Rafael Aquini
2012-Jul-17 16:50 UTC
[PATCH v4 0/3] make balloon pages movable by compaction
Memory fragmentation introduced by ballooning might reduce significantly
the number of 2MB contiguous memory blocks that can be used within a guest,
thus imposing performance penalties associated with the reduced number of
transparent huge pages that could be used by the guest workload.
This patch-set follows the main idea discussed at 2012 LSFMMS session:
"Ballooning for transparent huge pages" --
http://lwn.net/Articles/490114/
to introduce the required changes to the virtio_balloon driver, as well as
the changes to the core compaction & migration bits, in order to make those
subsystems aware of ballooned pages and allow memory balloon pages become
movable within a guest, thus avoiding the aforementioned fragmentation issue
Rafael Aquini (3):
mm: introduce compaction and migration for virtio ballooned pages
virtio_balloon: introduce migration primitives to balloon pages
mm: add vm event counters for balloon pages compaction
drivers/virtio/virtio_balloon.c | 146 ++++++++++++++++++++++++++++++++++++---
include/linux/mm.h | 15 ++++
include/linux/virtio_balloon.h | 4 ++
include/linux/vm_event_item.h | 2 +
mm/compaction.c | 127 +++++++++++++++++++++++++++++-----
mm/migrate.c | 32 ++++++++-
mm/vmstat.c | 4 ++
7 files changed, 302 insertions(+), 28 deletions(-)
Change log:
v4:
* address Rusty Russel's review comments on PATCH 02;
* re-base virtio_balloon patch on 9c378abc5c0c6fc8e3acf5968924d274503819b3;
V3:
* address reviewers nitpick suggestions on PATCH 01 (Mel, Minchan);
V2:
* address Mel Gorman's review comments on PATCH 01;
Preliminary test results:
(2 VCPU 1024mB RAM KVM guest running 3.5.0_rc7+ -- after a reboot)
* 64mB balloon:
[root at localhost ~]# awk '/compact/ {print}' /proc/vmstat
compact_blocks_moved 0
compact_pages_moved 0
compact_pagemigrate_failed 0
compact_stall 0
compact_fail 0
compact_success 0
compact_balloon_migrated 0
compact_balloon_failed 0
compact_balloon_isolated 0
compact_balloon_freed 0
[root at localhost ~]#
[root at localhost ~]# for i in $(seq 1 4); do echo 1 >
/proc/sys/vm/compact_memory & done &>/dev/null
[1] Done echo 1 > /proc/sys/vm/compact_memory
[2] Done echo 1 > /proc/sys/vm/compact_memory
[3]- Done echo 1 > /proc/sys/vm/compact_memory
[4]+ Done echo 1 > /proc/sys/vm/compact_memory
[root at localhost ~]#
[root at localhost ~]# awk '/compact/ {print}' /proc/vmstat
compact_blocks_moved 2842
compact_pages_moved 48429
compact_pagemigrate_failed 81
compact_stall 0
compact_fail 0
compact_success 0
compact_balloon_migrated 16364
compact_balloon_failed 0
compact_balloon_isolated 16364
compact_balloon_freed 16364
* 128mB balloon:
[root at localhost ~]# awk '/compact/ {print}' /proc/vmstat
compact_blocks_moved 0
compact_pages_moved 0
compact_pagemigrate_failed 0
compact_stall 0
compact_fail 0
compact_success 0
compact_balloon_migrated 0
compact_balloon_failed 0
compact_balloon_isolated 0
compact_balloon_freed 0
[root at localhost ~]#
[root at localhost ~]# for i in $(seq 1 4); do echo 1 >
/proc/sys/vm/compact_memory & done &>/dev/null
[1] Done echo 1 > /proc/sys/vm/compact_memory
[2] Done echo 1 > /proc/sys/vm/compact_memory
[3]- Done echo 1 > /proc/sys/vm/compact_memory
[4]+ Done echo 1 > /proc/sys/vm/compact_memory
[root at localhost ~]#
[root at localhost ~]# awk '/compact/ {print}' /proc/vmstat
compact_blocks_moved 2162
compact_pages_moved 33735
compact_pagemigrate_failed 69
compact_stall 0
compact_fail 0
compact_success 0
compact_balloon_migrated 21731
compact_balloon_failed 0
compact_balloon_isolated 21731
compact_balloon_freed 21731
--
1.7.10.4
Rafael Aquini
2012-Jul-17 16:50 UTC
[PATCH v4 1/3] mm: introduce compaction and migration for virtio ballooned pages
This patch introduces the helper functions as well as the necessary changes
to teach compaction and migration bits how to cope with pages which are
part of a guest memory balloon, in order to make them movable by memory
compaction procedures.
Signed-off-by: Rafael Aquini <aquini at redhat.com>
---
include/linux/mm.h | 15 +++++++
mm/compaction.c | 126 ++++++++++++++++++++++++++++++++++++++++++++--------
mm/migrate.c | 30 ++++++++++++-
3 files changed, 151 insertions(+), 20 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index b36d08c..3112198 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1629,5 +1629,20 @@ 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)
+extern bool putback_balloon_page(struct page *);
+extern struct address_space *balloon_mapping;
+
+static inline bool is_balloon_page(struct page *page)
+{
+ return (page->mapping == balloon_mapping) ? true : false;
+}
+#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 */
+
#endif /* __KERNEL__ */
#endif /* _LINUX_MM_H */
diff --git a/mm/compaction.c b/mm/compaction.c
index 2f42d95..51eac0c 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -14,6 +14,7 @@
#include <linux/backing-dev.h>
#include <linux/sysctl.h>
#include <linux/sysfs.h>
+#include <linux/export.h>
#include "internal.h"
#if defined CONFIG_COMPACTION || defined CONFIG_CMA
@@ -21,6 +22,85 @@
#define CREATE_TRACE_POINTS
#include <trace/events/compaction.h>
+#if defined(CONFIG_VIRTIO_BALLOON) || defined(CONFIG_VIRTIO_BALLOON_MODULE)
+/*
+ * Balloon pages special page->mapping.
+ * Users must properly allocate and initialize an instance of balloon_mapping,
+ * and set it as the page->mapping for balloon enlisted page instances.
+ * There is no need on utilizing struct address_space locking schemes for
+ * balloon_mapping as, once it gets initialized at balloon driver, it will
+ * remain just like a static reference that helps us on identifying a guest
+ * ballooned page by its mapping, as well as it will keep the 'a_ops'
callback
+ * pointers to the functions that will execute the balloon page mobility tasks.
+ *
+ * address_space_operations necessary methods for ballooned pages:
+ * .migratepage - used to perform balloon's page migration (as is)
+ * .invalidatepage - used to isolate a page from balloon's page list
+ * .freepage - used to reinsert an isolated page to balloon's page
list
+ */
+struct address_space *balloon_mapping;
+EXPORT_SYMBOL_GPL(balloon_mapping);
+
+static inline void __isolate_balloon_page(struct page *page)
+{
+ page->mapping->a_ops->invalidatepage(page, 0);
+}
+
+static inline void __putback_balloon_page(struct page *page)
+{
+ page->mapping->a_ops->freepage(page);
+}
+
+/* __isolate_lru_page() counterpart for a ballooned page */
+static bool isolate_balloon_page(struct page *page)
+{
+ if (WARN_ON(!is_balloon_page(page)))
+ return false;
+
+ if (likely(get_page_unless_zero(page))) {
+ /*
+ * We can race against move_to_new_page() & __unmap_and_move().
+ * If we stumble across a locked balloon page and succeed on
+ * isolating it, the result tends to be disastrous.
+ */
+ if (likely(trylock_page(page))) {
+ /*
+ * A ballooned page, by default, has just one refcount.
+ * Prevent concurrent compaction threads from isolating
+ * an already isolated balloon page.
+ */
+ if (is_balloon_page(page) && (page_count(page) == 2)) {
+ __isolate_balloon_page(page);
+ unlock_page(page);
+ return true;
+ }
+ unlock_page(page);
+ }
+ /* Drop refcount taken for this already isolated page */
+ put_page(page);
+ }
+ return false;
+}
+
+/* putback_lru_page() counterpart for a ballooned page */
+bool putback_balloon_page(struct page *page)
+{
+ if (WARN_ON(!is_balloon_page(page)))
+ return false;
+
+ if (likely(trylock_page(page))) {
+ if (is_balloon_page(page)) {
+ __putback_balloon_page(page);
+ put_page(page);
+ unlock_page(page);
+ return true;
+ }
+ unlock_page(page);
+ }
+ return false;
+}
+#endif /* CONFIG_VIRTIO_BALLOON || CONFIG_VIRTIO_BALLOON_MODULE */
+
static unsigned long release_freepages(struct list_head *freelist)
{
struct page *page, *next;
@@ -312,32 +392,40 @@ isolate_migratepages_range(struct zone *zone, struct
compact_control *cc,
continue;
}
- if (!PageLRU(page))
- continue;
-
/*
- * PageLRU is set, and lru_lock excludes isolation,
- * splitting and collapsing (collapsing has already
- * happened if PageLRU is set).
+ * It is possible to migrate LRU pages and balloon pages.
+ * Skip any other type of page.
*/
- if (PageTransHuge(page)) {
- low_pfn += (1 << compound_order(page)) - 1;
- continue;
- }
+ if (PageLRU(page)) {
+ /*
+ * PageLRU is set, and lru_lock excludes isolation,
+ * splitting and collapsing (collapsing has already
+ * happened if PageLRU is set).
+ */
+ if (PageTransHuge(page)) {
+ low_pfn += (1 << compound_order(page)) - 1;
+ continue;
+ }
- if (!cc->sync)
- mode |= ISOLATE_ASYNC_MIGRATE;
+ if (!cc->sync)
+ mode |= ISOLATE_ASYNC_MIGRATE;
- lruvec = mem_cgroup_page_lruvec(page, zone);
+ lruvec = mem_cgroup_page_lruvec(page, zone);
- /* Try isolate the page */
- if (__isolate_lru_page(page, mode) != 0)
- continue;
+ /* Try isolate the page */
+ if (__isolate_lru_page(page, mode) != 0)
+ continue;
+
+ VM_BUG_ON(PageTransCompound(page));
- VM_BUG_ON(PageTransCompound(page));
+ /* Successfully isolated */
+ del_page_from_lru_list(page, lruvec, page_lru(page));
+ } else if (is_balloon_page(page)) {
+ if (!isolate_balloon_page(page))
+ continue;
+ } else
+ continue;
- /* Successfully isolated */
- del_page_from_lru_list(page, lruvec, page_lru(page));
list_add(&page->lru, migratelist);
cc->nr_migratepages++;
nr_isolated++;
diff --git a/mm/migrate.c b/mm/migrate.c
index be26d5c..59c7bc5 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -78,7 +78,10 @@ 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));
- putback_lru_page(page);
+ if (unlikely(is_balloon_page(page)))
+ WARN_ON(!putback_balloon_page(page));
+ else
+ putback_lru_page(page);
}
}
@@ -783,6 +786,17 @@ static int __unmap_and_move(struct page *page, struct page
*newpage,
}
}
+ if (is_balloon_page(page)) {
+ /*
+ * A ballooned page does not need any special attention from
+ * physical to virtual reverse mapping procedures.
+ * Skip any attempt to unmap PTEs or to remap swap cache,
+ * in order to avoid burning cycles at rmap level.
+ */
+ remap_swapcache = 0;
+ goto skip_unmap;
+ }
+
/*
* Corner case handling:
* 1. When a new swap-cache page is read into, it is added to the LRU
@@ -852,6 +866,20 @@ static int unmap_and_move(new_page_t get_new_page, unsigned
long private,
goto out;
rc = __unmap_and_move(page, newpage, force, offlining, mode);
+
+ if (is_balloon_page(newpage)) {
+ /*
+ * A ballooned page has been migrated already. Now, it is the
+ * time to wrap-up counters, handle the old page back to Buddy
+ * and return.
+ */
+ list_del(&page->lru);
+ dec_zone_page_state(page, NR_ISOLATED_ANON +
+ page_is_file_cache(page));
+ put_page(page);
+ __free_page(page);
+ return rc;
+ }
out:
if (rc != -EAGAIN) {
/*
--
1.7.10.4
Rafael Aquini
2012-Jul-17 16:50 UTC
[PATCH v4 2/3] virtio_balloon: introduce migration primitives to balloon pages
Besides making balloon pages movable at allocation time and introducing
the necessary primitives to perform balloon page migration/compaction,
this patch also introduces the following locking scheme to provide the
proper synchronization and protection for struct virtio_balloon elements
against concurrent accesses due to parallel operations introduced by
memory compaction / page migration.
- balloon_lock (mutex) : synchronizes the access demand to elements of
struct virtio_balloon and its queue operations;
- pages_lock (spinlock): special protection to balloon pages list against
concurrent list handling operations;
Signed-off-by: Rafael Aquini <aquini at redhat.com>
---
drivers/virtio/virtio_balloon.c | 145 ++++++++++++++++++++++++++++++++++++---
include/linux/virtio_balloon.h | 4 ++
2 files changed, 141 insertions(+), 8 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 0908e60..7669bc8 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -27,6 +27,7 @@
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/module.h>
+#include <linux/fs.h>
/*
* Balloon device works in 4K page units. So each page is pointed to by
@@ -35,6 +36,9 @@
*/
#define VIRTIO_BALLOON_PAGES_PER_PAGE (PAGE_SIZE >>
VIRTIO_BALLOON_PFN_SHIFT)
+/* Synchronize accesses/updates to the struct virtio_balloon elements */
+DEFINE_MUTEX(balloon_lock);
+
struct virtio_balloon
{
struct virtio_device *vdev;
@@ -51,6 +55,10 @@ struct virtio_balloon
/* Number of balloon pages we've told the Host we're not using. */
unsigned int num_pages;
+
+ /* Protect 'pages' list against concurrent handling */
+ spinlock_t pages_lock;
+
/*
* The pages we've told the Host we're not using.
* Each page on this list adds VIRTIO_BALLOON_PAGES_PER_PAGE
@@ -125,10 +133,12 @@ static void fill_balloon(struct virtio_balloon *vb, size_t
num)
/* We can only do one array worth at a time. */
num = min(num, ARRAY_SIZE(vb->pfns));
+ mutex_lock(&balloon_lock);
for (vb->num_pfns = 0; vb->num_pfns < num;
vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
- struct page *page = alloc_page(GFP_HIGHUSER | __GFP_NORETRY |
- __GFP_NOMEMALLOC | __GFP_NOWARN);
+ struct page *page = alloc_page(GFP_HIGHUSER_MOVABLE |
+ __GFP_NORETRY | __GFP_NOWARN |
+ __GFP_NOMEMALLOC);
if (!page) {
if (printk_ratelimit())
dev_printk(KERN_INFO, &vb->vdev->dev,
@@ -141,7 +151,10 @@ 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--;
+ spin_lock(&vb->pages_lock);
list_add(&page->lru, &vb->pages);
+ page->mapping = balloon_mapping;
+ spin_unlock(&vb->pages_lock);
}
/* Didn't get any? Oh well. */
@@ -149,6 +162,7 @@ static void fill_balloon(struct virtio_balloon *vb, size_t
num)
return;
tell_host(vb, vb->inflate_vq);
+ mutex_unlock(&balloon_lock);
}
static void release_pages_by_pfn(const u32 pfns[], unsigned int num)
@@ -169,10 +183,22 @@ static void leak_balloon(struct virtio_balloon *vb, size_t
num)
/* We can only do one array worth at a time. */
num = min(num, ARRAY_SIZE(vb->pfns));
+ mutex_lock(&balloon_lock);
for (vb->num_pfns = 0; vb->num_pfns < num;
vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
+ /*
+ * We can race against virtballoon_isolatepage() and end up
+ * stumbling across a _temporarily_ empty 'pages' list.
+ */
+ spin_lock(&vb->pages_lock);
+ if (unlikely(list_empty(&vb->pages))) {
+ spin_unlock(&vb->pages_lock);
+ break;
+ }
page = list_first_entry(&vb->pages, struct page, lru);
+ page->mapping = NULL;
list_del(&page->lru);
+ spin_unlock(&vb->pages_lock);
set_page_pfns(vb->pfns + vb->num_pfns, page);
vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE;
}
@@ -182,8 +208,11 @@ static void leak_balloon(struct virtio_balloon *vb, size_t
num)
* virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST);
* is true, we *have* to do it in this order
*/
- tell_host(vb, vb->deflate_vq);
- release_pages_by_pfn(vb->pfns, vb->num_pfns);
+ if (vb->num_pfns > 0) {
+ tell_host(vb, vb->deflate_vq);
+ release_pages_by_pfn(vb->pfns, vb->num_pfns);
+ }
+ mutex_unlock(&balloon_lock);
}
static inline void update_stat(struct virtio_balloon *vb, int idx,
@@ -239,6 +268,7 @@ static void stats_handle_request(struct virtio_balloon *vb)
struct scatterlist sg;
unsigned int len;
+ mutex_lock(&balloon_lock);
vb->need_stats_update = 0;
update_balloon_stats(vb);
@@ -249,6 +279,7 @@ static void stats_handle_request(struct virtio_balloon *vb)
if (virtqueue_add_buf(vq, &sg, 1, 0, vb, GFP_KERNEL) < 0)
BUG();
virtqueue_kick(vq);
+ mutex_unlock(&balloon_lock);
}
static void virtballoon_changed(struct virtio_device *vdev)
@@ -261,22 +292,27 @@ static void virtballoon_changed(struct virtio_device
*vdev)
static inline s64 towards_target(struct virtio_balloon *vb)
{
__le32 v;
- s64 target;
+ s64 target, actual;
+ mutex_lock(&balloon_lock);
+ actual = vb->num_pages;
vb->vdev->config->get(vb->vdev,
offsetof(struct virtio_balloon_config, num_pages),
&v, sizeof(v));
target = le32_to_cpu(v);
- return target - vb->num_pages;
+ mutex_unlock(&balloon_lock);
+ return target - actual;
}
static void update_balloon_size(struct virtio_balloon *vb)
{
- __le32 actual = cpu_to_le32(vb->num_pages);
-
+ __le32 actual;
+ mutex_lock(&balloon_lock);
+ actual = cpu_to_le32(vb->num_pages);
vb->vdev->config->set(vb->vdev,
offsetof(struct virtio_balloon_config, actual),
&actual, sizeof(actual));
+ mutex_unlock(&balloon_lock);
}
static int balloon(void *_vballoon)
@@ -339,6 +375,82 @@ static int init_vqs(struct virtio_balloon *vb)
return 0;
}
+/*
+ * Populate balloon_mapping->a_ops->migratepage method to perform the
balloon
+ * page migration task.
+ *
+ * After a ballooned page gets isolated by compaction procedures, this is the
+ * function that performs the page migration on behalf of move_to_new_page(),
+ * when the last calls (page)->mapping->a_ops->migratepage.
+ *
+ * Page migration for virtio balloon is done in a simple swap fashion which
+ * follows these two steps:
+ * 1) insert newpage into vb->pages list and update the host about it;
+ * 2) update the host about the removed old page from vb->pages list;
+ */
+int virtballoon_migratepage(struct address_space *mapping,
+ struct page *newpage, struct page *page, enum migrate_mode mode)
+{
+ struct virtio_balloon *vb = (void *)mapping->backing_dev_info;
+
+ mutex_lock(&balloon_lock);
+
+ /* balloon's page migration 1st step */
+ vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
+ spin_lock(&vb->pages_lock);
+ list_add(&newpage->lru, &vb->pages);
+ spin_unlock(&vb->pages_lock);
+ set_page_pfns(vb->pfns, newpage);
+ tell_host(vb, vb->inflate_vq);
+
+ /* balloon's page migration 2nd step */
+ vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
+ set_page_pfns(vb->pfns, page);
+ tell_host(vb, vb->deflate_vq);
+
+ mutex_unlock(&balloon_lock);
+
+ return 0;
+}
+
+/*
+ * Populate balloon_mapping->a_ops->invalidatepage method to help
compaction on
+ * isolating a page from the balloon page list.
+ */
+void virtballoon_isolatepage(struct page *page, unsigned long mode)
+{
+ /*
+ * struct address_space.backing_dev_info specially holds the pointer
+ * to our struct virtio_balloon *vb
+ */
+ struct virtio_balloon *vb = (void *)page->mapping->backing_dev_info;
+ spin_lock(&vb->pages_lock);
+ list_del(&page->lru);
+ spin_unlock(&vb->pages_lock);
+}
+
+/*
+ * Populate balloon_mapping->a_ops->freepage method to help compaction on
+ * re-inserting an isolated page into the balloon page list.
+ */
+void virtballoon_putbackpage(struct page *page)
+{
+ /*
+ * struct address_space.backing_dev_info specially holds the pointer
+ * to our struct virtio_balloon *vb
+ */
+ struct virtio_balloon *vb = (void *)page->mapping->backing_dev_info;
+ spin_lock(&vb->pages_lock);
+ list_add(&page->lru, &vb->pages);
+ spin_unlock(&vb->pages_lock);
+}
+
+static const struct address_space_operations virtio_balloon_aops = {
+ .migratepage = virtballoon_migratepage,
+ .invalidatepage = virtballoon_isolatepage,
+ .freepage = virtballoon_putbackpage,
+};
+
static int virtballoon_probe(struct virtio_device *vdev)
{
struct virtio_balloon *vb;
@@ -351,12 +463,27 @@ static int virtballoon_probe(struct virtio_device *vdev)
}
INIT_LIST_HEAD(&vb->pages);
+ spin_lock_init(&vb->pages_lock);
+
vb->num_pages = 0;
init_waitqueue_head(&vb->config_change);
init_waitqueue_head(&vb->acked);
vb->vdev = vdev;
vb->need_stats_update = 0;
+ /* Init the ballooned page->mapping special balloon_mapping */
+ balloon_mapping = kmalloc(sizeof(*balloon_mapping), GFP_KERNEL);
+ if (!balloon_mapping) {
+ err = -ENOMEM;
+ goto out_free_vb;
+ }
+
+ INIT_RADIX_TREE(&balloon_mapping->page_tree, GFP_ATOMIC |
__GFP_NOWARN);
+ INIT_LIST_HEAD(&balloon_mapping->i_mmap_nonlinear);
+ spin_lock_init(&balloon_mapping->tree_lock);
+ balloon_mapping->a_ops = &virtio_balloon_aops;
+ balloon_mapping->backing_dev_info = (void *)vb;
+
err = init_vqs(vb);
if (err)
goto out_free_vb;
@@ -373,6 +500,7 @@ out_del_vqs:
vdev->config->del_vqs(vdev);
out_free_vb:
kfree(vb);
+ kfree(balloon_mapping);
out:
return err;
}
@@ -397,6 +525,7 @@ static void __devexit virtballoon_remove(struct
virtio_device *vdev)
kthread_stop(vb->thread);
remove_common(vb);
kfree(vb);
+ kfree(balloon_mapping);
}
#ifdef CONFIG_PM
diff --git a/include/linux/virtio_balloon.h b/include/linux/virtio_balloon.h
index 652dc8b..930f1b7 100644
--- a/include/linux/virtio_balloon.h
+++ b/include/linux/virtio_balloon.h
@@ -56,4 +56,8 @@ struct virtio_balloon_stat {
u64 val;
} __attribute__((packed));
+#if !defined(CONFIG_COMPACTION)
+struct address_space *balloon_mapping;
+#endif
+
#endif /* _LINUX_VIRTIO_BALLOON_H */
--
1.7.10.4
Rafael Aquini
2012-Jul-17 16:50 UTC
[PATCH v4 3/3] mm: add vm event counters for balloon pages compaction
This patch is only for testing report purposes and shall be dropped in case of
the rest of this patchset getting accepted for merging.
Signed-off-by: Rafael Aquini <aquini at redhat.com>
---
drivers/virtio/virtio_balloon.c | 1 +
include/linux/vm_event_item.h | 2 ++
mm/compaction.c | 1 +
mm/migrate.c | 6 ++++--
mm/vmstat.c | 4 ++++
5 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 7669bc8..c4ddcd7 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -410,6 +410,7 @@ int virtballoon_migratepage(struct address_space *mapping,
mutex_unlock(&balloon_lock);
+ count_vm_event(COMPACTBALLOONMIGRATED);
return 0;
}
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 06f8e38..e330c5a 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -40,6 +40,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
#ifdef CONFIG_COMPACTION
COMPACTBLOCKS, COMPACTPAGES, COMPACTPAGEFAILED,
COMPACTSTALL, COMPACTFAIL, COMPACTSUCCESS,
+ COMPACTBALLOONMIGRATED, COMPACTBALLOONFAILED,
+ COMPACTBALLOONISOLATED, COMPACTBALLOONFREED,
#endif
#ifdef CONFIG_HUGETLB_PAGE
HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,
diff --git a/mm/compaction.c b/mm/compaction.c
index 51eac0c..d212dde 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -72,6 +72,7 @@ static bool isolate_balloon_page(struct page *page)
if (is_balloon_page(page) && (page_count(page) == 2)) {
__isolate_balloon_page(page);
unlock_page(page);
+ count_vm_event(COMPACTBALLOONISOLATED);
return true;
}
unlock_page(page);
diff --git a/mm/migrate.c b/mm/migrate.c
index 59c7bc5..5838719 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -78,9 +78,10 @@ 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))) {
+ count_vm_event(COMPACTBALLOONFAILED);
WARN_ON(!putback_balloon_page(page));
- else
+ } else
putback_lru_page(page);
}
}
@@ -878,6 +879,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned
long private,
page_is_file_cache(page));
put_page(page);
__free_page(page);
+ count_vm_event(COMPACTBALLOONFREED);
return rc;
}
out:
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 1bbbbd9..3b7109f 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -767,6 +767,10 @@ const char * const vmstat_text[] = {
"compact_stall",
"compact_fail",
"compact_success",
+ "compact_balloon_migrated",
+ "compact_balloon_failed",
+ "compact_balloon_isolated",
+ "compact_balloon_freed",
#endif
#ifdef CONFIG_HUGETLB_PAGE
--
1.7.10.4
Reasonably Related Threads
- [PATCH v4 0/3] make balloon pages movable by compaction
- [PATCH v5 0/3] make balloon pages movable by compaction
- [PATCH v5 0/3] make balloon pages movable by compaction
- [PATCH v6 0/3] make balloon pages movable by compaction
- [PATCH v6 0/3] make balloon pages movable by compaction