* FAILED: patch "[PATCH] vmw_balloon: indicate success when effectively deflating" failed to apply to 6.17-stable tree
@ 2025-10-26 14:28 gregkh
2025-10-26 23:50 ` [PATCH 6.17.y 1/3] mm/migrate: remove MIGRATEPAGE_UNMAP Sasha Levin
0 siblings, 1 reply; 4+ messages in thread
From: gregkh @ 2025-10-26 14:28 UTC (permalink / raw)
To: david, akpm, arnd, bcm-kernel-feedback-list, gregkh,
jerrin.shaji-george, stable
Cc: stable
The patch below does not apply to the 6.17-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.17.y
git checkout FETCH_HEAD
git cherry-pick -x 4ba5a8a7faa647ada8eae61a36517cf369f5bbe4
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025102655-unequal-disown-9615@gregkh' --subject-prefix 'PATCH 6.17.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4ba5a8a7faa647ada8eae61a36517cf369f5bbe4 Mon Sep 17 00:00:00 2001
From: David Hildenbrand <david@redhat.com>
Date: Tue, 14 Oct 2025 14:44:55 +0200
Subject: [PATCH] vmw_balloon: indicate success when effectively deflating
during migration
When migrating a balloon page, we first deflate the old page to then
inflate the new page.
However, if inflating the new page succeeded, we effectively deflated the
old page, reducing the balloon size.
In that case, the migration actually worked: similar to migrating+
immediately deflating the new page. The old page will be freed back to
the buddy.
Right now, the core will leave the page be marked as isolated (as we
returned an error). When later trying to putback that page, we will run
into the WARN_ON_ONCE() in balloon_page_putback().
That handling was changed in commit 3544c4faccb8 ("mm/balloon_compaction:
stop using __ClearPageMovable()"); before that change, we would have
tolerated that way of handling it.
To fix it, let's just return 0 in that case, making the core effectively
just clear the "isolated" flag + freeing it back to the buddy as if the
migration succeeded. Note that the new page will also get freed when the
core puts the last reference.
Note that this also makes it all be more consistent: we will no longer
unisolate the page in the balloon driver while keeping it marked as being
isolated in migration core.
This was found by code inspection.
Link: https://lkml.kernel.org/r/20251014124455.478345-1-david@redhat.com
Fixes: 3544c4faccb8 ("mm/balloon_compaction: stop using __ClearPageMovable()")
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Broadcom internal kernel review list <bcm-kernel-feedback-list@broadcom.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 6df51ee8db62..cc1d18b3df5c 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1737,7 +1737,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
{
unsigned long status, flags;
struct vmballoon *b;
- int ret;
+ int ret = 0;
b = container_of(b_dev_info, struct vmballoon, b_dev_info);
@@ -1796,17 +1796,15 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
* A failure happened. While we can deflate the page we just
* inflated, this deflation can also encounter an error. Instead
* we will decrease the size of the balloon to reflect the
- * change and report failure.
+ * change.
*/
atomic64_dec(&b->size);
- ret = -EBUSY;
} else {
/*
* Success. Take a reference for the page, and we will add it to
* the list after acquiring the lock.
*/
get_page(newpage);
- ret = 0;
}
/* Update the balloon list under the @pages_lock */
@@ -1817,7 +1815,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
* If we succeed just insert it to the list and update the statistics
* under the lock.
*/
- if (!ret) {
+ if (status == VMW_BALLOON_SUCCESS) {
balloon_page_insert(&b->b_dev_info, newpage);
__count_vm_event(BALLOON_MIGRATE);
}
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 6.17.y 1/3] mm/migrate: remove MIGRATEPAGE_UNMAP
2025-10-26 14:28 FAILED: patch "[PATCH] vmw_balloon: indicate success when effectively deflating" failed to apply to 6.17-stable tree gregkh
@ 2025-10-26 23:50 ` Sasha Levin
2025-10-26 23:50 ` [PATCH 6.17.y 2/3] treewide: remove MIGRATEPAGE_SUCCESS Sasha Levin
2025-10-26 23:50 ` [PATCH 6.17.y 3/3] vmw_balloon: indicate success when effectively deflating during migration Sasha Levin
0 siblings, 2 replies; 4+ messages in thread
From: Sasha Levin @ 2025-10-26 23:50 UTC (permalink / raw)
To: stable
Cc: David Hildenbrand, Zi Yan, Lance Yang, Alistair Popple, Al Viro,
Arnd Bergmann, Benjamin LaHaise, Byungchul Park, Chris Mason,
Christian Brauner, Christophe Leroy, Dave Kleikamp, David Sterba,
Eugenio Pé rez, Greg Kroah-Hartman, Gregory Price,
Huang, Ying, Jan Kara, Jason Wang, Jerrin Shaji George,
Josef Bacik, Joshua Hahn, Madhavan Srinivasan, Mathew Brost,
Michael Ellerman, Michael S. Tsirkin, Minchan Kim, Muchun Song,
Nicholas Piggin, Oscar Salvador, Rakie Kim, Sergey Senozhatsky,
Xuan Zhuo, Dave Kleikamp, Andrew Morton, Sasha Levin
From: David Hildenbrand <david@redhat.com>
[ Upstream commit 95c2908f1a4fd608b1cdbb5acef3572e5d769e1c ]
migrate_folio_unmap() is the only user of MIGRATEPAGE_UNMAP. We want to
remove MIGRATEPAGE_* completely.
It's rather weird to have a generic MIGRATEPAGE_UNMAP, documented to be
returned from address-space callbacks, when it's only used for an internal
helper.
Let's start by having only a single "success" return value for
migrate_folio_unmap() -- 0 -- by moving the "folio was already freed"
check into the single caller.
There is a remaining comment for PG_isolated, which we renamed to
PG_movable_ops_isolated recently and forgot to update.
While we might still run into that case with zsmalloc, it's something we
want to get rid of soon. So let's just focus that optimization on real
folios only for now by excluding movable_ops pages. Note that concurrent
freeing can happen at any time and this "already freed" check is not
relevant for correctness.
[david@redhat.com: no need to pass "reason" to migrate_folio_unmap(), per Lance]
Link: https://lkml.kernel.org/r/3bb725f8-28d7-4aa2-b75f-af40d5cab280@redhat.com
Link: https://lkml.kernel.org/r/20250811143949.1117439-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Eugenio Pé rez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 4ba5a8a7faa6 ("vmw_balloon: indicate success when effectively deflating during migration")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/migrate.h | 1 -
mm/migrate.c | 45 ++++++++++++++++++++---------------------
2 files changed, 22 insertions(+), 24 deletions(-)
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 9009e27b5f44c..302f3e95faeaa 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -18,7 +18,6 @@ struct migration_target_control;
* - zero on page migration success;
*/
#define MIGRATEPAGE_SUCCESS 0
-#define MIGRATEPAGE_UNMAP 1
/**
* struct movable_operations - Driver page migration
diff --git a/mm/migrate.c b/mm/migrate.c
index 4ff6eea0ef7ed..e38c933d0c376 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1188,7 +1188,7 @@ static void migrate_folio_done(struct folio *src,
static int migrate_folio_unmap(new_folio_t get_new_folio,
free_folio_t put_new_folio, unsigned long private,
struct folio *src, struct folio **dstp, enum migrate_mode mode,
- enum migrate_reason reason, struct list_head *ret)
+ struct list_head *ret)
{
struct folio *dst;
int rc = -EAGAIN;
@@ -1197,16 +1197,6 @@ static int migrate_folio_unmap(new_folio_t get_new_folio,
bool locked = false;
bool dst_locked = false;
- if (folio_ref_count(src) == 1) {
- /* Folio was freed from under us. So we are done. */
- folio_clear_active(src);
- folio_clear_unevictable(src);
- /* free_pages_prepare() will clear PG_isolated. */
- list_del(&src->lru);
- migrate_folio_done(src, reason);
- return MIGRATEPAGE_SUCCESS;
- }
-
dst = get_new_folio(src, private);
if (!dst)
return -ENOMEM;
@@ -1296,7 +1286,7 @@ static int migrate_folio_unmap(new_folio_t get_new_folio,
if (unlikely(page_has_movable_ops(&src->page))) {
__migrate_folio_record(dst, old_page_state, anon_vma);
- return MIGRATEPAGE_UNMAP;
+ return 0;
}
/*
@@ -1326,7 +1316,7 @@ static int migrate_folio_unmap(new_folio_t get_new_folio,
if (!folio_mapped(src)) {
__migrate_folio_record(dst, old_page_state, anon_vma);
- return MIGRATEPAGE_UNMAP;
+ return 0;
}
out:
@@ -1869,14 +1859,27 @@ static int migrate_pages_batch(struct list_head *from,
continue;
}
+ /*
+ * If we are holding the last folio reference, the folio
+ * was freed from under us, so just drop our reference.
+ */
+ if (likely(!page_has_movable_ops(&folio->page)) &&
+ folio_ref_count(folio) == 1) {
+ folio_clear_active(folio);
+ folio_clear_unevictable(folio);
+ list_del(&folio->lru);
+ migrate_folio_done(folio, reason);
+ stats->nr_succeeded += nr_pages;
+ stats->nr_thp_succeeded += is_thp;
+ continue;
+ }
+
rc = migrate_folio_unmap(get_new_folio, put_new_folio,
- private, folio, &dst, mode, reason,
- ret_folios);
+ private, folio, &dst, mode, ret_folios);
/*
* The rules are:
- * Success: folio will be freed
- * Unmap: folio will be put on unmap_folios list,
- * dst folio put on dst_folios list
+ * 0: folio will be put on unmap_folios list,
+ * dst folio put on dst_folios list
* -EAGAIN: stay on the from list
* -ENOMEM: stay on the from list
* Other errno: put on ret_folios list
@@ -1926,11 +1929,7 @@ static int migrate_pages_batch(struct list_head *from,
thp_retry += is_thp;
nr_retry_pages += nr_pages;
break;
- case MIGRATEPAGE_SUCCESS:
- stats->nr_succeeded += nr_pages;
- stats->nr_thp_succeeded += is_thp;
- break;
- case MIGRATEPAGE_UNMAP:
+ case 0:
list_move_tail(&folio->lru, &unmap_folios);
list_add_tail(&dst->lru, &dst_folios);
break;
--
2.51.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 6.17.y 2/3] treewide: remove MIGRATEPAGE_SUCCESS
2025-10-26 23:50 ` [PATCH 6.17.y 1/3] mm/migrate: remove MIGRATEPAGE_UNMAP Sasha Levin
@ 2025-10-26 23:50 ` Sasha Levin
2025-10-26 23:50 ` [PATCH 6.17.y 3/3] vmw_balloon: indicate success when effectively deflating during migration Sasha Levin
1 sibling, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2025-10-26 23:50 UTC (permalink / raw)
To: stable
Cc: David Hildenbrand, Zi Yan, Dave Kleikamp, David Sterba,
Greg Kroah-Hartman, Byungchul Park, Alistair Popple, Al Viro,
Arnd Bergmann, Benjamin LaHaise, Chris Mason, Christian Brauner,
Christophe Leroy, Dave Kleikamp, Eugenio Pé rez,
Gregory Price, Huang, Ying, Jan Kara, Jason Wang,
Jerrin Shaji George, Josef Bacik, Joshua Hahn,
Madhavan Srinivasan, Mathew Brost, Michael Ellerman,
Michael S. Tsirkin, Minchan Kim, Muchun Song, Nicholas Piggin,
Oscar Salvador, Rakie Kim, Sergey Senozhatsky, Xuan Zhuo,
Lance Yang, Andrew Morton, Sasha Levin
From: David Hildenbrand <david@redhat.com>
[ Upstream commit fb49a4425cfa163faccd91f913773d3401d3a7d4 ]
At this point MIGRATEPAGE_SUCCESS is misnamed for all folio users,
and now that we remove MIGRATEPAGE_UNMAP, it's really the only "success"
return value that the code uses and expects.
Let's just get rid of MIGRATEPAGE_SUCCESS completely and just use "0"
for success.
Link: https://lkml.kernel.org/r/20250811143949.1117439-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com> [mm]
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com> [jfs]
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Byungchul Park <byungchul@sk.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Eugenio Pé rez <eperezma@redhat.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Lance Yang <lance.yang@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 4ba5a8a7faa6 ("vmw_balloon: indicate success when effectively deflating during migration")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/pseries/cmm.c | 2 +-
drivers/misc/vmw_balloon.c | 4 +--
drivers/virtio/virtio_balloon.c | 2 +-
fs/aio.c | 2 +-
fs/btrfs/inode.c | 4 +--
fs/hugetlbfs/inode.c | 4 +--
fs/jfs/jfs_metapage.c | 8 +++---
include/linux/migrate.h | 10 +------
mm/migrate.c | 40 +++++++++++++---------------
mm/migrate_device.c | 2 +-
mm/zsmalloc.c | 4 +--
11 files changed, 36 insertions(+), 46 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
index 5e0a718d1be7b..0823fa2da1516 100644
--- a/arch/powerpc/platforms/pseries/cmm.c
+++ b/arch/powerpc/platforms/pseries/cmm.c
@@ -545,7 +545,7 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info,
/* balloon page list reference */
put_page(page);
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
static void cmm_balloon_compaction_init(void)
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 6653fc53c951c..6df51ee8db621 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1806,7 +1806,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
* the list after acquiring the lock.
*/
get_page(newpage);
- ret = MIGRATEPAGE_SUCCESS;
+ ret = 0;
}
/* Update the balloon list under the @pages_lock */
@@ -1817,7 +1817,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
* If we succeed just insert it to the list and update the statistics
* under the lock.
*/
- if (ret == MIGRATEPAGE_SUCCESS) {
+ if (!ret) {
balloon_page_insert(&b->b_dev_info, newpage);
__count_vm_event(BALLOON_MIGRATE);
}
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index e299e18346a30..eae65136cdfb5 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -875,7 +875,7 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
balloon_page_finalize(page);
put_page(page); /* balloon reference */
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
#endif /* CONFIG_BALLOON_COMPACTION */
diff --git a/fs/aio.c b/fs/aio.c
index 7fc7b6221312c..059e03cfa088c 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -445,7 +445,7 @@ static int aio_migrate_folio(struct address_space *mapping, struct folio *dst,
folio_get(dst);
rc = folio_migrate_mapping(mapping, dst, src, 1);
- if (rc != MIGRATEPAGE_SUCCESS) {
+ if (rc) {
folio_put(dst);
goto out_unlock;
}
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index cd8a09e3d1dc0..4031cbdea0740 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7430,7 +7430,7 @@ static int btrfs_migrate_folio(struct address_space *mapping,
{
int ret = filemap_migrate_folio(mapping, dst, src, mode);
- if (ret != MIGRATEPAGE_SUCCESS)
+ if (ret)
return ret;
if (folio_test_ordered(src)) {
@@ -7438,7 +7438,7 @@ static int btrfs_migrate_folio(struct address_space *mapping,
folio_set_ordered(dst);
}
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
#else
#define btrfs_migrate_folio NULL
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index be4be99304bc0..5517d40266ddf 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -1054,7 +1054,7 @@ static int hugetlbfs_migrate_folio(struct address_space *mapping,
int rc;
rc = migrate_huge_page_move_mapping(mapping, dst, src);
- if (rc != MIGRATEPAGE_SUCCESS)
+ if (rc)
return rc;
if (hugetlb_folio_subpool(src)) {
@@ -1065,7 +1065,7 @@ static int hugetlbfs_migrate_folio(struct address_space *mapping,
folio_migrate_flags(dst, src);
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
#else
#define hugetlbfs_migrate_folio NULL
diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index b98cf3bb6c1fe..871cf4fb36366 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -169,7 +169,7 @@ static int __metapage_migrate_folio(struct address_space *mapping,
}
rc = filemap_migrate_folio(mapping, dst, src, mode);
- if (rc != MIGRATEPAGE_SUCCESS)
+ if (rc)
return rc;
for (i = 0; i < MPS_PER_PAGE; i++) {
@@ -199,7 +199,7 @@ static int __metapage_migrate_folio(struct address_space *mapping,
}
}
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
#endif /* CONFIG_MIGRATION */
@@ -242,7 +242,7 @@ static int __metapage_migrate_folio(struct address_space *mapping,
return -EAGAIN;
rc = filemap_migrate_folio(mapping, dst, src, mode);
- if (rc != MIGRATEPAGE_SUCCESS)
+ if (rc)
return rc;
if (unlikely(insert_metapage(dst, mp)))
@@ -253,7 +253,7 @@ static int __metapage_migrate_folio(struct address_space *mapping,
mp->folio = dst;
remove_metapage(src, mp);
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
#endif /* CONFIG_MIGRATION */
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 302f3e95faeaa..1f0ac122c3bfc 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -12,13 +12,6 @@ typedef void free_folio_t(struct folio *folio, unsigned long private);
struct migration_target_control;
-/*
- * Return values from addresss_space_operations.migratepage():
- * - negative errno on page migration failure;
- * - zero on page migration success;
- */
-#define MIGRATEPAGE_SUCCESS 0
-
/**
* struct movable_operations - Driver page migration
* @isolate_page:
@@ -34,8 +27,7 @@ struct migration_target_control;
* @src page. The driver should copy the contents of the
* @src page to the @dst page and set up the fields of @dst page.
* Both pages are locked.
- * If page migration is successful, the driver should
- * return MIGRATEPAGE_SUCCESS.
+ * If page migration is successful, the driver should return 0.
* If the driver cannot migrate the page at the moment, it can return
* -EAGAIN. The VM interprets this as a temporary migration failure and
* will retry it later. Any other error value is a permanent migration
diff --git a/mm/migrate.c b/mm/migrate.c
index e38c933d0c376..bf6b1753a1976 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -231,18 +231,17 @@ static void putback_movable_ops_page(struct page *page)
* src and dst are also released by migration core. These pages will not be
* folios in the future, so that must be reworked.
*
- * Returns MIGRATEPAGE_SUCCESS on success, otherwise a negative error
- * code.
+ * Returns 0 on success, otherwise a negative error code.
*/
static int migrate_movable_ops_page(struct page *dst, struct page *src,
enum migrate_mode mode)
{
- int rc = MIGRATEPAGE_SUCCESS;
+ int rc;
VM_WARN_ON_ONCE_PAGE(!page_has_movable_ops(src), src);
VM_WARN_ON_ONCE_PAGE(!PageMovableOpsIsolated(src), src);
rc = page_movable_ops(src)->migrate_page(dst, src, mode);
- if (rc == MIGRATEPAGE_SUCCESS)
+ if (!rc)
ClearPageMovableOpsIsolated(src);
return rc;
}
@@ -586,7 +585,7 @@ static int __folio_migrate_mapping(struct address_space *mapping,
if (folio_test_swapbacked(folio))
__folio_set_swapbacked(newfolio);
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
oldzone = folio_zone(folio);
@@ -687,7 +686,7 @@ static int __folio_migrate_mapping(struct address_space *mapping,
}
local_irq_enable();
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
int folio_migrate_mapping(struct address_space *mapping,
@@ -736,7 +735,7 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
xas_unlock_irq(&xas);
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
/*
@@ -852,14 +851,14 @@ static int __migrate_folio(struct address_space *mapping, struct folio *dst,
return rc;
rc = __folio_migrate_mapping(mapping, dst, src, expected_count);
- if (rc != MIGRATEPAGE_SUCCESS)
+ if (rc)
return rc;
if (src_private)
folio_attach_private(dst, folio_detach_private(src));
folio_migrate_flags(dst, src);
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
/**
@@ -966,7 +965,7 @@ static int __buffer_migrate_folio(struct address_space *mapping,
}
rc = filemap_migrate_folio(mapping, dst, src, mode);
- if (rc != MIGRATEPAGE_SUCCESS)
+ if (rc)
goto unlock_buffers;
bh = head;
@@ -1070,7 +1069,7 @@ static int fallback_migrate_folio(struct address_space *mapping,
*
* Return value:
* < 0 - error code
- * MIGRATEPAGE_SUCCESS - success
+ * 0 - success
*/
static int move_to_new_folio(struct folio *dst, struct folio *src,
enum migrate_mode mode)
@@ -1098,7 +1097,7 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
else
rc = fallback_migrate_folio(mapping, dst, src, mode);
- if (rc == MIGRATEPAGE_SUCCESS) {
+ if (!rc) {
/*
* For pagecache folios, src->mapping must be cleared before src
* is freed. Anonymous folios must stay anonymous until freed.
@@ -1448,7 +1447,7 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio,
if (folio_ref_count(src) == 1) {
/* page was freed from under us. So we are done. */
folio_putback_hugetlb(src);
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
dst = get_new_folio(src, private);
@@ -1511,8 +1510,7 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio,
rc = move_to_new_folio(dst, src, mode);
if (page_was_mapped)
- remove_migration_ptes(src,
- rc == MIGRATEPAGE_SUCCESS ? dst : src, 0);
+ remove_migration_ptes(src, !rc ? dst : src, 0);
unlock_put_anon:
folio_unlock(dst);
@@ -1521,7 +1519,7 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio,
if (anon_vma)
put_anon_vma(anon_vma);
- if (rc == MIGRATEPAGE_SUCCESS) {
+ if (!rc) {
move_hugetlb_state(src, dst, reason);
put_new_folio = NULL;
}
@@ -1529,7 +1527,7 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio,
out_unlock:
folio_unlock(src);
out:
- if (rc == MIGRATEPAGE_SUCCESS)
+ if (!rc)
folio_putback_hugetlb(src);
else if (rc != -EAGAIN)
list_move_tail(&src->lru, ret);
@@ -1639,7 +1637,7 @@ static int migrate_hugetlbs(struct list_head *from, new_folio_t get_new_folio,
reason, ret_folios);
/*
* The rules are:
- * Success: hugetlb folio will be put back
+ * 0: hugetlb folio will be put back
* -EAGAIN: stay on the from list
* -ENOMEM: stay on the from list
* Other errno: put on ret_folios list
@@ -1656,7 +1654,7 @@ static int migrate_hugetlbs(struct list_head *from, new_folio_t get_new_folio,
retry++;
nr_retry_pages += nr_pages;
break;
- case MIGRATEPAGE_SUCCESS:
+ case 0:
stats->nr_succeeded += nr_pages;
break;
default:
@@ -1710,7 +1708,7 @@ static void migrate_folios_move(struct list_head *src_folios,
reason, ret_folios);
/*
* The rules are:
- * Success: folio will be freed
+ * 0: folio will be freed
* -EAGAIN: stay on the unmap_folios list
* Other errno: put on ret_folios list
*/
@@ -1720,7 +1718,7 @@ static void migrate_folios_move(struct list_head *src_folios,
*thp_retry += is_thp;
*nr_retry_pages += nr_pages;
break;
- case MIGRATEPAGE_SUCCESS:
+ case 0:
stats->nr_succeeded += nr_pages;
stats->nr_thp_succeeded += is_thp;
break;
diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index e05e14d6eacdb..abd9f6850db65 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -778,7 +778,7 @@ static void __migrate_device_pages(unsigned long *src_pfns,
if (migrate && migrate->fault_page == page)
extra_cnt = 1;
r = folio_migrate_mapping(mapping, newfolio, folio, extra_cnt);
- if (r != MIGRATEPAGE_SUCCESS)
+ if (r)
src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
else
folio_migrate_flags(newfolio, folio);
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 805a10b41266a..153783d49d346 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1746,7 +1746,7 @@ static int zs_page_migrate(struct page *newpage, struct page *page,
* instead.
*/
if (!zpdesc->zspage)
- return MIGRATEPAGE_SUCCESS;
+ return 0;
/* The page is locked, so this pointer must remain valid */
zspage = get_zspage(zpdesc);
@@ -1813,7 +1813,7 @@ static int zs_page_migrate(struct page *newpage, struct page *page,
reset_zpdesc(zpdesc);
zpdesc_put(zpdesc);
- return MIGRATEPAGE_SUCCESS;
+ return 0;
}
static void zs_page_putback(struct page *page)
--
2.51.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 6.17.y 3/3] vmw_balloon: indicate success when effectively deflating during migration
2025-10-26 23:50 ` [PATCH 6.17.y 1/3] mm/migrate: remove MIGRATEPAGE_UNMAP Sasha Levin
2025-10-26 23:50 ` [PATCH 6.17.y 2/3] treewide: remove MIGRATEPAGE_SUCCESS Sasha Levin
@ 2025-10-26 23:50 ` Sasha Levin
1 sibling, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2025-10-26 23:50 UTC (permalink / raw)
To: stable
Cc: David Hildenbrand, Jerrin Shaji George,
Broadcom internal kernel review list, Arnd Bergmann,
Greg Kroah-Hartman, Andrew Morton, Sasha Levin
From: David Hildenbrand <david@redhat.com>
[ Upstream commit 4ba5a8a7faa647ada8eae61a36517cf369f5bbe4 ]
When migrating a balloon page, we first deflate the old page to then
inflate the new page.
However, if inflating the new page succeeded, we effectively deflated the
old page, reducing the balloon size.
In that case, the migration actually worked: similar to migrating+
immediately deflating the new page. The old page will be freed back to
the buddy.
Right now, the core will leave the page be marked as isolated (as we
returned an error). When later trying to putback that page, we will run
into the WARN_ON_ONCE() in balloon_page_putback().
That handling was changed in commit 3544c4faccb8 ("mm/balloon_compaction:
stop using __ClearPageMovable()"); before that change, we would have
tolerated that way of handling it.
To fix it, let's just return 0 in that case, making the core effectively
just clear the "isolated" flag + freeing it back to the buddy as if the
migration succeeded. Note that the new page will also get freed when the
core puts the last reference.
Note that this also makes it all be more consistent: we will no longer
unisolate the page in the balloon driver while keeping it marked as being
isolated in migration core.
This was found by code inspection.
Link: https://lkml.kernel.org/r/20251014124455.478345-1-david@redhat.com
Fixes: 3544c4faccb8 ("mm/balloon_compaction: stop using __ClearPageMovable()")
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Broadcom internal kernel review list <bcm-kernel-feedback-list@broadcom.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/misc/vmw_balloon.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 6df51ee8db621..cc1d18b3df5ca 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1737,7 +1737,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
{
unsigned long status, flags;
struct vmballoon *b;
- int ret;
+ int ret = 0;
b = container_of(b_dev_info, struct vmballoon, b_dev_info);
@@ -1796,17 +1796,15 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
* A failure happened. While we can deflate the page we just
* inflated, this deflation can also encounter an error. Instead
* we will decrease the size of the balloon to reflect the
- * change and report failure.
+ * change.
*/
atomic64_dec(&b->size);
- ret = -EBUSY;
} else {
/*
* Success. Take a reference for the page, and we will add it to
* the list after acquiring the lock.
*/
get_page(newpage);
- ret = 0;
}
/* Update the balloon list under the @pages_lock */
@@ -1817,7 +1815,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
* If we succeed just insert it to the list and update the statistics
* under the lock.
*/
- if (!ret) {
+ if (status == VMW_BALLOON_SUCCESS) {
balloon_page_insert(&b->b_dev_info, newpage);
__count_vm_event(BALLOON_MIGRATE);
}
--
2.51.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-10-26 23:50 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2025-10-26 14:28 FAILED: patch "[PATCH] vmw_balloon: indicate success when effectively deflating" failed to apply to 6.17-stable tree gregkh
2025-10-26 23:50 ` [PATCH 6.17.y 1/3] mm/migrate: remove MIGRATEPAGE_UNMAP Sasha Levin
2025-10-26 23:50 ` [PATCH 6.17.y 2/3] treewide: remove MIGRATEPAGE_SUCCESS Sasha Levin
2025-10-26 23:50 ` [PATCH 6.17.y 3/3] vmw_balloon: indicate success when effectively deflating during migration Sasha Levin
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