[PATCH 1/2] mm: Allow the page cache to allocate large pages

[William Kucharski <william.kucharski@oracle.com>]

Signed-off-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: William Kucharski <william.kucharski@oracle.com> 
---
 fs/afs/dir.c            |  2 +-
 fs/btrfs/compression.c  |  2 +-
 fs/cachefiles/rdwr.c    |  4 ++--
 fs/ceph/addr.c          |  2 +-
 fs/ceph/file.c          |  2 +-
 include/linux/pagemap.h | 13 +++++++++----
 mm/filemap.c            | 25 +++++++++++++------------
 mm/readahead.c          |  2 +-
 net/ceph/pagelist.c     |  4 ++--
 net/ceph/pagevec.c      |  2 +-
 10 files changed, 32 insertions(+), 26 deletions(-)

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index e640d67274be..0a392214f71e 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -274,7 +274,7 @@ static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key)
 				afs_stat_v(dvnode, n_inval);
 
 			ret = -ENOMEM;
-			req->pages[i] = __page_cache_alloc(gfp);
+			req->pages[i] = __page_cache_alloc(gfp, 0);
 			if (!req->pages[i])
 				goto error;
 			ret = add_to_page_cache_lru(req->pages[i],
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 60c47b417a4b..5280e7477b7e 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -466,7 +466,7 @@ static noinline int add_ra_bio_pages(struct inode *inode,
 		}
 
 		page = __page_cache_alloc(mapping_gfp_constraint(mapping,
-								 ~__GFP_FS));
+								 ~__GFP_FS), 0);
 		if (!page)
 			break;
 
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
index 44a3ce1e4ce4..11d30212745f 100644
--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -259,7 +259,7 @@ static int cachefiles_read_backing_file_one(struct cachefiles_object *object,
 			goto backing_page_already_present;
 
 		if (!newpage) {
-			newpage = __page_cache_alloc(cachefiles_gfp);
+			newpage = __page_cache_alloc(cachefiles_gfp, 0);
 			if (!newpage)
 				goto nomem_monitor;
 		}
@@ -495,7 +495,7 @@ static int cachefiles_read_backing_file(struct cachefiles_object *object,
 				goto backing_page_already_present;
 
 			if (!newpage) {
-				newpage = __page_cache_alloc(cachefiles_gfp);
+				newpage = __page_cache_alloc(cachefiles_gfp, 0);
 				if (!newpage)
 					goto nomem;
 			}
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index e078cc55b989..bcb41fbee533 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1707,7 +1707,7 @@ int ceph_uninline_data(struct file *filp, struct page *locked_page)
 		if (len > PAGE_SIZE)
 			len = PAGE_SIZE;
 	} else {
-		page = __page_cache_alloc(GFP_NOFS);
+		page = __page_cache_alloc(GFP_NOFS, 0);
 		if (!page) {
 			err = -ENOMEM;
 			goto out;
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 685a03cc4b77..ae58d7c31aa4 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1305,7 +1305,7 @@ static ssize_t ceph_read_iter(struct kiocb *iocb, struct iov_iter *to)
 		struct page *page = NULL;
 		loff_t i_size;
 		if (retry_op == READ_INLINE) {
-			page = __page_cache_alloc(GFP_KERNEL);
+			page = __page_cache_alloc(GFP_KERNEL, 0);
 			if (!page)
 				return -ENOMEM;
 		}
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index c7552459a15f..e9004e3cb6a3 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -208,17 +208,17 @@ static inline int page_cache_add_speculative(struct page *page, int count)
 }
 
 #ifdef CONFIG_NUMA
-extern struct page *__page_cache_alloc(gfp_t gfp);
+extern struct page *__page_cache_alloc(gfp_t gfp, unsigned int order);
 #else
-static inline struct page *__page_cache_alloc(gfp_t gfp)
+static inline struct page *__page_cache_alloc(gfp_t gfp, unsigned int order)
 {
-	return alloc_pages(gfp, 0);
+	return alloc_pages(gfp, order);
 }
 #endif
 
 static inline struct page *page_cache_alloc(struct address_space *x)
 {
-	return __page_cache_alloc(mapping_gfp_mask(x));
+	return __page_cache_alloc(mapping_gfp_mask(x), 0);
 }
 
 static inline gfp_t readahead_gfp_mask(struct address_space *x)
@@ -240,6 +240,11 @@ pgoff_t page_cache_prev_miss(struct address_space *mapping,
 #define FGP_NOFS		0x00000010
 #define FGP_NOWAIT		0x00000020
 #define FGP_FOR_MMAP		0x00000040
+/* If you add more flags, increment FGP_ORDER_SHIFT */
+#define	FGP_ORDER_SHIFT		7
+#define	FGP_PMD			((PMD_SHIFT - PAGE_SHIFT) << FGP_ORDER_SHIFT)
+#define	FGP_PUD			((PUD_SHIFT - PAGE_SHIFT) << FGP_ORDER_SHIFT)
+#define	fgp_get_order(fgp)	((fgp) >> FGP_ORDER_SHIFT)
 
 struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset,
 		int fgp_flags, gfp_t cache_gfp_mask);
diff --git a/mm/filemap.c b/mm/filemap.c
index d0cf700bf201..eb4c87428099 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -954,7 +954,7 @@ 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 page *__page_cache_alloc(gfp_t gfp, unsigned int order)
 {
 	int n;
 	struct page *page;
@@ -964,12 +964,12 @@ struct page *__page_cache_alloc(gfp_t gfp)
 		do {
 			cpuset_mems_cookie = read_mems_allowed_begin();
 			n = cpuset_mem_spread_node();
-			page = __alloc_pages_node(n, gfp, 0);
+			page = __alloc_pages_node(n, gfp, order);
 		} while (!page && read_mems_allowed_retry(cpuset_mems_cookie));
 
 		return page;
 	}
-	return alloc_pages(gfp, 0);
+	return alloc_pages(gfp, order);
 }
 EXPORT_SYMBOL(__page_cache_alloc);
 #endif
@@ -1597,12 +1597,12 @@ EXPORT_SYMBOL(find_lock_entry);
  * pagecache_get_page - find and get a page reference
  * @mapping: the address_space to search
  * @offset: the page index
- * @fgp_flags: PCG flags
+ * @fgp_flags: FGP flags
  * @gfp_mask: gfp mask to use for the page cache data page allocation
  *
  * Looks up the page cache slot at @mapping & @offset.
  *
- * PCG flags modify how the page is returned.
+ * FGP flags modify how the page is returned.
  *
  * @fgp_flags can be:
  *
@@ -1615,6 +1615,7 @@ EXPORT_SYMBOL(find_lock_entry);
  * - FGP_FOR_MMAP: Similar to FGP_CREAT, only we want to allow the caller to do
  *   its own locking dance if the page is already in cache, or unlock the page
  *   before returning if we had to add the page to pagecache.
+ * - FGP_PMD: If FGP_CREAT is specified, attempt to allocate a PMD-sized page.
  *
  * If FGP_LOCK or FGP_CREAT are specified then the function may sleep even
  * if the GFP flags specified for FGP_CREAT are atomic.
@@ -1660,12 +1661,13 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset,
 no_page:
 	if (!page && (fgp_flags & FGP_CREAT)) {
 		int err;
-		if ((fgp_flags & FGP_WRITE) && mapping_cap_account_dirty(mapping))
+		if ((fgp_flags & FGP_WRITE) &&
+			mapping_cap_account_dirty(mapping))
 			gfp_mask |= __GFP_WRITE;
 		if (fgp_flags & FGP_NOFS)
 			gfp_mask &= ~__GFP_FS;
 
-		page = __page_cache_alloc(gfp_mask);
+		page = __page_cache_alloc(gfp_mask, fgp_order(fgp_flags));
 		if (!page)
 			return NULL;
 
@@ -2802,15 +2804,14 @@ static struct page *wait_on_page_read(struct page *page)
 static struct page *do_read_cache_page(struct address_space *mapping,
 				pgoff_t index,
 				int (*filler)(void *, struct page *),
-				void *data,
-				gfp_t gfp)
+				void *data, unsigned int order, gfp_t gfp)
 {
 	struct page *page;
 	int err;
 repeat:
 	page = find_get_page(mapping, index);
 	if (!page) {
-		page = __page_cache_alloc(gfp);
+		page = __page_cache_alloc(gfp, order);
 		if (!page)
 			return ERR_PTR(-ENOMEM);
 		err = add_to_page_cache_lru(page, mapping, index, gfp);
@@ -2917,7 +2918,7 @@ struct page *read_cache_page(struct address_space *mapping,
 				int (*filler)(void *, struct page *),
 				void *data)
 {
-	return do_read_cache_page(mapping, index, filler, data,
+	return do_read_cache_page(mapping, index, filler, data, 0,
 			mapping_gfp_mask(mapping));
 }
 EXPORT_SYMBOL(read_cache_page);
@@ -2939,7 +2940,7 @@ struct page *read_cache_page_gfp(struct address_space *mapping,
 				pgoff_t index,
 				gfp_t gfp)
 {
-	return do_read_cache_page(mapping, index, NULL, NULL, gfp);
+	return do_read_cache_page(mapping, index, NULL, NULL, 0, gfp);
 }
 EXPORT_SYMBOL(read_cache_page_gfp);
 
diff --git a/mm/readahead.c b/mm/readahead.c
index 2fe72cd29b47..954760a612ea 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -193,7 +193,7 @@ unsigned int __do_page_cache_readahead(struct address_space *mapping,
 			continue;
 		}
 
-		page = __page_cache_alloc(gfp_mask);
+		page = __page_cache_alloc(gfp_mask, 0);
 		if (!page)
 			break;
 		page->index = page_offset;
diff --git a/net/ceph/pagelist.c b/net/ceph/pagelist.c
index 65e34f78b05d..0c3face908dc 100644
--- a/net/ceph/pagelist.c
+++ b/net/ceph/pagelist.c
@@ -56,7 +56,7 @@ static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
 	struct page *page;
 
 	if (!pl->num_pages_free) {
-		page = __page_cache_alloc(GFP_NOFS);
+		page = __page_cache_alloc(GFP_NOFS, 0);
 	} else {
 		page = list_first_entry(&pl->free_list, struct page, lru);
 		list_del(&page->lru);
@@ -107,7 +107,7 @@ int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space)
 	space = (space + PAGE_SIZE - 1) >> PAGE_SHIFT;   /* conv to num pages */
 
 	while (space > pl->num_pages_free) {
-		struct page *page = __page_cache_alloc(GFP_NOFS);
+		struct page *page = __page_cache_alloc(GFP_NOFS, 0);
 		if (!page)
 			return -ENOMEM;
 		list_add_tail(&page->lru, &pl->free_list);
diff --git a/net/ceph/pagevec.c b/net/ceph/pagevec.c
index 64305e7056a1..1d07e639216d 100644
--- a/net/ceph/pagevec.c
+++ b/net/ceph/pagevec.c
@@ -45,7 +45,7 @@ struct page **ceph_alloc_page_vector(int num_pages, gfp_t flags)
 	if (!pages)
 		return ERR_PTR(-ENOMEM);
 	for (i = 0; i < num_pages; i++) {
-		pages[i] = __page_cache_alloc(flags);
+		pages[i] = __page_cache_alloc(flags, 0);
 		if (pages[i] == NULL) {
 			ceph_release_page_vector(pages, i);
 			return ERR_PTR(-ENOMEM);
-- 
2.21.0