From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) (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 D076825634; Sat, 14 Sep 2024 06:50:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.17.235.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726296651; cv=none; b=PeeOGQCSFbQnTytr94ua2sdHR7R8zex4iqKyrIa+0B1SRpGgsm5wKv4h/37zcRF6GitZDhOym9vlw0+rSZcCPTjMIWIkDJI8DcrWn4PAzG/6lL6o6bBLaGrYdVyE5JemqeLHZcUAXLH9Uzb/gVCkMqJAiiFgEfKn8ABZOwY2Sao= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726296651; c=relaxed/simple; bh=OpHsdnn3hde6Gfx9ognkZFS3zIi7a702ZdtBcEsLG18=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kbkZg5G4ZrTjT3yODuJZoeWgQ66qn/Ci4xwigcN50Fnq6aN7zi7R/zt+3OGcCOLKg531pN8w2VAHVd67NCIW8TSeeYk8JOQLDIn18yY1taM3aA5NWuQ21ySU1oObLVylnLGo5WcEYlDRlTrkeC3LCSxn+RInayqn78MvntVjwGQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu; spf=pass smtp.mailfrom=csgroup.eu; arc=none smtp.client-ip=93.17.235.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=csgroup.eu Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4X5MJR3rhBz9sxD; Sat, 14 Sep 2024 08:50:47 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dq3uoKnkcrG6; Sat, 14 Sep 2024 08:50:47 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4X5MJR2xwPz9sxC; Sat, 14 Sep 2024 08:50:47 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 4E0A58B764; Sat, 14 Sep 2024 08:50:47 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id 4kDiXHNHMIzl; Sat, 14 Sep 2024 08:50:47 +0200 (CEST) Received: from [192.168.233.150] (unknown [192.168.233.150]) by messagerie.si.c-s.fr (Postfix) with ESMTP id AF0CE8B763; Sat, 14 Sep 2024 08:50:46 +0200 (CEST) Message-ID: <30e8dee7-e98e-42cb-aab3-6b75f1a6316d@csgroup.eu> Date: Sat, 14 Sep 2024 08:50:46 +0200 Precedence: bulk X-Mailing-List: linux-next@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v1] mm: fix build on powerpc with GCC 14 To: Matthew Wilcox , Mina Almasry Cc: netdev@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Simon Horman , Stephen Rothwell , Jakub Kicinski , David Miller , Paolo Abeni , Linux Next Mailing List , Arnd Bergmann , "linuxppc-dev@lists.ozlabs.org" References: <20240913192036.3289003-1-almasrymina@google.com> Content-Language: fr-FR From: Christophe Leroy In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi, Le 13/09/2024 à 21:22, Matthew Wilcox a écrit : > On Fri, Sep 13, 2024 at 07:20:36PM +0000, Mina Almasry wrote: >> +++ b/include/linux/page-flags.h >> @@ -239,8 +239,8 @@ static inline unsigned long _compound_head(const struct page *page) >> { >> unsigned long head = READ_ONCE(page->compound_head); >> >> - if (unlikely(head & 1)) >> - return head - 1; >> + if (unlikely(head & 1UL)) >> + return head & ~1UL; >> return (unsigned long)page_fixed_fake_head(page); > > NAK, that pessimises compound_head(). > Can you please give more details on what the difference is ? I can't see what it pessimises. In both cases, you test if the value is odd, when it is odd you make it even. Christophe