kernel/linux.git/drivers/misc/vmw_balloon.c, branch v7.0.10

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

mm: rename CONFIG_BALLOON_COMPACTION to CONFIG_BALLOON_MIGRATION

2026-01-31T22:22:36+00:00

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) Reviewed-by: Lorenzo Stoakes Acked-by: Michael S. Tsirkin Cc: Arnd Bergmann Cc: Christophe Leroy Cc: Eugenio Pérez Cc: Greg Kroah-Hartman Cc: Jason Wang Cc: Jerrin Shaji George Cc: Jonathan Corbet Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Oscar Salvador Cc: SeongJae Park Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Zi Yan Signed-off-by: Andrew Morton

mm: rename balloon_compaction.(c|h) to balloon.(c|h)

2026-01-31T22:22:35+00:00

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) Reviewed-by: Lorenzo Stoakes Acked-by: Michael S. Tsirkin Cc: Arnd Bergmann Cc: Christophe Leroy Cc: Eugenio Pérez Cc: Greg Kroah-Hartman Cc: Jason Wang Cc: Jerrin Shaji George Cc: Jonathan Corbet Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Oscar Salvador Cc: SeongJae Park Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Zi Yan Signed-off-by: Andrew Morton

vmw_balloon: stop using the balloon_dev_info lock

2026-01-31T22:22:32+00:00

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) Reviewed-by: Lorenzo Stoakes Acked-by: Michael S. Tsirkin Cc: Arnd Bergmann Cc: Christophe Leroy Cc: Eugenio Pérez Cc: Greg Kroah-Hartman Cc: Jason Wang Cc: Jerrin Shaji George Cc: Jonathan Corbet Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Oscar Salvador Cc: SeongJae Park Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Zi Yan Signed-off-by: Andrew Morton

mm/balloon_compaction: centralize basic page migration handling

2026-01-31T22:22:31+00:00

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) Acked-by: Michael S. Tsirkin Cc: Arnd Bergmann Cc: Christophe Leroy Cc: Eugenio Pérez Cc: Greg Kroah-Hartman Cc: Jason Wang Cc: Jerrin Shaji George Cc: Jonathan Corbet Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Oscar Salvador Cc: SeongJae Park Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Zi Yan Signed-off-by: Andrew Morton

vmw_balloon: remove vmballoon_compaction_init()

2026-01-31T22:22:31+00:00

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) Reviewed-by: Lorenzo Stoakes Acked-by: Michael S. Tsirkin Cc: Arnd Bergmann Cc: Christophe Leroy Cc: Eugenio Pérez Cc: Greg Kroah-Hartman Cc: Jason Wang Cc: Jerrin Shaji George Cc: Jonathan Corbet Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Oscar Salvador Cc: SeongJae Park Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Zi Yan Signed-off-by: Andrew Morton

vmw_balloon: adjust BALLOON_DEFLATE when deflating while migrating

2026-01-31T22:22:30+00:00

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) Reviewed-by: SeongJae Park Reviewed-by: Lorenzo Stoakes Acked-by: Michael S. Tsirkin Cc: Christophe Leroy Cc: Eugenio Pérez Cc: Greg Kroah-Hartman Cc: Jason Wang Cc: Jerrin Shaji George Cc: Jonathan Corbet Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Zi Yan Signed-off-by: Andrew Morton

vmw_balloon: indicate success when effectively deflating during migration

2025-10-21T22:46:17+00:00

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 Cc: Jerrin Shaji George Cc: Broadcom internal kernel review list Cc: Arnd Bergmann Cc: Greg Kroah-Hartman Cc: Signed-off-by: Andrew Morton

treewide: remove MIGRATEPAGE_SUCCESS

2025-09-13T23:54:50+00:00

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 Reviewed-by: Zi Yan [mm] Acked-by: Dave Kleikamp [jfs] Acked-by: David Sterba [btrfs] Acked-by: Greg Kroah-Hartman Reviewed-by: Byungchul Park Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Benjamin LaHaise Cc: Chris Mason Cc: Christian Brauner Cc: Christophe Leroy Cc: Dave Kleikamp Cc: Eugenio Pé rez Cc: Gregory Price Cc: "Huang, Ying" Cc: Jan Kara Cc: Jason Wang Cc: Jerrin Shaji George Cc: Josef Bacik Cc: Joshua Hahn Cc: Madhavan Srinivasan Cc: Mathew Brost Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Minchan Kim Cc: Muchun Song Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Rakie Kim Cc: Sergey Senozhatsky Cc: Xuan Zhuo Cc: Lance Yang Signed-off-by: Andrew Morton