[PATCH v13 061/137] mm/migrate: Add folio_migrate_flags()

Matthew Wilcox (Oracle)
2021-07-12T03:40:37Z

Turn migrate_page_states() into a wrapper around folio_migrate_flags().
Also convert two functions only called from folio_migrate_flags() to
be folio-based. ksm_migrate_page() becomes folio_migrate_ksm() and
copy_page_owner() becomes folio_copy_owner(). folio_migrate_flags()
alone shrinks by two thirds -- 1967 bytes down to 642 bytes.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/ksm.h | 4 +-
include/linux/migrate.h | 1 +
include/linux/page_owner.h | 8 ++--
mm/folio-compat.c | 6 +++
mm/ksm.c | 31 ++++++++------
mm/migrate.c | 84 +++++++++++++++++++-------------------
mm/page_owner.c | 10 ++---
7 files changed, 77 insertions(+), 67 deletions(-)

diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index 161e8164abcf..a38a5bca1ba5 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h
@@ -52,7 +52,7 @@ struct page *ksm_might_need_to_copy(struct page *page,
struct vm_area_struct *vma, unsigned long address);

void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc);
-void ksm_migrate_page(struct page *newpage, struct page *oldpage);
+void folio_migrate_ksm(struct folio *newfolio, struct folio *folio);

#else /* !CONFIG_KSM */

@@ -83,7 +83,7 @@ static inline void rmap_walk_ksm(struct page *page,
{
}

-static inline void ksm_migrate_page(struct page *newpage, struct page *oldpage)
+static inline void folio_migrate_ksm(struct folio *newfolio, struct folio *old)
{
}
#endif /* CONFIG_MMU */
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 52bf62763205..b9cd88915c6b 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -52,6 +52,7 @@ extern int migrate_huge_page_move_mapping(struct address_space *mapping,
extern int migrate_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page, int extra_count);
extern void copy_huge_page(struct page *dst, struct page *src);
+void folio_migrate_flags(struct folio *newfolio, struct folio *folio);
int folio_migrate_mapping(struct address_space *mapping,
struct folio *newfolio, struct folio *folio, int extra_count);
#else
diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h
index 719bfe5108c5..43c638c51c1f 100644
--- a/include/linux/page_owner.h
+++ b/include/linux/page_owner.h
@@ -12,7 +12,7 @@ extern void __reset_page_owner(struct page *page, unsigned int order);
extern void __set_page_owner(struct page *page,
unsigned int order, gfp_t gfp_mask);
extern void __split_page_owner(struct page *page, unsigned int nr);
-extern void __copy_page_owner(struct page *oldpage, struct page *newpage);
+extern void __folio_copy_owner(struct folio *newfolio, struct folio *old);
extern void __set_page_owner_migrate_reason(struct page *page, int reason);
extern void __dump_page_owner(const struct page *page);
extern void pagetypeinfo_showmixedcount_print(struct seq_file *m,
@@ -36,10 +36,10 @@ static inline void split_page_owner(struct page *page, unsigned int nr)
if (static_branch_unlikely(&page_owner_inited))
__split_page_owner(page, nr);
}
-static inline void copy_page_owner(struct page *oldpage, struct page *newpage)
+static inline void folio_copy_owner(struct folio *newfolio, struct folio *old)
{
if (static_branch_unlikely(&page_owner_inited))
- __copy_page_owner(oldpage, newpage);
+ __folio_copy_owner(newfolio, old);
}
static inline void set_page_owner_migrate_reason(struct page *page, int reason)
{
@@ -63,7 +63,7 @@ static inline void split_page_owner(struct page *page,
unsigned int order)
{
}
-static inline void copy_page_owner(struct page *oldpage, struct page *newpage)
+static inline void folio_copy_owner(struct folio *newfolio, struct folio *folio)
{
}
static inline void set_page_owner_migrate_reason(struct page *page, int reason)
diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index d883d964fd52..3f00ad92d1ff 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -58,4 +58,10 @@ int migrate_page_move_mapping(struct address_space *mapping,
page_folio(page), extra_count);
}
EXPORT_SYMBOL(migrate_page_move_mapping);
+
+void migrate_page_states(struct page *newpage, struct page *page)
+{
+ folio_migrate_flags(page_folio(newpage), page_folio(page));
+}
+EXPORT_SYMBOL(migrate_page_states);
#endif
diff --git a/mm/ksm.c b/mm/ksm.c
index 23d36b59f997..82875051872d 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -753,7 +753,7 @@ static struct page *get_ksm_page(struct stable_node *stable_node,
/*
* We come here from above when page->mapping or !PageSwapCache
* suggests that the node is stale; but it might be under migration.
- * We need smp_rmb(), matching the smp_wmb() in ksm_migrate_page(),
+ * We need smp_rmb(), matching the smp_wmb() in folio_migrate_ksm(),
* before checking whether node->kpfn has been changed.
*/
smp_rmb();
@@ -854,9 +854,14 @@ static int unmerge_ksm_pages(struct vm_area_struct *vma,
return err;
}

+static inline struct stable_node *folio_stable_node(struct folio *folio)
+{
+ return folio_ksm(folio) ? folio_rmapping(folio) : NULL;
+}
+
static inline struct stable_node *page_stable_node(struct page *page)
{
- return PageKsm(page) ? page_rmapping(page) : NULL;
+ return folio_stable_node(page_folio(page));
}

static inline void set_page_stable_node(struct page *page,
@@ -2661,26 +2666,26 @@ void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
}

#ifdef CONFIG_MIGRATION
-void ksm_migrate_page(struct page *newpage, struct page *oldpage)
+void folio_migrate_ksm(struct folio *newfolio, struct folio *folio)
{
struct stable_node *stable_node;

- VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
- VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
- VM_BUG_ON_PAGE(newpage->mapping != oldpage->mapping, newpage);
+ VM_BUG_ON_FOLIO(!folio_locked(folio), folio);
+ VM_BUG_ON_FOLIO(!folio_locked(newfolio), newfolio);
+ VM_BUG_ON_FOLIO(newfolio->mapping != folio->mapping, newfolio);

- stable_node = page_stable_node(newpage);
+ stable_node = folio_stable_node(folio);
if (stable_node) {
- VM_BUG_ON_PAGE(stable_node->kpfn != page_to_pfn(oldpage), oldpage);
- stable_node->kpfn = page_to_pfn(newpage);
+ VM_BUG_ON_FOLIO(stable_node->kpfn != folio_pfn(folio), folio);
+ stable_node->kpfn = folio_pfn(newfolio);
/*
- * newpage->mapping was set in advance; now we need smp_wmb()
+ * newfolio->mapping was set in advance; now we need smp_wmb()
* to make sure that the new stable_node->kpfn is visible
- * to get_ksm_page() before it can see that oldpage->mapping
- * has gone stale (or that PageSwapCache has been cleared).
+ * to get_ksm_page() before it can see that folio->mapping
+ * has gone stale (or that folio_swapcache has been cleared).
*/
smp_wmb();
- set_page_stable_node(oldpage, NULL);
+ set_page_stable_node(&folio->page, NULL);
}
}
#endif /* CONFIG_MIGRATION */
diff --git a/mm/migrate.c b/mm/migrate.c
index 19dd053b4a52..c16923052e13 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -586,82 +586,80 @@ void copy_huge_page(struct page *dst, struct page *src)
}

/*
- * Copy the page to its new location
+ * Copy the flags and some other ancillary information
*/
-void migrate_page_states(struct page *newpage, struct page *page)
+void folio_migrate_flags(struct folio *newfolio, struct folio *folio)
{
- struct folio *folio = page_folio(page);
- struct folio *newfolio = page_folio(newpage);
int cpupid;

- if (PageError(page))
- SetPageError(newpage);
- if (PageReferenced(page))
- SetPageReferenced(newpage);
- if (PageUptodate(page))
- SetPageUptodate(newpage);
- if (TestClearPageActive(page)) {
- VM_BUG_ON_PAGE(PageUnevictable(page), page);
- SetPageActive(newpage);
- } else if (TestClearPageUnevictable(page))
- SetPageUnevictable(newpage);
- if (PageWorkingset(page))
- SetPageWorkingset(newpage);
- if (PageChecked(page))
- SetPageChecked(newpage);
- if (PageMappedToDisk(page))
- SetPageMappedToDisk(newpage);
+ if (folio_error(folio))
+ folio_set_error_flag(newfolio);
+ if (folio_referenced(folio))
+ folio_set_referenced_flag(newfolio);
+ if (folio_uptodate(folio))
+ folio_mark_uptodate(newfolio);
+ if (folio_test_clear_active_flag(folio)) {
+ VM_BUG_ON_FOLIO(folio_unevictable(folio), folio);
+ folio_set_active_flag(newfolio);
+ } else if (folio_test_clear_unevictable_flag(folio))
+ folio_set_unevictable_flag(newfolio);
+ if (folio_workingset(folio))
+ folio_set_workingset_flag(newfolio);
+ if (folio_checked(folio))
+ folio_set_checked_flag(newfolio);
+ if (folio_mappedtodisk(folio))
+ folio_set_mappedtodisk_flag(newfolio);

/* Move dirty on pages not done by folio_migrate_mapping() */
- if (PageDirty(page))
- SetPageDirty(newpage);
+ if (folio_dirty(folio))
+ folio_set_dirty_flag(newfolio);

- if (page_is_young(page))
- set_page_young(newpage);
- if (page_is_idle(page))
- set_page_idle(newpage);
+ if (folio_young(folio))
+ folio_set_young_flag(newfolio);
+ if (folio_idle(folio))
+ folio_set_idle_flag(newfolio);

/*
* Copy NUMA information to the new page, to prevent over-eager
* future migrations of this same page.
*/
- cpupid = page_cpupid_xchg_last(page, -1);
- page_cpupid_xchg_last(newpage, cpupid);
+ cpupid = page_cpupid_xchg_last(&folio->page, -1);
+ page_cpupid_xchg_last(&newfolio->page, cpupid);

- ksm_migrate_page(newpage, page);
+ folio_migrate_ksm(newfolio, folio);
/*
* Please do not reorder this without considering how mm/ksm.c's
* get_ksm_page() depends upon ksm_migrate_page() and PageSwapCache().
*/
- if (PageSwapCache(page))
- ClearPageSwapCache(page);
- ClearPagePrivate(page);
+ if (folio_swapcache(folio))
+ folio_clear_swapcache_flag(folio);
+ folio_clear_private_flag(folio);

/* page->private contains hugetlb specific flags */
- if (!PageHuge(page))
- set_page_private(page, 0);
+ if (!folio_hugetlb(folio))
+ folio->private = NULL;

/*
* If any waiters have accumulated on the new page then
* wake them up.
*/
- if (PageWriteback(newpage))
- end_page_writeback(newpage);
+ if (folio_writeback(newfolio))
+ folio_end_writeback(newfolio);

/*
* PG_readahead shares the same bit with PG_reclaim. The above
* end_page_writeback() may clear PG_readahead mistakenly, so set the
* bit after that.
*/
- if (PageReadahead(page))
- SetPageReadahead(newpage);
+ if (folio_readahead(folio))
+ folio_set_readahead_flag(newfolio);

- copy_page_owner(page, newpage);
+ folio_copy_owner(folio, newfolio);

- if (!PageHuge(page))
+ if (!folio_hugetlb(folio))
mem_cgroup_migrate(folio, newfolio);
}
-EXPORT_SYMBOL(migrate_page_states);
+EXPORT_SYMBOL(folio_migrate_flags);

void migrate_page_copy(struct page *newpage, struct page *page)
{
@@ -702,7 +700,7 @@ int migrate_page(struct address_space *mapping,
if (mode != MIGRATE_SYNC_NO_COPY)
migrate_page_copy(newpage, page);
else
- migrate_page_states(newpage, page);
+ folio_migrate_flags(newfolio, folio);
return MIGRATEPAGE_SUCCESS;
}
EXPORT_SYMBOL(migrate_page);
diff --git a/mm/page_owner.c b/mm/page_owner.c
index f51a57e92aa3..23bfb074ca3f 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -210,10 +210,10 @@ void __split_page_owner(struct page *page, unsigned int nr)
}
}

-void __copy_page_owner(struct page *oldpage, struct page *newpage)
+void __folio_copy_owner(struct folio *newfolio, struct folio *old)
{
- struct page_ext *old_ext = lookup_page_ext(oldpage);
- struct page_ext *new_ext = lookup_page_ext(newpage);
+ struct page_ext *old_ext = lookup_page_ext(&old->page);
+ struct page_ext *new_ext = lookup_page_ext(&newfolio->page);
struct page_owner *old_page_owner, *new_page_owner;

if (unlikely(!old_ext || !new_ext))
@@ -231,11 +231,11 @@ void __copy_page_owner(struct page *oldpage, struct page *newpage)
new_page_owner->free_ts_nsec = old_page_owner->ts_nsec;

/*
- * We don't clear the bit on the oldpage as it's going to be freed
+ * We don't clear the bit on the old folio as it's going to be freed
* after migration. Until then, the info can be useful in case of
* a bug, and the overall stats will be off a bit only temporarily.
* Also, migrate_misplaced_transhuge_page() can still fail the
- * migration and then we want the oldpage to retain the info. But
+ * migration and then we want the old folio to retain the info. But
* in that case we also don't need to explicitly clear the info from
* the new page, which will be freed.
*/
--
2.30.2