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 Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 99A06C433EF for ; Tue, 7 Jun 2022 14:12:05 +0000 (UTC) Received: from [127.0.0.1] (helo=sfs-ml-4.v29.lw.sourceforge.com) by sfs-ml-4.v29.lw.sourceforge.com with esmtp (Exim 4.94.2) (envelope-from ) id 1nyZwD-0004rt-1L; Tue, 07 Jun 2022 14:12:03 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-4.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nyZwB-0004rb-Gb; Tue, 07 Jun 2022 14:12:02 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; 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:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=4nUpYTI4YzQUWe3MX/DeuqIdjPgTHj7mksBWnabO8pk=; b=J5Otw9dDfq9FxnBKeTM+ISyV9x mQ5Vv+jQ4j2LbkoPrF2ftfXDtRX8f2I4u9QPBptb95v0XMIv8w2mUPz/WwJFMRAlqJGQYY0u9Itte SpTJ2WG+PqF9X8FXPv/wHeQcUAsG4IcwzLXc+QE1utU41Jk24UOAhcWUCYpCATA/9JLg=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; 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:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=4nUpYTI4YzQUWe3MX/DeuqIdjPgTHj7mksBWnabO8pk=; b=JzakT+xOiMdL/kbtBMgWRy45fj zOY/e6G8/1f7qxOIlytmLbPQcWP2fssfbYVUEf9Z5LlVPV68Ebj9cKaQFJTMfPlMV9qLo2tKXPAhH YHl5RrWFZWMlsDS4QnKmjV+Fj30IFoksK88jJ0mUCWe57GcQYSHeY9Qs8JCGK63RM4qE=; Received: from casper.infradead.org ([90.155.50.34]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.94.2) id 1nyZw5-0000Ow-0d; Tue, 07 Jun 2022 14:12:02 +0000 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=4nUpYTI4YzQUWe3MX/DeuqIdjPgTHj7mksBWnabO8pk=; b=IoritkaL90aqbR+RUHZKoSo8fb np1ux4ttns5tYj2sJk/FAj12Ak/CQ/wW4eIuwXN5ulK6rhUSeL7wfME8a6K9gYUgIYgqg08BNe9+I tus3kQ04SmPJZl9V4GH+E2xTibe280AETqIE3sbtSug/TUXDR0128c42jRa/+qeI8q7uri0dQOk1f wWHM11+pgzBreVL8bkL3da/JDGIf99g2HUm8tnTrzT4cPM9I17c3dxlon1CkQMKJOgWEf9FbWmKJ9 h7TOtnv+jsL8ABFyKBR86bb03b2ZVDj0NIek4XcowncLGE0YjVino+xsZhqucJvOU+7lO9abDpL7s BM8iPWpg==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nyZvo-00BhC6-Sq; Tue, 07 Jun 2022 14:11:40 +0000 Date: Tue, 7 Jun 2022 15:11:40 +0100 From: Matthew Wilcox To: Brian Foster Message-ID: References: <20220606204050.2625949-1-willy@infradead.org> <20220606204050.2625949-6-willy@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Headers-End: 1nyZw5-0000Ow-0d Subject: Re: [f2fs-dev] [PATCH 05/20] mm/migrate: Convert expected_page_refs() to folio_expected_refs() X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-aio@kvack.org, linux-nfs@vger.kernel.org, cluster-devel@redhat.com, linux-ntfs-dev@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-mtd@lists.infradead.org, ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Tue, Jun 07, 2022 at 09:41:57AM -0400, Brian Foster wrote: > On Mon, Jun 06, 2022 at 09:40:35PM +0100, Matthew Wilcox (Oracle) wrote: > > -static int expected_page_refs(struct address_space *mapping, struct page *page) > > +static int folio_expected_refs(struct address_space *mapping, > > + struct folio *folio) > > { > > - int expected_count = 1; > > + int refs = 1; > > + if (!mapping) > > + return refs; > > > > - if (mapping) > > - expected_count += compound_nr(page) + page_has_private(page); > > - return expected_count; > > + refs += folio_nr_pages(folio); > > + if (folio_get_private(folio)) > > + refs++; > > Why not folio_has_private() (as seems to be used for later > page_has_private() conversions) here? We have a horrid confusion that I'm trying to clean up stealthily without anyone noticing. I would have gotten away with it too if it weren't for you pesky kids. #define PAGE_FLAGS_PRIVATE \ (1UL << PG_private | 1UL << PG_private_2) static inline int page_has_private(struct page *page) { return !!(page->flags & PAGE_FLAGS_PRIVATE); } So what this function is saying is that there is one extra refcount expected on the struct page if PG_private _or_ PG_private_2 is set. How are filesystems expected to manage their page's refcount with this rule? Increment the refcount when setting PG_private unless PG_private_2 is already set? Decrement the refcount when clearing PG_private_2 unless PG_private is set? This is garbage. IMO, PG_private_2 should have no bearing on the page's refcount. Only btrfs and the netfs's use private_2 and neither of them do anything to the refcount when setting/clearing it. So that's what I'm implementing here. > > + > > + return refs;; > > Nit: extra ; Oh, that's where it went ;-) I had a compile error due to a missing semicolon at some point, and thought it was just a typo ... _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel