Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66728C433F5 for ; Wed, 8 Dec 2021 14:24:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235081AbhLHO1w (ORCPT ); Wed, 8 Dec 2021 09:27:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231634AbhLHO1u (ORCPT ); Wed, 8 Dec 2021 09:27:50 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F27FAC061746 for ; Wed, 8 Dec 2021 06:24:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=OIge18wNGaV2CWmt7HmDIw7i2OCIURDyrD7/XMqGt5o=; b=OTs5QqZiTM8mzuF2H5EqzIQGH2 ZDfaaUQztY29HiGcDGy4OkeDiHusfpzl8jDwdJYkDiw3H1zfT9piOIskUz/2qyEr/pNp5JkY1Qi2A L0QIJ4H+ZuK4rh7uYR3o9cqeY/9QDHAsM8e1DPHvZdODd6zZwa/ahr8K0PjdoNg+Enl0ILgQXz5P3 ThYHQWCtwJe7CwuzL/rcuPJgu7NcqF1sY2pYqLqjka1udUgBHDHwVSK6R5h63lhSewhyMoLtPKICo RtIpMR+puPxfVZvUmgLy5Gt/maVxtROvgpfWzjDdjFyHtdYo+lRP+ZjjvJ4yoZlNs2txkHTFrbgZF hMWcyyMw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1muxrf-008UKQ-1Z; Wed, 08 Dec 2021 14:24:11 +0000 Date: Wed, 8 Dec 2021 14:24:11 +0000 From: Matthew Wilcox To: =?utf-8?B?6IOh546u5paH?= Cc: Minchan Kim , Andrew Morton , linux-mm , LKML Subject: Re: [RFC] mm: introduce page pinner Message-ID: References: <20211206184730.858850-1-minchan@kernel.org> <20211208115250.GA17274@DESKTOP-N4CECTO.huww98.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20211208115250.GA17274@DESKTOP-N4CECTO.huww98.cn> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 08, 2021 at 07:54:35PM +0800, 胡玮文 wrote: > @@ -406,6 +409,7 @@ int folio_migrate_mapping(struct address_space *mapping, > xas_lock_irq(&xas); > if (!folio_ref_freeze(folio, expected_count)) { > xas_unlock_irq(&xas); > + page_pinner_failure(&folio->page); > return -EAGAIN; > } > > I'm not sure what to do with the new folio, it seems using folio->page in new > codes is not correct. It's a transitional measure. Once everything that should be converted to folios has been converted, it can go away. Tail pages don't have their own refcounts, so the page pinner should actually be the folio pinner. I hadn't bothered to point this out because we're in the early days of the folio transition and it'd be unreasonable to criticise Minchan for not converting his patch from pages to folios.