mm: remove CONFIG_UNEVICTABLE_LRU config option

Currently, nobody wants to turn UNEVICTABLE_LRU off.  Thus this
configurability is unnecessary.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andi Kleen <andi@firstfloor.org>
Acked-by: Minchan Kim <minchan.kim@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6 files changed, 1 insertions, 68 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index db976b9f8791..889598537370 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -83,13 +83,8 @@ enum zone_stat_item {
 	NR_ACTIVE_ANON,		/*  "     "     "   "       "         */
 	NR_INACTIVE_FILE,	/*  "     "     "   "       "         */
 	NR_ACTIVE_FILE,		/*  "     "     "   "       "         */
-#ifdef CONFIG_UNEVICTABLE_LRU
 	NR_UNEVICTABLE,		/*  "     "     "   "       "         */
 	NR_MLOCK,		/* mlock()ed pages found and moved off LRU */
-#else
-	NR_UNEVICTABLE = NR_ACTIVE_FILE, /* avoid compiler errors in dead code */
-	NR_MLOCK = NR_ACTIVE_FILE,
-#endif
 	NR_ANON_PAGES,	/* Mapped anonymous pages */
 	NR_FILE_MAPPED,	/* pagecache pages mapped into pagetables.
 			   only modified from process context */
@@ -132,11 +127,7 @@ enum lru_list {
 	LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
 	LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
 	LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
-#ifdef CONFIG_UNEVICTABLE_LRU
 	LRU_UNEVICTABLE,
-#else
-	LRU_UNEVICTABLE = LRU_ACTIVE_FILE, /* avoid compiler errors in dead code */
-#endif
 	NR_LRU_LISTS
 };
 
@@ -156,11 +147,7 @@ static inline int is_active_lru(enum lru_list l)
 
 static inline int is_unevictable_lru(enum lru_list l)
 {
-#ifdef CONFIG_UNEVICTABLE_LRU
 	return (l == LRU_UNEVICTABLE);
-#else
-	return 0;
-#endif
 }
 
 enum zone_watermarks {
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 62214c7d2d93..d6792f88a176 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -95,9 +95,7 @@ enum pageflags {
 	PG_reclaim,		/* To be reclaimed asap */
 	PG_buddy,		/* Page is free, on buddy lists */
 	PG_swapbacked,		/* Page is backed by RAM/swap */
-#ifdef CONFIG_UNEVICTABLE_LRU
 	PG_unevictable,		/* Page is "unevictable"  */
-#endif
 #ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
 	PG_mlocked,		/* Page is vma mlocked */
 #endif
@@ -248,14 +246,8 @@ PAGEFLAG_FALSE(SwapCache)
 	SETPAGEFLAG_NOOP(SwapCache) CLEARPAGEFLAG_NOOP(SwapCache)
 #endif
 
-#ifdef CONFIG_UNEVICTABLE_LRU
 PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
 	TESTCLEARFLAG(Unevictable, unevictable)
-#else
-PAGEFLAG_FALSE(Unevictable) TESTCLEARFLAG_FALSE(Unevictable)
-	SETPAGEFLAG_NOOP(Unevictable) CLEARPAGEFLAG_NOOP(Unevictable)
-	__CLEARPAGEFLAG_NOOP(Unevictable)
-#endif
 
 #ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
 #define MLOCK_PAGES 1
@@ -382,12 +374,6 @@ static inline void __ClearPageTail(struct page *page)
 
 #endif /* !PAGEFLAGS_EXTENDED */
 
-#ifdef CONFIG_UNEVICTABLE_LRU
-#define __PG_UNEVICTABLE	(1 << PG_unevictable)
-#else
-#define __PG_UNEVICTABLE	0
-#endif
-
 #ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
 #define __PG_MLOCKED		(1 << PG_mlocked)
 #else
@@ -403,7 +389,7 @@ static inline void __ClearPageTail(struct page *page)
 	 1 << PG_private | 1 << PG_private_2 | \
 	 1 << PG_buddy	 | 1 << PG_writeback | 1 << PG_reserved | \
 	 1 << PG_slab	 | 1 << PG_swapcache | 1 << PG_active | \
-	 __PG_UNEVICTABLE | __PG_MLOCKED)
+	 1 << PG_unevictable | __PG_MLOCKED)
 
 /*
  * Flags checked when a page is prepped for return by the page allocator.
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 34da5230faab..aec3252afcf5 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -22,9 +22,7 @@ enum mapping_flags {
 	AS_EIO		= __GFP_BITS_SHIFT + 0,	/* IO error on async write */
 	AS_ENOSPC	= __GFP_BITS_SHIFT + 1,	/* ENOSPC on async write */
 	AS_MM_ALL_LOCKS	= __GFP_BITS_SHIFT + 2,	/* under mm_take_all_locks() */
-#ifdef CONFIG_UNEVICTABLE_LRU
 	AS_UNEVICTABLE	= __GFP_BITS_SHIFT + 3,	/* e.g., ramdisk, SHM_LOCK */
-#endif
 };
 
 static inline void mapping_set_error(struct address_space *mapping, int error)
@@ -37,8 +35,6 @@ static inline void mapping_set_error(struct address_space *mapping, int error)
 	}
 }
 
-#ifdef CONFIG_UNEVICTABLE_LRU
-
 static inline void mapping_set_unevictable(struct address_space *mapping)
 {
 	set_bit(AS_UNEVICTABLE, &mapping->flags);
@@ -55,14 +51,6 @@ static inline int mapping_unevictable(struct address_space *mapping)
 		return test_bit(AS_UNEVICTABLE, &mapping->flags);
 	return !!mapping;
 }
-#else
-static inline void mapping_set_unevictable(struct address_space *mapping) { }
-static inline void mapping_clear_unevictable(struct address_space *mapping) { }
-static inline int mapping_unevictable(struct address_space *mapping)
-{
-	return 0;
-}
-#endif
 
 static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
 {
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index b35bc0e19cd9..619379a1dd98 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -105,18 +105,11 @@ unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
  */
 int page_mkclean(struct page *);
 
-#ifdef CONFIG_UNEVICTABLE_LRU
 /*
  * called in munlock()/munmap() path to check for other vmas holding
  * the page mlocked.
  */
 int try_to_munlock(struct page *);
-#else
-static inline int try_to_munlock(struct page *page)
-{
-	return 0;	/* a.k.a. SWAP_SUCCESS */
-}
-#endif
 
 #else	/* !CONFIG_MMU */
 
diff --git a/include/linux/swap.h b/include/linux/swap.h
index d476aad3ff57..f30c06908f09 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -235,7 +235,6 @@ static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
 }
 #endif
 
-#ifdef CONFIG_UNEVICTABLE_LRU
 extern int page_evictable(struct page *page, struct vm_area_struct *vma);
 extern void scan_mapping_unevictable_pages(struct address_space *);
 
@@ -244,24 +243,6 @@ extern int scan_unevictable_handler(struct ctl_table *, int, struct file *,
 					void __user *, size_t *, loff_t *);
 extern int scan_unevictable_register_node(struct node *node);
 extern void scan_unevictable_unregister_node(struct node *node);
-#else
-static inline int page_evictable(struct page *page,
-						struct vm_area_struct *vma)
-{
-	return 1;
-}
-
-static inline void scan_mapping_unevictable_pages(struct address_space *mapping)
-{
-}
-
-static inline int scan_unevictable_register_node(struct node *node)
-{
-	return 0;
-}
-
-static inline void scan_unevictable_unregister_node(struct node *node) { }
-#endif
 
 extern int kswapd_run(int nid);
 
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 524cd1b28ecb..ff4696c6dce3 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -41,7 +41,6 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 #ifdef CONFIG_HUGETLB_PAGE
 		HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,
 #endif
-#ifdef CONFIG_UNEVICTABLE_LRU
 		UNEVICTABLE_PGCULLED,	/* culled to noreclaim list */
 		UNEVICTABLE_PGSCANNED,	/* scanned for reclaimability */
 		UNEVICTABLE_PGRESCUED,	/* rescued from noreclaim list */
@@ -50,7 +49,6 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 		UNEVICTABLE_PGCLEARED,	/* on COW, page truncate */
 		UNEVICTABLE_PGSTRANDED,	/* unable to isolate on unlock */
 		UNEVICTABLE_MLOCKFREED,
-#endif
 		NR_VM_EVENT_ITEMS
 };