ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 752 insertions, 0 deletions

diff --git a/Documentation/trace/postprocess/trace-vmscan-postprocess.pl b/Documentation/trace/postprocess/trace-vmscan-postprocess.pl
new file mode 100644
index 000000000..048dc0dbc
--- /dev/null
+++ b/Documentation/trace/postprocess/trace-vmscan-postprocess.pl
@@ -0,0 +1,752 @@
+#!/usr/bin/env perl
+# This is a POC for reading the text representation of trace output related to
+# page reclaim. It makes an attempt to extract some high-level information on
+# what is going on. The accuracy of the parser may vary
+#
+# Example usage: trace-vmscan-postprocess.pl < /sys/kernel/tracing/trace_pipe
+# other options
+#   --read-procstat	If the trace lacks process info, get it from /proc
+#   --ignore-pid	Aggregate processes of the same name together
+#
+# Copyright (c) IBM Corporation 2009
+# Author: Mel Gorman <mel@csn.ul.ie>
+use strict;
+use Getopt::Long;
+
+# Tracepoint events
+use constant MM_VMSCAN_DIRECT_RECLAIM_BEGIN	=> 1;
+use constant MM_VMSCAN_DIRECT_RECLAIM_END	=> 2;
+use constant MM_VMSCAN_KSWAPD_WAKE		=> 3;
+use constant MM_VMSCAN_KSWAPD_SLEEP		=> 4;
+use constant MM_VMSCAN_LRU_SHRINK_ACTIVE	=> 5;
+use constant MM_VMSCAN_LRU_SHRINK_INACTIVE	=> 6;
+use constant MM_VMSCAN_LRU_ISOLATE		=> 7;
+use constant MM_VMSCAN_WRITEPAGE_FILE_SYNC	=> 8;
+use constant MM_VMSCAN_WRITEPAGE_ANON_SYNC	=> 9;
+use constant MM_VMSCAN_WRITEPAGE_FILE_ASYNC	=> 10;
+use constant MM_VMSCAN_WRITEPAGE_ANON_ASYNC	=> 11;
+use constant MM_VMSCAN_WRITEPAGE_ASYNC		=> 12;
+use constant EVENT_UNKNOWN			=> 13;
+
+# Per-order events
+use constant MM_VMSCAN_DIRECT_RECLAIM_BEGIN_PERORDER => 11;
+use constant MM_VMSCAN_WAKEUP_KSWAPD_PERORDER 	=> 12;
+use constant MM_VMSCAN_KSWAPD_WAKE_PERORDER	=> 13;
+use constant HIGH_KSWAPD_REWAKEUP_PERORDER	=> 14;
+
+# Constants used to track state
+use constant STATE_DIRECT_BEGIN 		=> 15;
+use constant STATE_DIRECT_ORDER 		=> 16;
+use constant STATE_KSWAPD_BEGIN			=> 17;
+use constant STATE_KSWAPD_ORDER			=> 18;
+
+# High-level events extrapolated from tracepoints
+use constant HIGH_DIRECT_RECLAIM_LATENCY	=> 19;
+use constant HIGH_KSWAPD_LATENCY		=> 20;
+use constant HIGH_KSWAPD_REWAKEUP		=> 21;
+use constant HIGH_NR_SCANNED			=> 22;
+use constant HIGH_NR_TAKEN			=> 23;
+use constant HIGH_NR_RECLAIMED			=> 24;
+use constant HIGH_NR_FILE_SCANNED		=> 25;
+use constant HIGH_NR_ANON_SCANNED		=> 26;
+use constant HIGH_NR_FILE_RECLAIMED		=> 27;
+use constant HIGH_NR_ANON_RECLAIMED		=> 28;
+
+my %perprocesspid;
+my %perprocess;
+my %last_procmap;
+my $opt_ignorepid;
+my $opt_read_procstat;
+
+my $total_wakeup_kswapd;
+my ($total_direct_reclaim, $total_direct_nr_scanned);
+my ($total_direct_nr_file_scanned, $total_direct_nr_anon_scanned);
+my ($total_direct_latency, $total_kswapd_latency);
+my ($total_direct_nr_reclaimed);
+my ($total_direct_nr_file_reclaimed, $total_direct_nr_anon_reclaimed);
+my ($total_direct_writepage_file_sync, $total_direct_writepage_file_async);
+my ($total_direct_writepage_anon_sync, $total_direct_writepage_anon_async);
+my ($total_kswapd_nr_scanned, $total_kswapd_wake);
+my ($total_kswapd_nr_file_scanned, $total_kswapd_nr_anon_scanned);
+my ($total_kswapd_writepage_file_sync, $total_kswapd_writepage_file_async);
+my ($total_kswapd_writepage_anon_sync, $total_kswapd_writepage_anon_async);
+my ($total_kswapd_nr_reclaimed);
+my ($total_kswapd_nr_file_reclaimed, $total_kswapd_nr_anon_reclaimed);
+
+# Catch sigint and exit on request
+my $sigint_report = 0;
+my $sigint_exit = 0;
+my $sigint_pending = 0;
+my $sigint_received = 0;
+sub sigint_handler {
+	my $current_time = time;
+	if ($current_time - 2 > $sigint_received) {
+		print "SIGINT received, report pending. Hit ctrl-c again to exit\n";
+		$sigint_report = 1;
+	} else {
+		if (!$sigint_exit) {
+			print "Second SIGINT received quickly, exiting\n";
+		}
+		$sigint_exit++;
+	}
+
+	if ($sigint_exit > 3) {
+		print "Many SIGINTs received, exiting now without report\n";
+		exit;
+	}
+
+	$sigint_received = $current_time;
+	$sigint_pending = 1;
+}
+$SIG{INT} = "sigint_handler";
+
+# Parse command line options
+GetOptions(
+	'ignore-pid'	 =>	\$opt_ignorepid,
+	'read-procstat'	 =>	\$opt_read_procstat,
+);
+
+# Defaults for dynamically discovered regex's
+my $regex_direct_begin_default = 'order=([0-9]*) gfp_flags=([A-Z_|]*)';
+my $regex_direct_end_default = 'nr_reclaimed=([0-9]*)';
+my $regex_kswapd_wake_default = 'nid=([0-9]*) order=([0-9]*)';
+my $regex_kswapd_sleep_default = 'nid=([0-9]*)';
+my $regex_wakeup_kswapd_default = 'nid=([0-9]*) order=([0-9]*) gfp_flags=([A-Z_|]*)';
+my $regex_lru_isolate_default = 'classzone=([0-9]*) order=([0-9]*) nr_requested=([0-9]*) nr_scanned=([0-9]*) nr_skipped=([0-9]*) nr_taken=([0-9]*) lru=([a-z_]*)';
+my $regex_lru_shrink_inactive_default = 'nid=([0-9]*) nr_scanned=([0-9]*) nr_reclaimed=([0-9]*) nr_dirty=([0-9]*) nr_writeback=([0-9]*) nr_congested=([0-9]*) nr_immediate=([0-9]*) nr_activate_anon=([0-9]*) nr_activate_file=([0-9]*) nr_ref_keep=([0-9]*) nr_unmap_fail=([0-9]*) priority=([0-9]*) flags=([A-Z_|]*)';
+my $regex_lru_shrink_active_default = 'lru=([A-Z_]*) nr_taken=([0-9]*) nr_active=([0-9]*) nr_deactivated=([0-9]*) nr_referenced=([0-9]*) priority=([0-9]*) flags=([A-Z_|]*)' ;
+my $regex_writepage_default = 'page=([0-9a-f]*) pfn=([0-9]*) flags=([A-Z_|]*)';
+
+# Dyanically discovered regex
+my $regex_direct_begin;
+my $regex_direct_end;
+my $regex_kswapd_wake;
+my $regex_kswapd_sleep;
+my $regex_wakeup_kswapd;
+my $regex_lru_isolate;
+my $regex_lru_shrink_inactive;
+my $regex_lru_shrink_active;
+my $regex_writepage;
+
+# Static regex used. Specified like this for readability and for use with /o
+#                      (process_pid)     (cpus      )   ( time  )   (tpoint    ) (details)
+my $regex_traceevent = '\s*([a-zA-Z0-9-]*)\s*(\[[0-9]*\])(\s*[dX.][Nnp.][Hhs.][0-9a-fA-F.]*|)\s*([0-9.]*):\s*([a-zA-Z_]*):\s*(.*)';
+my $regex_statname = '[-0-9]*\s\((.*)\).*';
+my $regex_statppid = '[-0-9]*\s\(.*\)\s[A-Za-z]\s([0-9]*).*';
+
+sub generate_traceevent_regex {
+	my $event = shift;
+	my $default = shift;
+	my $regex;
+
+	# Read the event format or use the default
+	if (!open (FORMAT, "/sys/kernel/tracing/events/$event/format")) {
+		print("WARNING: Event $event format string not found\n");
+		return $default;
+	} else {
+		my $line;
+		while (!eof(FORMAT)) {
+			$line = <FORMAT>;
+			$line =~ s/, REC->.*//;
+			if ($line =~ /^print fmt:\s"(.*)".*/) {
+				$regex = $1;
+				$regex =~ s/%s/\([0-9a-zA-Z|_]*\)/g;
+				$regex =~ s/%p/\([0-9a-f]*\)/g;
+				$regex =~ s/%d/\([-0-9]*\)/g;
+				$regex =~ s/%ld/\([-0-9]*\)/g;
+				$regex =~ s/%lu/\([0-9]*\)/g;
+			}
+		}
+	}
+
+	# Can't handle the print_flags stuff but in the context of this
+	# script, it really doesn't matter
+	$regex =~ s/\(REC.*\) \? __print_flags.*//;
+
+	# Verify fields are in the right order
+	my $tuple;
+	foreach $tuple (split /\s/, $regex) {
+		my ($key, $value) = split(/=/, $tuple);
+		my $expected = shift;
+		if ($key ne $expected) {
+			print("WARNING: Format not as expected for event $event '$key' != '$expected'\n");
+			$regex =~ s/$key=\((.*)\)/$key=$1/;
+		}
+	}
+
+	if (defined shift) {
+		die("Fewer fields than expected in format");
+	}
+
+	return $regex;
+}
+
+$regex_direct_begin = generate_traceevent_regex(
+			"vmscan/mm_vmscan_direct_reclaim_begin",
+			$regex_direct_begin_default,
+			"order", "gfp_flags");
+$regex_direct_end = generate_traceevent_regex(
+			"vmscan/mm_vmscan_direct_reclaim_end",
+			$regex_direct_end_default,
+			"nr_reclaimed");
+$regex_kswapd_wake = generate_traceevent_regex(
+			"vmscan/mm_vmscan_kswapd_wake",
+			$regex_kswapd_wake_default,
+			"nid", "order");
+$regex_kswapd_sleep = generate_traceevent_regex(
+			"vmscan/mm_vmscan_kswapd_sleep",
+			$regex_kswapd_sleep_default,
+			"nid");
+$regex_wakeup_kswapd = generate_traceevent_regex(
+			"vmscan/mm_vmscan_wakeup_kswapd",
+			$regex_wakeup_kswapd_default,
+			"nid", "order", "gfp_flags");
+$regex_lru_isolate = generate_traceevent_regex(
+			"vmscan/mm_vmscan_lru_isolate",
+			$regex_lru_isolate_default,
+			"classzone", "order",
+			"nr_requested", "nr_scanned", "nr_skipped", "nr_taken",
+			"lru");
+$regex_lru_shrink_inactive = generate_traceevent_regex(
+			"vmscan/mm_vmscan_lru_shrink_inactive",
+			$regex_lru_shrink_inactive_default,
+			"nid", "nr_scanned", "nr_reclaimed", "nr_dirty", "nr_writeback",
+			"nr_congested", "nr_immediate", "nr_activate_anon",
+			"nr_activate_file", "nr_ref_keep",
+			"nr_unmap_fail", "priority", "flags");
+$regex_lru_shrink_active = generate_traceevent_regex(
+			"vmscan/mm_vmscan_lru_shrink_active",
+			$regex_lru_shrink_active_default,
+			"nid", "nr_taken", "nr_active", "nr_deactivated", "nr_referenced",
+			"priority", "flags");
+$regex_writepage = generate_traceevent_regex(
+			"vmscan/mm_vmscan_write_folio",
+			$regex_writepage_default,
+			"page", "pfn", "flags");
+
+sub read_statline($) {
+	my $pid = $_[0];
+	my $statline;
+
+	if (open(STAT, "/proc/$pid/stat")) {
+		$statline = <STAT>;
+		close(STAT);
+	}
+
+	if ($statline eq '') {
+		$statline = "-1 (UNKNOWN_PROCESS_NAME) R 0";
+	}
+
+	return $statline;
+}
+
+sub guess_process_pid($$) {
+	my $pid = $_[0];
+	my $statline = $_[1];
+
+	if ($pid == 0) {
+		return "swapper-0";
+	}
+
+	if ($statline !~ /$regex_statname/o) {
+		die("Failed to math stat line for process name :: $statline");
+	}
+	return "$1-$pid";
+}
+
+# Convert sec.usec timestamp format
+sub timestamp_to_ms($) {
+	my $timestamp = $_[0];
+
+	my ($sec, $usec) = split (/\./, $timestamp);
+	return ($sec * 1000) + ($usec / 1000);
+}
+
+sub process_events {
+	my $traceevent;
+	my $process_pid;
+	my $cpus;
+	my $timestamp;
+	my $tracepoint;
+	my $details;
+	my $statline;
+
+	# Read each line of the event log
+EVENT_PROCESS:
+	while ($traceevent = <STDIN>) {
+		if ($traceevent =~ /$regex_traceevent/o) {
+			$process_pid = $1;
+			$timestamp = $4;
+			$tracepoint = $5;
+
+			$process_pid =~ /(.*)-([0-9]*)$/;
+			my $process = $1;
+			my $pid = $2;
+
+			if ($process eq "") {
+				$process = $last_procmap{$pid};
+				$process_pid = "$process-$pid";
+			}
+			$last_procmap{$pid} = $process;
+
+			if ($opt_read_procstat) {
+				$statline = read_statline($pid);
+				if ($opt_read_procstat && $process eq '') {
+					$process_pid = guess_process_pid($pid, $statline);
+				}
+			}
+		} else {
+			next;
+		}
+
+		# Perl Switch() sucks majorly
+		if ($tracepoint eq "mm_vmscan_direct_reclaim_begin") {
+			$timestamp = timestamp_to_ms($timestamp);
+			$perprocesspid{$process_pid}->{MM_VMSCAN_DIRECT_RECLAIM_BEGIN}++;
+			$perprocesspid{$process_pid}->{STATE_DIRECT_BEGIN} = $timestamp;
+
+			$details = $6;
+			if ($details !~ /$regex_direct_begin/o) {
+				print "WARNING: Failed to parse mm_vmscan_direct_reclaim_begin as expected\n";
+				print "         $details\n";
+				print "         $regex_direct_begin\n";
+				next;
+			}
+			my $order = $1;
+			$perprocesspid{$process_pid}->{MM_VMSCAN_DIRECT_RECLAIM_BEGIN_PERORDER}[$order]++;
+			$perprocesspid{$process_pid}->{STATE_DIRECT_ORDER} = $order;
+		} elsif ($tracepoint eq "mm_vmscan_direct_reclaim_end") {
+			# Count the event itself
+			my $index = $perprocesspid{$process_pid}->{MM_VMSCAN_DIRECT_RECLAIM_END};
+			$perprocesspid{$process_pid}->{MM_VMSCAN_DIRECT_RECLAIM_END}++;
+
+			# Record how long direct reclaim took this time
+			if (defined $perprocesspid{$process_pid}->{STATE_DIRECT_BEGIN}) {
+				$timestamp = timestamp_to_ms($timestamp);
+				my $order = $perprocesspid{$process_pid}->{STATE_DIRECT_ORDER};
+				my $latency = ($timestamp - $perprocesspid{$process_pid}->{STATE_DIRECT_BEGIN});
+				$perprocesspid{$process_pid}->{HIGH_DIRECT_RECLAIM_LATENCY}[$index] = "$order-$latency";
+			}
+		} elsif ($tracepoint eq "mm_vmscan_kswapd_wake") {
+			$details = $6;
+			if ($details !~ /$regex_kswapd_wake/o) {
+				print "WARNING: Failed to parse mm_vmscan_kswapd_wake as expected\n";
+				print "         $details\n";
+				print "         $regex_kswapd_wake\n";
+				next;
+			}
+
+			my $order = $2;
+			$perprocesspid{$process_pid}->{STATE_KSWAPD_ORDER} = $order;
+			if (!$perprocesspid{$process_pid}->{STATE_KSWAPD_BEGIN}) {
+				$timestamp = timestamp_to_ms($timestamp);
+				$perprocesspid{$process_pid}->{MM_VMSCAN_KSWAPD_WAKE}++;
+				$perprocesspid{$process_pid}->{STATE_KSWAPD_BEGIN} = $timestamp;
+				$perprocesspid{$process_pid}->{MM_VMSCAN_KSWAPD_WAKE_PERORDER}[$order]++;
+			} else {
+				$perprocesspid{$process_pid}->{HIGH_KSWAPD_REWAKEUP}++;
+				$perprocesspid{$process_pid}->{HIGH_KSWAPD_REWAKEUP_PERORDER}[$order]++;
+			}
+		} elsif ($tracepoint eq "mm_vmscan_kswapd_sleep") {
+
+			# Count the event itself
+			my $index = $perprocesspid{$process_pid}->{MM_VMSCAN_KSWAPD_SLEEP};
+			$perprocesspid{$process_pid}->{MM_VMSCAN_KSWAPD_SLEEP}++;
+
+			# Record how long kswapd was awake
+			$timestamp = timestamp_to_ms($timestamp);
+			my $order = $perprocesspid{$process_pid}->{STATE_KSWAPD_ORDER};
+			my $latency = ($timestamp - $perprocesspid{$process_pid}->{STATE_KSWAPD_BEGIN});
+			$perprocesspid{$process_pid}->{HIGH_KSWAPD_LATENCY}[$index] = "$order-$latency";
+			$perprocesspid{$process_pid}->{STATE_KSWAPD_BEGIN} = 0;
+		} elsif ($tracepoint eq "mm_vmscan_wakeup_kswapd") {
+			$perprocesspid{$process_pid}->{MM_VMSCAN_WAKEUP_KSWAPD}++;
+
+			$details = $6;
+			if ($details !~ /$regex_wakeup_kswapd/o) {
+				print "WARNING: Failed to parse mm_vmscan_wakeup_kswapd as expected\n";
+				print "         $details\n";
+				print "         $regex_wakeup_kswapd\n";
+				next;
+			}
+			my $order = $2;
+			$perprocesspid{$process_pid}->{MM_VMSCAN_WAKEUP_KSWAPD_PERORDER}[$order]++;
+		} elsif ($tracepoint eq "mm_vmscan_lru_isolate") {
+			$details = $6;
+			if ($details !~ /$regex_lru_isolate/o) {
+				print "WARNING: Failed to parse mm_vmscan_lru_isolate as expected\n";
+				print "         $details\n";
+				print "         $regex_lru_isolate/o\n";
+				next;
+			}
+			my $nr_scanned = $4;
+			my $lru = $7;
+
+			# To closer match vmstat scanning statistics, only count
+			# inactive lru as scanning
+			if ($lru =~ /inactive_/) {
+				$perprocesspid{$process_pid}->{HIGH_NR_SCANNED} += $nr_scanned;
+				if ($lru =~ /_file/) {
+					$perprocesspid{$process_pid}->{HIGH_NR_FILE_SCANNED} += $nr_scanned;
+				} else {
+					$perprocesspid{$process_pid}->{HIGH_NR_ANON_SCANNED} += $nr_scanned;
+				}
+			}
+		} elsif ($tracepoint eq "mm_vmscan_lru_shrink_inactive") {
+			$details = $6;
+			if ($details !~ /$regex_lru_shrink_inactive/o) {
+				print "WARNING: Failed to parse mm_vmscan_lru_shrink_inactive as expected\n";
+				print "         $details\n";
+				print "         $regex_lru_shrink_inactive/o\n";
+				next;
+			}
+
+			my $nr_reclaimed = $3;
+			my $flags = $13;
+			my $file = 0;
+			if ($flags =~ /RECLAIM_WB_FILE/) {
+				$file = 1;
+			}
+			$perprocesspid{$process_pid}->{HIGH_NR_RECLAIMED} += $nr_reclaimed;
+			if ($file) {
+				$perprocesspid{$process_pid}->{HIGH_NR_FILE_RECLAIMED} += $nr_reclaimed;
+			} else {
+				$perprocesspid{$process_pid}->{HIGH_NR_ANON_RECLAIMED} += $nr_reclaimed;
+			}
+		} elsif ($tracepoint eq "mm_vmscan_writepage") {
+			$details = $6;
+			if ($details !~ /$regex_writepage/o) {
+				print "WARNING: Failed to parse mm_vmscan_writepage as expected\n";
+				print "         $details\n";
+				print "         $regex_writepage\n";
+				next;
+			}
+
+			my $flags = $3;
+			my $file = 0;
+			my $sync_io = 0;
+			if ($flags =~ /RECLAIM_WB_FILE/) {
+				$file = 1;
+			}
+			if ($flags =~ /RECLAIM_WB_SYNC/) {
+				$sync_io = 1;
+			}
+			if ($sync_io) {
+				if ($file) {
+					$perprocesspid{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_SYNC}++;
+				} else {
+					$perprocesspid{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_SYNC}++;
+				}
+			} else {
+				if ($file) {
+					$perprocesspid{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_ASYNC}++;
+				} else {
+					$perprocesspid{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_ASYNC}++;
+				}
+			}
+		} else {
+			$perprocesspid{$process_pid}->{EVENT_UNKNOWN}++;
+		}
+
+		if ($sigint_pending) {
+			last EVENT_PROCESS;
+		}
+	}
+}
+
+sub dump_stats {
+	my $hashref = shift;
+	my %stats = %$hashref;
+
+	# Dump per-process stats
+	my $process_pid;
+	my $max_strlen = 0;
+
+	# Get the maximum process name
+	foreach $process_pid (keys %perprocesspid) {
+		my $len = length($process_pid);
+		if ($len > $max_strlen) {
+			$max_strlen = $len;
+		}
+	}
+	$max_strlen += 2;
+
+	# Work out latencies
+	printf("\n") if !$opt_ignorepid;
+	printf("Reclaim latencies expressed as order-latency_in_ms\n") if !$opt_ignorepid;
+	foreach $process_pid (keys %stats) {
+
+		if (!$stats{$process_pid}->{HIGH_DIRECT_RECLAIM_LATENCY}[0] &&
+				!$stats{$process_pid}->{HIGH_KSWAPD_LATENCY}[0]) {
+			next;
+		}
+
+		printf "%-" . $max_strlen . "s ", $process_pid if !$opt_ignorepid;
+		my $index = 0;
+		while (defined $stats{$process_pid}->{HIGH_DIRECT_RECLAIM_LATENCY}[$index] ||
+			defined $stats{$process_pid}->{HIGH_KSWAPD_LATENCY}[$index]) {
+
+			if ($stats{$process_pid}->{HIGH_DIRECT_RECLAIM_LATENCY}[$index]) {
+				printf("%s ", $stats{$process_pid}->{HIGH_DIRECT_RECLAIM_LATENCY}[$index]) if !$opt_ignorepid;
+				my ($dummy, $latency) = split(/-/, $stats{$process_pid}->{HIGH_DIRECT_RECLAIM_LATENCY}[$index]);
+				$total_direct_latency += $latency;
+			} else {
+				printf("%s ", $stats{$process_pid}->{HIGH_KSWAPD_LATENCY}[$index]) if !$opt_ignorepid;
+				my ($dummy, $latency) = split(/-/, $stats{$process_pid}->{HIGH_KSWAPD_LATENCY}[$index]);
+				$total_kswapd_latency += $latency;
+			}
+			$index++;
+		}
+		print "\n" if !$opt_ignorepid;
+	}
+
+	# Print out process activity
+	printf("\n");
+	printf("%-" . $max_strlen . "s %8s %10s   %8s %8s  %8s %8s %8s %8s\n", "Process", "Direct",  "Wokeup", "Pages",   "Pages",   "Pages",   "Pages",     "Time");
+	printf("%-" . $max_strlen . "s %8s %10s   %8s %8s  %8s %8s %8s %8s\n", "details", "Rclms",   "Kswapd", "Scanned", "Rclmed",  "Sync-IO", "ASync-IO",  "Stalled");
+	foreach $process_pid (keys %stats) {
+
+		if (!$stats{$process_pid}->{MM_VMSCAN_DIRECT_RECLAIM_BEGIN}) {
+			next;
+		}
+
+		$total_direct_reclaim += $stats{$process_pid}->{MM_VMSCAN_DIRECT_RECLAIM_BEGIN};
+		$total_wakeup_kswapd += $stats{$process_pid}->{MM_VMSCAN_WAKEUP_KSWAPD};
+		$total_direct_nr_scanned += $stats{$process_pid}->{HIGH_NR_SCANNED};
+		$total_direct_nr_file_scanned += $stats{$process_pid}->{HIGH_NR_FILE_SCANNED};
+		$total_direct_nr_anon_scanned += $stats{$process_pid}->{HIGH_NR_ANON_SCANNED};
+		$total_direct_nr_reclaimed += $stats{$process_pid}->{HIGH_NR_RECLAIMED};
+		$total_direct_nr_file_reclaimed += $stats{$process_pid}->{HIGH_NR_FILE_RECLAIMED};
+		$total_direct_nr_anon_reclaimed += $stats{$process_pid}->{HIGH_NR_ANON_RECLAIMED};
+		$total_direct_writepage_file_sync += $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_SYNC};
+		$total_direct_writepage_anon_sync += $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_SYNC};
+		$total_direct_writepage_file_async += $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_ASYNC};
+
+		$total_direct_writepage_anon_async += $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_ASYNC};
+
+		my $index = 0;
+		my $this_reclaim_delay = 0;
+		while (defined $stats{$process_pid}->{HIGH_DIRECT_RECLAIM_LATENCY}[$index]) {
+			 my ($dummy, $latency) = split(/-/, $stats{$process_pid}->{HIGH_DIRECT_RECLAIM_LATENCY}[$index]);
+			$this_reclaim_delay += $latency;
+			$index++;
+		}
+
+		printf("%-" . $max_strlen . "s %8d %10d   %8u %8u  %8u %8u %8.3f",
+			$process_pid,
+			$stats{$process_pid}->{MM_VMSCAN_DIRECT_RECLAIM_BEGIN},
+			$stats{$process_pid}->{MM_VMSCAN_WAKEUP_KSWAPD},
+			$stats{$process_pid}->{HIGH_NR_SCANNED},
+			$stats{$process_pid}->{HIGH_NR_FILE_SCANNED},
+			$stats{$process_pid}->{HIGH_NR_ANON_SCANNED},
+			$stats{$process_pid}->{HIGH_NR_RECLAIMED},
+			$stats{$process_pid}->{HIGH_NR_FILE_RECLAIMED},
+			$stats{$process_pid}->{HIGH_NR_ANON_RECLAIMED},
+			$stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_SYNC} + $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_SYNC},
+			$stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_ASYNC} + $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_ASYNC},
+			$this_reclaim_delay / 1000);
+
+		if ($stats{$process_pid}->{MM_VMSCAN_DIRECT_RECLAIM_BEGIN}) {
+			print "      ";
+			for (my $order = 0; $order < 20; $order++) {
+				my $count = $stats{$process_pid}->{MM_VMSCAN_DIRECT_RECLAIM_BEGIN_PERORDER}[$order];
+				if ($count != 0) {
+					print "direct-$order=$count ";
+				}
+			}
+		}
+		if ($stats{$process_pid}->{MM_VMSCAN_WAKEUP_KSWAPD}) {
+			print "      ";
+			for (my $order = 0; $order < 20; $order++) {
+				my $count = $stats{$process_pid}->{MM_VMSCAN_WAKEUP_KSWAPD_PERORDER}[$order];
+				if ($count != 0) {
+					print "wakeup-$order=$count ";
+				}
+			}
+		}
+
+		print "\n";
+	}
+
+	# Print out kswapd activity
+	printf("\n");
+	printf("%-" . $max_strlen . "s %8s %10s   %8s   %8s %8s %8s\n", "Kswapd",   "Kswapd",  "Order",     "Pages",   "Pages",   "Pages",  "Pages");
+	printf("%-" . $max_strlen . "s %8s %10s   %8s   %8s %8s %8s\n", "Instance", "Wakeups", "Re-wakeup", "Scanned", "Rclmed",  "Sync-IO", "ASync-IO");
+	foreach $process_pid (keys %stats) {
+
+		if (!$stats{$process_pid}->{MM_VMSCAN_KSWAPD_WAKE}) {
+			next;
+		}
+
+		$total_kswapd_wake += $stats{$process_pid}->{MM_VMSCAN_KSWAPD_WAKE};
+		$total_kswapd_nr_scanned += $stats{$process_pid}->{HIGH_NR_SCANNED};
+		$total_kswapd_nr_file_scanned += $stats{$process_pid}->{HIGH_NR_FILE_SCANNED};
+		$total_kswapd_nr_anon_scanned += $stats{$process_pid}->{HIGH_NR_ANON_SCANNED};
+		$total_kswapd_nr_reclaimed += $stats{$process_pid}->{HIGH_NR_RECLAIMED};
+		$total_kswapd_nr_file_reclaimed += $stats{$process_pid}->{HIGH_NR_FILE_RECLAIMED};
+		$total_kswapd_nr_anon_reclaimed += $stats{$process_pid}->{HIGH_NR_ANON_RECLAIMED};
+		$total_kswapd_writepage_file_sync += $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_SYNC};
+		$total_kswapd_writepage_anon_sync += $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_SYNC};
+		$total_kswapd_writepage_file_async += $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_ASYNC};
+		$total_kswapd_writepage_anon_async += $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_ASYNC};
+
+		printf("%-" . $max_strlen . "s %8d %10d   %8u %8u  %8i %8u",
+			$process_pid,
+			$stats{$process_pid}->{MM_VMSCAN_KSWAPD_WAKE},
+			$stats{$process_pid}->{HIGH_KSWAPD_REWAKEUP},
+			$stats{$process_pid}->{HIGH_NR_SCANNED},
+			$stats{$process_pid}->{HIGH_NR_FILE_SCANNED},
+			$stats{$process_pid}->{HIGH_NR_ANON_SCANNED},
+			$stats{$process_pid}->{HIGH_NR_RECLAIMED},
+			$stats{$process_pid}->{HIGH_NR_FILE_RECLAIMED},
+			$stats{$process_pid}->{HIGH_NR_ANON_RECLAIMED},
+			$stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_SYNC} + $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_SYNC},
+			$stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_ASYNC} + $stats{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_ASYNC});
+
+		if ($stats{$process_pid}->{MM_VMSCAN_KSWAPD_WAKE}) {
+			print "      ";
+			for (my $order = 0; $order < 20; $order++) {
+				my $count = $stats{$process_pid}->{MM_VMSCAN_KSWAPD_WAKE_PERORDER}[$order];
+				if ($count != 0) {
+					print "wake-$order=$count ";
+				}
+			}
+		}
+		if ($stats{$process_pid}->{HIGH_KSWAPD_REWAKEUP}) {
+			print "      ";
+			for (my $order = 0; $order < 20; $order++) {
+				my $count = $stats{$process_pid}->{HIGH_KSWAPD_REWAKEUP_PERORDER}[$order];
+				if ($count != 0) {
+					print "rewake-$order=$count ";
+				}
+			}
+		}
+		printf("\n");
+	}
+
+	# Print out summaries
+	$total_direct_latency /= 1000;
+	$total_kswapd_latency /= 1000;
+	print "\nSummary\n";
+	print "Direct reclaims:     			$total_direct_reclaim\n";
+	print "Direct reclaim pages scanned:		$total_direct_nr_scanned\n";
+	print "Direct reclaim file pages scanned:	$total_direct_nr_file_scanned\n";
+	print "Direct reclaim anon pages scanned:	$total_direct_nr_anon_scanned\n";
+	print "Direct reclaim pages reclaimed:		$total_direct_nr_reclaimed\n";
+	print "Direct reclaim file pages reclaimed:	$total_direct_nr_file_reclaimed\n";
+	print "Direct reclaim anon pages reclaimed:	$total_direct_nr_anon_reclaimed\n";
+	print "Direct reclaim write file sync I/O:	$total_direct_writepage_file_sync\n";
+	print "Direct reclaim write anon sync I/O:	$total_direct_writepage_anon_sync\n";
+	print "Direct reclaim write file async I/O:	$total_direct_writepage_file_async\n";
+	print "Direct reclaim write anon async I/O:	$total_direct_writepage_anon_async\n";
+	print "Wake kswapd requests:			$total_wakeup_kswapd\n";
+	printf "Time stalled direct reclaim: 		%-1.2f seconds\n", $total_direct_latency;
+	print "\n";
+	print "Kswapd wakeups:				$total_kswapd_wake\n";
+	print "Kswapd pages scanned:			$total_kswapd_nr_scanned\n";
+	print "Kswapd file pages scanned:		$total_kswapd_nr_file_scanned\n";
+	print "Kswapd anon pages scanned:		$total_kswapd_nr_anon_scanned\n";
+	print "Kswapd pages reclaimed:			$total_kswapd_nr_reclaimed\n";
+	print "Kswapd file pages reclaimed:		$total_kswapd_nr_file_reclaimed\n";
+	print "Kswapd anon pages reclaimed:		$total_kswapd_nr_anon_reclaimed\n";
+	print "Kswapd reclaim write file sync I/O:	$total_kswapd_writepage_file_sync\n";
+	print "Kswapd reclaim write anon sync I/O:	$total_kswapd_writepage_anon_sync\n";
+	print "Kswapd reclaim write file async I/O:	$total_kswapd_writepage_file_async\n";
+	print "Kswapd reclaim write anon async I/O:	$total_kswapd_writepage_anon_async\n";
+	printf "Time kswapd awake:			%-1.2f seconds\n", $total_kswapd_latency;
+}
+
+sub aggregate_perprocesspid() {
+	my $process_pid;
+	my $process;
+	undef %perprocess;
+
+	foreach $process_pid (keys %perprocesspid) {
+		$process = $process_pid;
+		$process =~ s/-([0-9])*$//;
+		if ($process eq '') {
+			$process = "NO_PROCESS_NAME";
+		}
+
+		$perprocess{$process}->{MM_VMSCAN_DIRECT_RECLAIM_BEGIN} += $perprocesspid{$process_pid}->{MM_VMSCAN_DIRECT_RECLAIM_BEGIN};
+		$perprocess{$process}->{MM_VMSCAN_KSWAPD_WAKE} += $perprocesspid{$process_pid}->{MM_VMSCAN_KSWAPD_WAKE};
+		$perprocess{$process}->{MM_VMSCAN_WAKEUP_KSWAPD} += $perprocesspid{$process_pid}->{MM_VMSCAN_WAKEUP_KSWAPD};
+		$perprocess{$process}->{HIGH_KSWAPD_REWAKEUP} += $perprocesspid{$process_pid}->{HIGH_KSWAPD_REWAKEUP};
+		$perprocess{$process}->{HIGH_NR_SCANNED} += $perprocesspid{$process_pid}->{HIGH_NR_SCANNED};
+		$perprocess{$process}->{HIGH_NR_FILE_SCANNED} += $perprocesspid{$process_pid}->{HIGH_NR_FILE_SCANNED};
+		$perprocess{$process}->{HIGH_NR_ANON_SCANNED} += $perprocesspid{$process_pid}->{HIGH_NR_ANON_SCANNED};
+		$perprocess{$process}->{HIGH_NR_RECLAIMED} += $perprocesspid{$process_pid}->{HIGH_NR_RECLAIMED};
+		$perprocess{$process}->{HIGH_NR_FILE_RECLAIMED} += $perprocesspid{$process_pid}->{HIGH_NR_FILE_RECLAIMED};
+		$perprocess{$process}->{HIGH_NR_ANON_RECLAIMED} += $perprocesspid{$process_pid}->{HIGH_NR_ANON_RECLAIMED};
+		$perprocess{$process}->{MM_VMSCAN_WRITEPAGE_FILE_SYNC} += $perprocesspid{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_SYNC};
+		$perprocess{$process}->{MM_VMSCAN_WRITEPAGE_ANON_SYNC} += $perprocesspid{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_SYNC};
+		$perprocess{$process}->{MM_VMSCAN_WRITEPAGE_FILE_ASYNC} += $perprocesspid{$process_pid}->{MM_VMSCAN_WRITEPAGE_FILE_ASYNC};
+		$perprocess{$process}->{MM_VMSCAN_WRITEPAGE_ANON_ASYNC} += $perprocesspid{$process_pid}->{MM_VMSCAN_WRITEPAGE_ANON_ASYNC};
+
+		for (my $order = 0; $order < 20; $order++) {
+			$perprocess{$process}->{MM_VMSCAN_DIRECT_RECLAIM_BEGIN_PERORDER}[$order] += $perprocesspid{$process_pid}->{MM_VMSCAN_DIRECT_RECLAIM_BEGIN_PERORDER}[$order];
+			$perprocess{$process}->{MM_VMSCAN_WAKEUP_KSWAPD_PERORDER}[$order] += $perprocesspid{$process_pid}->{MM_VMSCAN_WAKEUP_KSWAPD_PERORDER}[$order];
+			$perprocess{$process}->{MM_VMSCAN_KSWAPD_WAKE_PERORDER}[$order] += $perprocesspid{$process_pid}->{MM_VMSCAN_KSWAPD_WAKE_PERORDER}[$order];
+
+		}
+
+		# Aggregate direct reclaim latencies
+		my $wr_index = $perprocess{$process}->{MM_VMSCAN_DIRECT_RECLAIM_END};
+		my $rd_index = 0;
+		while (defined $perprocesspid{$process_pid}->{HIGH_DIRECT_RECLAIM_LATENCY}[$rd_index]) {
+			$perprocess{$process}->{HIGH_DIRECT_RECLAIM_LATENCY}[$wr_index] = $perprocesspid{$process_pid}->{HIGH_DIRECT_RECLAIM_LATENCY}[$rd_index];
+			$rd_index++;
+			$wr_index++;
+		}
+		$perprocess{$process}->{MM_VMSCAN_DIRECT_RECLAIM_END} = $wr_index;
+
+		# Aggregate kswapd latencies
+		my $wr_index = $perprocess{$process}->{MM_VMSCAN_KSWAPD_SLEEP};
+		my $rd_index = 0;
+		while (defined $perprocesspid{$process_pid}->{HIGH_KSWAPD_LATENCY}[$rd_index]) {
+			$perprocess{$process}->{HIGH_KSWAPD_LATENCY}[$wr_index] = $perprocesspid{$process_pid}->{HIGH_KSWAPD_LATENCY}[$rd_index];
+			$rd_index++;
+			$wr_index++;
+		}
+		$perprocess{$process}->{MM_VMSCAN_DIRECT_RECLAIM_END} = $wr_index;
+	}
+}
+
+sub report() {
+	if (!$opt_ignorepid) {
+		dump_stats(\%perprocesspid);
+	} else {
+		aggregate_perprocesspid();
+		dump_stats(\%perprocess);
+	}
+}
+
+# Process events or signals until neither is available
+sub signal_loop() {
+	my $sigint_processed;
+	do {
+		$sigint_processed = 0;
+		process_events();
+
+		# Handle pending signals if any
+		if ($sigint_pending) {
+			my $current_time = time;
+
+			if ($sigint_exit) {
+				print "Received exit signal\n";
+				$sigint_pending = 0;
+			}
+			if ($sigint_report) {
+				if ($current_time >= $sigint_received + 2) {
+					report();
+					$sigint_report = 0;
+					$sigint_pending = 0;
+					$sigint_processed = 1;
+				}
+			}
+		}
+	} while ($sigint_pending || $sigint_processed);
+}
+
+signal_loop();
+report();