mm, lockdep: annotate reclaim context to zone reclaim too

Commit cf40bd16fd ("lockdep: annotate reclaim context") introduced reclaim
context annotation.  But it didn't annotate zone reclaim.  This patch do
it.

The point is, commit cf40bd16fd annotate __alloc_pages_direct_reclaim but
zone-reclaim doesn't use __alloc_pages_direct_reclaim.

current call graph is

__alloc_pages_nodemask
   get_page_from_freelist
       zone_reclaim()
   __alloc_pages_slowpath
       __alloc_pages_direct_reclaim
           try_to_free_pages

Actually, if zone_reclaim_mode=1, VM never call
__alloc_pages_direct_reclaim in usual VM pressure.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Nick Piggin <npiggin@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

@@ -2557,6 +2557,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 	 * and RECLAIM_SWAP.
 	 */
 	p->flags |= PF_MEMALLOC | PF_SWAPWRITE;
+	lockdep_set_current_reclaim_state(gfp_mask);
 	reclaim_state.reclaimed_slab = 0;
 	p->reclaim_state = &reclaim_state;
 
@@ -2600,6 +2601,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 
 	p->reclaim_state = NULL;
 	current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE);
+	lockdep_clear_current_reclaim_state();
 	return sc.nr_reclaimed >= nr_pages;
 }