyB0aGF0IHVudXNlZCBwYXJhbWV0ZXJzIGFyZSBleHBlY3Rl ZCB0byBiZSBhbGxvd2VkIGluIHRoZQprZXJuZWwgYW5kIGl0IGlzbid0IGhlbHBmdWwgdG8gZ28g YWdhaW5zdCB0aGF0IGV4cGVjdGF0aW9uIGluIGp1c3QgYQpzbWFsbCBzdWJzZXQgb2Yga3NlbGZ0 ZXN0cy4KCi0gS2V2aW4KCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fCmxpbnV4LXJpc2N2IG1haWxpbmcgbGlzdApsaW51eC1yaXNjdkBsaXN0cy5pbmZyYWRl YWQub3JnCmh0dHA6Ly9saXN0cy5pbmZyYWRlYWQub3JnL21haWxtYW4vbGlzdGluZm8vbGludXgt cmlzY3YK