From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id D74916B00CB for ; Wed, 23 Nov 2011 04:19:39 -0500 (EST) Date: Wed, 23 Nov 2011 09:19:33 +0000 From: Mel Gorman Subject: Re: [PATCH 5/7] mm: compaction: make isolate_lru_page() filter-aware again Message-ID: <20111123091933.GL19415@suse.de> References: <1321900608-27687-1-git-send-email-mgorman@suse.de> <1321900608-27687-6-git-send-email-mgorman@suse.de> <20111122173018.GD15253@barrios-laptop.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20111122173018.GD15253@barrios-laptop.redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Linux-MM , Andrea Arcangeli , Jan Kara , Andy Isaacson , Johannes Weiner , Rik van Riel , Nai Xia , LKML On Wed, Nov 23, 2011 at 02:30:18AM +0900, Minchan Kim wrote: > > > > + /* > > + * To minimise LRU disruption, the caller can indicate that it only > > + * wants to isolate pages it will be able to operate on without > > + * blocking - clean pages for the most part. > > + * > > + * ISOLATE_CLEAN means that only clean pages should be isolated. This > > + * is used by reclaim when it is cannot write to backing storage > > + * > > + * ISOLATE_ASYNC_MIGRATE is used to indicate that it only wants to pages > > + * that it is possible to migrate without blocking with a ->migratepage > > + * handler > > + */ > > + if (mode & (ISOLATE_CLEAN|ISOLATE_ASYNC_MIGRATE)) { > > + /* All the caller can do on PageWriteback is block */ > > + if (PageWriteback(page)) > > + return ret; > > + > > + if (PageDirty(page)) { > > + struct address_space *mapping; > > + > > + /* ISOLATE_CLEAN means only clean pages */ > > + if (mode & ISOLATE_CLEAN) > > + return ret; > > + > > + /* > > + * Only the ->migratepage callback knows if a dirty > > + * page can be migrated without blocking. Skip the > > + * page unless there is a ->migratepage callback. > > + */ > > + mapping = page_mapping(page); > > + if (!mapping || !mapping->a_ops->migratepage) > > I didn't review 4/7 carefully yet. Thanks for reviewing the others. > In case of page_mapping is NULL, move_to_new_page calls migrate_page > which is non-blocking function. So, I guess it could be migrated without blocking. > Well spotted /* * Only pages without mappings or that have a * ->migratepage callback are possible to * migrate without blocking */ mapping = page_mapping(page); if (mapping && !mapping->a_ops->migratepage) return ret; -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org