[PATCH v13 084/137] mm/filemap: Add filemap_alloc_folio

Matthew Wilcox (Oracle)
2021-07-12T03:53:27Z

Reimplement __page_cache_alloc as a wrapper around filemap_alloc_folio
to allow filesystems to be converted at our leisure. Increases
kernel text size by 133 bytes, mostly in cachefiles_read_backing_file().
pagecache_get_page() shrinks by 32 bytes, though.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
include/linux/pagemap.h | 11 ++++++++---
mm/filemap.c | 14 +++++++-------
2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index c0506722d209..5c9d8235fc4e 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -262,14 +262,19 @@ static inline void *detach_page_private(struct page *page)
}

#ifdef CONFIG_NUMA
-extern struct page *__page_cache_alloc(gfp_t gfp);
+struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order);
#else
-static inline struct page *__page_cache_alloc(gfp_t gfp)
+static inline struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order)
{
- return alloc_pages(gfp, 0);
+ return alloc_folio(gfp, order);
}
#endif

+static inline struct page *__page_cache_alloc(gfp_t gfp)
+{
+ return &filemap_alloc_folio(gfp, 0)->page;
+}
+
static inline struct page *page_cache_alloc(struct address_space *x)
{
return __page_cache_alloc(mapping_gfp_mask(x));
diff --git a/mm/filemap.c b/mm/filemap.c
index b0c9b4030144..6e721b283cb5 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -989,24 +989,24 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
EXPORT_SYMBOL_GPL(add_to_page_cache_lru);

#ifdef CONFIG_NUMA
-struct page *__page_cache_alloc(gfp_t gfp)
+struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order)
{
int n;
- struct page *page;
+ struct folio *folio;

if (cpuset_do_page_mem_spread()) {
unsigned int cpuset_mems_cookie;
do {
cpuset_mems_cookie = read_mems_allowed_begin();
n = cpuset_mem_spread_node();
- page = __alloc_pages_node(n, gfp, 0);
- } while (!page && read_mems_allowed_retry(cpuset_mems_cookie));
+ folio = __alloc_folio_node(gfp, order, n);
+ } while (!folio && read_mems_allowed_retry(cpuset_mems_cookie));

- return page;
+ return folio;
}
- return alloc_pages(gfp, 0);
+ return alloc_folio(gfp, order);
}
-EXPORT_SYMBOL(__page_cache_alloc);
+EXPORT_SYMBOL(filemap_alloc_folio);
#endif

/*
--
2.30.2