From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) (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 786EE23F262; Mon, 24 Feb 2025 07:59:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=150.107.74.76 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740383955; cv=none; b=Jo1Wf697rz058wDGL6vBSiGhYMWPeACRyPrqmuID+wqcpBp/zy++qwXyMGj0CEo4XJprKMmuRQmmdkuWVCSx9vTQ0/1U4KUcItyJougaFelPcS+5EFjl2HysyZlfpxWjlr7aDIwCARK+3ZdbArwQwy5OWaONBOp2WANhCuliajg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740383955; c=relaxed/simple; bh=KH7gHdSS1itQHQoP3z+uj401oB/rX1ncYfhBdSQWuUg=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=rxNAG4XkEKg8SXwtLnENY2koC7N6BtJ06hNOVDduKyLxSFtnhNFNtPzY/UgsZDeqxFpfFT+QQE722EWDPKP7lXePBaiwvWFD8V4dFX4SlKexB5HGedPDu0TLMGjlMe0Sq8P3p7dQQODUXVhfCqa/1uLD7hHQ+OI6uSHS8lTwfi0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ozlabs.org; spf=pass smtp.mailfrom=ozlabs.org; dkim=pass (2048-bit key) header.d=ozlabs.org header.i=@ozlabs.org header.b=ims34gfQ; arc=none smtp.client-ip=150.107.74.76 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ozlabs.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ozlabs.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ozlabs.org header.i=@ozlabs.org header.b="ims34gfQ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ozlabs.org; s=201707; t=1740383950; bh=KH7gHdSS1itQHQoP3z+uj401oB/rX1ncYfhBdSQWuUg=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=ims34gfQA1vb1TN04LB3UWi8oHvR4gxRnPiIctjK103CyZjimW58U3jEvwGUiodUv Za6iGn3q5AdLIxYyGTz781CdTkRRuzvuzvB+jqoRCFNgqP3roPHIeinGtWFwJEKkks APqv1lGjpK23uVFnzo7nVVS6b3xXCg06P8jTIx1RlPQEEsIl6RAASM53YXWxfxgCPT YuWYvczKQgqWnAIi87XjLoll+9D2dsL+De6hgIcZaT1OeN4O1e1mvYID5Q0/x192AI cIKrTswlatGOS2XEjLU/PxGrM3nDGtjSOtqs2L52iQ/z9EMvUaOHQjKU3ndigQC8xz 42ZoJR/u2NoBg== Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by mail.ozlabs.org (Postfix) with ESMTPSA id 4Z1Y5l5GVTz4wby; Mon, 24 Feb 2025 18:58:51 +1100 (AEDT) Message-ID: <1cebfebb9c205a1ebc5722ca7e3b87339ceb3c79.camel@ozlabs.org> Subject: Re: [PATCH 00/17] Introduce and use generic parity32/64 helper From: Jeremy Kerr To: Kuan-Wei Chiu , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, joel@jms.id.au, eajames@linux.ibm.com, andrzej.hajda@intel.com, neil.armstrong@linaro.org, rfoss@kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch, dmitry.torokhov@gmail.com, mchehab@kernel.org, awalls@md.metrocast.net, hverkuil@xs4all.nl, miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com, louis.peens@corigine.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, parthiban.veerasooran@microchip.com, arend.vanspriel@broadcom.com, johannes@sipsolutions.net, gregkh@linuxfoundation.org, jirislaby@kernel.org, yury.norov@gmail.com, akpm@linux-foundation.org Cc: hpa@zytor.com, alistair@popple.id.au, linux@rasmusvillemoes.dk, Laurent.pinchart@ideasonboard.com, jonas@kwiboo.se, jernej.skrabec@gmail.com, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-fsi@lists.ozlabs.org, dri-devel@lists.freedesktop.org, linux-input@vger.kernel.org, linux-media@vger.kernel.org, linux-mtd@lists.infradead.org, oss-drivers@corigine.com, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, brcm80211@lists.linux.dev, brcm80211-dev-list.pdl@broadcom.com, linux-serial@vger.kernel.org, bpf@vger.kernel.org, jserv@ccns.ncku.edu.tw, Yu-Chun Lin Date: Mon, 24 Feb 2025 15:58:49 +0800 In-Reply-To: <20250223164217.2139331-1-visitorckw@gmail.com> References: <20250223164217.2139331-1-visitorckw@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.46.4-2 Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Hi Kuan-Wei, > Several parts of the kernel contain redundant implementations of parity > calculations for 32-bit and 64-bit values. Introduces generic > parity32() and parity64() helpers in bitops.h, providing a standardized > and optimized implementation.=C2=A0=20 More so than __builtin_parity() ? I'm all for reducing the duplication, but the compiler may well have a better parity approach than the xor-folding implementation here. Looks like we can get this to two instructions on powerpc64, for example. Cheers, Jeremy