This patch adds page state PageBallon() and functions __Set/ClearPageBalloon.
Like PageBuddy() PageBalloon() looks like page-flag but actually this is special
state of page->_mapcount counter. There is no conflict because ballooned pages
cannot be mapped and cannot be in buddy allocator.
Ballooned pages are counted in vmstat counter NR_BALLOON_PAGES, it's shown them
in /proc/meminfo and /proc/meminfo. Also this patch it exports PageBallon into
userspace via /proc/kpageflags as KPF_BALLOON.
All this code including mm/balloon_compaction.o is under CONFIG_MEMORY_BALLOON,
it should be selected by ballooning driver which want use this feature.
Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@xxxxxxxxxxx>
---
Documentation/filesystems/proc.txt | 2 ++
drivers/base/node.c | 16 ++++++++++------
drivers/virtio/Kconfig | 1 +
fs/proc/meminfo.c | 6 ++++++
fs/proc/page.c | 3 +++
include/linux/mm.h | 10 ++++++++++
include/linux/mmzone.h | 3 +++
include/uapi/linux/kernel-page-flags.h | 1 +
mm/Kconfig | 5 +++++
mm/Makefile | 3 ++-
mm/balloon_compaction.c | 14 ++++++++++++++
mm/vmstat.c | 8 +++++++-
tools/vm/page-types.c | 1 +
13 files changed, 65 insertions(+), 8 deletions(-)
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index eb8a10e..154a345 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -796,6 +796,7 @@ VmallocTotal: 112216 kB
VmallocUsed: 428 kB
VmallocChunk: 111088 kB
AnonHugePages: 49152 kB
+BalloonPages: 0 kB
MemTotal: Total usable ram (i.e. physical ram minus a few reserved
bits and the kernel binary code)
@@ -838,6 +839,7 @@ MemAvailable: An estimate of how much memory is available for starting new
Writeback: Memory which is actively being written back to the disk
AnonPages: Non-file backed pages mapped into userspace page tables
AnonHugePages: Non-file backed huge pages mapped into userspace page tables
+BalloonPages: Memory which was ballooned, not included into MemTotal
Mapped: files which have been mmaped, such as libraries
Slab: in-kernel data structures cache
SReclaimable: Part of Slab, that might be reclaimed, such as caches
diff --git a/drivers/base/node.c b/drivers/base/node.c
index c6d3ae0..59e565c 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -120,6 +120,9 @@ static ssize_t node_read_meminfo(struct device *dev,
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
"Node %d AnonHugePages: %8lu kB\n"
#endif
+#ifdef CONFIG_MEMORY_BALLOON
+ "Node %d BalloonPages: %8lu kB\n"
+#endif
,
nid, K(node_page_state(nid, NR_FILE_DIRTY)),
nid, K(node_page_state(nid, NR_WRITEBACK)),
@@ -136,14 +139,15 @@ static ssize_t node_read_meminfo(struct device *dev,
nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) +
node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)),
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE))
- , nid,
- K(node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
- HPAGE_PMD_NR));
-#else
- nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)));
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ ,nid, K(node_page_state(nid,
+ NR_ANON_TRANSPARENT_HUGEPAGES) * HPAGE_PMD_NR)
+#endif
+#ifdef CONFIG_MEMORY_BALLOON
+ ,nid, K(node_page_state(nid, NR_BALLOON_PAGES))
#endif
+ );
n += hugetlb_report_node_meminfo(nid, buf + n);
return n;
}
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/fs/proc/meminfo.c b/fs/proc/meminfo.c
index aa1eee0..f897fbf 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -138,6 +138,9 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
"AnonHugePages: %8lu kB\n"
#endif
+#ifdef CONFIG_MEMORY_BALLOON
+ "BalloonPages: %8lu kB\n"
+#endif
,
K(i.totalram),
K(i.freeram),
@@ -193,6 +196,9 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
,K(global_page_state(NR_ANON_TRANSPARENT_HUGEPAGES) *
HPAGE_PMD_NR)
#endif
+#ifdef CONFIG_MEMORY_BALLOON
+ ,K(global_page_state(NR_BALLOON_PAGES))
+#endif
);
hugetlb_report_meminfo(m);
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/mm.h b/include/linux/mm.h
index 8981cc8..d2dd497 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -553,6 +553,16 @@ static inline void __ClearPageBuddy(struct page *page)
atomic_set(&page->_mapcount, -1);
}
+#define PAGE_BALLOON_MAPCOUNT_VALUE (-256)
+
+static inline int PageBalloon(struct page *page)
+{
+ return IS_ENABLED(CONFIG_MEMORY_BALLOON) &&
+ atomic_read(&page->_mapcount) == PAGE_BALLOON_MAPCOUNT_VALUE;
+}
+void __SetPageBalloon(struct page *page);
+void __ClearPageBalloon(struct page *page);
+
void put_page(struct page *page);
void put_pages_list(struct list_head *pages);
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 318df70..d88fd01 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -157,6 +157,9 @@ enum zone_stat_item {
WORKINGSET_NODERECLAIM,
NR_ANON_TRANSPARENT_HUGEPAGES,
NR_FREE_CMA_PAGES,
+#ifdef CONFIG_MEMORY_BALLOON
+ NR_BALLOON_PAGES,
+#endif
NR_VM_ZONE_STAT_ITEMS };
/*
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..72e0db0 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -228,6 +228,11 @@ config ARCH_ENABLE_SPLIT_PMD_PTLOCK
boolean
#
+# support for memory ballooning
+config MEMORY_BALLOON
+ boolean
+
+#
# support for memory balloon compaction
config BALLOON_COMPACTION
bool "Allow for balloon memory compaction/migration"
diff --git a/mm/Makefile b/mm/Makefile
index 632ae77..2d33d7f 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -16,7 +16,7 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.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 $(mmu-y)
@@ -64,3 +64,4 @@ obj-$(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 6e45a50..533c567 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -10,6 +10,20 @@
#include <linux/export.h>
#include <linux/balloon_compaction.h>
+void __SetPageBalloon(struct page *page)
+{
+ VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page);
+ atomic_set(&page->_mapcount, PAGE_BALLOON_MAPCOUNT_VALUE);
+ inc_zone_page_state(page, NR_BALLOON_PAGES);
+}
+
+void __ClearPageBalloon(struct page *page)
+{
+ VM_BUG_ON_PAGE(!PageBalloon(page), page);
+ atomic_set(&page->_mapcount, -1);
+ dec_zone_page_state(page, NR_BALLOON_PAGES);
+}
+
/*
* balloon_devinfo_alloc - allocates a balloon device information descriptor.
* @balloon_dev_descriptor: pointer to reference the balloon device which
diff --git a/mm/vmstat.c b/mm/vmstat.c
index e9ab104..6e704cc 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -735,7 +735,7 @@ 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",
@@ -778,10 +778,16 @@ const char * const vmstat_text[] = {
"workingset_nodereclaim",
"nr_anon_transparent_hugepages",
"nr_free_cma",
+#ifdef CONFIG_MEMORY_BALLOON
+ "nr_balloon_pages",
+#endif
+
+ /* 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",
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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