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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 19881C433ED for ; Mon, 10 May 2021 15:45:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E6488611C1 for ; Mon, 10 May 2021 15:45:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231409AbhEJPqp (ORCPT ); Mon, 10 May 2021 11:46:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231389AbhEJPqj (ORCPT ); Mon, 10 May 2021 11:46:39 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23705C061574 for ; Mon, 10 May 2021 08:45:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=Flo9l/jYDkRKwx0f14g3k6U8nqbHT13bVIHshVunBVM=; b=gujTuZIsMzIdK8d25Kl1FvLEEb nlA8vBvFfU8SvSQhTMVA2CmdHJffyObUCHMeV+VywGbf0oHAjVxz9s4/F9Eg03L50I8ud0n8GLdFn xkss71KzHy1YbzOB8Pz69/AqtkgkDugtVNPhcKce4+WXDxqIv1IL9BG/8NdBbwmV+Pz5IfdwVHXXS u4xcakk04MW9kx0dZ3CHLm9e37hqI08KFVG0BM32h7oajOtKIb25WDP5dYUYrsSk0iKO/SvGsIqq2 Xr5biMYWvey86Dp/R5reHBkDbLw/ZAHvsm20rwi1b+IgVIaK064zKvdvuIyNeVs3OCXefoNkOuik5 +8q+vX0Q==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lg84n-006KCh-T2; Mon, 10 May 2021 15:44:25 +0000 Date: Mon, 10 May 2021 16:44:09 +0100 From: Matthew Wilcox To: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Vlastimil Babka , cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm: kmalloc_index: make compiler break when size is not supported Message-ID: References: <20210508221328.7338-1-42.hyeyoo@gmail.com> <20210510135857.GA3594@hyeyoo> <9d0ffe49-a2e2-6c81-377b-4c8d2147dff8@suse.cz> <20210510150230.GA74915@hyeyoo> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210510150230.GA74915@hyeyoo> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 11, 2021 at 12:02:30AM +0900, Hyeonggon Yoo wrote: > @@ -382,8 +385,8 @@ static __always_inline unsigned int kmalloc_index(size_t size) > if (size <= 8 * 1024 * 1024) return 23; > if (size <= 16 * 1024 * 1024) return 24; > if (size <= 32 * 1024 * 1024) return 25; > - if (size <= 64 * 1024 * 1024) return 26; > - BUG(); > + > + BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()"); we're being encouraged to use static_assert() these days. https://en.cppreference.com/w/c/language/_Static_assert