mm, thp: convert from optimistic swapin collapsing to conservative

To detect whether khugepaged swapin is worthwhile, this patch checks the
amount of young pages.  There should be at least half of HPAGE_PMD_NR to
swapin.

Link: http://lkml.kernel.org/r/1468109451-1615-1-git-send-email-ebru.akagunduz@gmail.com
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Suggested-by: Minchan Kim <minchan@kernel.org>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h
index 830d47d..04f58ac 100644
--- a/include/trace/events/huge_memory.h
+++ b/include/trace/events/huge_memory.h
@@ -13,7 +13,7 @@
 	EM( SCAN_EXCEED_NONE_PTE,	"exceed_none_pte")		\
 	EM( SCAN_PTE_NON_PRESENT,	"pte_non_present")		\
 	EM( SCAN_PAGE_RO,		"no_writable_page")		\
-	EM( SCAN_NO_REFERENCED_PAGE,	"no_referenced_page")		\
+	EM( SCAN_LACK_REFERENCED_PAGE,	"lack_referenced_page")		\
 	EM( SCAN_PAGE_NULL,		"page_null")			\
 	EM( SCAN_SCAN_ABORT,		"scan_aborted")			\
 	EM( SCAN_PAGE_COUNT,		"not_suitable_page_count")	\
@@ -47,7 +47,7 @@
 TRACE_EVENT(mm_khugepaged_scan_pmd,
 
 	TP_PROTO(struct mm_struct *mm, struct page *page, bool writable,
-		 bool referenced, int none_or_zero, int status, int unmapped),
+		 int referenced, int none_or_zero, int status, int unmapped),
 
 	TP_ARGS(mm, page, writable, referenced, none_or_zero, status, unmapped),
 
@@ -55,7 +55,7 @@
 		__field(struct mm_struct *, mm)
 		__field(unsigned long, pfn)
 		__field(bool, writable)
-		__field(bool, referenced)
+		__field(int, referenced)
 		__field(int, none_or_zero)
 		__field(int, status)
 		__field(int, unmapped)
@@ -108,14 +108,14 @@
 TRACE_EVENT(mm_collapse_huge_page_isolate,
 
 	TP_PROTO(struct page *page, int none_or_zero,
-		 bool referenced, bool  writable, int status),
+		 int referenced, bool  writable, int status),
 
 	TP_ARGS(page, none_or_zero, referenced, writable, status),
 
 	TP_STRUCT__entry(
 		__field(unsigned long, pfn)
 		__field(int, none_or_zero)
-		__field(bool, referenced)
+		__field(int, referenced)
 		__field(bool, writable)
 		__field(int, status)
 	),
@@ -138,25 +138,28 @@
 
 TRACE_EVENT(mm_collapse_huge_page_swapin,
 
-	TP_PROTO(struct mm_struct *mm, int swapped_in, int ret),
+	TP_PROTO(struct mm_struct *mm, int swapped_in, int referenced, int ret),
 
-	TP_ARGS(mm, swapped_in, ret),
+	TP_ARGS(mm, swapped_in, referenced, ret),
 
 	TP_STRUCT__entry(
 		__field(struct mm_struct *, mm)
 		__field(int, swapped_in)
+		__field(int, referenced)
 		__field(int, ret)
 	),
 
 	TP_fast_assign(
 		__entry->mm = mm;
 		__entry->swapped_in = swapped_in;
+		__entry->referenced = referenced;
 		__entry->ret = ret;
 	),
 
-	TP_printk("mm=%p, swapped_in=%d, ret=%d",
+	TP_printk("mm=%p, swapped_in=%d, referenced=%d, ret=%d",
 		__entry->mm,
 		__entry->swapped_in,
+		__entry->referenced,
 		__entry->ret)
 );