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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 075A7C0044C for ; Tue, 6 Nov 2018 00:32:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB84020827 for ; Tue, 6 Nov 2018 00:32:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB84020827 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=acm.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729276AbeKFJzS (ORCPT ); Tue, 6 Nov 2018 04:55:18 -0500 Received: from mail-pf1-f195.google.com ([209.85.210.195]:36385 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725839AbeKFJzS (ORCPT ); Tue, 6 Nov 2018 04:55:18 -0500 Received: by mail-pf1-f195.google.com with SMTP id j22-v6so5256160pfh.3 for ; Mon, 05 Nov 2018 16:32:53 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=biljzU61Ceh7QjOjGSZnVU9x0gpA9weTl6OrYDuZk9s=; b=ohwf+FCc7YRXUvBsSHstnTiDD67NhbT9YUypYy2tOix6TDtPBa5O6xQ5CO/kGbIEJa i44fCmsT/wJkVYj5Gc9tOvEP0TKU68qC3vUSwPnVT0/hSFfiSQXG/qcFOe/7sMqtDe8q JnIIoYkH0HPs0ntlC54WGUKwRCTFkxhlfHWBg2IYxBTIIAC/gWtgPGWrSTEsC01G1JjC TTuIqBW8goqL/Y49fv5jh80udrJLwVDU56rJOU45lGyeMNRi5Dujt539iBv2tj2GPEy5 SJD4g+SgRoAnlqOLjQOssL2l73ca6ioyrARyj2dFDyyJEQ69oiTXPDuI2z9G8FVBFuq/ KFow== X-Gm-Message-State: AGRZ1gK4MKrHAt/Uo/aD42igUM7apLm69kYf9QeoxQp29H/ygaqG5In+ VqO06Eow12KboIEIF047YfE= X-Google-Smtp-Source: AJdET5fxdSm+lHqSlsTSX4Mmj2EODQCT7yIQ9vda7MLif6+TKdfzgqLpa4K1zoYY2HruMH82OAGPTA== X-Received: by 2002:a63:1412:: with SMTP id u18mr21460242pgl.247.1541464372634; Mon, 05 Nov 2018 16:32:52 -0800 (PST) Received: from ?IPv6:2620:15c:2cd:203:5cdc:422c:7b28:ebb5? ([2620:15c:2cd:203:5cdc:422c:7b28:ebb5]) by smtp.gmail.com with ESMTPSA id b29-v6sm78606642pfj.183.2018.11.05.16.32.51 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 05 Nov 2018 16:32:52 -0800 (PST) Message-ID: <1541464370.196084.166.camel@acm.org> Subject: Re: [PATCH] slab.h: Avoid using & for logical and of booleans From: Bart Van Assche To: Alexander Duyck Cc: linux@rasmusvillemoes.dk, Andrew Morton , LKML , Vlastimil Babka , Mel Gorman , Christoph Lameter , guro@fb.com, Pekka Enberg , David Rientjes , Joonsoo Kim , linux-mm Date: Mon, 05 Nov 2018 16:32:50 -0800 In-Reply-To: References: <20181105204000.129023-1-bvanassche@acm.org> <20181105131305.574d85469f08a4b76592feb6@linux-foundation.org> <1541454489.196084.157.camel@acm.org> <1541457654.196084.159.camel@acm.org> <1541462466.196084.163.camel@acm.org> Content-Type: text/plain; charset="UTF-7" X-Mailer: Evolution 3.26.2-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2018-11-05 at 16:11 -0800, Alexander Duyck wrote: +AD4 If we really don't care then why even bother with the switch statement +AD4 anyway? It seems like you could just do one ternary operator and be +AD4 done with it. Basically all you need is: +AD4 return (defined(CONFIG+AF8-ZONE+AF8-DMA) +ACYAJg (flags +ACY +AF8AXw-GFP+AF8-DMA)) ? KMALLOC+AF8-DMA : +AD4 (flags +ACY +AF8AXw-GFP+AF8-RECLAIMABLE) ? KMALLOC+AF8-RECLAIM : 0+ADs +AD4 +AD4 Why bother with all the extra complexity of the switch statement? I don't think that defined() can be used in a C expression. Hence the IS+AF8-ENABLED() macro. If you fix that, leave out four superfluous parentheses, test your patch, post that patch and cc me then I will add my Reviewed-by. Bart.