From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6B0A5411687; Wed, 1 Jul 2026 10:23:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782901438; cv=none; b=f3SltPWUlXxJ82RBRhyXSr7dnl+n0PiIzKOShJkBPZZ1jNAAnS2423H+SQ08veQ/gcXPdmuNI1nwI7i1Z83i3p8XQdfkbClshvzV0J4QqCFBR8Y7JDfaQbH7DQLGP9t4cKX/d4F0IPSKOOQk1iy437J2+gW1swjyXV2oQ0x2ApE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782901438; c=relaxed/simple; bh=f3MCFPev4jMX0HIBqokaLJ61HFq3aRAPErTa46USvas=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WwnAz7Kp677WZhtERs9QEuhMRNs4yPcy0RahEfLg/etTTqOKXgMIKStP9ALvfRarS4PYTrSCjtAR4X6w66p4LJkfvw0WFLIftmjYAp84QmHiCiDGqqIvRY8dMPa7kEPK6/9aWzRk6IlCuFBfeZAoOx7STY8ZWvwKUDuD/gqiyEs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=X0gX0K89; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="X0gX0K89" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0407C1F000E9; Wed, 1 Jul 2026 10:23:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782901434; bh=wQ8qOYDe5kXztHH+xJLUrlU+iOY7jfOVJOn8zyUOgpA=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=X0gX0K89AEhl6+DSq4hnkO/hI4W5rOjmCIJb0AR9m+PwyStRVf0lIsm/lmnjt2vr3 QxxOaKesl67hWCdXgvKo+yOXn58N6erfdHWm5E5l6GC7BwwLVwkXmXRyxW5k3Sdh8a pFg3Ga20/wO8l/9OrwmZWpU6QT16+77MTPfQtnqjmXLhA97yuKPAMSI8Ce8HQUgOiD Z9Z+zl5gR/d5+5LKPvAE1TbLsnsdcls0ABM3ZpwFrdUIwSmvHq1LahwFbuwY2jpleM q24N7RvO92QuU/OrfqEfDeB3FWoTeokeWPDzPMfSDJ/vOpgSizL3Y7rBN2vzef42g/ o6Wu3FpN1225A== Date: Wed, 1 Jul 2026 11:23:42 +0100 From: Lorenzo Stoakes To: Ye Liu Cc: Muchun Song , Oscar Salvador , Andrew Morton , David Hildenbrand , Steven Rostedt , Masami Hiramatsu , Vlastimil Babka , Zi Yan , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , "Liam R. Howlett" , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Mathieu Desnoyers , Brendan Jackman , Johannes Weiner , 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 Message-ID: References: <20260701061101.344679-1-ye.liu@linux.dev> <20260701061101.344679-4-ye.liu@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 > Reviewed-by: Zi Yan > Reviewed-by: Vlastimil Babka (SUSE) 1 nit below but otherwise LGTM so: Reviewed-by: Lorenzo Stoakes > --- > 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 > +#include > > #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