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David Hildenbrand (Red Hat)
cd8e95d80b 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>
 2026-01-31 14:22:36 -08:00
David Hildenbrand (Red Hat)
7cf3318a25 mm/kconfig: make BALLOON_COMPACTION depend on MIGRATION 
Migration support for balloon memory depends on MIGRATION not COMPACTION. 
Compaction is simply another user of page migration.

The last dependency on compaction.c was effectively removed with commit
3d388584d5 ("mm: convert "movable" flag in page->mapping to a page
flag").  Ever since, everything for handling movable_ops page migration
resides in core migration code.

So let's change the dependency and adjust the description + help text.

We'll rename BALLOON_COMPACTION separately next.

Link: https://lkml.kernel.org/r/20260119230133.3551867-22-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>
 2026-01-31 14:22:35 -08:00
David Hildenbrand (Red Hat)
25b48b4cdf mm: rename balloon_compaction.(c|h) to balloon.(c|h) 
Even without CONFIG_BALLOON_COMPACTION this infrastructure implements
basic list and page management for a memory balloon.

Link: https://lkml.kernel.org/r/20260119230133.3551867-21-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>
 2026-01-31 14:22:35 -08:00
David Hildenbrand (Red Hat)
a3db9e136c mm/vmscan: drop inclusion of balloon_compaction.h 
Before commit b1123ea6d3 ("mm: balloon: use general non-lru movable page
feature"), the include was required because of isolated_balloon_page().

It's no longer required, so let's remove it.

Link: https://lkml.kernel.org/r/20260119230133.3551867-20-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>
 2026-01-31 14:22:35 -08:00
David Hildenbrand (Red Hat)
92ec9260d5 mm/balloon_compaction: remove "extern" from functions 
Adding "extern" to functions is frowned-upon.  Let's just get rid of it
for all functions here.

Link: https://lkml.kernel.org/r/20260119230133.3551867-19-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>
 2026-01-31 14:22:35 -08:00
David Hildenbrand (Red Hat)
eee00d0414 mm/balloon_compaction: mark remaining functions for having proper kerneldoc 
Looks like all we are missing for proper kerneldoc is another "*".

Link: https://lkml.kernel.org/r/20260119230133.3551867-18-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>
 2026-01-31 14:22:34 -08:00
David Hildenbrand (Red Hat)
631eb22826 mm/balloon_compaction: assert that the balloon_pages_lock is held 
Let's add some sanity checks for holding the balloon_pages_lock when we're
effectively inflating/deflating a page.

Link: https://lkml.kernel.org/r/20260119230133.3551867-17-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>
 2026-01-31 14:22:34 -08:00
David Hildenbrand (Red Hat)
03d6a2f684 mm/balloon_compaction: move internal helpers to balloon_compaction.c 
Let's move the helpers that are not required by drivers anymore.

While at it, drop the doc of balloon_page_device() as it is trivial.

[david@kernel.org: move balloon_page_device() under CONFIG_BALLOON_COMPACTION]
  Link: https://lkml.kernel.org/r/27f0adf1-54c1-4d99-8b7f-fd45574e7f41@kernel.org
Link: https://lkml.kernel.org/r/20260119230133.3551867-16-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>
 2026-01-31 14:22:34 -08:00
David Hildenbrand (Red Hat)
9d792ef33e mm/balloon_compaction: fold balloon_mapping_gfp_mask() into balloon_page_alloc() 
Let's just remove balloon_mapping_gfp_mask().

Link: https://lkml.kernel.org/r/20260119230133.3551867-15-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>
 2026-01-31 14:22:34 -08:00
David Hildenbrand (Red Hat)
0fa3e9a48b mm/balloon_compaction: remove balloon_page_push/pop() 
Let's remove these helpers as they are unused now.

Link: https://lkml.kernel.org/r/20260119230133.3551867-14-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>
 2026-01-31 14:22:33 -08:00
David Hildenbrand (Red Hat)
f7e1537314 drivers/virtio/virtio_balloon: stop using balloon_page_push/pop() 
Let's stop using these functions so we can remove them.  They look like
belonging to the balloon API for managing the device balloon list when
really they are just simple helpers only used by virtio-balloon.

Let's just inline them and switch to a proper list_for_each_entry_safe().

Link: https://lkml.kernel.org/r/20260119230133.3551867-13-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>
 2026-01-31 14:22:33 -08:00
David Hildenbrand (Red Hat)
aa974cbf94 mm/balloon_compaction: drop fs.h include from balloon_compaction.h 
Ever since commit 68f2736a85 ("mm: Convert all PageMovable users to
movable_operations") we no longer store an inode in balloon_dev_info, so
we can stop including "fs.h".

Link: https://lkml.kernel.org/r/20260119230133.3551867-12-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>
 2026-01-31 14:22:33 -08:00
David Hildenbrand (Red Hat)
ddc50a97be mm/balloon_compaction: make balloon_mops static 
There is no need to expose this anymore, so let's just make it static.

Link: https://lkml.kernel.org/r/20260119230133.3551867-11-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>
 2026-01-31 14:22:33 -08:00
David Hildenbrand (Red Hat)
a3fafdd389 mm/balloon_compaction: remove dependency on page lock 
Let's stop using the page lock in balloon code and instead use only the
balloon_device_lock.

As soon as we set the PG_movable_ops flag, we might now get isolation
callbacks for that page as we are no longer holding the page lock.  In
there, we'll simply synchronize using the balloon_device_lock.

So in balloon_page_isolate() lookup the balloon_dev_info through
page->private under balloon_device_lock.

It's crucial that we update page->private under the balloon_device_lock,
so the isolation callback can properly deal with concurrent deflation.

Consequently, make sure that balloon_page_finalize() is called under
balloon_device_lock as we remove a page from the list and clear
page->private.  balloon_page_insert() is already called with the
balloon_device_lock held.

Note that the core will still lock the pages, for example in
isolate_movable_ops_page().  The lock is there still relevant for handling
the PageMovableOpsIsolated flag, but that can be later changed to use an
atomic test-and-set instead, or moved into the movable_ops backends.

Link: https://lkml.kernel.org/r/20260119230133.3551867-10-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
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: Lorenzo Stoakes <lorenzo.stoakes@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>
 2026-01-31 14:22:32 -08:00
David Hildenbrand (Red Hat)
8202313e3d mm/balloon_compaction: use a device-independent balloon (list) lock 
In order to remove the dependency on the page lock for balloon pages, we
need a lock that is independent of the page.

It's crucial that we can handle the scenario where balloon deflation
(clearing page->private) can race with page isolation (using page->private
to obtain the balloon_dev_info where the lock currently resides).

The current lock in balloon_dev_info is therefore not suitable.

Fortunately, we never really have more than a single balloon device per
VM, so we can just keep it simple and use a static lock to protect all
balloon devices.

Based on this change we will remove the dependency on the page lock next.

Link: https://lkml.kernel.org/r/20260119230133.3551867-9-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
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: Lorenzo Stoakes <lorenzo.stoakes@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>
 2026-01-31 14:22:32 -08:00
David Hildenbrand (Red Hat)
c33b47c334 vmw_balloon: stop using the balloon_dev_info lock 
Let's not piggy-back on the existing lock and use a separate lock for the
huge page list.  Now that we use a separate lock, there is no need to
disable interrupts, so use the non-irqsave variants.  We only required the
irqsave variants because of the balloon device lock.

This is a preparation for changing the locking used to protect
balloon_dev_info.

While at it, talk about "page migration" instead of "page compaction". 
We'll change that in core code soon as well.

Link: https://lkml.kernel.org/r/20260119230133.3551867-8-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>
 2026-01-31 14:22:32 -08:00
David Hildenbrand (Red Hat)
a00de9ba30 mm/balloon_compaction: centralize adjust_managed_page_count() handling 
Let's centralize it, by allowing for the driver to enable this handling
through a new flag (bool for now) in the balloon device info.

Note that we now adjust the counter when adding/removing a page into the
balloon list: when removing a page to deflate it, it will now happen
before the driver communicated with hypervisor, not afterwards.

This shouldn't make a difference in practice.

Link: https://lkml.kernel.org/r/20260119230133.3551867-7-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Acked-by: Liam R. Howlett <Liam.Howlett@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: Lorenzo Stoakes <lorenzo.stoakes@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>
 2026-01-31 14:22:32 -08:00
David Hildenbrand (Red Hat)
1258460bd3 mm/balloon_compaction: centralize basic page migration handling 
Let's update the balloon page references, the balloon page list, the
BALLOON_MIGRATE counter and the isolated-pages counter in
balloon_page_migrate(), after letting the balloon->migratepage() callback
deal with the actual inflation+deflation.

Note that we now perform the balloon list modifications outside of any
implementation-specific locks: which is fine, there is nothing special
about these page actions that the lock would be protecting.

The old page is already no longer in the list (isolated) and the new page
is not yet in the list.

Let's use -ENOENT to communicate the special "inflation of new page failed
after already deflating the old page" to balloon_page_migrate() so it can
handle it accordingly.

While at it, rename balloon->b_dev_info to make it match the other
functions.  Also, drop the comment above balloon_page_migrate(), which
seems unnecessary.

Link: https://lkml.kernel.org/r/20260119230133.3551867-6-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
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: Lorenzo Stoakes <lorenzo.stoakes@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>
 2026-01-31 14:22:31 -08:00
David Hildenbrand (Red Hat)
6af05dfe9a mm/balloon_compaction: improve comments for WARN_ON_ONCE(!b_dev_info) 
Let's clarify a bit by extending the comments.

Link: https://lkml.kernel.org/r/20260119230133.3551867-5-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
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: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michael S. Tsirkin <mst@redhat.com>
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>
 2026-01-31 14:22:31 -08:00
David Hildenbrand (Red Hat)
5b3342cbf0 powerpc/pseries/cmm: remove cmm_balloon_compaction_init() 
Now that there is not a lot of logic left, let's just inline setting up
the migration function.

To avoid #ifdef in the caller we can instead use IS_ENABLED() and make the
compiler happy by only providing the function declaration.

Now that the function is gone, drop the "out_balloon_compaction" label. 
Note that before commit 68f2736a85 ("mm: Convert all PageMovable users
to movable_operations") we actually had to undo something, now not
anymore.

Link: https://lkml.kernel.org/r/20260119230133.3551867-4-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>
 2026-01-31 14:22:31 -08:00
David Hildenbrand (Red Hat)
d2346b09c5 vmw_balloon: remove vmballoon_compaction_init() 
Now that there is not a lot of logic left, let's just inline setting up
the migration function and drop all these excessive comments that are not
really required (or true) anymore.

To avoid #ifdef in the caller we can instead use IS_ENABLED() and make the
compiler happy by only providing the function declaration.

Link: https://lkml.kernel.org/r/20260119230133.3551867-3-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>
 2026-01-31 14:22:31 -08:00
David Hildenbrand (Red Hat)
6e31add91a vmw_balloon: adjust BALLOON_DEFLATE when deflating while migrating 
Patch series "mm: balloon infrastructure cleanups", v3.

I started with wanting to remove the dependency of the balloon
infrastructure on the page lock, but ended up performing various other
cleanups, some of which I had on my todo list for years.

This series heavily cleans up and simplifies our balloon infrastructure,
including our balloon page migration functionality.

With this series, we no longer make use of the page lock for PageOffline
pages as part of the balloon infrastructure (preparing for memdescs where
PageOffline pages won't have any such lock), and simplifies migration
handling such that refcounting can more easily be adjusted later
(long-term focus is for PageOffline pages to not have a refcount either).

Plenty of related cleanups.


This patch (of 24):

When we're effectively deflating the balloon while migrating a page
because inflating the new page failed, we're not adjusting
BALLOON_DEFLATE.

Let's do that.  This is a preparation for factoring out this handling to
the core code, making it work in a similar way first.

As this (deflating while migrating because of inflation error) is a corner
case that I don't really expect to happen in practice and the stats are
not that crucial, this likely doesn't classify as a fix.

Link: https://lkml.kernel.org/r/20260119230133.3551867-1-david@kernel.org
Link: https://lkml.kernel.org/r/20260119230133.3551867-2-david@kernel.org
Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: SeongJae Park <sj@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: 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>
 2026-01-31 14:22:30 -08:00
Shivank Garg
9c284c91b0 mm/khugepaged: make khugepaged_collapse_control static 
The global variable 'khugepaged_collapse_control' is not used outside of
mm/khugepaged.c.  Make it static to limit its scope.

Link: https://lkml.kernel.org/r/20260118192253.9263-14-shivankg@amd.com
Signed-off-by: Shivank Garg <shivankg@amd.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-31 14:22:30 -08:00
Shivank Garg
40bd4ff090 mm/khugepaged: use enum scan_result for result variables and return types 
Convert result variables and return types from int to enum scan_result
throughout khugepaged code.  This improves type safety and code clarity by
making the intent explicit.

No functional change.

Link: https://lkml.kernel.org/r/20260118192253.9263-12-shivankg@amd.com
Signed-off-by: Shivank Garg <shivankg@amd.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Tested-by: Nico Pache <npache@redhat.com>
Reviewed-by: Nico Pache <npache@redhat.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-31 14:22:30 -08:00
Shivank Garg
3ab981c1fc mm/khugepaged: change collapse_pte_mapped_thp() to return void 
The only external caller of collapse_pte_mapped_thp() is uprobe, which
ignores the return value.  Change the external API to return void to
simplify the interface.

Introduce try_collapse_pte_mapped_thp() for internal use that preserves
the return value.  This prepares for future patch that will convert the
return type to use enum scan_result.

Link: https://lkml.kernel.org/r/20260118192253.9263-10-shivankg@amd.com
Signed-off-by: Shivank Garg <shivankg@amd.com>
Suggested-by: David Hildenbrand (Red Hat) <david@kernel.org>
Acked-by: Lance Yang <lance.yang@linux.dev>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Tested-by: Nico Pache <npache@redhat.com>
Reviewed-by: Nico Pache <npache@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-31 14:22:30 -08:00
Shivank Garg
7832e4d583 mm/khugepaged: remove unnecessary goto 'skip' label 
Patch series "mm/khugepaged: cleanups and scan limit fix", v3.

This series contains several cleanups for mm/khugepaged.c to improve code
readability and type safety, and one functional fix to ensure
khugepaged_scan_mm_slot() correctly accounts for small VMAs towards scan
limit.


This patch (of 4):

Replace goto skip with actual logic for better code readability.

No functional change.

Link: https://lkml.kernel.org/r/20260118192253.9263-4-shivankg@amd.com
Link: https://lkml.kernel.org/r/20260118192253.9263-6-shivankg@amd.com
Signed-off-by: Shivank Garg <shivankg@amd.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Tested-by: Nico Pache <npache@redhat.com>
Reviewed-by: Nico Pache <npache@redhat.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-31 14:22:29 -08:00
Andrew Morton
f84b65b045 Merge branch 'mm-hotfixes-stable' into mm-stable to pick up "mm/shmem, 
swap: fix race of truncate and swap entry split", needed for merging "mm,
swap: cleanup swap entry management workflow".
 2026-01-31 14:20:03 -08:00
SeongJae Park
6fe0e6d599 mm/damon: hide kdamond and kdamond_lock of damon_ctx 
There is no DAMON API caller that directly access 'kdamond' and
'kdamond_lock' fields of 'struct damon_ctx'.  Keeping those exposed could
only encourage creative but error-prone usages.  Hide them from DAMON API
callers by marking those as private fields.

Link: https://lkml.kernel.org/r/20260115152047.68415-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:38 -08:00
SeongJae Park
33402229d2 mm/damon/reclaim: use damon_kdamond_pid() 
DAMON_RECLAIM directly uses damon_ctx->kdamond field with manual
synchronization using damon_ctx->kdamond_lock, to get the pid of the
kdamond.  Use a new dedicated function for the purpose, namely
damon_kdamond_pid(), since that doesn't require manual and error-prone
synchronization.

Link: https://lkml.kernel.org/r/20260115152047.68415-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:38 -08:00
SeongJae Park
306550f0a5 mm/damon/lru_sort: use damon_kdamond_pid() 
DAMON_LRU_SORT directly uses damon_ctx->kdamond field with manual
synchronization using damon_ctx->kdamond_lock, to get the pid of the
kdamond.  Use a new dedicated function for the purpose, namely
damon_kdamond_pid(), since that doesn't require manual and error-prone
synchronization.

Link: https://lkml.kernel.org/r/20260115152047.68415-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:37 -08:00
SeongJae Park
f54b51ce31 mm/damon/sysfs: use damon_kdamond_pid() 
DAMON sysfs interface directly uses damon_ctx->kdamond field with manual
synchronization using damon_ctx->kdamond_lock, to get the pid of the
kdamond.  Use a new dedicated function for the purpose, namely
damon_kdamond_pid(), since that doesn't require manual and error-prone
synchronization.

Avoid use of kdamond_lock outside of the core.

Link: https://lkml.kernel.org/r/20260115152047.68415-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:37 -08:00
SeongJae Park
4262c53236 mm/damon/core: implement damon_kdamond_pid() 
Patch series "mm/damon: hide kdamond and kdamond_lock from API callers".

'kdamond' and 'kdamond_lock' fields initially exposed to DAMON API callers
for flexible synchronization and use cases.  As DAMON API became somewhat
complicated compared to the early days, Keeping those exposed could only
encourage the API callers to invent more creative but complicated and
difficult-to-debug use cases.

Fortunately DAMON API callers didn't invent that many creative use cases. 
There exist only two use cases of 'kdamond' and 'kdamond_lock'.  Finding
whether the kdamond is actively running, and getting the pid of the
kdamond.  For the first use case, a dedicated API function, namely
'damon_is_running()' is provided, and all DAMON API callers are using the
function for the use case.  Hence only the second use case is where the
fields are directly being used by DAMON API callers.

To prevent future invention of complicated and erroneous use cases of the
fields, hide the fields from the API callers.  For that, provide new
dedicated DAMON API functions for the remaining use case, namely
damon_kdamond_pid(), migrate DAMON API callers to use the new function,
and mark the fields as private fields.


This patch (of 5):

'kdamond' and 'kdamond_lock' are directly being used by DAMON API callers
for getting the pid of the corresponding kdamond.  To discourage invention
of creative but complicated and erroneous new usages of the fields that
require careful synchronization, implement a new API function that can
simply be used without the manual synchronizations.

Link: https://lkml.kernel.org/r/20260115152047.68415-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20260115152047.68415-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:37 -08:00
Yury Norov
291487b753 cgroup: use nodes_and() output where appropriate 
Now that nodes_and() returns true if the result nodemask is not empty,
drop useless nodes_intersects() in guarantee_online_mems() and
nodes_empty() in update_nodemasks_hier(), which both are O(N).

Link: https://lkml.kernel.org/r/20260114172217.861204-4-ynorov@nvidia.com
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:37 -08:00
Yury Norov
386781df63 mm: use nodes_and() return value to simplify client code 
establish_demotion_targets() and kernel_migrate_pages() call node_empty()
immediately after calling nodes_and().  Now that nodes_and() return false
if nodemask is empty, drop the latter.

Link: https://lkml.kernel.org/r/20260114172217.861204-3-ynorov@nvidia.com
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:36 -08:00
Yury Norov
cbc064e708 nodemask: propagate boolean for nodes_and{,not} 
Patch series "nodemask: align nodes_and{,not} with underlying bitmap ops".

nodes_and{,not} are void despite that underlying bitmap_and(,not) return
boolean, true if the result bitmap is non-empty.  Align nodemask API, and
simplify client code.


This patch (of 3):

Bitmap functions bitmap_and{,not} return boolean depending on emptiness of
the result bitmap.  The corresponding nodemask helpers ignore the returned
value.

Propagate the underlying bitmaps result to nodemasks users, as it
simplifies user code.

Link: https://lkml.kernel.org/r/20260114172217.861204-1-ynorov@nvidia.com
Link: https://lkml.kernel.org/r/20260114172217.861204-2-ynorov@nvidia.com
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reviewed-by: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:36 -08:00
Rohan McLure
641d47d4c9 powerpc/mm: support page table check 
On creation and clearing of a page table mapping, instrument such calls by
invoking page_table_check_pte_set and page_table_check_pte_clear
respectively.  These calls serve as a sanity check against illegal
mappings.

Enable ARCH_SUPPORTS_PAGE_TABLE_CHECK on powerpc, except when HUGETLB_PAGE
is enabled (powerpc has some weirdness in how it implements
set_huge_pte_at(), which may require some further work).

See also:

riscv support in commit 3fee229a8e ("riscv/mm: enable
ARCH_SUPPORTS_PAGE_TABLE_CHECK")
arm64 in commit 42b2547137 ("arm64/mm: enable
ARCH_SUPPORTS_PAGE_TABLE_CHECK")
x86_64 in commit d283d422c6 ("x86: mm: add x86_64 support for page table
check")

[ajd@linux.ibm.com: rebase, add additional instrumentation, misc fixes]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-12-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:36 -08:00
Rohan McLure
2360f523a4 powerpc/mm: use set_pte_at_unchecked() for internal usages 
In the new set_ptes() API, set_pte_at() (a special case of set_ptes()) is
intended to be instrumented by the page table check facility.  There are
however several other routines that constitute the API for setting page
table entries, including set_pmd_at() among others.  Such routines are
themselves implemented in terms of set_ptes_at().

A future patch providing support for page table checking on powerpc must
take care to avoid duplicate calls to page_table_check_p{te,md,ud}_set(). 
Allow for assignment of pte entries without instrumentation through the
set_pte_at_unchecked() routine introduced in this patch.

Cause API-facing routines that call set_pte_at() to instead call
set_pte_at_unchecked(), which will remain uninstrumented by page table
check.  set_ptes() is itself implemented by calls to __set_pte_at(), so
this eliminates redundant code.

[ajd@linux.ibm.com: don't change to unchecked for early boot/kernel mappings]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-11-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Acked-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:36 -08:00
Rohan McLure
2f5e576598 powerpc/mm: implement *_user_accessible_page() for ptes 
Page table checking depends on architectures providing an implementation
of p{te,md,ud}_user_accessible_page.  With refactorisations made on
powerpc/mm, the pte_access_permitted() and similar methods verify whether
a userland page is accessible with the required permissions.

Since page table checking is the only user of
p{te,md,ud}_user_accessible_page(), implement these for all platforms,
using some of the same preliminary checks taken by pte_access_permitted()
on that platform.

Since commit 8e9bd41e4c ("powerpc/nohash: Replace pte_user() by
pte_read()") pte_user() is no longer required to be present on all
platforms as it may be equivalent to or implied by pte_read().  Hence
implementations of pte_user_accessible_page() are specialised.

[ajd@linux.ibm.com: rebase and clean up]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-10-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:35 -08:00
Rohan McLure
d79f9c9cf7 mm: provide address parameter to p{te,md,ud}_user_accessible_page() 
On several powerpc platforms, a page table entry may not imply whether the
relevant mapping is for userspace or kernelspace.  Instead, such platforms
infer this by the address which is being accessed.

Add an additional address argument to each of these routines in order to
provide support for page table check on powerpc.

[ajd@linux.ibm.com: rebase on arm64 changes]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-9-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org>  # x86
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:35 -08:00
Rohan McLure
d7b4b67eb6 mm/page_table_check: reinstate address parameter in [__]page_table_check_pte_clear() 
This reverts commit aa232204c4 ("mm/page_table_check: remove unused
parameter in [__]page_table_check_pte_clear").

Reinstate previously unused parameters for the purpose of supporting
powerpc platforms, as many do not encode user/kernel ownership of the page
in the pte, but instead in the address of the access.

[ajd@linux.ibm.com: rebase, fix additional occurrence and loop handling]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-8-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org>  # x86
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:35 -08:00
Rohan McLure
649ec9e3d0 mm/page_table_check: reinstate address parameter in [__]page_table_check_pmd_clear() 
This reverts commit 1831414cd7 ("mm/page_table_check: remove unused
parameter in [__]page_table_check_pmd_clear").

Reinstate previously unused parameters for the purpose of supporting
powerpc platforms, as many do not encode user/kernel ownership of the page
in the pte, but instead in the address of the access.

[ajd@linux.ibm.com: rebase on arm64 changes]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-7-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org>  # x86
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:35 -08:00
Rohan McLure
2e6ac078ce mm/page_table_check: reinstate address parameter in [__]page_table_check_pud_clear() 
This reverts commit 931c38e164 ("mm/page_table_check: remove unused
parameter in [__]page_table_check_pud_clear").

Reinstate previously unused parameters for the purpose of supporting
powerpc platforms, as many do not encode user/kernel ownership of the page
in the pte, but instead in the address of the access.

[ajd@linux.ibm.com: rebase on arm64 changes]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-6-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org>  # x86
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:34 -08:00
Rohan McLure
0a5ae44831 mm/page_table_check: provide addr parameter to page_table_check_ptes_set() 
To provide support for powerpc platforms, provide an addr parameter to the
__page_table_check_ptes_set() and page_table_check_ptes_set() routines. 
This parameter is needed on some powerpc platforms which do not encode
whether a mapping is for user or kernel in the pte.  On such platforms,
this can be inferred from the addr parameter.

[ajd@linux.ibm.com: rebase on arm64 + riscv changes, update commit message]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-5-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:34 -08:00
Rohan McLure
6e2d8f9fc4 mm/page_table_check: reinstate address parameter in [__]page_table_check_pmd[s]_set() 
This reverts commit a3b837130b ("mm/page_table_check: remove unused
parameter in [__]page_table_check_pmd_set").

Reinstate previously unused parameters for the purpose of supporting
powerpc platforms, as many do not encode user/kernel ownership of the
page in the pte, but instead in the address of the access.

Apply this to __page_table_check_pmds_set(), page_table_check_pmd_set(), and
the page_table_check_pmd_set() wrapper macro.

[ajd@linux.ibm.com: rebase on arm64 + riscv changes, update commit message]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-4-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org>  # x86
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:34 -08:00
Rohan McLure
c4a0c5ff85 mm/page_table_check: reinstate address parameter in [__]page_table_check_pud[s]_set() 
This reverts commit 6d144436d9 ("mm/page_table_check: remove unused
parameter in [__]page_table_check_pud_set").

Reinstate previously unused parameters for the purpose of supporting
powerpc platforms, as many do not encode user/kernel ownership of the page
in the pte, but instead in the address of the access.

Apply this to __page_table_check_puds_set(), page_table_check_puds_set()
and the page_table_check_pud_set() wrapper macro.

[ajd@linux.ibm.com: rebase on riscv + arm64 changes, update commit message]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-3-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org>  # x86
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:33 -08:00
Andrew Donnellan
ee329c29fd arm64/mm: add addr parameter to __ptep_get_and_clear_anysz() 
To provide support for page table check on powerpc, we need to
reinstate the address parameter in several functions, including
page_table_check_{pte,pmd,pud}_clear().

In preparation for this, add the addr parameter to arm64's
__ptep_get_and_clear_anysz() and change its callsites accordingly.

Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-2-755bc151a50b@linux.ibm.com
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Rohan McLure <rmclure@linux.ibm.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:33 -08:00
Andrew Donnellan
9ac4941ace arm64/mm: add addr parameter to __set_ptes_anysz() 
Patch series "Support page table check on PowerPC", v18.

Support page table check on PowerPC.  Page table check tracks the usage of
of page table entries at each level to ensure that anonymous mappings have
at most one writable consumer, and likewise that file-backed mappings are
not simultaneously also anonymous mappings.

In order to support this infrastructure, a number of helpers or stubs must
be defined or updated for all powerpc platforms.  Additionally, we
separate set_pte_at() and set_pte_at_unchecked(), to allow for internal,
uninstrumented mappings.

On some PowerPC platforms, implementing
{pte,pmd,pud}_user_accessible_page() requires the address.  We revert
previous changes that removed the address parameter from various
interfaces, and add it to some other interfaces, in order to allow this.

For now, we don't allow page table check alongside HUGETLB_PAGE, due to
the arch-specific complexity of set_huge_page_at().  (I'm sure I could
figure this out, but I have to get this version on this list before I
leave my job.)

This series was initially written by Rohan McLure, who has left IBM and is
no longer working on powerpc.


This patch (of 18):

To provide support for page table check on powerpc, we need to reinstate
the address parameter in several functions, including
page_table_check_{ptes,pmds,puds}_set().

In preparation for this, add the addr parameter to arm64's
__set_ptes_anysz() and change its callsites accordingly.

Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-0-755bc151a50b@linux.ibm.com
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-1-755bc151a50b@linux.ibm.com
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:33 -08:00
Matthew Wilcox (Oracle)
832d95b531 migrate: replace RMP_ flags with TTU_ flags 
Instead of translating between RMP_ and TTU_ flags, remove the RMP_ flags
and just use the TTU_ flag space; there's plenty available.

Possibly we should rename these to RMAP_ flags, and maybe even pass them
in through rmap_walk_arg, but that can be done later.

Link: https://lkml.kernel.org/r/20260109041345.3863089-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Jann Horn <jannh@google.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:33 -08:00
Jinjiang Tu
3d702678f5 mm/mempolicy: fix mpol_rebind_nodemask() for MPOL_F_NUMA_BALANCING 
commit bda420b985 ("numa balancing: migrate on fault among multiple
bound nodes") adds new flag MPOL_F_NUMA_BALANCING to enable NUMA balancing
for MPOL_BIND memory policy.

When the cpuset of tasks changes, the mempolicy of the task is rebound by
mpol_rebind_nodemask().  When MPOL_F_STATIC_NODES and
MPOL_F_RELATIVE_NODES are both not set, the behaviour of rebinding should
be same whenever MPOL_F_NUMA_BALANCING is set or not.  So, when an
application calls set_mempolicy() with MPOL_F_NUMA_BALANCING set but both
MPOL_F_STATIC_NODES and MPOL_F_RELATIVE_NODES cleared,
mempolicy.w.cpuset_mems_allowed should be set to
cpuset_current_mems_allowed nodemask.  However, in current implementation,
mpol_store_user_nodemask() wrongly returns true, causing
mempolicy->w.user_nodemask to be incorrectly set to the user-specified
nodemask.  Later, when the cpuset of the application changes,
mpol_rebind_nodemask() ends up rebinding based on the user-specified
nodemask rather than the cpuset_mems_allowed nodemask as intended.

I can reproduce with the following steps in qemu with 4 NUMA nodes:
1. echo '+cpuset' > /sys/fs/cgroup/cgroup.subtree_control
2. mkdir /sys/fs/cgroup/test
3. ./reproducer &
4. cat /proc/$pid/numa_maps, the task is bound to NUMA 1
5. echo $pid > /sys/fs/cgroup/test/cgroup.procs
6. cat /proc/$pid/numa_maps, the task is bound to NUMA 0 now.

The reproducer code:

int main()
{
        struct bitmask *bmp;
        int ret;

        bmp = numa_parse_nodestring("1");
        ret = set_mempolicy(MPOL_BIND | MPOL_F_NUMA_BALANCING,
                bmp->maskp, bmp->size + 1);
        if (ret < 0) {
                perror("Failed to call set_mempolicy");
                exit(-1);
        }

        while (1);
        return 0;
}

If I call set_mempolicy() without MPOL_F_NUMA_BALANCING in the reproducer
code.  After step 5, the task is still bound to NUMA 1.

To fix this, only set mempolicy->w.user_nodemask to the user-specified
nodemask if MPOL_F_STATIC_NODES or MPOL_F_RELATIVE_NODES is present.

Link: https://lkml.kernel.org/r/20260120011018.1256654-1-tujinjiang@huawei.com
Link: https://lkml.kernel.org/r/20251223110523.1161421-1-tujinjiang@huawei.com
Fixes: bda420b985 ("numa balancing: migrate on fault among multiple bound nodes")
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:32 -08:00
Sergey Senozhatsky
dc2e4982cb zsmalloc: introduce SG-list based object read API 
Currently, zsmalloc performs address linearization on read (which
sometimes requires memcpy() to a local buffer).  Not all zsmalloc users
need a linear address.  For example, Crypto API supports SG-list,
performing linearization under the hood, if needed.  In addition, some
compressors can have native SG-list support, completely avoiding the
linearization step.

Provide an SG-list based zsmalloc read API:
- zs_obj_read_sg_begin()
- zs_obj_read_sg_end()

This API allows callers to obtain an SG representation of the object (one
entry for objects that are contained in a single page and two entries for
spanning objects), avoiding the need for a bounce buffer and memcpy.

[senozhatsky@chromium.org: make zs_obj_read_sg_begin() return void, per Yosry]
  Link: https://lkml.kernel.org/r/20260117024900.792237-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20260113034645.2729998-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-01-26 20:02:32 -08:00