Merge branch 'akpm-incoming-1'

* akpm-incoming-1: (176 commits)
  scripts/checkpatch.pl: add check for declaration of pci_device_id
  scripts/checkpatch.pl: add warnings for static char that could be static const char
  checkpatch: version 0.31
  checkpatch: statement/block context analyser should look at sanitised lines
  checkpatch: handle EXPORT_SYMBOL for DEVICE_ATTR and similar
  checkpatch: clean up structure definition macro handline
  checkpatch: update copyright dates
  checkpatch: Add additional attribute #defines
  checkpatch: check for incorrect permissions
  checkpatch: ensure kconfig help checks only apply when we are adding help
  checkpatch: simplify and consolidate "missing space after" checks
  checkpatch: add check for space after struct, union, and enum
  checkpatch: returning errno typically should be negative
  checkpatch: handle casts better fixing false categorisation of : as binary
  checkpatch: ensure we do not collapse bracketed sections into constants
  checkpatch: suggest cleanpatch and cleanfile when appropriate
  checkpatch: types may sit on a line on their own
  checkpatch: fix regressions in "fix handling of leading spaces"
  div64_u64(): improve precision on 32bit platforms
  lib/parser: cleanup match_number()
  ...

6 files changed, 452 insertions, 17 deletions

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index a6aca874088..a563b74c7ae 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -374,13 +374,13 @@ Swap:                  0 kB
 KernelPageSize:        4 kB
 MMUPageSize:           4 kB
 
-The first  of these lines shows  the same information  as is displayed for the
-mapping in /proc/PID/maps.  The remaining lines show  the size of the mapping,
-the amount of the mapping that is currently resident in RAM, the "proportional
-set size” (divide each shared page by the number of processes sharing it), the
-number of clean and dirty shared pages in the mapping, and the number of clean
-and dirty private pages in the mapping.  The "Referenced" indicates the amount
-of memory currently marked as referenced or accessed.
+The first of these lines shows the same information as is displayed for the
+mapping in /proc/PID/maps.  The remaining lines show the size of the mapping
+(size), the amount of the mapping that is currently resident in RAM (RSS), the
+process' proportional share of this mapping (PSS), the number of clean and
+dirty shared pages in the mapping, and the number of clean and dirty private
+pages in the mapping.  The "Referenced" indicates the amount of memory
+currently marked as referenced or accessed.
 
 This file is only present if the CONFIG_MMU kernel configuration option is
 enabled.
diff --git a/Documentation/misc-devices/apds990x.txt b/Documentation/misc-devices/apds990x.txt
new file mode 100644
index 00000000000..d5408cade32
--- /dev/null
+++ b/Documentation/misc-devices/apds990x.txt
@@ -0,0 +1,111 @@
+Kernel driver apds990x
+======================
+
+Supported chips:
+Avago APDS990X
+
+Data sheet:
+Not freely available
+
+Author:
+Samu Onkalo <samu.p.onkalo@nokia.com>
+
+Description
+-----------
+
+APDS990x is a combined ambient light and proximity sensor. ALS and proximity
+functionality are highly connected. ALS measurement path must be running
+while the proximity functionality is enabled.
+
+ALS produces raw measurement values for two channels: Clear channel
+(infrared + visible light) and IR only. However, threshold comparisons happen
+using clear channel only. Lux value and the threshold level on the HW
+might vary quite much depending the spectrum of the light source.
+
+Driver makes necessary conversions to both directions so that user handles
+only lux values. Lux value is calculated using information from the both
+channels. HW threshold level is calculated from the given lux value to match
+with current type of the lightning. Sometimes inaccuracy of the estimations
+lead to false interrupt, but that doesn't harm.
+
+ALS contains 4 different gain steps. Driver automatically
+selects suitable gain step. After each measurement, reliability of the results
+is estimated and new measurement is trigged if necessary.
+
+Platform data can provide tuned values to the conversion formulas if
+values are known. Otherwise plain sensor default values are used.
+
+Proximity side is little bit simpler. There is no need for complex conversions.
+It produces directly usable values.
+
+Driver controls chip operational state using pm_runtime framework.
+Voltage regulators are controlled based on chip operational state.
+
+SYSFS
+-----
+
+
+chip_id
+	RO - shows detected chip type and version
+
+power_state
+	RW - enable / disable chip. Uses counting logic
+	     1 enables the chip
+	     0 disables the chip
+lux0_input
+	RO - measured lux value
+	     sysfs_notify called when threshold interrupt occurs
+
+lux0_sensor_range
+	RO - lux0_input max value. Actually never reaches since sensor tends
+	     to saturate much before that. Real max value varies depending
+	     on the light spectrum etc.
+
+lux0_rate
+	RW - measurement rate in Hz
+
+lux0_rate_avail
+	RO - supported measurement rates
+
+lux0_calibscale
+	RW - calibration value. Set to neutral value by default.
+	     Output results are multiplied with calibscale / calibscale_default
+	     value.
+
+lux0_calibscale_default
+	RO - neutral calibration value
+
+lux0_thresh_above_value
+	RW - HI level threshold value. All results above the value
+	     trigs an interrupt. 65535 (i.e. sensor_range) disables the above
+	     interrupt.
+
+lux0_thresh_below_value
+	RW - LO level threshold value. All results below the value
+	     trigs an interrupt. 0 disables the below interrupt.
+
+prox0_raw
+	RO - measured proximity value
+	     sysfs_notify called when threshold interrupt occurs
+
+prox0_sensor_range
+	RO - prox0_raw max value (1023)
+
+prox0_raw_en
+	RW - enable / disable proximity - uses counting logic
+	     1 enables the proximity
+	     0 disables the proximity
+
+prox0_reporting_mode
+	RW - trigger / periodic. In "trigger" mode the driver tells two possible
+	     values: 0 or prox0_sensor_range value. 0 means no proximity,
+	     1023 means proximity. This causes minimal number of interrupts.
+	     In "periodic" mode the driver reports all values above
+	     prox0_thresh_above. This causes more interrupts, but it can give
+	     _rough_ estimate about the distance.
+
+prox0_reporting_mode_avail
+	RO - accepted values to prox0_reporting_mode (trigger, periodic)
+
+prox0_thresh_above_value
+	RW - threshold level which trigs proximity events.
diff --git a/Documentation/misc-devices/bh1770glc.txt b/Documentation/misc-devices/bh1770glc.txt
new file mode 100644
index 00000000000..7d64c014dc7
--- /dev/null
+++ b/Documentation/misc-devices/bh1770glc.txt
@@ -0,0 +1,116 @@
+Kernel driver bh1770glc
+=======================
+
+Supported chips:
+ROHM BH1770GLC
+OSRAM SFH7770
+
+Data sheet:
+Not freely available
+
+Author:
+Samu Onkalo <samu.p.onkalo@nokia.com>
+
+Description
+-----------
+BH1770GLC and SFH7770 are combined ambient light and proximity sensors.
+ALS and proximity parts operates on their own, but they shares common I2C
+interface and interrupt logic. In principle they can run on their own,
+but ALS side results are used to estimate reliability of the proximity sensor.
+
+ALS produces 16 bit lux values. The chip contains interrupt logic to produce
+low and high threshold interrupts.
+
+Proximity part contains IR-led driver up to 3 IR leds. The chip measures
+amount of reflected IR light and produces proximity result. Resolution is
+8 bit. Driver supports only one channel. Driver uses ALS results to estimate
+reliability of the proximity results. Thus ALS is always running while
+proximity detection is needed.
+
+Driver uses threshold interrupts to avoid need for polling the values.
+Proximity low interrupt doesn't exists in the chip. This is simulated
+by using a delayed work. As long as there is proximity threshold above
+interrupts the delayed work is pushed forward. So, when proximity level goes
+below the threshold value, there is no interrupt and the delayed work will
+finally run. This is handled as no proximity indication.
+
+Chip state is controlled via runtime pm framework when enabled in config.
+
+Calibscale factor is used to hide differences between the chips. By default
+value set to neutral state meaning factor of 1.00. To get proper values,
+calibrated source of light is needed as a reference. Calibscale factor is set
+so that measurement produces about the expected lux value.
+
+SYSFS
+-----
+
+chip_id
+	RO - shows detected chip type and version
+
+power_state
+	RW - enable / disable chip. Uses counting logic
+	     1 enables the chip
+	     0 disables the chip
+
+lux0_input
+	RO - measured lux value
+	     sysfs_notify called when threshold interrupt occurs
+
+lux0_sensor_range
+	RO - lux0_input max value
+
+lux0_rate
+	RW - measurement rate in Hz
+
+lux0_rate_avail
+	RO - supported measurement rates
+
+lux0_thresh_above_value
+	RW - HI level threshold value. All results above the value
+	     trigs an interrupt. 65535 (i.e. sensor_range) disables the above
+	     interrupt.
+
+lux0_thresh_below_value
+	RW - LO level threshold value. All results below the value
+	     trigs an interrupt. 0 disables the below interrupt.
+
+lux0_calibscale
+	RW - calibration value. Set to neutral value by default.
+	     Output results are multiplied with calibscale / calibscale_default
+	     value.
+
+lux0_calibscale_default
+	RO - neutral calibration value
+
+prox0_raw
+	RO - measured proximity value
+	     sysfs_notify called when threshold interrupt occurs
+
+prox0_sensor_range
+	RO - prox0_raw max value
+
+prox0_raw_en
+	RW - enable / disable proximity - uses counting logic
+	     1 enables the proximity
+	     0 disables the proximity
+
+prox0_thresh_above_count
+	RW - number of proximity interrupts needed before triggering the event
+
+prox0_rate_above
+	RW - Measurement rate (in Hz) when the level is above threshold
+	     i.e. when proximity on has been reported.
+
+prox0_rate_below
+	RW - Measurement rate (in Hz) when the level is below threshold
+	     i.e. when proximity off has been reported.
+
+prox0_rate_avail
+	RO - Supported proximity measurement rates in Hz
+
+prox0_thresh_above0_value
+	RW - threshold level which trigs proximity events.
+	     Filtered by persistence filter (prox0_thresh_above_count)
+
+prox0_thresh_above1_value
+	RW - threshold level which trigs event immediately
diff --git a/Documentation/timers/hpet_example.c b/Documentation/timers/hpet_example.c
index 4bfafb7bc4c..9a3e7012c19 100644
--- a/Documentation/timers/hpet_example.c
+++ b/Documentation/timers/hpet_example.c
@@ -97,6 +97,33 @@ hpet_open_close(int argc, const char **argv)
 void
 hpet_info(int argc, const char **argv)
 {
+	struct hpet_info	info;
+	int			fd;
+
+	if (argc != 1) {
+		fprintf(stderr, "hpet_info: device-name\n");
+		return;
+	}
+
+	fd = open(argv[0], O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "hpet_info: open of %s failed\n", argv[0]);
+		return;
+	}
+
+	if (ioctl(fd, HPET_INFO, &info) < 0) {
+		fprintf(stderr, "hpet_info: failed to get info\n");
+		goto out;
+	}
+
+	fprintf(stderr, "hpet_info: hi_irqfreq 0x%lx hi_flags 0x%lx ",
+		info.hi_ireqfreq, info.hi_flags);
+	fprintf(stderr, "hi_hpet %d hi_timer %d\n",
+		info.hi_hpet, info.hi_timer);
+
+out:
+	close(fd);
+	return;
 }
 
 void
diff --git a/Documentation/trace/postprocess/trace-vmscan-postprocess.pl b/Documentation/trace/postprocess/trace-vmscan-postprocess.pl
index 1b55146d1c8..b3e73ddb156 100644
--- a/Documentation/trace/postprocess/trace-vmscan-postprocess.pl
+++ b/Documentation/trace/postprocess/trace-vmscan-postprocess.pl
@@ -46,7 +46,7 @@ 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_RECLAIM			=> 24;
+use constant HIGH_NR_RECLAIMED			=> 24;
 use constant HIGH_NR_CONTIG_DIRTY		=> 25;
 
 my %perprocesspid;
@@ -58,11 +58,13 @@ my $opt_read_procstat;
 my $total_wakeup_kswapd;
 my ($total_direct_reclaim, $total_direct_nr_scanned);
 my ($total_direct_latency, $total_kswapd_latency);
+my ($total_direct_nr_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_writepage_file_sync, $total_kswapd_writepage_file_async);
 my ($total_kswapd_writepage_anon_sync, $total_kswapd_writepage_anon_async);
+my ($total_kswapd_nr_reclaimed);
 
 # Catch sigint and exit on request
 my $sigint_report = 0;
@@ -104,7 +106,7 @@ 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]*) zid=([0-9]*) order=([0-9]*)';
 my $regex_lru_isolate_default = 'isolate_mode=([0-9]*) order=([0-9]*) nr_requested=([0-9]*) nr_scanned=([0-9]*) nr_taken=([0-9]*) contig_taken=([0-9]*) contig_dirty=([0-9]*) contig_failed=([0-9]*)';
-my $regex_lru_shrink_inactive_default = 'lru=([A-Z_]*) nr_scanned=([0-9]*) nr_reclaimed=([0-9]*) priority=([0-9]*)';
+my $regex_lru_shrink_inactive_default = 'nid=([0-9]*) zid=([0-9]*) nr_scanned=([0-9]*) nr_reclaimed=([0-9]*) priority=([0-9]*) flags=([A-Z_|]*)';
 my $regex_lru_shrink_active_default = 'lru=([A-Z_]*) nr_scanned=([0-9]*) nr_rotated=([0-9]*) priority=([0-9]*)';
 my $regex_writepage_default = 'page=([0-9a-f]*) pfn=([0-9]*) flags=([A-Z_|]*)';
 
@@ -203,8 +205,8 @@ $regex_lru_shrink_inactive = generate_traceevent_regex(
 			"vmscan/mm_vmscan_lru_shrink_inactive",
 			$regex_lru_shrink_inactive_default,
 			"nid", "zid",
-			"lru",
-			"nr_scanned", "nr_reclaimed", "priority");
+			"nr_scanned", "nr_reclaimed", "priority",
+			"flags");
 $regex_lru_shrink_active = generate_traceevent_regex(
 			"vmscan/mm_vmscan_lru_shrink_active",
 			$regex_lru_shrink_active_default,
@@ -375,6 +377,16 @@ EVENT_PROCESS:
 			my $nr_contig_dirty = $7;
 			$perprocesspid{$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 = $5;
+			if ($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 = $4;
+			$perprocesspid{$process_pid}->{HIGH_NR_RECLAIMED} += $nr_reclaimed;
 		} elsif ($tracepoint eq "mm_vmscan_writepage") {
 			$details = $5;
 			if ($details !~ /$regex_writepage/o) {
@@ -464,8 +476,8 @@ sub dump_stats {
 
 	# Print out process activity
 	printf("\n");
-	printf("%-" . $max_strlen . "s %8s %10s   %8s   %8s %8s %8s %8s\n", "Process", "Direct",  "Wokeup", "Pages",   "Pages",   "Pages",     "Time");
-	printf("%-" . $max_strlen . "s %8s %10s   %8s   %8s %8s %8s %8s\n", "details", "Rclms",   "Kswapd", "Scanned", "Sync-IO", "ASync-IO",  "Stalled");
+	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}) {
@@ -475,6 +487,7 @@ sub dump_stats {
 		$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_reclaimed += $stats{$process_pid}->{HIGH_NR_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};
@@ -489,11 +502,12 @@ sub dump_stats {
 			$index++;
 		}
 
-		printf("%-" . $max_strlen . "s %8d %10d   %8u   %8u %8u %8.3f",
+		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_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);
@@ -529,8 +543,8 @@ sub dump_stats {
 
 	# Print out kswapd activity
 	printf("\n");
-	printf("%-" . $max_strlen . "s %8s %10s   %8s   %8s %8s %8s\n", "Kswapd",   "Kswapd",  "Order",     "Pages",   "Pages",  "Pages");
-	printf("%-" . $max_strlen . "s %8s %10s   %8s   %8s %8s %8s\n", "Instance", "Wakeups", "Re-wakeup", "Scanned", "Sync-IO", "ASync-IO");
+	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}) {
@@ -539,16 +553,18 @@ sub dump_stats {
 
 		$total_kswapd_wake += $stats{$process_pid}->{MM_VMSCAN_KSWAPD_WAKE};
 		$total_kswapd_nr_scanned += $stats{$process_pid}->{HIGH_NR_SCANNED};
+		$total_kswapd_nr_reclaimed += $stats{$process_pid}->{HIGH_NR_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   %8i %8u",
+		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_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});
 
@@ -579,6 +595,7 @@ sub dump_stats {
 	print "\nSummary\n";
 	print "Direct reclaims:     			$total_direct_reclaim\n";
 	print "Direct reclaim pages scanned:		$total_direct_nr_scanned\n";
+	print "Direct reclaim pages reclaimed:		$total_direct_nr_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";
@@ -588,6 +605,7 @@ sub dump_stats {
 	print "\n";
 	print "Kswapd wakeups:				$total_kswapd_wake\n";
 	print "Kswapd pages scanned:			$total_kswapd_nr_scanned\n";
+	print "Kswapd pages reclaimed:			$total_kswapd_nr_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";
@@ -612,6 +630,7 @@ sub aggregate_perprocesspid() {
 		$perprocess{$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_RECLAIMED} += $perprocesspid{$process_pid}->{HIGH_NR_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};
diff --git a/Documentation/vm/highmem.txt b/Documentation/vm/highmem.txt
new file mode 100644
index 00000000000..4324d24ffac
--- /dev/null
+++ b/Documentation/vm/highmem.txt
@@ -0,0 +1,162 @@
+
+			     ====================
+			     HIGH MEMORY HANDLING
+			     ====================
+
+By: Peter Zijlstra <a.p.zijlstra@chello.nl>
+
+Contents:
+
+ (*) What is high memory?
+
+ (*) Temporary virtual mappings.
+
+ (*) Using kmap_atomic.
+
+ (*) Cost of temporary mappings.
+
+ (*) i386 PAE.
+
+
+====================
+WHAT IS HIGH MEMORY?
+====================
+
+High memory (highmem) is used when the size of physical memory approaches or
+exceeds the maximum size of virtual memory.  At that point it becomes
+impossible for the kernel to keep all of the available physical memory mapped
+at all times.  This means the kernel needs to start using temporary mappings of
+the pieces of physical memory that it wants to access.
+
+The part of (physical) memory not covered by a permanent mapping is what we
+refer to as 'highmem'.  There are various architecture dependent constraints on
+where exactly that border lies.
+
+In the i386 arch, for example, we choose to map the kernel into every process's
+VM space so that we don't have to pay the full TLB invalidation costs for
+kernel entry/exit.  This means the available virtual memory space (4GiB on
+i386) has to be divided between user and kernel space.
+
+The traditional split for architectures using this approach is 3:1, 3GiB for
+userspace and the top 1GiB for kernel space:
+
+		+--------+ 0xffffffff
+		| Kernel |
+		+--------+ 0xc0000000
+		|        |
+		| User   |
+		|        |
+		+--------+ 0x00000000
+
+This means that the kernel can at most map 1GiB of physical memory at any one
+time, but because we need virtual address space for other things - including
+temporary maps to access the rest of the physical memory - the actual direct
+map will typically be less (usually around ~896MiB).
+
+Other architectures that have mm context tagged TLBs can have separate kernel
+and user maps.  Some hardware (like some ARMs), however, have limited virtual
+space when they use mm context tags.
+
+
+==========================
+TEMPORARY VIRTUAL MAPPINGS
+==========================
+
+The kernel contains several ways of creating temporary mappings:
+
+ (*) vmap().  This can be used to make a long duration mapping of multiple
+     physical pages into a contiguous virtual space.  It needs global
+     synchronization to unmap.
+
+ (*) kmap().  This permits a short duration mapping of a single page.  It needs
+     global synchronization, but is amortized somewhat.  It is also prone to
+     deadlocks when using in a nested fashion, and so it is not recommended for
+     new code.
+
+ (*) kmap_atomic().  This permits a very short duration mapping of a single
+     page.  Since the mapping is restricted to the CPU that issued it, it
+     performs well, but the issuing task is therefore required to stay on that
+     CPU until it has finished, lest some other task displace its mappings.
+
+     kmap_atomic() may also be used by interrupt contexts, since it is does not
+     sleep and the caller may not sleep until after kunmap_atomic() is called.
+
+     It may be assumed that k[un]map_atomic() won't fail.
+
+
+=================
+USING KMAP_ATOMIC
+=================
+
+When and where to use kmap_atomic() is straightforward.  It is used when code
+wants to access the contents of a page that might be allocated from high memory
+(see __GFP_HIGHMEM), for example a page in the pagecache.  The API has two
+functions, and they can be used in a manner similar to the following:
+
+	/* Find the page of interest. */
+	struct page *page = find_get_page(mapping, offset);
+
+	/* Gain access to the contents of that page. */
+	void *vaddr = kmap_atomic(page);
+
+	/* Do something to the contents of that page. */
+	memset(vaddr, 0, PAGE_SIZE);
+
+	/* Unmap that page. */
+	kunmap_atomic(vaddr);
+
+Note that the kunmap_atomic() call takes the result of the kmap_atomic() call
+not the argument.
+
+If you need to map two pages because you want to copy from one page to
+another you need to keep the kmap_atomic calls strictly nested, like:
+
+	vaddr1 = kmap_atomic(page1);
+	vaddr2 = kmap_atomic(page2);
+
+	memcpy(vaddr1, vaddr2, PAGE_SIZE);
+
+	kunmap_atomic(vaddr2);
+	kunmap_atomic(vaddr1);
+
+
+==========================
+COST OF TEMPORARY MAPPINGS
+==========================
+
+The cost of creating temporary mappings can be quite high.  The arch has to
+manipulate the kernel's page tables, the data TLB and/or the MMU's registers.
+
+If CONFIG_HIGHMEM is not set, then the kernel will try and create a mapping
+simply with a bit of arithmetic that will convert the page struct address into
+a pointer to the page contents rather than juggling mappings about.  In such a
+case, the unmap operation may be a null operation.
+
+If CONFIG_MMU is not set, then there can be no temporary mappings and no
+highmem.  In such a case, the arithmetic approach will also be used.
+
+
+========
+i386 PAE
+========
+
+The i386 arch, under some circumstances, will permit you to stick up to 64GiB
+of RAM into your 32-bit machine.  This has a number of consequences:
+
+ (*) Linux needs a page-frame structure for each page in the system and the
+     pageframes need to live in the permanent mapping, which means:
+
+ (*) you can have 896M/sizeof(struct page) page-frames at most; with struct
+     page being 32-bytes that would end up being something in the order of 112G
+     worth of pages; the kernel, however, needs to store more than just
+     page-frames in that memory...
+
+ (*) PAE makes your page tables larger - which slows the system down as more
+     data has to be accessed to traverse in TLB fills and the like.  One
+     advantage is that PAE has more PTE bits and can provide advanced features
+     like NX and PAT.
+
+The general recommendation is that you don't use more than 8GiB on a 32-bit
+machine - although more might work for you and your workload, you're pretty
+much on your own - don't expect kernel developers to really care much if things
+come apart.