[PATCH v8, part3 12/14] mm: correctly update zone->mamaged_pages

[PATCH v8, part3 12/14] mm: correctly update zone->mamaged_pages

[Jiang Liu]

Enhance adjust_managed_page_count() to adjust totalhigh_pages for
highmem pages. And change code which directly adjusts totalram_pages
to use adjust_managed_page_count() because it adjusts totalram_pages,
totalhigh_pages and zone->managed_pages altogether in a safe way.

Remove inc_totalhigh_pages() and dec_totalhigh_pages() from xen/balloon
driver bacause adjust_managed_page_count() has already adjusted
totalhigh_pages.

This patch also fixes two bugs:
1) enhances virtio_balloon driver to adjust totalhigh_pages when
   reserve/unreserve pages.
2) enhance memory_hotplug.c to adjust totalhigh_pages when hot-removing
   memory.

We still need to deal with modifications of totalram_pages in file
arch/powerpc/platforms/pseries/cmm.c, but need help from PPC experts.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xensource.com
Cc: linux-mm@kvack.org
---
 drivers/virtio/virtio_balloon.c |  8 +++++---
 drivers/xen/balloon.c           | 23 +++++------------------
 mm/hugetlb.c                    |  2 +-
 mm/memory_hotplug.c             | 16 +++-------------
 mm/page_alloc.c                 | 10 +++++-----
 5 files changed, 19 insertions(+), 40 deletions(-)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index bd3ae32..6649968 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -148,7 +148,7 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num)
 		}
 		set_page_pfns(vb->pfns + vb->num_pfns, page);
 		vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE;
-		totalram_pages--;
+		adjust_managed_page_count(page, -1);
 	}
 
 	/* Did we get any? */
@@ -160,11 +160,13 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num)
 static void release_pages_by_pfn(const u32 pfns[], unsigned int num)
 {
 	unsigned int i;
+	struct page *page;
 
 	/* Find pfns pointing at start of each page, get pages and free them. */
 	for (i = 0; i < num; i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
-		balloon_page_free(balloon_pfn_to_page(pfns[i]));
-		totalram_pages++;
+		page = balloon_pfn_to_page(pfns[i]);
+		balloon_page_free(page);
+		adjust_managed_page_count(page, 1);
 	}
 }
 
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 930fb68..c8aab4e 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -89,14 +89,6 @@ EXPORT_SYMBOL_GPL(balloon_stats);
 /* We increase/decrease in batches which fit in a page */
 static xen_pfn_t frame_list[PAGE_SIZE / sizeof(unsigned long)];
 
-#ifdef CONFIG_HIGHMEM
-#define inc_totalhigh_pages() (totalhigh_pages++)
-#define dec_totalhigh_pages() (totalhigh_pages--)
-#else
-#define inc_totalhigh_pages() do {} while (0)
-#define dec_totalhigh_pages() do {} while (0)
-#endif
-
 /* List of ballooned pages, threaded through the mem_map array. */
 static LIST_HEAD(ballooned_pages);
 
@@ -132,9 +124,7 @@ static void __balloon_append(struct page *page)
 static void balloon_append(struct page *page)
 {
 	__balloon_append(page);
-	if (PageHighMem(page))
-		dec_totalhigh_pages();
-	totalram_pages--;
+	adjust_managed_page_count(page, -1);
 }
 
 /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */
@@ -151,13 +141,12 @@ static struct page *balloon_retrieve(bool prefer_highmem)
 		page = list_entry(ballooned_pages.next, struct page, lru);
 	list_del(&page->lru);
 
-	if (PageHighMem(page)) {
+	if (PageHighMem(page))
 		balloon_stats.balloon_high--;
-		inc_totalhigh_pages();
-	} else
+	else
 		balloon_stats.balloon_low--;
 
-	totalram_pages++;
+	adjust_managed_page_count(page, 1);
 
 	return page;
 }
@@ -372,9 +361,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages)
 #endif
 
 		/* Relinquish the page back to the allocator. */
-		ClearPageReserved(page);
-		init_page_count(page);
-		__free_page(page);
+		__free_reserved_page(page);
 	}
 
 	balloon_stats.current_pages += rc;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index f8feeec..95c5a6b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1246,7 +1246,7 @@ static void __init gather_bootmem_prealloc(void)
 		 * side-effects, like CommitLimit going negative.
 		 */
 		if (h->order > (MAX_ORDER - 1))
-			totalram_pages += 1 << h->order;
+			adjust_managed_page_count(page, 1 << h->order);
 	}
 }
 
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 1a16ea0..7244e67 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -772,20 +772,13 @@ EXPORT_SYMBOL_GPL(__online_page_set_limits);
 
 void __online_page_increment_counters(struct page *page)
 {
-	totalram_pages++;
-
-#ifdef CONFIG_HIGHMEM
-	if (PageHighMem(page))
-		totalhigh_pages++;
-#endif
+	adjust_managed_page_count(page, 1);
 }
 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
 
 void __online_page_free(struct page *page)
 {
-	ClearPageReserved(page);
-	init_page_count(page);
-	__free_page(page);
+	__free_reserved_page(page);
 }
 EXPORT_SYMBOL_GPL(__online_page_free);
 
@@ -983,7 +976,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
 		return ret;
 	}
 
-	zone->managed_pages += onlined_pages;
 	zone->present_pages += onlined_pages;
 
 	pgdat_resize_lock(zone->zone_pgdat, &flags);
@@ -1572,15 +1564,13 @@ repeat:
 	/* reset pagetype flags and makes migrate type to be MOVABLE */
 	undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
 	/* removal success */
-	zone->managed_pages -= offlined_pages;
+	adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
 	zone->present_pages -= offlined_pages;
 
 	pgdat_resize_lock(zone->zone_pgdat, &flags);
 	zone->zone_pgdat->node_present_pages -= offlined_pages;
 	pgdat_resize_unlock(zone->zone_pgdat, &flags);
 
-	totalram_pages -= offlined_pages;
-
 	init_per_zone_wmark_min();
 
 	if (!populated_zone(zone)) {
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 403afa6..5b27db4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -783,11 +783,7 @@ void __init init_cma_reserved_pageblock(struct page *page)
 	set_page_refcounted(page);
 	set_pageblock_migratetype(page, MIGRATE_CMA);
 	__free_pages(page, pageblock_order);
-	totalram_pages += pageblock_nr_pages;
-#ifdef CONFIG_HIGHMEM
-	if (PageHighMem(page))
-		totalhigh_pages += pageblock_nr_pages;
-#endif
+	adjust_managed_page_count(page, pageblock_nr_pages);
 }
 #endif
 
@@ -5232,6 +5228,10 @@ void adjust_managed_page_count(struct page *page, long count)
 	spin_lock(&managed_page_count_lock);
 	page_zone(page)->managed_pages += count;
 	totalram_pages += count;
+#ifdef	CONFIG_HIGHMEM
+	if (PageHighMem(page))
+		totalhigh_pages += count;
+#endif
 	spin_unlock(&managed_page_count_lock);
 }
 EXPORT_SYMBOL(adjust_managed_page_count);
-- 
1.8.1.2

Re: [PATCH v8, part3 12/14] mm: correctly update zone->mamaged_pages

[Wanpeng Li]

On Sun, May 26, 2013 at 09:38:40PM +0800, Jiang Liu wrote:
>Enhance adjust_managed_page_count() to adjust totalhigh_pages for
>highmem pages. And change code which directly adjusts totalram_pages
>to use adjust_managed_page_count() because it adjusts totalram_pages,
>totalhigh_pages and zone->managed_pages altogether in a safe way.
>
>Remove inc_totalhigh_pages() and dec_totalhigh_pages() from xen/balloon
>driver bacause adjust_managed_page_count() has already adjusted
>totalhigh_pages.
>
>This patch also fixes two bugs:
>1) enhances virtio_balloon driver to adjust totalhigh_pages when
>   reserve/unreserve pages.
>2) enhance memory_hotplug.c to adjust totalhigh_pages when hot-removing
>   memory.
>
>We still need to deal with modifications of totalram_pages in file
>arch/powerpc/platforms/pseries/cmm.c, but need help from PPC experts.
>
>Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
>Cc: Chris Metcalf <cmetcalf@tilera.com>
>Cc: Rusty Russell <rusty@rustcorp.com.au>
>Cc: "Michael S. Tsirkin" <mst@redhat.com>
>Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>Cc: Jeremy Fitzhardinge <jeremy@goop.org>
>Cc: Wen Congyang <wency@cn.fujitsu.com>
>Cc: Andrew Morton <akpm@linux-foundation.org>
>Cc: Tang Chen <tangchen@cn.fujitsu.com>
>Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>Cc: Mel Gorman <mgorman@suse.de>
>Cc: Minchan Kim <minchan@kernel.org>
>Cc: linux-kernel@vger.kernel.org
>Cc: virtualization@lists.linux-foundation.org
>Cc: xen-devel@lists.xensource.com
>Cc: linux-mm@kvack.org
>---
> drivers/virtio/virtio_balloon.c |  8 +++++---
> drivers/xen/balloon.c           | 23 +++++------------------
> mm/hugetlb.c                    |  2 +-
> mm/memory_hotplug.c             | 16 +++-------------
> mm/page_alloc.c                 | 10 +++++-----
> 5 files changed, 19 insertions(+), 40 deletions(-)
>
>diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
>index bd3ae32..6649968 100644
>--- a/drivers/virtio/virtio_balloon.c
>+++ b/drivers/virtio/virtio_balloon.c
>@@ -148,7 +148,7 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num)
> 		}
> 		set_page_pfns(vb->pfns + vb->num_pfns, page);
> 		vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE;
>-		totalram_pages--;
>+		adjust_managed_page_count(page, -1);
> 	}
>
> 	/* Did we get any? */
>@@ -160,11 +160,13 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num)
> static void release_pages_by_pfn(const u32 pfns[], unsigned int num)
> {
> 	unsigned int i;
>+	struct page *page;
>
> 	/* Find pfns pointing at start of each page, get pages and free them. */
> 	for (i = 0; i < num; i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
>-		balloon_page_free(balloon_pfn_to_page(pfns[i]));
>-		totalram_pages++;
>+		page = balloon_pfn_to_page(pfns[i]);
>+		balloon_page_free(page);
>+		adjust_managed_page_count(page, 1);
> 	}
> }
>
>diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
>index 930fb68..c8aab4e 100644
>--- a/drivers/xen/balloon.c
>+++ b/drivers/xen/balloon.c
>@@ -89,14 +89,6 @@ EXPORT_SYMBOL_GPL(balloon_stats);
> /* We increase/decrease in batches which fit in a page */
> static xen_pfn_t frame_list[PAGE_SIZE / sizeof(unsigned long)];
>
>-#ifdef CONFIG_HIGHMEM
>-#define inc_totalhigh_pages() (totalhigh_pages++)
>-#define dec_totalhigh_pages() (totalhigh_pages--)
>-#else
>-#define inc_totalhigh_pages() do {} while (0)
>-#define dec_totalhigh_pages() do {} while (0)
>-#endif
>-
> /* List of ballooned pages, threaded through the mem_map array. */
> static LIST_HEAD(ballooned_pages);
>
>@@ -132,9 +124,7 @@ static void __balloon_append(struct page *page)
> static void balloon_append(struct page *page)
> {
> 	__balloon_append(page);
>-	if (PageHighMem(page))
>-		dec_totalhigh_pages();
>-	totalram_pages--;
>+	adjust_managed_page_count(page, -1);
> }
>
> /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */
>@@ -151,13 +141,12 @@ static struct page *balloon_retrieve(bool prefer_highmem)
> 		page = list_entry(ballooned_pages.next, struct page, lru);
> 	list_del(&page->lru);
>
>-	if (PageHighMem(page)) {
>+	if (PageHighMem(page))
> 		balloon_stats.balloon_high--;
>-		inc_totalhigh_pages();
>-	} else
>+	else
> 		balloon_stats.balloon_low--;
>
>-	totalram_pages++;
>+	adjust_managed_page_count(page, 1);
>
> 	return page;
> }
>@@ -372,9 +361,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages)
> #endif
>
> 		/* Relinquish the page back to the allocator. */
>-		ClearPageReserved(page);
>-		init_page_count(page);
>-		__free_page(page);
>+		__free_reserved_page(page);
> 	}
>
> 	balloon_stats.current_pages += rc;
>diff --git a/mm/hugetlb.c b/mm/hugetlb.c
>index f8feeec..95c5a6b 100644
>--- a/mm/hugetlb.c
>+++ b/mm/hugetlb.c
>@@ -1246,7 +1246,7 @@ static void __init gather_bootmem_prealloc(void)
> 		 * side-effects, like CommitLimit going negative.
> 		 */
> 		if (h->order > (MAX_ORDER - 1))
>-			totalram_pages += 1 << h->order;
>+			adjust_managed_page_count(page, 1 << h->order);
> 	}
> }
>
>diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>index 1a16ea0..7244e67 100644
>--- a/mm/memory_hotplug.c
>+++ b/mm/memory_hotplug.c
>@@ -772,20 +772,13 @@ EXPORT_SYMBOL_GPL(__online_page_set_limits);
>
> void __online_page_increment_counters(struct page *page)
> {
>-	totalram_pages++;
>-
>-#ifdef CONFIG_HIGHMEM
>-	if (PageHighMem(page))
>-		totalhigh_pages++;
>-#endif
>+	adjust_managed_page_count(page, 1);
> }
> EXPORT_SYMBOL_GPL(__online_page_increment_counters);
>
> void __online_page_free(struct page *page)
> {
>-	ClearPageReserved(page);
>-	init_page_count(page);
>-	__free_page(page);
>+	__free_reserved_page(page);
> }
> EXPORT_SYMBOL_GPL(__online_page_free);
>
>@@ -983,7 +976,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
> 		return ret;
> 	}
>
>-	zone->managed_pages += onlined_pages;
> 	zone->present_pages += onlined_pages;
>
> 	pgdat_resize_lock(zone->zone_pgdat, &flags);
>@@ -1572,15 +1564,13 @@ repeat:
> 	/* reset pagetype flags and makes migrate type to be MOVABLE */
> 	undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
> 	/* removal success */
>-	zone->managed_pages -= offlined_pages;
>+	adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
> 	zone->present_pages -= offlined_pages;
>
> 	pgdat_resize_lock(zone->zone_pgdat, &flags);
> 	zone->zone_pgdat->node_present_pages -= offlined_pages;
> 	pgdat_resize_unlock(zone->zone_pgdat, &flags);
>
>-	totalram_pages -= offlined_pages;
>-
> 	init_per_zone_wmark_min();
>
> 	if (!populated_zone(zone)) {
>diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>index 403afa6..5b27db4 100644
>--- a/mm/page_alloc.c
>+++ b/mm/page_alloc.c
>@@ -783,11 +783,7 @@ void __init init_cma_reserved_pageblock(struct page *page)
> 	set_page_refcounted(page);
> 	set_pageblock_migratetype(page, MIGRATE_CMA);
> 	__free_pages(page, pageblock_order);
>-	totalram_pages += pageblock_nr_pages;
>-#ifdef CONFIG_HIGHMEM
>-	if (PageHighMem(page))
>-		totalhigh_pages += pageblock_nr_pages;
>-#endif
>+	adjust_managed_page_count(page, pageblock_nr_pages);
> }
> #endif
>
>@@ -5232,6 +5228,10 @@ void adjust_managed_page_count(struct page *page, long count)
> 	spin_lock(&managed_page_count_lock);
> 	page_zone(page)->managed_pages += count;
> 	totalram_pages += count;
>+#ifdef	CONFIG_HIGHMEM

Don't need CONFIG_HIGHMEM here.

Regards,
Wanpeng Li 

>+	if (PageHighMem(page))
>+		totalhigh_pages += count;
>+#endif
> 	spin_unlock(&managed_page_count_lock);
> }
> EXPORT_SYMBOL(adjust_managed_page_count);
>-- 
>1.8.1.2
>
>--
>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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v8, part3 12/14] mm: correctly update zone->mamaged_pages

[Sergei Shtylyov]

On 26-05-2013 17:38, Jiang Liu wrote:

    Typo in the subject: s/mamaged_pages/managed_pages/.

> Enhance adjust_managed_page_count() to adjust totalhigh_pages for
> highmem pages. And change code which directly adjusts totalram_pages
> to use adjust_managed_page_count() because it adjusts totalram_pages,
> totalhigh_pages and zone->managed_pages altogether in a safe way.

> Remove inc_totalhigh_pages() and dec_totalhigh_pages() from xen/balloon
> driver bacause adjust_managed_page_count() has already adjusted
> totalhigh_pages.

> This patch also fixes two bugs:
> 1) enhances virtio_balloon driver to adjust totalhigh_pages when
>     reserve/unreserve pages.
> 2) enhance memory_hotplug.c to adjust totalhigh_pages when hot-removing
>     memory.

> We still need to deal with modifications of totalram_pages in file
> arch/powerpc/platforms/pseries/cmm.c, but need help from PPC experts.

> Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
> Cc: Chris Metcalf <cmetcalf@tilera.com>
> Cc: Rusty Russell <rusty@rustcorp.com.au>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Cc: Jeremy Fitzhardinge <jeremy@goop.org>
> Cc: Wen Congyang <wency@cn.fujitsu.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Tang Chen <tangchen@cn.fujitsu.com>
> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: linux-kernel@vger.kernel.org
> Cc: virtualization@lists.linux-foundation.org
> Cc: xen-devel@lists.xensource.com
> Cc: linux-mm@kvack.org
> ---
>   drivers/virtio/virtio_balloon.c |  8 +++++---
>   drivers/xen/balloon.c           | 23 +++++------------------
>   mm/hugetlb.c                    |  2 +-
>   mm/memory_hotplug.c             | 16 +++-------------
>   mm/page_alloc.c                 | 10 +++++-----
>   5 files changed, 19 insertions(+), 40 deletions(-)

> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index bd3ae32..6649968 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
[...]
> @@ -160,11 +160,13 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num)
>   static void release_pages_by_pfn(const u32 pfns[], unsigned int num)
>   {
>   	unsigned int i;
> +	struct page *page;

    Why not declare it right in the *for* loop? You could use intializer 
then...

>
>   	/* Find pfns pointing at start of each page, get pages and free them. */
>   	for (i = 0; i < num; i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
> -		balloon_page_free(balloon_pfn_to_page(pfns[i]));
> -		totalram_pages++;
> +		page = balloon_pfn_to_page(pfns[i]);
> +		balloon_page_free(page);
> +		adjust_managed_page_count(page, 1);
>   	}
>   }
>
[...]

WBR, Sergei

Re: [PATCH v8, part3 12/14] mm: correctly update zone->mamaged_pages

[Liu Jiang]

Hi Sergei,
	Thanks for review!

On 05/27/2013 09:57 PM, Sergei Shtylyov wrote:
> On 26-05-2013 17:38, Jiang Liu wrote:
> 
>    Typo in the subject: s/mamaged_pages/managed_pages/.
Will fix it in next version.

> 
>> Enhance adjust_managed_page_count() to adjust totalhigh_pages for
>> highmem pages. And change code which directly adjusts totalram_pages
>> to use adjust_managed_page_count() because it adjusts totalram_pages,
>> totalhigh_pages and zone->managed_pages altogether in a safe way.
> 
>> Remove inc_totalhigh_pages() and dec_totalhigh_pages() from xen/balloon
>> driver bacause adjust_managed_page_count() has already adjusted
>> totalhigh_pages.
> 
>> This patch also fixes two bugs:
>> 1) enhances virtio_balloon driver to adjust totalhigh_pages when
>>     reserve/unreserve pages.
>> 2) enhance memory_hotplug.c to adjust totalhigh_pages when hot-removing
>>     memory.
> 
>> We still need to deal with modifications of totalram_pages in file
>> arch/powerpc/platforms/pseries/cmm.c, but need help from PPC experts.
> 
>> Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
>> Cc: Chris Metcalf <cmetcalf@tilera.com>
>> Cc: Rusty Russell <rusty@rustcorp.com.au>
>> Cc: "Michael S. Tsirkin" <mst@redhat.com>
>> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>> Cc: Jeremy Fitzhardinge <jeremy@goop.org>
>> Cc: Wen Congyang <wency@cn.fujitsu.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Tang Chen <tangchen@cn.fujitsu.com>
>> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>> Cc: Mel Gorman <mgorman@suse.de>
>> Cc: Minchan Kim <minchan@kernel.org>
>> Cc: linux-kernel@vger.kernel.org
>> Cc: virtualization@lists.linux-foundation.org
>> Cc: xen-devel@lists.xensource.com
>> Cc: linux-mm@kvack.org
>> ---
>>   drivers/virtio/virtio_balloon.c |  8 +++++---
>>   drivers/xen/balloon.c           | 23 +++++------------------
>>   mm/hugetlb.c                    |  2 +-
>>   mm/memory_hotplug.c             | 16 +++-------------
>>   mm/page_alloc.c                 | 10 +++++-----
>>   5 files changed, 19 insertions(+), 40 deletions(-)
> 
>> diff --git a/drivers/virtio/virtio_balloon.c
>> b/drivers/virtio/virtio_balloon.c
>> index bd3ae32..6649968 100644
>> --- a/drivers/virtio/virtio_balloon.c
>> +++ b/drivers/virtio/virtio_balloon.c
> [...]
>> @@ -160,11 +160,13 @@ static void fill_balloon(struct virtio_balloon
>> *vb, size_t num)
>>   static void release_pages_by_pfn(const u32 pfns[], unsigned int num)
>>   {
>>       unsigned int i;
>> +    struct page *page;
> 
>    Why not declare it right in the *for* loop? You could use intializer
> then...
Good suggestion, will change it in next version.

> 
>>
>>       /* Find pfns pointing at start of each page, get pages and free
>> them. */
>>       for (i = 0; i < num; i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
>> -        balloon_page_free(balloon_pfn_to_page(pfns[i]));
>> -        totalram_pages++;
>> +        page = balloon_pfn_to_page(pfns[i]);
>> +        balloon_page_free(page);
>> +        adjust_managed_page_count(page, 1);
>>       }
>>   }
>>
> [...]
> 
> WBR, Sergei
>