mm: compaction: add trace event for fast freepages isolation

The fast_isolate_freepages() can also isolate freepages, but we can not
know the fast isolation efficiency to understand the fast isolation
pressure.  So add a trace event to show some numbers to help to understand
the efficiency for fast freepages isolation.

Link: https://lkml.kernel.org/r/78d2932d0160d122c15372aceb3f2c45460a17fc.1685018752.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/trace/events/compaction.h b/include/trace/events/compaction.h
index 3313eb8..2b2a975 100644 (file)
--- a/include/trace/events/compaction.h
+++ b/include/trace/events/compaction.h
@@ -64,6 +64,17 @@ DEFINE_EVENT(mm_compaction_isolate_template, mm_compaction_isolate_freepages,
        TP_ARGS(start_pfn, end_pfn, nr_scanned, nr_taken)
 );
 
+DEFINE_EVENT(mm_compaction_isolate_template, mm_compaction_fast_isolate_freepages,
+
+       TP_PROTO(
+               unsigned long start_pfn,
+               unsigned long end_pfn,
+               unsigned long nr_scanned,
+               unsigned long nr_taken),
+
+       TP_ARGS(start_pfn, end_pfn, nr_scanned, nr_taken)
+);
+
 #ifdef CONFIG_COMPACTION
 TRACE_EVENT(mm_compaction_migratepages,
 

diff --git a/mm/compaction.c b/mm/compaction.c
index 3b09d8d..ce6293b 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1416,7 +1416,7 @@ static int next_search_order(struct compact_control *cc, int order)
 static void fast_isolate_freepages(struct compact_control *cc)
 {
        unsigned int limit = max(1U, freelist_scan_limit(cc) >> 1);
-       unsigned int nr_scanned = 0;
+       unsigned int nr_scanned = 0, total_isolated = 0;
        unsigned long low_pfn, min_pfn, highest = 0;
        unsigned long nr_isolated = 0;
        unsigned long distance;
@@ -1515,6 +1515,7 @@ static void fast_isolate_freepages(struct compact_control *cc)
                                set_page_private(page, order);
                                nr_isolated = 1 << order;
                                nr_scanned += nr_isolated - 1;
+                               total_isolated += nr_isolated;
                                cc->nr_freepages += nr_isolated;
                                list_add_tail(&page->lru, &cc->freepages);
                                count_compact_events(COMPACTISOLATED, nr_isolated);
@@ -1535,6 +1536,9 @@ static void fast_isolate_freepages(struct compact_control *cc)
                        limit = max(1U, limit >> 1);
        }
 
+       trace_mm_compaction_fast_isolate_freepages(min_pfn, cc->free_pfn,
+                                                  nr_scanned, total_isolated);
+
        if (!page) {
                cc->fast_search_fail++;
                if (scan_start) {