PM/Suspend: Do not shrink memory before suspend

Remove the shrinking of memory from the suspend-to-RAM code, where
it is not really necessary.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NNigel Cunningham <nigel@tuxonice.net>
Acked-by: NWu Fengguang <fengguang.wu@intel.com>

kernel/power/main.c

@@ -188,9 +188,6 @@ static void suspend_test_finish(const char *label)
 
 #endif
 
-/* This is just an arbitrary number */
-#define FREE_PAGE_NUMBER (100)
-
 static struct platform_suspend_ops *suspend_ops;
 
 /**
@@ -226,7 +223,6 @@ int suspend_valid_only_mem(suspend_state_t state)
 static int suspend_prepare(void)
 {
 	int error;
-	unsigned int free_pages;
 
 	if (!suspend_ops || !suspend_ops->enter)
 		return -EPERM;
@@ -241,24 +237,10 @@ static int suspend_prepare(void)
 	if (error)
 		goto Finish;
 
-	if (suspend_freeze_processes()) {
-		error = -EAGAIN;
-		goto Thaw;
-	}
-
-	free_pages = global_page_state(NR_FREE_PAGES);
-	if (free_pages < FREE_PAGE_NUMBER) {
-		pr_debug("PM: free some memory\n");
-		shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
-		if (nr_free_pages() < FREE_PAGE_NUMBER) {
-			error = -ENOMEM;
-			printk(KERN_ERR "PM: No enough memory\n");
-		}
-	}
+	error = suspend_freeze_processes();
 	if (!error)
 		return 0;
 
- Thaw:
 	suspend_thaw_processes();
 	usermodehelper_enable();
  Finish:

mm/vmscan.c

@@ -2056,7 +2056,7 @@ unsigned long global_lru_pages(void)
 		+ global_page_state(NR_INACTIVE_FILE);
 }
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_HIBERNATION
 /*
  * Helper function for shrink_all_memory().  Tries to reclaim 'nr_pages' pages
  * from LRU lists system-wide, for given pass and priority.
@@ -2196,7 +2196,7 @@ unsigned long shrink_all_memory(unsigned long nr_pages)
 
 	return sc.nr_reclaimed;
 }
-#endif
+#endif /* CONFIG_HIBERNATION */
 
 /* It's optimal to keep kswapds on the same CPUs as their memory, but
    not required for correctness.  So if the last cpu in a node goes