Re: [PATCH 7/9] mm: page_isolation: do not take slab pages for free

[Zi Yan]

On 27 Oct 2026, at 11:46, Vlastimil Babka (SUSE) wrote:

> From: Josef Bacik <josef@xxxxxxxxxxxxxx>
>
> page_is_unmovable() regards a page with a reference count of zero as free
> or about to be freed. Since slab allocates frozen pages, they will
> be wrongly considered to be freed if order 0 (higher-order compound
> pages are caught earlier).
>
> If such slabs are the only unmovable pages of a memory block, memory
> offlining now isolates the block, this can lead to offline_pages()
> looping without progress.
>
> Thus detect the slab pages as removable to return -EBUSY, as would
> happen before commit 9aec2fb0fd5e ("slab: allocate frozen pages").
>
> Fixes: 9aec2fb0fd5e ("slab: allocate frozen pages")
> Assisted-by: LLM
> Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
> Signed-off-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
> Signed-off-by: Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx>
> ---
>  mm/memory_hotplug.c | 7 +++++++
>  mm/page_isolation.c | 7 +++++++
>  2 files changed, 14 insertions(+)
>
LGTM.

Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>

Best Regards,
Yan, Zi