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>

7 files changed, 2 insertions, 73 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index 71830ba7b98..97d2c88b745 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -203,25 +203,13 @@ config VIRT_TO_BUS
 	def_bool y
 	depends on !ARCH_NO_VIRT_TO_BUS
 
-config UNEVICTABLE_LRU
-	bool "Add LRU list to track non-evictable pages"
-	default y
-	help
-	  Keeps unevictable pages off of the active and inactive pageout
-	  lists, so kswapd will not waste CPU time or have its balancing
-	  algorithms thrown off by scanning these pages.  Selecting this
-	  will use one page flag and increase the code size a little,
-	  say Y unless you know what you are doing.
-
-	  See Documentation/vm/unevictable-lru.txt for more information.
-
 config HAVE_MLOCK
 	bool
 	default y if MMU=y
 
 config HAVE_MLOCKED_PAGE_BIT
 	bool
-	default y if HAVE_MLOCK=y && UNEVICTABLE_LRU=y
+	default y if HAVE_MLOCK=y
 
 config MMU_NOTIFIER
 	bool
diff --git a/mm/internal.h b/mm/internal.h
index b4ac332e807..f02c7508068 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -73,7 +73,6 @@ static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
 }
 #endif
 
-#ifdef CONFIG_UNEVICTABLE_LRU
 /*
  * unevictable_migrate_page() called only from migrate_page_copy() to
  * migrate unevictable flag to new page.
@@ -85,11 +84,6 @@ static inline void unevictable_migrate_page(struct page *new, struct page *old)
 	if (TestClearPageUnevictable(old))
 		SetPageUnevictable(new);
 }
-#else
-static inline void unevictable_migrate_page(struct page *new, struct page *old)
-{
-}
-#endif
 
 #ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
 /*
diff --git a/mm/mlock.c b/mm/mlock.c
index ac130433c7d..45eb650b965 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -31,7 +31,6 @@ int can_do_mlock(void)
 }
 EXPORT_SYMBOL(can_do_mlock);
 
-#ifdef CONFIG_UNEVICTABLE_LRU
 /*
  * Mlocked pages are marked with PageMlocked() flag for efficient testing
  * in vmscan and, possibly, the fault path; and to support semi-accurate
@@ -261,27 +260,6 @@ static int __mlock_posix_error_return(long retval)
 	return retval;
 }
 
-#else /* CONFIG_UNEVICTABLE_LRU */
-
-/*
- * Just make pages present if VM_LOCKED.  No-op if unlocking.
- */
-static long __mlock_vma_pages_range(struct vm_area_struct *vma,
-				   unsigned long start, unsigned long end,
-				   int mlock)
-{
-	if (mlock && (vma->vm_flags & VM_LOCKED))
-		return make_pages_present(start, end);
-	return 0;
-}
-
-static inline int __mlock_posix_error_return(long retval)
-{
-	return 0;
-}
-
-#endif /* CONFIG_UNEVICTABLE_LRU */
-
 /**
  * mlock_vma_pages_range() - mlock pages in specified vma range.
  * @vma - the vma containing the specfied address range
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 00e293734fc..c95a77cd581 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2077,19 +2077,14 @@ void show_free_areas(void)
 
 	printk("Active_anon:%lu active_file:%lu inactive_anon:%lu\n"
 		" inactive_file:%lu"
-//TODO:  check/adjust line lengths
-#ifdef CONFIG_UNEVICTABLE_LRU
 		" unevictable:%lu"
-#endif
 		" dirty:%lu writeback:%lu unstable:%lu\n"
 		" free:%lu slab:%lu mapped:%lu pagetables:%lu bounce:%lu\n",
 		global_page_state(NR_ACTIVE_ANON),
 		global_page_state(NR_ACTIVE_FILE),
 		global_page_state(NR_INACTIVE_ANON),
 		global_page_state(NR_INACTIVE_FILE),
-#ifdef CONFIG_UNEVICTABLE_LRU
 		global_page_state(NR_UNEVICTABLE),
-#endif
 		global_page_state(NR_FILE_DIRTY),
 		global_page_state(NR_WRITEBACK),
 		global_page_state(NR_UNSTABLE_NFS),
@@ -2113,9 +2108,7 @@ void show_free_areas(void)
 			" inactive_anon:%lukB"
 			" active_file:%lukB"
 			" inactive_file:%lukB"
-#ifdef CONFIG_UNEVICTABLE_LRU
 			" unevictable:%lukB"
-#endif
 			" present:%lukB"
 			" pages_scanned:%lu"
 			" all_unreclaimable? %s"
@@ -2129,9 +2122,7 @@ void show_free_areas(void)
 			K(zone_page_state(zone, NR_INACTIVE_ANON)),
 			K(zone_page_state(zone, NR_ACTIVE_FILE)),
 			K(zone_page_state(zone, NR_INACTIVE_FILE)),
-#ifdef CONFIG_UNEVICTABLE_LRU
 			K(zone_page_state(zone, NR_UNEVICTABLE)),
-#endif
 			K(zone->present_pages),
 			zone->pages_scanned,
 			(zone_is_all_unreclaimable(zone) ? "yes" : "no")
diff --git a/mm/rmap.c b/mm/rmap.c
index 23122af3261..316c9d6930a 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1202,7 +1202,6 @@ int try_to_unmap(struct page *page, int migration)
 	return ret;
 }
 
-#ifdef CONFIG_UNEVICTABLE_LRU
 /**
  * try_to_munlock - try to munlock a page
  * @page: the page to be munlocked
@@ -1226,4 +1225,4 @@ int try_to_munlock(struct page *page)
 	else
 		return try_to_unmap_file(page, 1, 0);
 }
-#endif
+
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 879d034930c..2c4b945b011 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -514,7 +514,6 @@ int remove_mapping(struct address_space *mapping, struct page *page)
  *
  * lru_lock must not be held, interrupts must be enabled.
  */
-#ifdef CONFIG_UNEVICTABLE_LRU
 void putback_lru_page(struct page *page)
 {
 	int lru;
@@ -568,20 +567,6 @@ redo:
 	put_page(page);		/* drop ref from isolate */
 }
 
-#else /* CONFIG_UNEVICTABLE_LRU */
-
-void putback_lru_page(struct page *page)
-{
-	int lru;
-	VM_BUG_ON(PageLRU(page));
-
-	lru = !!TestClearPageActive(page) + page_is_file_cache(page);
-	lru_cache_add_lru(page, lru);
-	put_page(page);
-}
-#endif /* CONFIG_UNEVICTABLE_LRU */
-
-
 /*
  * shrink_page_list() returns the number of reclaimed pages
  */
@@ -2470,7 +2455,6 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 }
 #endif
 
-#ifdef CONFIG_UNEVICTABLE_LRU
 /*
  * page_evictable - test whether a page is evictable
  * @page: the page to test
@@ -2717,4 +2701,3 @@ void scan_unevictable_unregister_node(struct node *node)
 	sysdev_remove_file(&node->sysdev, &attr_scan_unevictable_pages);
 }
 
-#endif
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 1e151cf6bf8..1e3aa8139f2 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -629,10 +629,8 @@ static const char * const vmstat_text[] = {
 	"nr_active_anon",
 	"nr_inactive_file",
 	"nr_active_file",
-#ifdef CONFIG_UNEVICTABLE_LRU
 	"nr_unevictable",
 	"nr_mlock",
-#endif
 	"nr_anon_pages",
 	"nr_mapped",
 	"nr_file_pages",
@@ -687,7 +685,6 @@ static const char * const vmstat_text[] = {
 	"htlb_buddy_alloc_success",
 	"htlb_buddy_alloc_fail",
 #endif
-#ifdef CONFIG_UNEVICTABLE_LRU
 	"unevictable_pgs_culled",
 	"unevictable_pgs_scanned",
 	"unevictable_pgs_rescued",
@@ -697,7 +694,6 @@ static const char * const vmstat_text[] = {
 	"unevictable_pgs_stranded",
 	"unevictable_pgs_mlockfreed",
 #endif
-#endif
 };
 
 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,