Indirect calls are expensive, thanks to Spectre. Test for
TRANSHUGE_PAGE_DTOR and destroy the folio appropriately. Move the
free_compound_page() call into destroy_large_folio() to simplify later
patches.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
include/linux/huge_mm.h | 2 --
include/linux/mm.h | 2 --
mm/huge_memory.c | 22 +++++++++++-----------
mm/internal.h | 2 ++
mm/page_alloc.c | 9 ++++++---
5 files changed, 19 insertions(+), 18 deletions(-)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 20284387b841..f351c3f9d58b 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -144,8 +144,6 @@ unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags);
void prep_transhuge_page(struct page *page);
-void free_transhuge_page(struct page *page);
-
bool can_split_folio(struct folio *folio, int *pextra_pins);
int split_huge_page_to_list(struct page *page, struct list_head *list);
static inline int split_huge_page(struct page *page)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 19493d6a2bb8..6c338b65b86b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1281,9 +1281,7 @@ enum compound_dtor_id {
#ifdef CONFIG_HUGETLB_PAGE
HUGETLB_PAGE_DTOR,
#endif
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
TRANSHUGE_PAGE_DTOR,
-#endif
NR_COMPOUND_DTORS,
};
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8480728fa220..9598bbe6c792 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2779,10 +2779,9 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
return ret;
}
-void free_transhuge_page(struct page *page)
+void folio_undo_large_rmappable(struct folio *folio)
{
- struct folio *folio = (struct folio *)page;
- struct deferred_split *ds_queue = get_deferred_split_queue(folio);
+ struct deferred_split *ds_queue;
unsigned long flags;
/*
@@ -2790,15 +2789,16 @@ void free_transhuge_page(struct page *page)
* deferred_list. If folio is not in deferred_list, it's safe
* to check without acquiring the split_queue_lock.
*/
- if (data_race(!list_empty(&folio->_deferred_list))) {
- spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
- if (!list_empty(&folio->_deferred_list)) {
- ds_queue->split_queue_len--;
- list_del(&folio->_deferred_list);
- }
- spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
+ if (data_race(list_empty(&folio->_deferred_list)))
+ return;
+
+ ds_queue = get_deferred_split_queue(folio);
+ spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
+ if (!list_empty(&folio->_deferred_list)) {
+ ds_queue->split_queue_len--;
+ list_del(&folio->_deferred_list);
}
- free_compound_page(page);
+ spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
}
void deferred_split_folio(struct folio *folio)
diff --git a/mm/internal.h b/mm/internal.h
index 5a03bc4782a2..1e98c867f0de 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -413,6 +413,8 @@ static inline void folio_set_order(struct folio *folio, unsigned int order)
#endif
}
+void folio_undo_large_rmappable(struct folio *folio);
+
static inline void prep_compound_head(struct page *page, unsigned int order)
{
struct folio *folio = (struct folio *)page;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b569fd5562aa..0dbc2ecdefa5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -287,9 +287,6 @@ const char * const migratetype_names[MIGRATE_TYPES] = {
static compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS] = {
[NULL_COMPOUND_DTOR] = NULL,
[COMPOUND_PAGE_DTOR] = free_compound_page,
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- [TRANSHUGE_PAGE_DTOR] = free_transhuge_page,
-#endif
};
int min_free_kbytes = 1024;
@@ -624,6 +621,12 @@ void destroy_large_folio(struct folio *folio)
return;
}
+ if (folio_test_transhuge(folio) && dtor == TRANSHUGE_PAGE_DTOR) {
+ folio_undo_large_rmappable(folio);
+ free_compound_page(&folio->page);
+ return;
+ }
+
VM_BUG_ON_FOLIO(dtor >= NR_COMPOUND_DTORS, folio);
compound_page_dtors[dtor](&folio->page);
}
--
2.40.1
