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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 DF951C32789 for ; Tue, 6 Nov 2018 15:44:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A6EEE2085B for ; Tue, 6 Nov 2018 15:44:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="I/krtLzh" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A6EEE2085B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.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 S2388988AbeKGBKZ (ORCPT ); Tue, 6 Nov 2018 20:10:25 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:53932 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388760AbeKGBKZ (ORCPT ); Tue, 6 Nov 2018 20:10:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=AbfHk1xjSkV+08tMGRcAsH709qMoOdW+0t6p1e6IYpA=; b=I/krtLzhOSB8c1mD1nOa7TOIy UajzeReN1hWcUEezFBOeQTYvOmjl8FCArnwmI7znnEemUMjjn6i/OCbsveHtBWwMoG4oKt/lvrI31 rUONMrEcCjTfqJOqzGQxZgDUz8vN4iUDr3t03IzagSktsDiLfrHGWXN8BQGQEbVZ2KLIQzVnMAlbL UMG9WPsNUHgtiFmKfYXzXpLZ90O7eZwRICgbFFotgRjwZdJF9ya5py9UKrEIELFviKBfgQpnVqzee IPSa+Duhy1V6hN1kLZaUmz0RJySHsEfPANnywZ2oN+AtS1yCi12ZAzISGKJPNwGkYfKg8F4mDGq4e Wsa0Aw3iA==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1gK3Wv-0005E3-Il; Tue, 06 Nov 2018 15:44:37 +0000 Date: Tue, 6 Nov 2018 07:44:37 -0800 From: Matthew Wilcox To: Alexey Dobriyan Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, linux-arch@vger.kernel.org Subject: Re: + fls-change-parameter-to-unsigned-int.patch added to -mm tree Message-ID: <20181106154437.GF3074@bombadil.infradead.org> References: <20181105233301.KlgdF%akpm@linux-foundation.org> <20181106151444.GA11221@avx2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181106151444.GA11221@avx2> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 06, 2018 at 06:14:44PM +0300, Alexey Dobriyan wrote: > On Mon, Nov 05, 2018 at 03:33:01PM -0800, akpm@linux-foundation.org wrote: > > > -static inline int fls(int x) > > +static inline int fls(unsigned int x) > > { > > - return fls64((unsigned int) x); > > + return fls64(x); > > } > > Should it return "unsigned"? Logically it should. > I remember doing this and there was some code size increase :-( Yes, it returns a number in the range [0-32], so it can absolutely be unsigned. I'm kind of surprised it made any difference. When you say "doing this", what did you try? unsigned fls(unsigned), int fls(unsigned) or unsigned fls(int) ?