[PATCH v3 3/4] mm/balloon_compaction: add vmstat counters and kpageflags bit

From: Konstantin Khlebnikov
Date: Sat Sep 27 2014 - 15:16:23 EST


From: Konstantin Khlebnikov <k.khlebnikov@xxxxxxxxxxx>

Always mark pages with PageBalloon even if balloon compaction is
disabled and expose this mark in /proc/kpageflags as KPF_BALLOON.

Also this patch adds three counters into /proc/vmstat: "balloon_inflate",
"balloon_deflate" and "balloon_migrate". They accumulate balloon activity.
Current size of balloon is (balloon_inflate - balloon_deflate) pages.

All generic balloon code now gathered under option CONFIG_MEMORY_BALLOON.
It should be selected by ballooning driver which wants use this feature.
Currently virtio-balloon is the only user.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@xxxxxxxxxxx>
Cc: Rafael Aquini <aquini@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/virtio/Kconfig | 1 +
drivers/virtio/virtio_balloon.c | 1 +
fs/proc/page.c | 3 +++
include/linux/balloon_compaction.h | 2 ++
include/linux/vm_event_item.h | 7 +++++++
include/uapi/linux/kernel-page-flags.h | 1 +
mm/Kconfig | 7 ++++++-
mm/Makefile | 3 ++-
mm/balloon_compaction.c | 2 ++
mm/vmstat.c | 12 +++++++++++-
tools/vm/page-types.c | 1 +
11 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index c6683f2..00b2286 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -25,6 +25,7 @@ config VIRTIO_PCI
config VIRTIO_BALLOON
tristate "Virtio balloon driver"
depends on VIRTIO
+ select MEMORY_BALLOON
---help---
This driver supports increasing and decreasing the amount
of memory within a KVM guest.
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 2bad7f9..f893148 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -396,6 +396,7 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
spin_lock_irqsave(&vb_dev_info->pages_lock, flags);
balloon_page_insert(vb_dev_info, newpage);
vb_dev_info->isolated_pages--;
+ __count_vm_event(BALLOON_MIGRATE);
spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags);
vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
set_page_pfns(vb->pfns, newpage);
diff --git a/fs/proc/page.c b/fs/proc/page.c
index e647c55..1e3187d 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -133,6 +133,9 @@ u64 stable_page_flags(struct page *page)
if (PageBuddy(page))
u |= 1 << KPF_BUDDY;

+ if (PageBalloon(page))
+ u |= 1 << KPF_BALLOON;
+
u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);

u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
index bc3d298..9b0a15d 100644
--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_compaction.h
@@ -166,11 +166,13 @@ static inline gfp_t balloon_mapping_gfp_mask(void)
static inline void balloon_page_insert(struct balloon_dev_info *balloon,
struct page *page)
{
+ __SetPageBalloon(page);
list_add(&page->lru, &balloon->pages);
}

static inline void balloon_page_delete(struct page *page)
{
+ __ClearPageBalloon(page);
list_del(&page->lru);
}

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index ced9234..730334c 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -72,6 +72,13 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
THP_ZERO_PAGE_ALLOC,
THP_ZERO_PAGE_ALLOC_FAILED,
#endif
+#ifdef CONFIG_MEMORY_BALLOON
+ BALLOON_INFLATE,
+ BALLOON_DEFLATE,
+#ifdef CONFIG_BALLOON_COMPACTION
+ BALLOON_MIGRATE,
+#endif
+#endif
#ifdef CONFIG_DEBUG_TLBFLUSH
#ifdef CONFIG_SMP
NR_TLB_REMOTE_FLUSH, /* cpu tried to flush others' tlbs */
diff --git a/include/uapi/linux/kernel-page-flags.h b/include/uapi/linux/kernel-page-flags.h
index 5116a0e..2f96d23 100644
--- a/include/uapi/linux/kernel-page-flags.h
+++ b/include/uapi/linux/kernel-page-flags.h
@@ -31,6 +31,7 @@

#define KPF_KSM 21
#define KPF_THP 22
+#define KPF_BALLOON 23


#endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */
diff --git a/mm/Kconfig b/mm/Kconfig
index 886db21..83250e4 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -228,11 +228,16 @@ config ARCH_ENABLE_SPLIT_PMD_PTLOCK
boolean

#
+# support for memory balloon
+config MEMORY_BALLOON
+ boolean
+
+#
# support for memory balloon compaction
config BALLOON_COMPACTION
bool "Allow for balloon memory compaction/migration"
def_bool y
- depends on COMPACTION && VIRTIO_BALLOON
+ depends on COMPACTION && MEMORY_BALLOON
help
Memory fragmentation introduced by ballooning might reduce
significantly the number of 2MB contiguous memory blocks that can be
diff --git a/mm/Makefile b/mm/Makefile
index 7b77050..e88d9b9 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -16,7 +16,7 @@ obj-y := filemap.o mempool.o oom_kill.o \
readahead.o swap.o truncate.o vmscan.o shmem.o \
util.o mmzone.o vmstat.o backing-dev.o \
mm_init.o mmu_context.o percpu.o slab_common.o \
- compaction.o balloon_compaction.o vmacache.o \
+ compaction.o vmacache.o \
interval_tree.o list_lru.o workingset.o \
iov_iter.o debug.o $(mmu-y)

@@ -68,3 +68,4 @@ obj-$(CONFIG_ZBUD) += zbud.o
obj-$(CONFIG_ZSMALLOC) += zsmalloc.o
obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
obj-$(CONFIG_CMA) += cma.o
+obj-$(CONFIG_MEMORY_BALLOON) += balloon_compaction.o
diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 3afdabd..b3cbe19 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -36,6 +36,7 @@ struct page *balloon_page_enqueue(struct balloon_dev_info *b_dev_info)
BUG_ON(!trylock_page(page));
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
balloon_page_insert(b_dev_info, page);
+ __count_vm_event(BALLOON_INFLATE);
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
unlock_page(page);
return page;
@@ -74,6 +75,7 @@ struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info)
}
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
balloon_page_delete(page);
+ __count_vm_event(BALLOON_DEFLATE);
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
unlock_page(page);
dequeued_page = true;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index c53a50a..5da8834 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -751,7 +751,7 @@ static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
TEXT_FOR_HIGHMEM(xx) xx "_movable",

const char * const vmstat_text[] = {
- /* Zoned VM counters */
+ /* enum zone_stat_item countes */
"nr_free_pages",
"nr_alloc_batch",
"nr_inactive_anon",
@@ -794,10 +794,13 @@ const char * const vmstat_text[] = {
"workingset_nodereclaim",
"nr_anon_transparent_hugepages",
"nr_free_cma",
+
+ /* enum writeback_stat_item counters */
"nr_dirty_threshold",
"nr_dirty_background_threshold",

#ifdef CONFIG_VM_EVENT_COUNTERS
+ /* enum vm_event_item counters */
"pgpgin",
"pgpgout",
"pswpin",
@@ -876,6 +879,13 @@ const char * const vmstat_text[] = {
"thp_zero_page_alloc",
"thp_zero_page_alloc_failed",
#endif
+#ifdef CONFIG_MEMORY_BALLOON
+ "balloon_inflate",
+ "balloon_deflate",
+#ifdef CONFIG_BALLOON_COMPACTION
+ "balloon_migrate",
+#endif
+#endif /* CONFIG_MEMORY_BALLOON */
#ifdef CONFIG_DEBUG_TLBFLUSH
#ifdef CONFIG_SMP
"nr_tlb_remote_flush",
diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c
index c4d6d2e..264fbc2 100644
--- a/tools/vm/page-types.c
+++ b/tools/vm/page-types.c
@@ -132,6 +132,7 @@ static const char * const page_flag_names[] = {
[KPF_NOPAGE] = "n:nopage",
[KPF_KSM] = "x:ksm",
[KPF_THP] = "t:thp",
+ [KPF_BALLOON] = "o:balloon",

[KPF_RESERVED] = "r:reserved",
[KPF_MLOCKED] = "m:mlocked",

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