[PATCH RFC 16/29] mm: rename __PageMovable() to page_has_movable_ops()
David Hildenbrand
david at redhat.com
Tue Jun 24 01:47:26 AEST 2025
On 20.06.25 22:37, Zi Yan wrote:
> On 18 Jun 2025, at 13:39, David Hildenbrand wrote:
>
>> Let's make it clearer that we are talking about movable_ops pages.
>>
>> Signed-off-by: David Hildenbrand <david at redhat.com>
>> ---
>> include/linux/migrate.h | 2 +-
>> include/linux/page-flags.h | 2 +-
>> mm/compaction.c | 7 ++-----
>> mm/memory-failure.c | 4 ++--
>> mm/memory_hotplug.c | 8 +++-----
>> mm/migrate.c | 8 ++++----
>> mm/page_alloc.c | 2 +-
>> mm/page_isolation.c | 10 +++++-----
>> 8 files changed, 19 insertions(+), 24 deletions(-)
>>
>> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
>> index 204e89eac998f..c575778456f97 100644
>> --- a/include/linux/migrate.h
>> +++ b/include/linux/migrate.h
>> @@ -115,7 +115,7 @@ static inline void __SetPageMovable(struct page *page,
>> static inline
>> const struct movable_operations *page_movable_ops(struct page *page)
>> {
>> - VM_BUG_ON(!__PageMovable(page));
>> + VM_BUG_ON(!page_has_movable_ops(page));
>>
>> return (const struct movable_operations *)
>> ((unsigned long)page->mapping - PAGE_MAPPING_MOVABLE);
>> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
>> index 4fe5ee67535b2..c67163b73c5ec 100644
>> --- a/include/linux/page-flags.h
>> +++ b/include/linux/page-flags.h
>> @@ -750,7 +750,7 @@ static __always_inline bool __folio_test_movable(const struct folio *folio)
>> PAGE_MAPPING_MOVABLE;
>> }
>>
>> -static __always_inline bool __PageMovable(const struct page *page)
>> +static __always_inline bool page_has_movable_ops(const struct page *page)
>> {
>> return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
>> PAGE_MAPPING_MOVABLE;
>> diff --git a/mm/compaction.c b/mm/compaction.c
>> index 5c37373017014..f8b7c09e2e48c 100644
>> --- a/mm/compaction.c
>> +++ b/mm/compaction.c
>> @@ -1056,11 +1056,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
>> * Skip any other type of page
>> */
>> if (!PageLRU(page)) {
>> - /*
>> - * __PageMovable can return false positive so we need
>> - * to verify it under page_lock.
>> - */
>> - if (unlikely(__PageMovable(page)) &&
>> + /* Isolation will grab the page lock. */
>
> I feel that the removed comment should stay, since the current comment
> makes no sense when I read it alone.
Well, talking about the page lock is moot either way. The thing is,
anything can change while we don't hold a page reference. So should we
change the comment to
/* isolation code will deal with any races. */
... or drop it completely?
>
> In addition, why is __PageMovable() is renamed to page_has_movable_ops() but
> __SetPageMovable() stays the same? page_has_movable_ops() and __SetPageMovable()
> are functions for checking and setting PAGE_MAPPING_MOVABLE. The naming just
> does not look symmetric.
See follow-up commits where __SetPageMovable() is cleaned up.
--
Cheers,
David / dhildenb
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