From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=S930=4K=kvack.org=owner-linux-mm@kernel.org>
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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,
	SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 9E3B5C35669
	for <linux-mm@archiver.kernel.org>; Sat, 22 Feb 2020 00:15:31 +0000 (UTC)
Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17])
	by mail.kernel.org (Postfix) with ESMTP id 63D8B207FD
	for <linux-mm@archiver.kernel.org>; Sat, 22 Feb 2020 00:15:31 +0000 (UTC)
Authentication-Results: mail.kernel.org;
	dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="p2+0C6I2"
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 63D8B207FD
Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com
Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org
Received: by kanga.kvack.org (Postfix)
	id EFBBD6B0003; Fri, 21 Feb 2020 19:15:30 -0500 (EST)
Received: by kanga.kvack.org (Postfix, from userid 40)
	id EACAB6B0006; Fri, 21 Feb 2020 19:15:30 -0500 (EST)
X-Delivered-To: int-list-linux-mm@kvack.org
Received: by kanga.kvack.org (Postfix, from userid 63042)
	id D9B856B0007; Fri, 21 Feb 2020 19:15:30 -0500 (EST)
X-Delivered-To: linux-mm@kvack.org
Received: from forelay.hostedemail.com (smtprelay0155.hostedemail.com [216.40.44.155])
	by kanga.kvack.org (Postfix) with ESMTP id BE10D6B0003
	for <linux-mm@kvack.org>; Fri, 21 Feb 2020 19:15:30 -0500 (EST)
Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251])
	by forelay03.hostedemail.com (Postfix) with ESMTP id 6F1918248076
	for <linux-mm@kvack.org>; Sat, 22 Feb 2020 00:15:30 +0000 (UTC)
X-FDA: 76515844020.10.cable72_4d1a37dfe090f
X-HE-Tag: cable72_4d1a37dfe090f
X-Filterd-Recvd-Size: 5165
Received: from hqnvemgate25.nvidia.com (hqnvemgate25.nvidia.com [216.228.121.64])
	by imf46.hostedemail.com (Postfix) with ESMTP
	for <linux-mm@kvack.org>; Sat, 22 Feb 2020 00:15:29 +0000 (UTC)
Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA)
	id <B5e50727e0001>; Fri, 21 Feb 2020 16:14:54 -0800
Received: from hqmail.nvidia.com ([172.20.161.6])
  by hqpgpgate101.nvidia.com (PGP Universal service);
  Fri, 21 Feb 2020 16:15:28 -0800
X-PGP-Universal: processed;
	by hqpgpgate101.nvidia.com on Fri, 21 Feb 2020 16:15:28 -0800
Received: from [10.110.48.28] (10.124.1.5) by HQMAIL107.nvidia.com
 (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Sat, 22 Feb
 2020 00:15:28 +0000
Subject: Re: [PATCH v7 01/24] mm: Move readahead prototypes from mm.h
To: Matthew Wilcox <willy@infradead.org>
CC: <linux-fsdevel@vger.kernel.org>, <linux-mm@kvack.org>,
	<linux-kernel@vger.kernel.org>, <linux-btrfs@vger.kernel.org>,
	<linux-erofs@lists.ozlabs.org>, <linux-ext4@vger.kernel.org>,
	<linux-f2fs-devel@lists.sourceforge.net>, <cluster-devel@redhat.com>,
	<ocfs2-devel@oss.oracle.com>, <linux-xfs@vger.kernel.org>
References: <20200219210103.32400-1-willy@infradead.org>
 <20200219210103.32400-2-willy@infradead.org>
 <e065679e-222f-7323-9782-0c4471bb9233@nvidia.com>
 <20200221214853.GF24185@bombadil.infradead.org>
From: John Hubbard <jhubbard@nvidia.com>
X-Nvconfidentiality: public
Message-ID: <69fa8779-3433-9d35-a1f4-f115dc86c6d8@nvidia.com>
Date: Fri, 21 Feb 2020 16:15:27 -0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.5.0
MIME-Version: 1.0
In-Reply-To: <20200221214853.GF24185@bombadil.infradead.org>
X-Originating-IP: [10.124.1.5]
X-ClientProxiedBy: HQMAIL105.nvidia.com (172.20.187.12) To
 HQMAIL107.nvidia.com (172.20.187.13)
Content-Type: text/plain; charset="utf-8"
Content-Language: en-US
Content-Transfer-Encoding: 7bit
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1;
	t=1582330494; bh=Xu1W/y2f9OTxnj+6T8DBBjck/f2ICJjqDeKYJhM73bw=;
	h=X-PGP-Universal:Subject:To:CC:References:From:X-Nvconfidentiality:
	 Message-ID:Date:User-Agent:MIME-Version:In-Reply-To:
	 X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language:
	 Content-Transfer-Encoding;
	b=p2+0C6I2/yxvNQ1pZnv87YfPksTddG+e8cc03+sVRvODjU2CaK7MWQBiokHBWhwgb
	 ieVI22Ga85j5LMOJVhYhtaccRh8zhO2H+xRsWBU/P8jaMdk1KeAHP1UgdQZbuh/fxI
	 hzO1rCi0fPdivx/Gdy87keJKQLfBTMl82lrGPg+HtMx4bbn1scu0JW30tCh15BSQmD
	 mQSimv7RYwfVWTinVZWGntdq5fdSKt8II8eY04QJynTy8RS0zcVz5otr5kwPPCZ2pE
	 v1Ek68IoRy4J0my4VYUXkHH4q/cEli9/t/FTx/7/JWNBZEw7tWg2FKjPvsTsMCyd6G
	 n45AbsLmye9OQ==
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: <linux-mm.kvack.org>

On 2/21/20 1:48 PM, Matthew Wilcox wrote:
> On Thu, Feb 20, 2020 at 06:43:31PM -0800, John Hubbard wrote:
>> Yes. But I think these files also need a similar change:
>>
>>     fs/btrfs/disk-io.c
> 
> That gets pagemap.h through ctree.h, so I think it's fine.  It's
> already using mapping_set_gfp_mask(), so it already depends on pagemap.h.
> 
>>     fs/nfs/super.c
> 
> That gets it through linux/nfs_fs.h.
> 
> I was reluctant to not add it to blk-core.c because it doesn't seem
> necessarily intuitive that the block device core would include pagemap.h.
> 
> That said, blkdev.h does include pagemap.h, so maybe I don't need to
> include it here.

OK. Looks good (either through blkdev.h or as-is), so:

    Reviewed-by: John Hubbard <jhubbard@nvidia.com>


> 
>> ...because they also use VM_READAHEAD_PAGES, and do not directly include
>> pagemap.h yet.
> 
>>> +#define VM_READAHEAD_PAGES	(SZ_128K / PAGE_SIZE)
>>> +
>>> +void page_cache_sync_readahead(struct address_space *, struct file_ra_state *,
>>> +		struct file *, pgoff_t index, unsigned long req_count);
>>
>> Yes, "struct address_space *mapping" is weird, but I don't know if it's
>> "misleading", given that it's actually one of the things you have to learn
>> right from the beginning, with linux-mm, right? Or is that about to change?
>>
>> I'm not asking to restore this to "struct address_space *mapping", but I thought
>> it's worth mentioning out loud, especially if you or others are planning on
>> changing those names or something. Just curious.
> 
> No plans (on my part) to change the name, although I have heard people
> grumbling that there's very little need for it to be a separate struct
> from inode, except for the benefit of coda, which is not exactly a
> filesystem with a lot of users ...
> 
> Anyway, no plans to change it.  If there were something _special_ about
> it like a theoretical:
> 
> void mapping_dedup(struct address_space *canonical,
> 		struct address_space *victim);
> 
> then that's useful information and shouldn't be deleted.  But I don't
> think the word 'mapping' there conveys anything useful (other than the
> convention is to call a 'struct address_space' a mapping, which you'll
> see soon enough once you look at any of the .c files).
> 

OK, that's consistent and makes sense.


thanks,
-- 
John Hubbard
NVIDIA