This is a preparation for migrc mechanism that frees folios at a better time later, rather than the moment migrating folios. The folios freed by migrc are too old to keep in pcp. Signed-off-by: Byungchul Park <byungchul@xxxxxx> --- include/linux/mm.h | 23 +++++++++++++++++++++++ mm/internal.h | 1 + mm/page_alloc.c | 10 ++++++++++ mm/swap.c | 7 +++++++ 4 files changed, 41 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index da5219b48d52..fc0581cce3a7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1284,6 +1284,7 @@ static inline struct folio *virt_to_folio(const void *x) } void __folio_put(struct folio *folio); +void __folio_put_small_nopcp(struct folio *folio); void put_pages_list(struct list_head *pages); @@ -1483,6 +1484,28 @@ static inline void folio_put(struct folio *folio) __folio_put(folio); } +/** + * folio_put_small_nopcp - Decrement the reference count on a folio. + * @folio: The folio. + * + * This is only for a single page folio to release directly to the buddy + * allocator bypassing pcp. + * + * If the folio's reference count reaches zero, the memory will be + * released back to the page allocator and may be used by another + * allocation immediately. Do not access the memory or the struct folio + * after calling folio_put_small_nopcp() unless you can be sure that it + * wasn't the last reference. + * + * Context: May be called in process or interrupt context, but not in NMI + * context. May be called while holding a spinlock. + */ +static inline void folio_put_small_nopcp(struct folio *folio) +{ + if (folio_put_testzero(folio)) + __folio_put_small_nopcp(folio); +} + /** * folio_put_refs - Reduce the reference count on a folio. * @folio: The folio. diff --git a/mm/internal.h b/mm/internal.h index b880f1e78700..3be8fd5604e8 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -451,6 +451,7 @@ extern int user_min_free_kbytes; extern void free_unref_page(struct page *page, unsigned int order); extern void free_unref_page_list(struct list_head *list); +extern void free_pages_nopcp(struct page *page, unsigned int order); extern void zone_pcp_reset(struct zone *zone); extern void zone_pcp_disable(struct zone *zone); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 733732e7e0ba..21b8c8cd1673 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -565,6 +565,16 @@ static inline void free_the_page(struct page *page, unsigned int order) __free_pages_ok(page, order, FPI_NONE); } +void free_pages_nopcp(struct page *page, unsigned int order) +{ + /* + * This function will be used in case that the pages are too + * cold to keep in pcp e.g. migrc mechanism. So it'd better + * release the pages to the tail. + */ + __free_pages_ok(page, order, FPI_TO_TAIL); +} + /* * Higher-order pages are called "compound pages". They are structured thusly: * diff --git a/mm/swap.c b/mm/swap.c index cd8f0150ba3a..3f37496a1184 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -106,6 +106,13 @@ static void __folio_put_small(struct folio *folio) free_unref_page(&folio->page, 0); } +void __folio_put_small_nopcp(struct folio *folio) +{ + __page_cache_release(folio); + mem_cgroup_uncharge(folio); + free_pages_nopcp(&folio->page, 0); +} + static void __folio_put_large(struct folio *folio) { /* -- 2.17.1