mm/compaction: Get rid of RT ifdeffery

Move the RT dependency for the initial value of
sysctl_compact_unevictable_allowed into Kconfig.

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: KAGA-KOKO

mm/Kconfig

@@ -579,6 +579,12 @@ config COMPACTION
 	  it and then we would be really interested to hear about that at
 	  [email protected].
 
+config COMPACT_UNEVICTABLE_DEFAULT
+	int
+	depends on COMPACTION
+	default 0 if PREEMPT_RT
+	default 1
+
 #
 # support for free page reporting
 config PAGE_REPORTING

mm/compaction.c

@@ -1727,11 +1727,7 @@ typedef enum {
  * Allow userspace to control policy on scanning the unevictable LRU for
  * compactable pages.
  */
-#ifdef CONFIG_PREEMPT_RT
-int sysctl_compact_unevictable_allowed __read_mostly = 0;
-#else
-int sysctl_compact_unevictable_allowed __read_mostly = 1;
-#endif
+int sysctl_compact_unevictable_allowed __read_mostly = CONFIG_COMPACT_UNEVICTABLE_DEFAULT;
 
 static inline void
 update_fast_start_pfn(struct compact_control *cc, unsigned long pfn)