Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 579 insertions, 0 deletions

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
new file mode 100644
index 000000000..c4922684f
--- /dev/null
+++ b/drivers/cpuidle/governors/menu.c
@@ -0,0 +1,579 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * menu.c - the menu idle governor
+ *
+ * Copyright (C) 2006-2007 Adam Belay <abelay@novell.com>
+ * Copyright (C) 2009 Intel Corporation
+ * Author:
+ *        Arjan van de Ven <arjan@linux.intel.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/cpuidle.h>
+#include <linux/time.h>
+#include <linux/ktime.h>
+#include <linux/hrtimer.h>
+#include <linux/tick.h>
+#include <linux/sched.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/stat.h>
+#include <linux/math64.h>
+
+#define BUCKETS 12
+#define INTERVAL_SHIFT 3
+#define INTERVALS (1UL << INTERVAL_SHIFT)
+#define RESOLUTION 1024
+#define DECAY 8
+#define MAX_INTERESTING (50000 * NSEC_PER_USEC)
+
+/*
+ * Concepts and ideas behind the menu governor
+ *
+ * For the menu governor, there are 3 decision factors for picking a C
+ * state:
+ * 1) Energy break even point
+ * 2) Performance impact
+ * 3) Latency tolerance (from pmqos infrastructure)
+ * These three factors are treated independently.
+ *
+ * Energy break even point
+ * -----------------------
+ * C state entry and exit have an energy cost, and a certain amount of time in
+ * the  C state is required to actually break even on this cost. CPUIDLE
+ * provides us this duration in the "target_residency" field. So all that we
+ * need is a good prediction of how long we'll be idle. Like the traditional
+ * menu governor, we start with the actual known "next timer event" time.
+ *
+ * Since there are other source of wakeups (interrupts for example) than
+ * the next timer event, this estimation is rather optimistic. To get a
+ * more realistic estimate, a correction factor is applied to the estimate,
+ * that is based on historic behavior. For example, if in the past the actual
+ * duration always was 50% of the next timer tick, the correction factor will
+ * be 0.5.
+ *
+ * menu uses a running average for this correction factor, however it uses a
+ * set of factors, not just a single factor. This stems from the realization
+ * that the ratio is dependent on the order of magnitude of the expected
+ * duration; if we expect 500 milliseconds of idle time the likelihood of
+ * getting an interrupt very early is much higher than if we expect 50 micro
+ * seconds of idle time. A second independent factor that has big impact on
+ * the actual factor is if there is (disk) IO outstanding or not.
+ * (as a special twist, we consider every sleep longer than 50 milliseconds
+ * as perfect; there are no power gains for sleeping longer than this)
+ *
+ * For these two reasons we keep an array of 12 independent factors, that gets
+ * indexed based on the magnitude of the expected duration as well as the
+ * "is IO outstanding" property.
+ *
+ * Repeatable-interval-detector
+ * ----------------------------
+ * There are some cases where "next timer" is a completely unusable predictor:
+ * Those cases where the interval is fixed, for example due to hardware
+ * interrupt mitigation, but also due to fixed transfer rate devices such as
+ * mice.
+ * For this, we use a different predictor: We track the duration of the last 8
+ * intervals and if the stand deviation of these 8 intervals is below a
+ * threshold value, we use the average of these intervals as prediction.
+ *
+ * Limiting Performance Impact
+ * ---------------------------
+ * C states, especially those with large exit latencies, can have a real
+ * noticeable impact on workloads, which is not acceptable for most sysadmins,
+ * and in addition, less performance has a power price of its own.
+ *
+ * As a general rule of thumb, menu assumes that the following heuristic
+ * holds:
+ *     The busier the system, the less impact of C states is acceptable
+ *
+ * This rule-of-thumb is implemented using a performance-multiplier:
+ * If the exit latency times the performance multiplier is longer than
+ * the predicted duration, the C state is not considered a candidate
+ * for selection due to a too high performance impact. So the higher
+ * this multiplier is, the longer we need to be idle to pick a deep C
+ * state, and thus the less likely a busy CPU will hit such a deep
+ * C state.
+ *
+ * Two factors are used in determing this multiplier:
+ * a value of 10 is added for each point of "per cpu load average" we have.
+ * a value of 5 points is added for each process that is waiting for
+ * IO on this CPU.
+ * (these values are experimentally determined)
+ *
+ * The load average factor gives a longer term (few seconds) input to the
+ * decision, while the iowait value gives a cpu local instantanious input.
+ * The iowait factor may look low, but realize that this is also already
+ * represented in the system load average.
+ *
+ */
+
+struct menu_device {
+	int             needs_update;
+	int             tick_wakeup;
+
+	u64		next_timer_ns;
+	unsigned int	bucket;
+	unsigned int	correction_factor[BUCKETS];
+	unsigned int	intervals[INTERVALS];
+	int		interval_ptr;
+};
+
+static inline int which_bucket(u64 duration_ns, unsigned int nr_iowaiters)
+{
+	int bucket = 0;
+
+	/*
+	 * We keep two groups of stats; one with no
+	 * IO pending, one without.
+	 * This allows us to calculate
+	 * E(duration)|iowait
+	 */
+	if (nr_iowaiters)
+		bucket = BUCKETS/2;
+
+	if (duration_ns < 10ULL * NSEC_PER_USEC)
+		return bucket;
+	if (duration_ns < 100ULL * NSEC_PER_USEC)
+		return bucket + 1;
+	if (duration_ns < 1000ULL * NSEC_PER_USEC)
+		return bucket + 2;
+	if (duration_ns < 10000ULL * NSEC_PER_USEC)
+		return bucket + 3;
+	if (duration_ns < 100000ULL * NSEC_PER_USEC)
+		return bucket + 4;
+	return bucket + 5;
+}
+
+/*
+ * Return a multiplier for the exit latency that is intended
+ * to take performance requirements into account.
+ * The more performance critical we estimate the system
+ * to be, the higher this multiplier, and thus the higher
+ * the barrier to go to an expensive C state.
+ */
+static inline int performance_multiplier(unsigned int nr_iowaiters)
+{
+	/* for IO wait tasks (per cpu!) we add 10x each */
+	return 1 + 10 * nr_iowaiters;
+}
+
+static DEFINE_PER_CPU(struct menu_device, menu_devices);
+
+static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev);
+
+/*
+ * Try detecting repeating patterns by keeping track of the last 8
+ * intervals, and checking if the standard deviation of that set
+ * of points is below a threshold. If it is... then use the
+ * average of these 8 points as the estimated value.
+ */
+static unsigned int get_typical_interval(struct menu_device *data,
+					 unsigned int predicted_us)
+{
+	int i, divisor;
+	unsigned int min, max, thresh, avg;
+	uint64_t sum, variance;
+
+	thresh = INT_MAX; /* Discard outliers above this value */
+
+again:
+
+	/* First calculate the average of past intervals */
+	min = UINT_MAX;
+	max = 0;
+	sum = 0;
+	divisor = 0;
+	for (i = 0; i < INTERVALS; i++) {
+		unsigned int value = data->intervals[i];
+		if (value <= thresh) {
+			sum += value;
+			divisor++;
+			if (value > max)
+				max = value;
+
+			if (value < min)
+				min = value;
+		}
+	}
+
+	/*
+	 * If the result of the computation is going to be discarded anyway,
+	 * avoid the computation altogether.
+	 */
+	if (min >= predicted_us)
+		return UINT_MAX;
+
+	if (divisor == INTERVALS)
+		avg = sum >> INTERVAL_SHIFT;
+	else
+		avg = div_u64(sum, divisor);
+
+	/* Then try to determine variance */
+	variance = 0;
+	for (i = 0; i < INTERVALS; i++) {
+		unsigned int value = data->intervals[i];
+		if (value <= thresh) {
+			int64_t diff = (int64_t)value - avg;
+			variance += diff * diff;
+		}
+	}
+	if (divisor == INTERVALS)
+		variance >>= INTERVAL_SHIFT;
+	else
+		do_div(variance, divisor);
+
+	/*
+	 * The typical interval is obtained when standard deviation is
+	 * small (stddev <= 20 us, variance <= 400 us^2) or standard
+	 * deviation is small compared to the average interval (avg >
+	 * 6*stddev, avg^2 > 36*variance). The average is smaller than
+	 * UINT_MAX aka U32_MAX, so computing its square does not
+	 * overflow a u64. We simply reject this candidate average if
+	 * the standard deviation is greater than 715 s (which is
+	 * rather unlikely).
+	 *
+	 * Use this result only if there is no timer to wake us up sooner.
+	 */
+	if (likely(variance <= U64_MAX/36)) {
+		if ((((u64)avg*avg > variance*36) && (divisor * 4 >= INTERVALS * 3))
+							|| variance <= 400) {
+			return avg;
+		}
+	}
+
+	/*
+	 * If we have outliers to the upside in our distribution, discard
+	 * those by setting the threshold to exclude these outliers, then
+	 * calculate the average and standard deviation again. Once we get
+	 * down to the bottom 3/4 of our samples, stop excluding samples.
+	 *
+	 * This can deal with workloads that have long pauses interspersed
+	 * with sporadic activity with a bunch of short pauses.
+	 */
+	if ((divisor * 4) <= INTERVALS * 3)
+		return UINT_MAX;
+
+	thresh = max - 1;
+	goto again;
+}
+
+/**
+ * menu_select - selects the next idle state to enter
+ * @drv: cpuidle driver containing state data
+ * @dev: the CPU
+ * @stop_tick: indication on whether or not to stop the tick
+ */
+static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
+		       bool *stop_tick)
+{
+	struct menu_device *data = this_cpu_ptr(&menu_devices);
+	s64 latency_req = cpuidle_governor_latency_req(dev->cpu);
+	unsigned int predicted_us;
+	u64 predicted_ns;
+	u64 interactivity_req;
+	unsigned int nr_iowaiters;
+	ktime_t delta, delta_tick;
+	int i, idx;
+
+	if (data->needs_update) {
+		menu_update(drv, dev);
+		data->needs_update = 0;
+	}
+
+	/* determine the expected residency time, round up */
+	delta = tick_nohz_get_sleep_length(&delta_tick);
+	if (unlikely(delta < 0)) {
+		delta = 0;
+		delta_tick = 0;
+	}
+	data->next_timer_ns = delta;
+
+	nr_iowaiters = nr_iowait_cpu(dev->cpu);
+	data->bucket = which_bucket(data->next_timer_ns, nr_iowaiters);
+
+	if (unlikely(drv->state_count <= 1 || latency_req == 0) ||
+	    ((data->next_timer_ns < drv->states[1].target_residency_ns ||
+	      latency_req < drv->states[1].exit_latency_ns) &&
+	     !dev->states_usage[0].disable)) {
+		/*
+		 * In this case state[0] will be used no matter what, so return
+		 * it right away and keep the tick running if state[0] is a
+		 * polling one.
+		 */
+		*stop_tick = !(drv->states[0].flags & CPUIDLE_FLAG_POLLING);
+		return 0;
+	}
+
+	/* Round up the result for half microseconds. */
+	predicted_us = div_u64(data->next_timer_ns *
+			       data->correction_factor[data->bucket] +
+			       (RESOLUTION * DECAY * NSEC_PER_USEC) / 2,
+			       RESOLUTION * DECAY * NSEC_PER_USEC);
+	/* Use the lowest expected idle interval to pick the idle state. */
+	predicted_ns = (u64)min(predicted_us,
+				get_typical_interval(data, predicted_us)) *
+				NSEC_PER_USEC;
+
+	if (tick_nohz_tick_stopped()) {
+		/*
+		 * If the tick is already stopped, the cost of possible short
+		 * idle duration misprediction is much higher, because the CPU
+		 * may be stuck in a shallow idle state for a long time as a
+		 * result of it.  In that case say we might mispredict and use
+		 * the known time till the closest timer event for the idle
+		 * state selection.
+		 */
+		if (predicted_ns < TICK_NSEC)
+			predicted_ns = data->next_timer_ns;
+	} else {
+		/*
+		 * Use the performance multiplier and the user-configurable
+		 * latency_req to determine the maximum exit latency.
+		 */
+		interactivity_req = div64_u64(predicted_ns,
+					      performance_multiplier(nr_iowaiters));
+		if (latency_req > interactivity_req)
+			latency_req = interactivity_req;
+	}
+
+	/*
+	 * Find the idle state with the lowest power while satisfying
+	 * our constraints.
+	 */
+	idx = -1;
+	for (i = 0; i < drv->state_count; i++) {
+		struct cpuidle_state *s = &drv->states[i];
+
+		if (dev->states_usage[i].disable)
+			continue;
+
+		if (idx == -1)
+			idx = i; /* first enabled state */
+
+		if (s->target_residency_ns > predicted_ns) {
+			/*
+			 * Use a physical idle state, not busy polling, unless
+			 * a timer is going to trigger soon enough.
+			 */
+			if ((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) &&
+			    s->exit_latency_ns <= latency_req &&
+			    s->target_residency_ns <= data->next_timer_ns) {
+				predicted_ns = s->target_residency_ns;
+				idx = i;
+				break;
+			}
+			if (predicted_ns < TICK_NSEC)
+				break;
+
+			if (!tick_nohz_tick_stopped()) {
+				/*
+				 * If the state selected so far is shallow,
+				 * waking up early won't hurt, so retain the
+				 * tick in that case and let the governor run
+				 * again in the next iteration of the loop.
+				 */
+				predicted_ns = drv->states[idx].target_residency_ns;
+				break;
+			}
+
+			/*
+			 * If the state selected so far is shallow and this
+			 * state's target residency matches the time till the
+			 * closest timer event, select this one to avoid getting
+			 * stuck in the shallow one for too long.
+			 */
+			if (drv->states[idx].target_residency_ns < TICK_NSEC &&
+			    s->target_residency_ns <= delta_tick)
+				idx = i;
+
+			return idx;
+		}
+		if (s->exit_latency_ns > latency_req)
+			break;
+
+		idx = i;
+	}
+
+	if (idx == -1)
+		idx = 0; /* No states enabled. Must use 0. */
+
+	/*
+	 * Don't stop the tick if the selected state is a polling one or if the
+	 * expected idle duration is shorter than the tick period length.
+	 */
+	if (((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) ||
+	     predicted_ns < TICK_NSEC) && !tick_nohz_tick_stopped()) {
+		*stop_tick = false;
+
+		if (idx > 0 && drv->states[idx].target_residency_ns > delta_tick) {
+			/*
+			 * The tick is not going to be stopped and the target
+			 * residency of the state to be returned is not within
+			 * the time until the next timer event including the
+			 * tick, so try to correct that.
+			 */
+			for (i = idx - 1; i >= 0; i--) {
+				if (dev->states_usage[i].disable)
+					continue;
+
+				idx = i;
+				if (drv->states[i].target_residency_ns <= delta_tick)
+					break;
+			}
+		}
+	}
+
+	return idx;
+}
+
+/**
+ * menu_reflect - records that data structures need update
+ * @dev: the CPU
+ * @index: the index of actual entered state
+ *
+ * NOTE: it's important to be fast here because this operation will add to
+ *       the overall exit latency.
+ */
+static void menu_reflect(struct cpuidle_device *dev, int index)
+{
+	struct menu_device *data = this_cpu_ptr(&menu_devices);
+
+	dev->last_state_idx = index;
+	data->needs_update = 1;
+	data->tick_wakeup = tick_nohz_idle_got_tick();
+}
+
+/**
+ * menu_update - attempts to guess what happened after entry
+ * @drv: cpuidle driver containing state data
+ * @dev: the CPU
+ */
+static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
+{
+	struct menu_device *data = this_cpu_ptr(&menu_devices);
+	int last_idx = dev->last_state_idx;
+	struct cpuidle_state *target = &drv->states[last_idx];
+	u64 measured_ns;
+	unsigned int new_factor;
+
+	/*
+	 * Try to figure out how much time passed between entry to low
+	 * power state and occurrence of the wakeup event.
+	 *
+	 * If the entered idle state didn't support residency measurements,
+	 * we use them anyway if they are short, and if long,
+	 * truncate to the whole expected time.
+	 *
+	 * Any measured amount of time will include the exit latency.
+	 * Since we are interested in when the wakeup begun, not when it
+	 * was completed, we must subtract the exit latency. However, if
+	 * the measured amount of time is less than the exit latency,
+	 * assume the state was never reached and the exit latency is 0.
+	 */
+
+	if (data->tick_wakeup && data->next_timer_ns > TICK_NSEC) {
+		/*
+		 * The nohz code said that there wouldn't be any events within
+		 * the tick boundary (if the tick was stopped), but the idle
+		 * duration predictor had a differing opinion.  Since the CPU
+		 * was woken up by a tick (that wasn't stopped after all), the
+		 * predictor was not quite right, so assume that the CPU could
+		 * have been idle long (but not forever) to help the idle
+		 * duration predictor do a better job next time.
+		 */
+		measured_ns = 9 * MAX_INTERESTING / 10;
+	} else if ((drv->states[last_idx].flags & CPUIDLE_FLAG_POLLING) &&
+		   dev->poll_time_limit) {
+		/*
+		 * The CPU exited the "polling" state due to a time limit, so
+		 * the idle duration prediction leading to the selection of that
+		 * state was inaccurate.  If a better prediction had been made,
+		 * the CPU might have been woken up from idle by the next timer.
+		 * Assume that to be the case.
+		 */
+		measured_ns = data->next_timer_ns;
+	} else {
+		/* measured value */
+		measured_ns = dev->last_residency_ns;
+
+		/* Deduct exit latency */
+		if (measured_ns > 2 * target->exit_latency_ns)
+			measured_ns -= target->exit_latency_ns;
+		else
+			measured_ns /= 2;
+	}
+
+	/* Make sure our coefficients do not exceed unity */
+	if (measured_ns > data->next_timer_ns)
+		measured_ns = data->next_timer_ns;
+
+	/* Update our correction ratio */
+	new_factor = data->correction_factor[data->bucket];
+	new_factor -= new_factor / DECAY;
+
+	if (data->next_timer_ns > 0 && measured_ns < MAX_INTERESTING)
+		new_factor += div64_u64(RESOLUTION * measured_ns,
+					data->next_timer_ns);
+	else
+		/*
+		 * we were idle so long that we count it as a perfect
+		 * prediction
+		 */
+		new_factor += RESOLUTION;
+
+	/*
+	 * We don't want 0 as factor; we always want at least
+	 * a tiny bit of estimated time. Fortunately, due to rounding,
+	 * new_factor will stay nonzero regardless of measured_us values
+	 * and the compiler can eliminate this test as long as DECAY > 1.
+	 */
+	if (DECAY == 1 && unlikely(new_factor == 0))
+		new_factor = 1;
+
+	data->correction_factor[data->bucket] = new_factor;
+
+	/* update the repeating-pattern data */
+	data->intervals[data->interval_ptr++] = ktime_to_us(measured_ns);
+	if (data->interval_ptr >= INTERVALS)
+		data->interval_ptr = 0;
+}
+
+/**
+ * menu_enable_device - scans a CPU's states and does setup
+ * @drv: cpuidle driver
+ * @dev: the CPU
+ */
+static int menu_enable_device(struct cpuidle_driver *drv,
+				struct cpuidle_device *dev)
+{
+	struct menu_device *data = &per_cpu(menu_devices, dev->cpu);
+	int i;
+
+	memset(data, 0, sizeof(struct menu_device));
+
+	/*
+	 * if the correction factor is 0 (eg first time init or cpu hotplug
+	 * etc), we actually want to start out with a unity factor.
+	 */
+	for(i = 0; i < BUCKETS; i++)
+		data->correction_factor[i] = RESOLUTION * DECAY;
+
+	return 0;
+}
+
+static struct cpuidle_governor menu_governor = {
+	.name =		"menu",
+	.rating =	20,
+	.enable =	menu_enable_device,
+	.select =	menu_select,
+	.reflect =	menu_reflect,
+};
+
+/**
+ * init_menu - initializes the governor
+ */
+static int __init init_menu(void)
+{
+	return cpuidle_register_governor(&menu_governor);
+}
+
+postcore_initcall(init_menu);