mm: rename CONFIG_BALLOON_COMPACTION to CONFIG_BALLOON_MIGRATION

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 */".

Link: https://lkml.kernel.org/r/20260119230133.3551867-23-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst
index 6581558fd0d7a28bb7a4c05d1f9801a51721d276..0207f87251421ccaef4b6ae4b9375539ed99ce7b 100644 (file)
--- 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 7a3c4922685ab4cc2682d94a9d40b76df8575276..8d83df12430f29c9ccb6b04aec4aa44179e9d0a2 100644 (file)
--- 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 7fd3f709108c211d6263c9406d30fa329fbc6db2..216a1639596849d3c0c214b9458aabdda3e5153b 100644 (file)
--- 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 @@ out_unlock:
        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 de8041c3285a1bb17e124bfec12d6c1f059057e0..4e549abe59ff1a45bf23d744f50e33b38bb29c31 100644 (file)
--- 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 82585542300d628974480d9b827fb475dd3cb601..ca5b15150f4255625ae2e6fd91be828868b9b729 100644 (file)
--- 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 92f80b4d69a6db191fb3e277b4d4702091babe6d..fca34d3473b6b1f4a2c69873148fdcce00769e91 100644 (file)
--- 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 c5374f3cf1c81dacab00c083fca04d6bf9255ccb..cd6896c1ba7de25472e2b62cedcf9ca43a58eafe 100644 (file)
--- 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 0f068b97e5d84a49ae4621cce9986589760b9dc2..96a8f1e20bc66ae46a571a4f51243789bb362925 100644 (file)
--- a/mm/balloon.c
+++ b/mm/balloon.c
@@ -29,7 +29,7 @@ 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);
        }
@@ -46,7 +46,7 @@ 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. */
 }
@@ -148,7 +148,7 @@ 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;
@@ -227,7 +227,7 @@ 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 struct balloon_dev_info *balloon_page_device(struct page *page)
 {
        return (struct balloon_dev_info *)page_private(page);
@@ -341,4 +341,4 @@ 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 389989a28abe06481e90cf324e348de9d4ab3c75..bc805029da517585bf89ea7adee769eeaf49b411 100644 (file)
--- 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 4750a2ba15fef7e204862bf2125dea79e7fd317b..1bf2cf8c44dd441be0084198067dd41ca9b3ca1e 100644 (file)
--- 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 6ae8891c9693eb8de6debe3a5c486ebfc28dd58a..e96a344ab59740740dcfe863fdcf7b9183a96a49 100644 (file)
--- 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",