mm/vmscan: drop may_writepage and classzone_idx from direct reclaim begin template

There are three tracepoints using this template, which are
mm_vmscan_direct_reclaim_begin,
mm_vmscan_memcg_reclaim_begin,
mm_vmscan_memcg_softlimit_reclaim_begin.

Regarding mm_vmscan_direct_reclaim_begin,
sc.may_writepage is !laptop_mode, that's a static setting, and
reclaim_idx is derived from gfp_mask which is already show in this
tracepoint.

Regarding mm_vmscan_memcg_reclaim_begin,
may_writepage is !laptop_mode too, and reclaim_idx is (MAX_NR_ZONES-1),
which are both static value.

mm_vmscan_memcg_softlimit_reclaim_begin is the same with
mm_vmscan_memcg_reclaim_begin.

So we can drop them all.

Link: http://lkml.kernel.org/r/1553736322-32235-1-git-send-email-laoar.shao@gmail.comSigned-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/trace/events/vmscan.h

@@ -106,51 +106,45 @@ TRACE_EVENT(mm_vmscan_wakeup_kswapd,
 
 DECLARE_EVENT_CLASS(mm_vmscan_direct_reclaim_begin_template,
 
-	TP_PROTO(int order, int may_writepage, gfp_t gfp_flags, int classzone_idx),
+	TP_PROTO(int order, gfp_t gfp_flags),
 
-	TP_ARGS(order, may_writepage, gfp_flags, classzone_idx),
+	TP_ARGS(order, gfp_flags),
 
 	TP_STRUCT__entry(
 		__field(	int,	order		)
-		__field(	int,	may_writepage	)
 		__field(	gfp_t,	gfp_flags	)
-		__field(	int,	classzone_idx	)
 	),
 
 	TP_fast_assign(
 		__entry->order		= order;
-		__entry->may_writepage	= may_writepage;
 		__entry->gfp_flags	= gfp_flags;
-		__entry->classzone_idx	= classzone_idx;
 	),
 
-	TP_printk("order=%d may_writepage=%d gfp_flags=%s classzone_idx=%d",
+	TP_printk("order=%d gfp_flags=%s",
 		__entry->order,
-		__entry->may_writepage,
-		show_gfp_flags(__entry->gfp_flags),
-		__entry->classzone_idx)
+		show_gfp_flags(__entry->gfp_flags))
 );
 
 DEFINE_EVENT(mm_vmscan_direct_reclaim_begin_template, mm_vmscan_direct_reclaim_begin,
 
-	TP_PROTO(int order, int may_writepage, gfp_t gfp_flags, int classzone_idx),
+	TP_PROTO(int order, gfp_t gfp_flags),
 
-	TP_ARGS(order, may_writepage, gfp_flags, classzone_idx)
+	TP_ARGS(order, gfp_flags)
 );
 
 #ifdef CONFIG_MEMCG
 DEFINE_EVENT(mm_vmscan_direct_reclaim_begin_template, mm_vmscan_memcg_reclaim_begin,
 
-	TP_PROTO(int order, int may_writepage, gfp_t gfp_flags, int classzone_idx),
+	TP_PROTO(int order, gfp_t gfp_flags),
 
-	TP_ARGS(order, may_writepage, gfp_flags, classzone_idx)
+	TP_ARGS(order, gfp_flags)
 );
 
 DEFINE_EVENT(mm_vmscan_direct_reclaim_begin_template, mm_vmscan_memcg_softlimit_reclaim_begin,
 
-	TP_PROTO(int order, int may_writepage, gfp_t gfp_flags, int classzone_idx),
+	TP_PROTO(int order, gfp_t gfp_flags),
 
-	TP_ARGS(order, may_writepage, gfp_flags, classzone_idx)
+	TP_ARGS(order, gfp_flags)
 );
 #endif /* CONFIG_MEMCG */
 

mm/vmscan.c

@@ -3174,10 +3174,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 	if (throttle_direct_reclaim(sc.gfp_mask, zonelist, nodemask))
 		return 1;
 
-	trace_mm_vmscan_direct_reclaim_begin(order,
-				sc.may_writepage,
-				sc.gfp_mask,
-				sc.reclaim_idx);
+	trace_mm_vmscan_direct_reclaim_begin(order, sc.gfp_mask);
 
 	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
 
@@ -3208,9 +3205,7 @@ unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
 			(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
 
 	trace_mm_vmscan_memcg_softlimit_reclaim_begin(sc.order,
-						      sc.may_writepage,
-						      sc.gfp_mask,
-						      sc.reclaim_idx);
+						      sc.gfp_mask);
 
 	/*
 	 * NOTE: Although we can get the priority field, using it
@@ -3259,10 +3254,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
 
 	zonelist = &NODE_DATA(nid)->node_zonelists[ZONELIST_FALLBACK];
 
-	trace_mm_vmscan_memcg_reclaim_begin(0,
-					    sc.may_writepage,
-					    sc.gfp_mask,
-					    sc.reclaim_idx);
+	trace_mm_vmscan_memcg_reclaim_begin(0, sc.gfp_mask);
 
 	psi_memstall_enter(&pflags);
 	noreclaim_flag = memalloc_noreclaim_save();