Re: [PATCH RESEND v3 01/10] mm/vma: rename VMA_LOCK_OFFSET to VM_REFCNT_EXCLUDE_READERS_FLAG

Vlastimil Babka
2026-01-22T16:26:17Z

On 1/22/26 14:01, Lorenzo Stoakes wrote:
> The VMA_LOCK_OFFSET value encodes a flag which vma->vm_refcnt is set to in
> order to indicate that a VMA is in the process of having VMA read-locks
> excluded in __vma_enter_locked() (that is, first checking if there are any
> VMA read locks held, and if there are, waiting on them to be released).
>
> This happens when a VMA write lock is being established, or a VMA is being
> marked detached and discovers that the VMA reference count is elevated due
> to read-locks temporarily elevating the reference count only to discover a
> VMA write lock is in place.
>
> The naming does not convey any of this, so rename VMA_LOCK_OFFSET to
> VM_REFCNT_EXCLUDE_READERS_FLAG (with a sensible new prefix to differentiate
> from the newly introduced VMA_*_BIT flags).
>
> Also rename VMA_REF_LIMIT to VM_REFCNT_LIMIT to make this consistent also.
>
> Update comments to reflect this.
>
> No functional change intended.
>
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>

git grep tells me VMA_LOCK_OFFSET is still used in
tools/testing/vma/vma_internal.h but I guess it doesn't break the tests?