Remove the leftover pglist_data::numabalancing_migrate_lock and its
initialization, we stopped using this lock with:
  
efaffc5e40ae ("mm, sched/numa: Remove rate-limiting of automatic NUMA balancing migration")
[ mingo: Rewrote the changelog. ]
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1538824999-31230-1-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
        enum zone_type kcompactd_classzone_idx;
        wait_queue_head_t kcompactd_wait;
        struct task_struct *kcompactd;
-#endif
-#ifdef CONFIG_NUMA_BALANCING
-       /* Lock serializing the migrate rate limiting window */
-       spinlock_t numabalancing_migrate_lock;
 #endif
        /*
         * This is a per-node reserve of pages that are not available
 
        return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
 }
 
-#ifdef CONFIG_NUMA_BALANCING
-static void pgdat_init_numabalancing(struct pglist_data *pgdat)
-{
-       spin_lock_init(&pgdat->numabalancing_migrate_lock);
-}
-#else
-static void pgdat_init_numabalancing(struct pglist_data *pgdat) {}
-#endif
-
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 static void pgdat_init_split_queue(struct pglist_data *pgdat)
 {
 {
        pgdat_resize_init(pgdat);
 
-       pgdat_init_numabalancing(pgdat);
        pgdat_init_split_queue(pgdat);
        pgdat_init_kcompactd(pgdat);