From nobody Sat Feb 7 18:52:08 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 45276296BC8; Mon, 19 Jan 2026 23:04:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768863855; cv=none; b=DWDlAKuDsxbxL+CwhoVaJCTB/KE9sUvHK8SaumLA4Ra5tGitll9aas6cPTqfKtA1tCxym9eUF3KJt8+6TTuyuhyl6S3EVbQtvnkGWvsb1TPwUroPTNX9Fev0pakfVYRCPAxaMoGwi/6h7VjGCHEbGuK4gl4XRJAMBhsBOKlO9MI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768863855; c=relaxed/simple; bh=rfLKWCy9vJo0cdwgW26hFt2Hmw6jpwEGhVTR8rbPNG0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AJVuKDZnDelPHHBB2VjIlACbsO7euTO3HKUNwg/38oTKIjPI5MyBQFX4HkcT3QKIJ7yetncj61mKChOkdqt3mR4xV2Ba1mvyvgdvU5V+cqHHhZfhmsvdwDpldvIcUsvZuymQNxVK6v8b9br8FYyIqTFHQig3cnwJUsh/lKQrZ0c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oYhem+Ry; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oYhem+Ry" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D026BC116C6; Mon, 19 Jan 2026 23:04:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768863854; bh=rfLKWCy9vJo0cdwgW26hFt2Hmw6jpwEGhVTR8rbPNG0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oYhem+RyIfPYbRq/FfuQqbLgtWgy8BpIVjnZIFIo2pyBjNu0tkitvJixH2VAC5iwL 0udZb3Nwm9Nm9mnEfvtHLW9oTj17v3gePhwKqKsuwG2spWtGT7wrjMglu7Jk7xwwVL qgc0gO5oasN5SIWAvQ+fmSdW5X/8qWWN/6b89nNhT8qBhxDZLcl0dhrwWMDIQKhrbL 4k0sEibe6agRVrTRCbUTDZod92Sk3LXFSBCuK4MfajLCooB3qJFV8miYoiSDHNq1rg rRJf65xLWtvgrRdbaPTINUhuOO9OWGtADn303tSQQFRZaQP/O2FnwV9COpZS1oFNGo 4HRrRgQ99HmKA== From: "David Hildenbrand (Red Hat)" To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, Broadcom internal kernel review list , linux-doc@vger.kernel.org, virtualization@lists.linux.dev, "David Hildenbrand (Red Hat)" , Andrew Morton , Oscar Salvador , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Arnd Bergmann , Greg Kroah-Hartman , Jerrin Shaji George , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Zi Yan Subject: [PATCH v3 22/24] mm: rename CONFIG_BALLOON_COMPACTION to CONFIG_BALLOON_MIGRATION Date: Tue, 20 Jan 2026 00:01:30 +0100 Message-ID: <20260119230133.3551867-23-david@kernel.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260119230133.3551867-1-david@kernel.org> References: <20260119230133.3551867-1-david@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 Acked-by: Michael S. Tsirkin Signed-off-by: David Hildenbrand (Red Hat) --- 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/Documentatio= n/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 o= ffline memory blocks is not a typical case, though. =20 -- 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 incomp= atible + with ZONE_MOVABLE. Only some implementations, such as virtio-balloon and + pseries CMM, fully support balloon memory migration. =20 - 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 =3D { .priority =3D CMM_MEM_HOTPLUG_PRI }; =20 -#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 *newp= age, struct page *page, enum migrate_mode mode); -#endif /* CONFIG_BALLOON_COMPACTION */ +#endif /* CONFIG_BALLOON_MIGRATION */ =20 /** * cmm_init - Module initialization @@ -540,7 +540,7 @@ static int cmm_init(void) =20 balloon_devinfo_init(&b_dev_info); b_dev_info.adjust_managed_page_count =3D true; - if (IS_ENABLED(CONFIG_BALLOON_COMPACTION)) + if (IS_ENABLED(CONFIG_BALLOON_MIGRATION)) b_dev_info.migratepage =3D cmm_migratepage; =20 rc =3D 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 vmba= lloon *b) #endif /* CONFIG_DEBUG_FS */ =20 =20 -#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 */ =20 static int __init vmballoon_init(void) { @@ -1827,7 +1827,7 @@ static int __init vmballoon_init(void) return error; =20 balloon_devinfo_init(&balloon.b_dev_info); - if (IS_ENABLED(CONFIG_BALLOON_COMPACTION)) + if (IS_ENABLED(CONFIG_BALLOON_MIGRATION)) balloon.b_dev_info.migratepage =3D vmballoon_migratepage; =20 INIT_LIST_HEAD(&balloon.huge_pages); diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloo= n.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 *w= ork) } } =20 -#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_i= nfo *vb_dev_info, mutex_unlock(&vb->balloon_lock); return 0; } -#endif /* CONFIG_BALLOON_COMPACTION */ +#endif /* CONFIG_BALLOON_MIGRATION */ =20 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) =20 if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) vb->vb_dev_info.adjust_managed_page_count =3D true; -#ifdef CONFIG_BALLOON_COMPACTION +#ifdef CONFIG_BALLOON_MIGRATION vb->vb_dev_info.migratepage =3D 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 lockl= ess * procedure (from a page standpoint), it might bring some racy situations= while - * performing balloon page compaction. In order to sort out these racy sce= narios - * and safely perform balloon's page compaction and migration we must, alw= ays, - * ensure following these simple rules: + * performing balloon page migration. In order to sort out these racy scen= arios + * and safely perform balloon's page migration we must, always, ensure fol= lowing + * these simple rules: * * i. Inflation/deflation must set/clear page->private under the * balloon_pages_lock @@ -45,10 +45,10 @@ =20 /* * 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 drive= r 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 =20 # -# 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 =3D __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; =20 - if (IS_ENABLED(CONFIG_BALLOON_COMPACTION)) + if (IS_ENABLED(CONFIG_BALLOON_MIGRATION)) gfp_flags |=3D GFP_HIGHUSER_MOVABLE; else gfp_flags |=3D GFP_HIGHUSER; @@ -232,7 +232,7 @@ struct page *balloon_page_dequeue(struct balloon_dev_in= fo *b_dev_info) } EXPORT_SYMBOL_GPL(balloon_page_dequeue); =20 -#ifdef CONFIG_BALLOON_COMPACTION +#ifdef CONFIG_BALLOON_MIGRATION =20 static bool balloon_page_isolate(struct page *page, isolate_mode_t mode) =20 @@ -342,4 +342,4 @@ static int __init balloon_init(void) } core_initcall(balloon_init); =20 -#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 compact= ion - * 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[] =3D { #ifdef CONFIG_MEMORY_BALLOON [I(BALLOON_INFLATE)] =3D "balloon_inflate", [I(BALLOON_DEFLATE)] =3D "balloon_deflate", -#ifdef CONFIG_BALLOON_COMPACTION +#ifdef CONFIG_BALLOON_MIGRATION [I(BALLOON_MIGRATE)] =3D "balloon_migrate", -#endif +#endif /* CONFIG_BALLOON_MIGRATION */ #endif /* CONFIG_MEMORY_BALLOON */ #ifdef CONFIG_DEBUG_TLBFLUSH [I(NR_TLB_REMOTE_FLUSH)] =3D "nr_tlb_remote_flush", --=20 2.52.0