From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752630Ab2GSBBg (ORCPT ); Wed, 18 Jul 2012 21:01:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:7265 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751558Ab2GSBBe (ORCPT ); Wed, 18 Jul 2012 21:01:34 -0400 Date: Wed, 18 Jul 2012 22:00:48 -0300 From: Rafael Aquini To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Rusty Russell , "Michael S. Tsirkin" , Rik van Riel , Mel Gorman , Andi Kleen , Konrad Rzeszutek Wilk , Minchan Kim , Rafael Aquini Subject: Re: [PATCH v4 1/3] mm: introduce compaction and migration for virtio ballooned pages Message-ID: <20120719010047.GD2313@t510.redhat.com> References: <49f828a9331c9b729fcf77226006921ec5bc52fa.1342485774.git.aquini@redhat.com> <20120718154605.cb0591bc.akpm@linux-foundation.org> <20120718230706.GB2313@t510.redhat.com> <20120718161239.9449e6b5.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120718161239.9449e6b5.akpm@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 18, 2012 at 04:12:39PM -0700, Andrew Morton wrote: > On Wed, 18 Jul 2012 20:07:07 -0300 > Rafael Aquini wrote: > > > > > > > > +} > > > > +#else > > > > +static inline bool is_balloon_page(struct page *page) { return false; } > > > > +static inline bool isolate_balloon_page(struct page *page) { return false; } > > > > +static inline bool putback_balloon_page(struct page *page) { return false; } > > > > +#endif /* (VIRTIO_BALLOON || VIRTIO_BALLOON_MODULE) && COMPACTION */ > > > > > > This means that if CONFIG_VIRTIO_BALLOON=y and CONFIG_COMPACTION=n, > > > is_balloon_page() will always return NULL. IOW, no pages are balloon > > > pages! This is wrong. > > > > > I believe it's right, actually, as we can see CONFIG_COMPACTION=n associated with > > CONFIG_MIGRATION=y (and CONFIG_VIRTIO_BALLOON=y). > > For such config case we cannot perform the is_balloon_page() test branches > > placed on mm/migration.c > > No, it isn't right. Look at the name: "is_balloon_page". If a caller > runs is_balloon_page() against a balloon page with CONFIG_COMPACTION=n > then they will get "false", which is incorrect. > You're right, I got your point. > So the function needs a better name - one which communicates that it is > a balloon page *for the purposes of processing by the compaction code*. > Making the function private to compaction.c would help with that, if > feasible. > How about this (adjusted) approach: diff --git a/include/linux/mm.h b/include/linux/mm.h index b94f17a..02a8f80 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1629,8 +1629,7 @@ static inline unsigned int debug_guardpage_minorder(void) { return 0; } static inline bool page_is_guard(struct page *page) { return false; } #endif /* CONFIG_DEBUG_PAGEALLOC */ -#if (defined(CONFIG_VIRTIO_BALLOON) || \ - defined(CONFIG_VIRTIO_BALLOON_MODULE)) && defined(CONFIG_COMPACTION) +#if (defined(CONFIG_VIRTIO_BALLOON) ||defined(CONFIG_VIRTIO_BALLOON_MODULE)) extern bool putback_balloon_page(struct page *); extern struct address_space *balloon_mapping; @@ -1638,11 +1637,13 @@ static inline bool is_balloon_page(struct page *page) { return (page->mapping && page->mapping == balloon_mapping); } +#if defined(CONFIG_COMPACTION) +static inline bool balloon_compaction_enabled(void) { return true; } #else -static inline bool is_balloon_page(struct page *page) { return false; } -static inline bool isolate_balloon_page(struct page *page) { return false; } -static inline bool putback_balloon_page(struct page *page) { return false; } -#endif /* (VIRTIO_BALLOON || VIRTIO_BALLOON_MODULE) && COMPACTION */ +static inline bool putback_balloon_page(struct page *page) { return false; } +static inline bool balloon_compaction_enabled(void) { return false; } +#endif /* CONFIG_COMPACTION */ +#endif /* (CONFIG_VIRTIO_BALLOON || CONFIG_VIRTIO_BALLOON_MODULE) */ #endif /* __KERNEL__ */ #endif /* _LINUX_MM_H */ diff --git a/mm/migrate.c b/mm/migrate.c index 59c7bc5..f5f6a7d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -78,7 +78,8 @@ void putback_lru_pages(struct list_head *l) list_del(&page->lru); dec_zone_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page)); - if (unlikely(is_balloon_page(page))) + if (unlikely(is_balloon_page(page)) && + balloon_compaction_enabled()) WARN_ON(!putback_balloon_page(page)); else putback_lru_page(page); @@ -786,7 +787,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, } } - if (is_balloon_page(page)) { + if (is_balloon_page(page) && balloon_compaction_enabled()) { /* * A ballooned page does not need any special attention from * physical to virtual reverse mapping procedures. @@ -867,7 +868,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, rc = __unmap_and_move(page, newpage, force, offlining, mode); - if (is_balloon_page(newpage)) { + if (is_balloon_page(newpage) && balloon_compaction_enabled()) { /* * A ballooned page has been migrated already. Now, it is the * time to wrap-up counters, handle the old page back to Buddy From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx105.postini.com [74.125.245.105]) by kanga.kvack.org (Postfix) with SMTP id 1CCEC6B004D for ; Wed, 18 Jul 2012 21:01:26 -0400 (EDT) Date: Wed, 18 Jul 2012 22:00:48 -0300 From: Rafael Aquini Subject: Re: [PATCH v4 1/3] mm: introduce compaction and migration for virtio ballooned pages Message-ID: <20120719010047.GD2313@t510.redhat.com> References: <49f828a9331c9b729fcf77226006921ec5bc52fa.1342485774.git.aquini@redhat.com> <20120718154605.cb0591bc.akpm@linux-foundation.org> <20120718230706.GB2313@t510.redhat.com> <20120718161239.9449e6b5.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120718161239.9449e6b5.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Rusty Russell , "Michael S. Tsirkin" , Rik van Riel , Mel Gorman , Andi Kleen , Konrad Rzeszutek Wilk , Minchan Kim , Rafael Aquini On Wed, Jul 18, 2012 at 04:12:39PM -0700, Andrew Morton wrote: > On Wed, 18 Jul 2012 20:07:07 -0300 > Rafael Aquini wrote: > > > > > > > > +} > > > > +#else > > > > +static inline bool is_balloon_page(struct page *page) { return false; } > > > > +static inline bool isolate_balloon_page(struct page *page) { return false; } > > > > +static inline bool putback_balloon_page(struct page *page) { return false; } > > > > +#endif /* (VIRTIO_BALLOON || VIRTIO_BALLOON_MODULE) && COMPACTION */ > > > > > > This means that if CONFIG_VIRTIO_BALLOON=y and CONFIG_COMPACTION=n, > > > is_balloon_page() will always return NULL. IOW, no pages are balloon > > > pages! This is wrong. > > > > > I believe it's right, actually, as we can see CONFIG_COMPACTION=n associated with > > CONFIG_MIGRATION=y (and CONFIG_VIRTIO_BALLOON=y). > > For such config case we cannot perform the is_balloon_page() test branches > > placed on mm/migration.c > > No, it isn't right. Look at the name: "is_balloon_page". If a caller > runs is_balloon_page() against a balloon page with CONFIG_COMPACTION=n > then they will get "false", which is incorrect. > You're right, I got your point. > So the function needs a better name - one which communicates that it is > a balloon page *for the purposes of processing by the compaction code*. > Making the function private to compaction.c would help with that, if > feasible. > How about this (adjusted) approach: diff --git a/include/linux/mm.h b/include/linux/mm.h index b94f17a..02a8f80 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1629,8 +1629,7 @@ static inline unsigned int debug_guardpage_minorder(void) { return 0; } static inline bool page_is_guard(struct page *page) { return false; } #endif /* CONFIG_DEBUG_PAGEALLOC */ -#if (defined(CONFIG_VIRTIO_BALLOON) || \ - defined(CONFIG_VIRTIO_BALLOON_MODULE)) && defined(CONFIG_COMPACTION) +#if (defined(CONFIG_VIRTIO_BALLOON) ||defined(CONFIG_VIRTIO_BALLOON_MODULE)) extern bool putback_balloon_page(struct page *); extern struct address_space *balloon_mapping; @@ -1638,11 +1637,13 @@ static inline bool is_balloon_page(struct page *page) { return (page->mapping && page->mapping == balloon_mapping); } +#if defined(CONFIG_COMPACTION) +static inline bool balloon_compaction_enabled(void) { return true; } #else -static inline bool is_balloon_page(struct page *page) { return false; } -static inline bool isolate_balloon_page(struct page *page) { return false; } -static inline bool putback_balloon_page(struct page *page) { return false; } -#endif /* (VIRTIO_BALLOON || VIRTIO_BALLOON_MODULE) && COMPACTION */ +static inline bool putback_balloon_page(struct page *page) { return false; } +static inline bool balloon_compaction_enabled(void) { return false; } +#endif /* CONFIG_COMPACTION */ +#endif /* (CONFIG_VIRTIO_BALLOON || CONFIG_VIRTIO_BALLOON_MODULE) */ #endif /* __KERNEL__ */ #endif /* _LINUX_MM_H */ diff --git a/mm/migrate.c b/mm/migrate.c index 59c7bc5..f5f6a7d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -78,7 +78,8 @@ void putback_lru_pages(struct list_head *l) list_del(&page->lru); dec_zone_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page)); - if (unlikely(is_balloon_page(page))) + if (unlikely(is_balloon_page(page)) && + balloon_compaction_enabled()) WARN_ON(!putback_balloon_page(page)); else putback_lru_page(page); @@ -786,7 +787,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, } } - if (is_balloon_page(page)) { + if (is_balloon_page(page) && balloon_compaction_enabled()) { /* * A ballooned page does not need any special attention from * physical to virtual reverse mapping procedures. @@ -867,7 +868,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, rc = __unmap_and_move(page, newpage, force, offlining, mode); - if (is_balloon_page(newpage)) { + if (is_balloon_page(newpage) && balloon_compaction_enabled()) { /* * A ballooned page has been migrated already. Now, it is the * time to wrap-up counters, handle the old page back to Buddy -- 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/ . Don't email: email@kvack.org