From: Lorenzo Stoakes <ljs@kernel.org>
To: Ye Liu <ye.liu@linux.dev>
Cc: Muchun Song <muchun.song@linux.dev>,
Oscar Salvador <osalvador@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Vlastimil Babka <vbabka@kernel.org>, Zi Yan <ziy@nvidia.com>,
Matthew Brost <matthew.brost@intel.com>,
Joshua Hahn <joshua.hahnjy@gmail.com>,
Rakie Kim <rakie.kim@sk.com>, Byungchul Park <byungchul@sk.com>,
Gregory Price <gourry@gourry.net>,
Ying Huang <ying.huang@linux.alibaba.com>,
Alistair Popple <apopple@nvidia.com>,
"Liam R. Howlett" <liam@infradead.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Brendan Jackman <jackmanb@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH v5 3/9] mm: use enum migrate_reason instead of int for migration reason parameters
Date: Wed, 1 Jul 2026 11:23:42 +0100 [thread overview]
Message-ID: <akTqXYFncsSLniIn@lucifer> (raw)
In-Reply-To: <20260701061101.344679-4-ye.liu@linux.dev>
On Wed, Jul 01, 2026 at 02:10:46PM +0800, Ye Liu wrote:
> Replace all 'int reason' function parameters that carry migrate_reason
> values with the proper 'enum migrate_reason' type. This makes the
> intent explicit and leverages compiler type checking. The affected
> subsystems are:
>
> - page_owner: __folio_set_owner_migrate_reason(),
> folio_set_owner_migrate_reason()
> - migrate: migrate_pages(), migrate_pages_sync(),
> migrate_pages_batch(), migrate_folios_move(),
> migrate_hugetlbs(), unmap_and_move_huge_page()
> - hugetlb: move_hugetlb_state(), htlb_allow_alloc_fallback()
> - trace: mm_migrate_pages and mm_migrate_pages_start events
>
> The 'short last_migrate_reason' struct field and internal helper
> parameter in page_owner are intentionally left as 'short' since they
> store per-page metadata where size matters.
Based on my own personal experience, it's ok to be short ;)
>
> No functional change.
>
> Signed-off-by: Ye Liu <ye.liu@linux.dev>
> Reviewed-by: Zi Yan <ziy@nvidia.com>
> Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
1 nit below but otherwise LGTM so:
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
> ---
> include/linux/hugetlb.h | 9 +++++----
> include/linux/migrate.h | 6 ++++--
> include/linux/page_owner.h | 7 ++++---
> include/trace/events/migrate.h | 8 ++++----
> mm/hugetlb.c | 3 ++-
> mm/migrate.c | 12 ++++++------
> mm/page_owner.c | 2 +-
> 7 files changed, 26 insertions(+), 21 deletions(-)
>
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 2abaf99321e9..fa828232dfcc 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -154,7 +154,8 @@ long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
> bool folio_isolate_hugetlb(struct folio *folio, struct list_head *list);
> int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison);
> void folio_putback_hugetlb(struct folio *folio);
> -void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio, int reason);
> +void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio,
> + enum migrate_reason reason);
> void hugetlb_fix_reserve_counts(struct inode *inode);
> extern struct mutex *hugetlb_fault_mutex_table;
> u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx);
> @@ -424,7 +425,7 @@ static inline void folio_putback_hugetlb(struct folio *folio)
> }
>
> static inline void move_hugetlb_state(struct folio *old_folio,
> - struct folio *new_folio, int reason)
> + struct folio *new_folio, enum migrate_reason reason)
> {
> }
>
> @@ -956,7 +957,7 @@ static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask)
> return modified_mask;
> }
>
> -static inline bool htlb_allow_alloc_fallback(int reason)
> +static inline bool htlb_allow_alloc_fallback(enum migrate_reason reason)
> {
> bool allowed_fallback = false;
>
> @@ -1238,7 +1239,7 @@ static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask)
> return 0;
> }
>
> -static inline bool htlb_allow_alloc_fallback(int reason)
> +static inline bool htlb_allow_alloc_fallback(enum migrate_reason reason)
> {
> return false;
> }
> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
> index d5af2b7f577b..1f83924615d6 100644
> --- a/include/linux/migrate.h
> +++ b/include/linux/migrate.h
> @@ -57,7 +57,8 @@ void putback_movable_pages(struct list_head *l);
> int migrate_folio(struct address_space *mapping, struct folio *dst,
> struct folio *src, enum migrate_mode mode);
> int migrate_pages(struct list_head *l, new_folio_t new, free_folio_t free,
> - unsigned long private, enum migrate_mode mode, int reason,
> + unsigned long private, enum migrate_mode mode,
> + enum migrate_reason reason,
> unsigned int *ret_succeeded);
> struct folio *alloc_migration_target(struct folio *src, unsigned long private);
> bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode);
> @@ -77,7 +78,8 @@ int set_movable_ops(const struct movable_operations *ops, enum pagetype type);
> static inline void putback_movable_pages(struct list_head *l) {}
> static inline int migrate_pages(struct list_head *l, new_folio_t new,
> free_folio_t free, unsigned long private,
> - enum migrate_mode mode, int reason, unsigned int *ret_succeeded)
> + enum migrate_mode mode, enum migrate_reason reason,
> + unsigned int *ret_succeeded)
> { return -ENOSYS; }
> static inline struct folio *alloc_migration_target(struct folio *src,
> unsigned long private)
> diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h
> index 3328357f6dba..9fe51dfccf26 100644
> --- a/include/linux/page_owner.h
> +++ b/include/linux/page_owner.h
> @@ -3,6 +3,7 @@
> #define __LINUX_PAGE_OWNER_H
>
> #include <linux/jump_label.h>
> +#include <linux/migrate_mode.h>
>
> #ifdef CONFIG_PAGE_OWNER
> extern struct static_key_false page_owner_inited;
> @@ -14,7 +15,7 @@ extern void __set_page_owner(struct page *page,
> extern void __split_page_owner(struct page *page, int old_order,
> int new_order);
> extern void __folio_copy_owner(struct folio *newfolio, struct folio *old);
> -extern void __folio_set_owner_migrate_reason(struct folio *folio, int reason);
> +extern void __folio_set_owner_migrate_reason(struct folio *folio, enum migrate_reason reason);
NIT: We drop externs when we change them as a rule, the extern is unnecessary.
> extern void __dump_page_owner(const struct page *page);
> extern void pagetypeinfo_showmixedcount_print(struct seq_file *m,
> pg_data_t *pgdat, struct zone *zone);
> @@ -43,7 +44,7 @@ static inline void folio_copy_owner(struct folio *newfolio, struct folio *old)
> if (static_branch_unlikely(&page_owner_inited))
> __folio_copy_owner(newfolio, old);
> }
> -static inline void folio_set_owner_migrate_reason(struct folio *folio, int reason)
> +static inline void folio_set_owner_migrate_reason(struct folio *folio, enum migrate_reason reason)
> {
> if (static_branch_unlikely(&page_owner_inited))
> __folio_set_owner_migrate_reason(folio, reason);
> @@ -68,7 +69,7 @@ static inline void split_page_owner(struct page *page, int old_order,
> static inline void folio_copy_owner(struct folio *newfolio, struct folio *folio)
> {
> }
> -static inline void folio_set_owner_migrate_reason(struct folio *folio, int reason)
> +static inline void folio_set_owner_migrate_reason(struct folio *folio, enum migrate_reason reason)
> {
> }
> static inline void dump_page_owner(const struct page *page)
> diff --git a/include/trace/events/migrate.h b/include/trace/events/migrate.h
> index 11bc0aa14c7e..15ee2ef201b5 100644
> --- a/include/trace/events/migrate.h
> +++ b/include/trace/events/migrate.h
> @@ -52,7 +52,7 @@ TRACE_EVENT(mm_migrate_pages,
> TP_PROTO(unsigned long succeeded, unsigned long failed,
> unsigned long thp_succeeded, unsigned long thp_failed,
> unsigned long thp_split, unsigned long large_folio_split,
> - enum migrate_mode mode, int reason),
> + enum migrate_mode mode, enum migrate_reason reason),
>
> TP_ARGS(succeeded, failed, thp_succeeded, thp_failed,
> thp_split, large_folio_split, mode, reason),
> @@ -65,7 +65,7 @@ TRACE_EVENT(mm_migrate_pages,
> __field( unsigned long, thp_split)
> __field( unsigned long, large_folio_split)
> __field( enum migrate_mode, mode)
> - __field( int, reason)
> + __field( enum migrate_reason, reason)
> ),
>
> TP_fast_assign(
> @@ -92,13 +92,13 @@ TRACE_EVENT(mm_migrate_pages,
>
> TRACE_EVENT(mm_migrate_pages_start,
>
> - TP_PROTO(enum migrate_mode mode, int reason),
> + TP_PROTO(enum migrate_mode mode, enum migrate_reason reason),
>
> TP_ARGS(mode, reason),
>
> TP_STRUCT__entry(
> __field(enum migrate_mode, mode)
> - __field(int, reason)
> + __field(enum migrate_reason, reason)
> ),
>
> TP_fast_assign(
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 571212b80835..17732d1fdc5e 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -7182,7 +7182,8 @@ void folio_putback_hugetlb(struct folio *folio)
> folio_put(folio);
> }
>
> -void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio, int reason)
> +void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio,
> + enum migrate_reason reason)
> {
> struct hstate *h = folio_hstate(old_folio);
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index d9b23909d716..49e10feeb094 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1469,7 +1469,7 @@ static int migrate_folio_move(free_folio_t put_new_folio, unsigned long private,
> static int unmap_and_move_huge_page(new_folio_t get_new_folio,
> free_folio_t put_new_folio, unsigned long private,
> struct folio *src, int force, enum migrate_mode mode,
> - int reason, struct list_head *ret)
> + enum migrate_reason reason, struct list_head *ret)
> {
> struct folio *dst;
> int rc = -EAGAIN;
> @@ -1626,7 +1626,7 @@ struct migrate_pages_stats {
> */
> static int migrate_hugetlbs(struct list_head *from, new_folio_t get_new_folio,
> free_folio_t put_new_folio, unsigned long private,
> - enum migrate_mode mode, int reason,
> + enum migrate_mode mode, enum migrate_reason reason,
> struct migrate_pages_stats *stats,
> struct list_head *ret_folios)
> {
> @@ -1716,7 +1716,7 @@ static int migrate_hugetlbs(struct list_head *from, new_folio_t get_new_folio,
> static void migrate_folios_move(struct list_head *src_folios,
> struct list_head *dst_folios,
> free_folio_t put_new_folio, unsigned long private,
> - enum migrate_mode mode, int reason,
> + enum migrate_mode mode, enum migrate_reason reason,
> struct list_head *ret_folios,
> struct migrate_pages_stats *stats,
> int *retry, int *thp_retry, int *nr_failed,
> @@ -1799,7 +1799,7 @@ static void migrate_folios_undo(struct list_head *src_folios,
> */
> static int migrate_pages_batch(struct list_head *from,
> new_folio_t get_new_folio, free_folio_t put_new_folio,
> - unsigned long private, enum migrate_mode mode, int reason,
> + unsigned long private, enum migrate_mode mode, enum migrate_reason reason,
> struct list_head *ret_folios, struct list_head *split_folios,
> struct migrate_pages_stats *stats, int nr_pass)
> {
> @@ -2011,7 +2011,7 @@ static int migrate_pages_batch(struct list_head *from,
>
> static int migrate_pages_sync(struct list_head *from, new_folio_t get_new_folio,
> free_folio_t put_new_folio, unsigned long private,
> - enum migrate_mode mode, int reason,
> + enum migrate_mode mode, enum migrate_reason reason,
> struct list_head *ret_folios, struct list_head *split_folios,
> struct migrate_pages_stats *stats)
> {
> @@ -2088,7 +2088,7 @@ static int migrate_pages_sync(struct list_head *from, new_folio_t get_new_folio,
> */
> int migrate_pages(struct list_head *from, new_folio_t get_new_folio,
> free_folio_t put_new_folio, unsigned long private,
> - enum migrate_mode mode, int reason, unsigned int *ret_succeeded)
> + enum migrate_mode mode, enum migrate_reason reason, unsigned int *ret_succeeded)
> {
> int rc, rc_gather;
> int nr_pages;
> diff --git a/mm/page_owner.c b/mm/page_owner.c
> index c2f43ab860eb..4e352941a6e2 100644
> --- a/mm/page_owner.c
> +++ b/mm/page_owner.c
> @@ -345,7 +345,7 @@ noinline void __set_page_owner(struct page *page, unsigned short order,
> inc_stack_record_count(handle, gfp_mask, 1 << order);
> }
>
> -void __folio_set_owner_migrate_reason(struct folio *folio, int reason)
> +void __folio_set_owner_migrate_reason(struct folio *folio, enum migrate_reason reason)
> {
> struct page_ext *page_ext = page_ext_get(&folio->page);
> struct page_owner *page_owner;
> --
> 2.43.0
>
Cheers, Lorenzo
next prev parent reply other threads:[~2026-07-01 10:23 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-01 6:10 [PATCH v5 0/9] mm/page_owner: misc cleanups Ye Liu
2026-07-01 6:10 ` [PATCH v5 1/9] mm/page_owner: extract skip_buddy_pages() helper to unify buddy page skipping Ye Liu
2026-07-01 6:10 ` [PATCH v5 2/9] mm/page_owner: add MR_NEVER to enum migrate_reason and use it for last_migrate_reason Ye Liu
2026-07-01 6:10 ` [PATCH v5 3/9] mm: use enum migrate_reason instead of int for migration reason parameters Ye Liu
2026-07-01 10:23 ` Lorenzo Stoakes [this message]
2026-07-01 6:10 ` [PATCH v5 4/9] mm/page_owner: hoist CONFIG_MEMCG to function level for print_page_owner_memcg() Ye Liu
2026-07-01 6:10 ` [PATCH v5 5/9] mm/page_owner: add missing newline to count_threshold format string Ye Liu
2026-07-01 6:10 ` [PATCH v5 6/9] mm/page_owner: move free_ts_nsec output to free section in __dump_page_owner() Ye Liu
2026-07-01 6:10 ` [PATCH v5 7/9] mm/page_owner: drop redundant page_owner prefix from static symbols Ye Liu
2026-07-01 6:10 ` [PATCH v5 8/9] mm/page_owner: clamp skip_buddy_pages() PFN advance at MAX_ORDER_NR_PAGES boundary Ye Liu
2026-07-01 6:34 ` Vlastimil Babka (SUSE)
2026-07-01 6:10 ` [PATCH v5 9/9] mm/page_owner: use memcg_data snapshot instead of PageMemcgKmem() to avoid TOCTOU VM_BUG_ON Ye Liu
2026-07-01 6:49 ` Vlastimil Babka (SUSE)
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