[PATCH v3 22/24] mm: rename CONFIG_BALLOON_COMPACTION to CONFIG_BALLOON_MIGRATION
David Hildenbrand (Red Hat)
david at kernel.org
Tue Jan 20 10:01:30 AEDT 2026
While compaction depends on migration, the other direction is not the
case. So let's make it clearer that this is all about migration of
balloon pages.
Adjust all comments/docs in the core to talk about "migration" instead
of "compaction".
While at it add some "/* CONFIG_BALLOON_MIGRATION */".
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes at oracle.com>
Acked-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: David Hildenbrand (Red Hat) <david at kernel.org>
---
Documentation/admin-guide/mm/memory-hotplug.rst | 8 ++++----
arch/powerpc/platforms/pseries/cmm.c | 8 ++++----
drivers/misc/vmw_balloon.c | 8 ++++----
drivers/virtio/virtio_balloon.c | 6 +++---
include/linux/balloon.h | 12 ++++++------
include/linux/vm_event_item.h | 4 ++--
mm/Kconfig | 4 ++--
mm/balloon.c | 10 +++++-----
mm/memory_hotplug.c | 4 ++--
mm/migrate.c | 2 +-
mm/vmstat.c | 4 ++--
11 files changed, 35 insertions(+), 35 deletions(-)
diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst
index 6581558fd0d7a..0207f87251421 100644
--- a/Documentation/admin-guide/mm/memory-hotplug.rst
+++ b/Documentation/admin-guide/mm/memory-hotplug.rst
@@ -603,11 +603,11 @@ ZONE_MOVABLE, especially when fine-tuning zone ratios:
memory for metadata and page tables in the direct map; having a lot of offline
memory blocks is not a typical case, though.
-- Memory ballooning without balloon compaction is incompatible with
- ZONE_MOVABLE. Only some implementations, such as virtio-balloon and
- pseries CMM, fully support balloon compaction.
+- Memory ballooning without support for balloon memory migration is incompatible
+ with ZONE_MOVABLE. Only some implementations, such as virtio-balloon and
+ pseries CMM, fully support balloon memory migration.
- Further, the CONFIG_BALLOON_COMPACTION kernel configuration option might be
+ Further, the CONFIG_BALLOON_MIGRATION kernel configuration option might be
disabled. In that case, balloon inflation will only perform unmovable
allocations and silently create a zone imbalance, usually triggered by
inflation requests from the hypervisor.
diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
index 7a3c4922685ab..8d83df12430f2 100644
--- a/arch/powerpc/platforms/pseries/cmm.c
+++ b/arch/powerpc/platforms/pseries/cmm.c
@@ -494,7 +494,7 @@ static struct notifier_block cmm_mem_nb = {
.priority = CMM_MEM_HOTPLUG_PRI
};
-#ifdef CONFIG_BALLOON_COMPACTION
+#ifdef CONFIG_BALLOON_MIGRATION
static int cmm_migratepage(struct balloon_dev_info *b_dev_info,
struct page *newpage, struct page *page,
enum migrate_mode mode)
@@ -520,10 +520,10 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info,
plpar_page_set_active(page);
return 0;
}
-#else /* CONFIG_BALLOON_COMPACTION */
+#else /* CONFIG_BALLOON_MIGRATION */
int cmm_migratepage(struct balloon_dev_info *b_dev_info, struct page *newpage,
struct page *page, enum migrate_mode mode);
-#endif /* CONFIG_BALLOON_COMPACTION */
+#endif /* CONFIG_BALLOON_MIGRATION */
/**
* cmm_init - Module initialization
@@ -540,7 +540,7 @@ static int cmm_init(void)
balloon_devinfo_init(&b_dev_info);
b_dev_info.adjust_managed_page_count = true;
- if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
+ if (IS_ENABLED(CONFIG_BALLOON_MIGRATION))
b_dev_info.migratepage = cmm_migratepage;
rc = register_oom_notifier(&cmm_oom_nb);
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 7fd3f709108c2..216a163959684 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1719,7 +1719,7 @@ static inline void vmballoon_debugfs_exit(struct vmballoon *b)
#endif /* CONFIG_DEBUG_FS */
-#ifdef CONFIG_BALLOON_COMPACTION
+#ifdef CONFIG_BALLOON_MIGRATION
/**
* vmballoon_migratepage() - migrates a balloon page.
* @b_dev_info: balloon device information descriptor.
@@ -1803,11 +1803,11 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
up_read(&b->conf_sem);
return ret;
}
-#else /* CONFIG_BALLOON_COMPACTION */
+#else /* CONFIG_BALLOON_MIGRATION */
int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
struct page *newpage, struct page *page,
enum migrate_mode mode);
-#endif /* CONFIG_BALLOON_COMPACTION */
+#endif /* CONFIG_BALLOON_MIGRATION */
static int __init vmballoon_init(void)
{
@@ -1827,7 +1827,7 @@ static int __init vmballoon_init(void)
return error;
balloon_devinfo_init(&balloon.b_dev_info);
- if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
+ if (IS_ENABLED(CONFIG_BALLOON_MIGRATION))
balloon.b_dev_info.migratepage = vmballoon_migratepage;
INIT_LIST_HEAD(&balloon.huge_pages);
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index de8041c3285a1..4e549abe59ff1 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -802,7 +802,7 @@ static void report_free_page_func(struct work_struct *work)
}
}
-#ifdef CONFIG_BALLOON_COMPACTION
+#ifdef CONFIG_BALLOON_MIGRATION
/*
* virtballoon_migratepage - perform the balloon page migration on behalf of
* a compaction thread. (called under page lock)
@@ -851,7 +851,7 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
mutex_unlock(&vb->balloon_lock);
return 0;
}
-#endif /* CONFIG_BALLOON_COMPACTION */
+#endif /* CONFIG_BALLOON_MIGRATION */
static unsigned long shrink_free_pages(struct virtio_balloon *vb,
unsigned long pages_to_free)
@@ -948,7 +948,7 @@ static int virtballoon_probe(struct virtio_device *vdev)
if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
vb->vb_dev_info.adjust_managed_page_count = true;
-#ifdef CONFIG_BALLOON_COMPACTION
+#ifdef CONFIG_BALLOON_MIGRATION
vb->vb_dev_info.migratepage = virtballoon_migratepage;
#endif
if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
diff --git a/include/linux/balloon.h b/include/linux/balloon.h
index 82585542300d6..ca5b15150f425 100644
--- a/include/linux/balloon.h
+++ b/include/linux/balloon.h
@@ -22,9 +22,9 @@
*
* As the page isolation scanning step a compaction thread does is a lockless
* procedure (from a page standpoint), it might bring some racy situations while
- * performing balloon page compaction. In order to sort out these racy scenarios
- * and safely perform balloon's page compaction and migration we must, always,
- * ensure following these simple rules:
+ * performing balloon page migration. In order to sort out these racy scenarios
+ * and safely perform balloon's page migration we must, always, ensure following
+ * these simple rules:
*
* i. Inflation/deflation must set/clear page->private under the
* balloon_pages_lock
@@ -45,10 +45,10 @@
/*
* Balloon device information descriptor.
- * This struct is used to allow the common balloon compaction interface
+ * This struct is used to allow the common balloon page migration interface
* procedures to find the proper balloon device holding memory pages they'll
- * have to cope for page compaction / migration, as well as it serves the
- * balloon driver as a page book-keeper for its registered balloon devices.
+ * have to cope for page migration, as well as it serves the balloon driver as
+ * a page book-keeper for its registered balloon devices.
*/
struct balloon_dev_info {
unsigned long isolated_pages; /* # of isolated pages for migration */
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 92f80b4d69a6d..fca34d3473b6b 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -125,9 +125,9 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
#ifdef CONFIG_MEMORY_BALLOON
BALLOON_INFLATE,
BALLOON_DEFLATE,
-#ifdef CONFIG_BALLOON_COMPACTION
+#ifdef CONFIG_BALLOON_MIGRATION
BALLOON_MIGRATE,
-#endif
+#endif /* CONFIG_BALLOON_MIGRATION */
#endif
#ifdef CONFIG_DEBUG_TLBFLUSH
NR_TLB_REMOTE_FLUSH, /* cpu tried to flush others' tlbs */
diff --git a/mm/Kconfig b/mm/Kconfig
index 0d13c1b36e1c1..460a148d5b71a 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -597,8 +597,8 @@ config MEMORY_BALLOON
bool
#
-# support for memory balloon compaction
-config BALLOON_COMPACTION
+# support for memory balloon page migration
+config BALLOON_MIGRATION
bool "Allow for balloon memory migration"
default y
depends on MIGRATION && MEMORY_BALLOON
diff --git a/mm/balloon.c b/mm/balloon.c
index 25e2a1e71eba9..834f86c3c116d 100644
--- a/mm/balloon.c
+++ b/mm/balloon.c
@@ -34,7 +34,7 @@ static void balloon_page_insert(struct balloon_dev_info *balloon,
{
lockdep_assert_held(&balloon_pages_lock);
__SetPageOffline(page);
- if (IS_ENABLED(CONFIG_BALLOON_COMPACTION)) {
+ if (IS_ENABLED(CONFIG_BALLOON_MIGRATION)) {
SetPageMovableOps(page);
set_page_private(page, (unsigned long)balloon);
}
@@ -51,7 +51,7 @@ static void balloon_page_insert(struct balloon_dev_info *balloon,
static void balloon_page_finalize(struct page *page)
{
lockdep_assert_held(&balloon_pages_lock);
- if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
+ if (IS_ENABLED(CONFIG_BALLOON_MIGRATION))
set_page_private(page, 0);
/* PageOffline is sticky until the page is freed to the buddy. */
}
@@ -153,7 +153,7 @@ struct page *balloon_page_alloc(void)
{
gfp_t gfp_flags = __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
- if (IS_ENABLED(CONFIG_BALLOON_COMPACTION))
+ if (IS_ENABLED(CONFIG_BALLOON_MIGRATION))
gfp_flags |= GFP_HIGHUSER_MOVABLE;
else
gfp_flags |= GFP_HIGHUSER;
@@ -232,7 +232,7 @@ struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info)
}
EXPORT_SYMBOL_GPL(balloon_page_dequeue);
-#ifdef CONFIG_BALLOON_COMPACTION
+#ifdef CONFIG_BALLOON_MIGRATION
static bool balloon_page_isolate(struct page *page, isolate_mode_t mode)
@@ -342,4 +342,4 @@ static int __init balloon_init(void)
}
core_initcall(balloon_init);
-#endif /* CONFIG_BALLOON_COMPACTION */
+#endif /* CONFIG_BALLOON_MIGRATION */
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 389989a28abe0..bc805029da517 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -946,8 +946,8 @@ static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn
* We rely on "present pages" instead of "managed pages", as the latter is
* highly unreliable and dynamic in virtualized environments, and does not
* consider boot time allocations. For example, memory ballooning adjusts the
- * managed pages when inflating/deflating the balloon, and balloon compaction
- * can even migrate inflated pages between zones.
+ * managed pages when inflating/deflating the balloon, and balloon page
+ * migration can even migrate inflated pages between zones.
*
* Using "present pages" is better but some things to keep in mind are:
*
diff --git a/mm/migrate.c b/mm/migrate.c
index 4750a2ba15fef..1bf2cf8c44dd4 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -88,7 +88,7 @@ static const struct movable_operations *page_movable_ops(struct page *page)
* back to the buddy.
*/
if (PageOffline(page))
- /* Only balloon compaction sets PageOffline pages movable. */
+ /* Only balloon page migration sets PageOffline pages movable. */
return offline_movable_ops;
if (PageZsmalloc(page))
return zsmalloc_movable_ops;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 6ae8891c9693e..e96a344ab5974 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1422,9 +1422,9 @@ const char * const vmstat_text[] = {
#ifdef CONFIG_MEMORY_BALLOON
[I(BALLOON_INFLATE)] = "balloon_inflate",
[I(BALLOON_DEFLATE)] = "balloon_deflate",
-#ifdef CONFIG_BALLOON_COMPACTION
+#ifdef CONFIG_BALLOON_MIGRATION
[I(BALLOON_MIGRATE)] = "balloon_migrate",
-#endif
+#endif /* CONFIG_BALLOON_MIGRATION */
#endif /* CONFIG_MEMORY_BALLOON */
#ifdef CONFIG_DEBUG_TLBFLUSH
[I(NR_TLB_REMOTE_FLUSH)] = "nr_tlb_remote_flush",
--
2.52.0
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