Commit 0cd6144a authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

mm + fs: prepare for non-page entries in page cache radix trees 



shmem mappings already contain exceptional entries where swap slot
information is remembered.

To be able to store eviction information for regular page cache, prepare
every site dealing with the radix trees directly to handle entries other
than pages.

The common lookup functions will filter out non-page entries and return
NULL for page cache holes, just as before.  But provide a raw version of
the API which returns non-page entries as well, and switch shmem over to
use it.

Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: default avatarRik van Riel <riel@redhat.com>
Reviewed-by: default avatarMinchan Kim <minchan@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Metin Doslu <metin@citusdata.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ozgun Erdogan <ozgun@citusdata.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e7b563bb

fs/btrfs/compression.c

+1 −1
Original line number Diff line number Diff line
@@ -472,7 +472,7 @@ static noinline int add_ra_bio_pages(struct inode *inode, 
		rcu_read_lock();

		page = radix_tree_lookup(&mapping->page_tree, pg_index);

		rcu_read_unlock();

		if (page) {

		if (page && !radix_tree_exceptional_entry(page)) {

			misses++;

			if (misses > 4)

				break;

include/linux/mm.h

+8 −0
Original line number Diff line number Diff line
@@ -1041,6 +1041,14 @@ extern void show_free_areas(unsigned int flags); 
extern bool skip_free_areas_node(unsigned int flags, int nid);



int shmem_zero_setup(struct vm_area_struct *);

#ifdef CONFIG_SHMEM

bool shmem_mapping(struct address_space *mapping);

#else

static inline bool shmem_mapping(struct address_space *mapping)

{

	return false;

}

#endif



extern int can_do_mlock(void);

extern int user_shm_lock(size_t, struct user_struct *);

include/linux/pagemap.h

+9 −6
Original line number Diff line number Diff line
@@ -248,12 +248,15 @@ pgoff_t page_cache_next_hole(struct address_space *mapping, 
pgoff_t page_cache_prev_hole(struct address_space *mapping,

			     pgoff_t index, unsigned long max_scan);



extern struct page * find_get_page(struct address_space *mapping,

				pgoff_t index);

extern struct page * find_lock_page(struct address_space *mapping,

				pgoff_t index);

extern struct page * find_or_create_page(struct address_space *mapping,

				pgoff_t index, gfp_t gfp_mask);

struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);

struct page *find_get_page(struct address_space *mapping, pgoff_t offset);

struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset);

struct page *find_lock_page(struct address_space *mapping, pgoff_t offset);

struct page *find_or_create_page(struct address_space *mapping, pgoff_t index,

				 gfp_t gfp_mask);

unsigned find_get_entries(struct address_space *mapping, pgoff_t start,

			  unsigned int nr_entries, struct page **entries,

			  pgoff_t *indices);

unsigned find_get_pages(struct address_space *mapping, pgoff_t start,

			unsigned int nr_pages, struct page **pages);

unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,

include/linux/pagevec.h

+5 −0
Original line number Diff line number Diff line
@@ -22,6 +22,11 @@ struct pagevec { 


void __pagevec_release(struct pagevec *pvec);

void __pagevec_lru_add(struct pagevec *pvec);

unsigned pagevec_lookup_entries(struct pagevec *pvec,

				struct address_space *mapping,

				pgoff_t start, unsigned nr_entries,

				pgoff_t *indices);

void pagevec_remove_exceptionals(struct pagevec *pvec);

unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,

		pgoff_t start, unsigned nr_pages);

unsigned pagevec_lookup_tag(struct pagevec *pvec,

include/linux/shmem_fs.h

+1 −0
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ extern struct file *shmem_kernel_file_setup(const char *name, loff_t size, 
					    unsigned long flags);

extern int shmem_zero_setup(struct vm_area_struct *);

extern int shmem_lock(struct file *file, int lock, struct user_struct *user);

extern bool shmem_mapping(struct address_space *mapping);

extern void shmem_unlock_mapping(struct address_space *mapping);

extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,

					pgoff_t index, gfp_t gfp_mask);

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