mm: vmscan: tracepoint: account for scanned pages similarly for both ftrace and vmstat
authorMel Gorman <mel@csn.ul.ie>
Wed, 22 Dec 2010 01:24:18 +0000 (17:24 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 23 Dec 2010 03:43:33 +0000 (19:43 -0800)
When correlating ftrace results with /proc/vmstat, I noticed that the
reporting scripts value for "pages scanned" differed significantly.  Both
values were "right" depending on how you look at it.

The difference is due to vmstat only counting scanning of the inactive
list towards pages scanned.  The analysis script for the tracepoint counts
active and inactive list yielding a far higher value than vmstat.  The
resulting scanning/reclaim ratio looks much worse.  The tracepoint is ok
but this patch updates the reporting script so that the report values for
scanned are similar to vmstat.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Documentation/trace/postprocess/trace-vmscan-postprocess.pl

index b3e73ddb1567902fdeb9d65e1a661db9bca7780d..12cecc83cd91c658c71524bba59762b83f810829 100644 (file)
@@ -373,9 +373,18 @@ EVENT_PROCESS:
                                print "         $regex_lru_isolate/o\n";
                                next;
                        }
                                print "         $regex_lru_isolate/o\n";
                                next;
                        }
+                       my $isolate_mode = $1;
                        my $nr_scanned = $4;
                        my $nr_contig_dirty = $7;
                        my $nr_scanned = $4;
                        my $nr_contig_dirty = $7;
-                       $perprocesspid{$process_pid}->{HIGH_NR_SCANNED} += $nr_scanned;
+
+                       # To closer match vmstat scanning statistics, only count isolate_both
+                       # and isolate_inactive as scanning. isolate_active is rotation
+                       # isolate_inactive == 0
+                       # isolate_active   == 1
+                       # isolate_both     == 2
+                       if ($isolate_mode != 1) {
+                               $perprocesspid{$process_pid}->{HIGH_NR_SCANNED} += $nr_scanned;
+                       }
                        $perprocesspid{$process_pid}->{HIGH_NR_CONTIG_DIRTY} += $nr_contig_dirty;
                } elsif ($tracepoint eq "mm_vmscan_lru_shrink_inactive") {
                        $details = $5;
                        $perprocesspid{$process_pid}->{HIGH_NR_CONTIG_DIRTY} += $nr_contig_dirty;
                } elsif ($tracepoint eq "mm_vmscan_lru_shrink_inactive") {
                        $details = $5;