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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 6742EC61DD8 for ; Sat, 14 Nov 2020 19:12:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DF04C22263 for ; Sat, 14 Nov 2020 19:12:09 +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="jmZpwLSi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DF04C22263 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E49EA6B005C; Sat, 14 Nov 2020 14:12:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DFB4D6B005D; Sat, 14 Nov 2020 14:12:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CEAAB6B0068; Sat, 14 Nov 2020 14:12:08 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0247.hostedemail.com [216.40.44.247]) by kanga.kvack.org (Postfix) with ESMTP id 9D7DA6B005C for ; Sat, 14 Nov 2020 14:12:08 -0500 (EST) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 4C4511EE6 for ; Sat, 14 Nov 2020 19:12:08 +0000 (UTC) X-FDA: 77483969136.12.spoon18_5b0f4d12731a Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin12.hostedemail.com (Postfix) with ESMTP id 2DBA0180054C4 for ; Sat, 14 Nov 2020 19:12:08 +0000 (UTC) X-HE-Tag: spoon18_5b0f4d12731a X-Filterd-Recvd-Size: 2593 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Sat, 14 Nov 2020 19:12:07 +0000 (UTC) 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=WxkHg606XkyvNta0/g/LnAPObU1iotZ1sOfBfOHWffc=; b=jmZpwLSiLutZKV2fkbiPqmxFEn iS47AQF/5TyY8mMIqGDEzaBXMaFhv9xBeUePelOl+MiVGz7+pRcdQLzhxCFKY3a0WGGn+wzbzm6Sa d9scRAX8mKrEsABz70XIkQbBypiyaL453USpeyrVnG7lDVUVlXB7IwoGAAF1ToIxKUzVpDJjt6ESC EiMby6+nEQMurMn9/XHn0p8FBB2NxqB2uLdx3KsMtqxPbsAfJSP4MApvjEx0NUBocUhwQ7EHixsQl JHsDi8W57QWbncdnklLQ+RuhvCQeRSChQEiPo4UucxxkMU4y1KpDQxkoD0eyXmL/drkNQ0W9w6eix rVtvhY8w==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1ke0xq-0004sf-75; Sat, 14 Nov 2020 19:11:58 +0000 Date: Sat, 14 Nov 2020 19:11:58 +0000 From: Matthew Wilcox To: Andrew Morton Cc: Hui Su , hughd@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, pankaj.gupta.linux@gmail.com, lkp@intel.com Subject: Re: [PATCH v2] mm/shmem.c: make shmem_mapping() inline Message-ID: <20201114191158.GN17076@casper.infradead.org> References: <20201114055134.GA186011@rlk> <20201114105039.4d44e3036e22e10c9a70912c@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201114105039.4d44e3036e22e10c9a70912c@linux-foundation.org> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, Nov 14, 2020 at 10:50:39AM -0800, Andrew Morton wrote: > But really, shmem_mapping() isn't worth an out-of-line call from any > callsite - it would be best to make it inlined everywhere. > > - make shmem_aops global > - declare shmem_aops in shmem_fs.h > - export shmem_aops to modules for drivers/dma-buf/udmabuf.c > - include linux/fs.h in shmem_fs.h for address_space_operations (we already > include fs.h via swap.h, but we shouldn't depend on that) > - make shmem_mapping() a static inline in shmem_fs.h. ... or use an AS_ bit to make shmem_mapping() global inline without exposing the shmem_aops symbol. We're not short of AS_ bits, and it's probably even cheaper than a pointer comparison. A really good changelog would explain why we need shmem_mapping() everywhere that we currently use it. It's not immediately obvious why so many places need to know.