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=-7.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS autolearn=no 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 44833C433E1 for ; Mon, 24 Aug 2020 19:18:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17B5A20897 for ; Mon, 24 Aug 2020 19:18:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598296731; bh=ruAaLHXCUgvFAIHtl74jpOBw0Y8uv95WYxQPoUYU1cY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=qRbg120iZc5BE+AEIuefiscyrGrL0TiTupDzPcfcIhkZN8Xjrm5uS4QiV2/X2huxT nOgZGW4x2vmJTqHCCIALQdUeL3t+a80yeNziyP4YA05KP+CtvmfQkrq2Z8hJ8dgIYv Yc9lKJn7vHCU/Exg+VAt35nDwIle1bAnBzSj03Gk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727981AbgHXTSt (ORCPT ); Mon, 24 Aug 2020 15:18:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:40452 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727073AbgHXTSl (ORCPT ); Mon, 24 Aug 2020 15:18:41 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 02AC120578; Mon, 24 Aug 2020 19:18:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598296721; bh=ruAaLHXCUgvFAIHtl74jpOBw0Y8uv95WYxQPoUYU1cY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=NedftIdrJSSiWqFW1zJ5dFmP61Pu/QmDrouLYmttdGPY33KM++6Saxqxq+SmyfGfN Qh64t3Q9lqnThGaAwsG1e0Jkjk86fDm6q0F0h4UOyEcyWd0zGGFzg9U9foXOGdeXjP DJURi9DXi/CdIz1nILadUy+sbGVFU+bu6aoUF0Fo= Date: Mon, 24 Aug 2020 12:18:40 -0700 From: Andrew Morton To: Miaohe Lin Cc: , Subject: Re: [PATCH] mm/mempool: Add 'else' to split mutually exclusive case Message-Id: <20200824121840.4cd7eb3dce03e8e1473221b3@linux-foundation.org> In-Reply-To: <20200824115354.7879-1-linmiaohe@huawei.com> References: <20200824115354.7879-1-linmiaohe@huawei.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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, 24 Aug 2020 07:53:54 -0400 Miaohe Lin wrote: > Add else to split mutually exclusive case and avoid some unnecessary check. > > --- a/mm/mempool.c > +++ b/mm/mempool.c > @@ -60,9 +60,8 @@ static void check_element(mempool_t *pool, void *element) > /* Mempools backed by slab allocator */ > if (pool->free == mempool_free_slab || pool->free == mempool_kfree) > __check_element(pool, element, ksize(element)); > - > /* Mempools backed by page allocator */ > - if (pool->free == mempool_free_pages) { > + else if (pool->free == mempool_free_pages) { > int order = (int)(long)pool->pool_data; > void *addr = kmap_atomic((struct page *)element); > It doesn't seem to change code generation (compiler is smart), but I think it helps readability.