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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	"Mika Penttilä" <mika.penttila@nextfour.com>,
	"Wanpeng Li" <kernellwp@gmail.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Anthoine Bourgeois" <anthoine.bourgeois@blade-group.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>
Subject: [PATCH 4.14 62/62] KVM: x86: remove APIC Timer periodic/oneshot spikes
Date: Mon, 14 May 2018 08:49:18 +0200	[thread overview]
Message-ID: <20180514064819.929970573@linuxfoundation.org> (raw)
In-Reply-To: <20180514064816.436958006@linuxfoundation.org>

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Anthoine Bourgeois <anthoine.bourgeois@blade-group.com>

commit ecf08dad723d3e000aecff6c396f54772d124733 upstream.

Since the commit "8003c9ae204e: add APIC Timer periodic/oneshot mode VMX
preemption timer support", a Windows 10 guest has some erratic timer
spikes.

Here the results on a 150000 times 1ms timer without any load:
	  Before 8003c9ae204e | After 8003c9ae204e
Max           1834us          |  86000us
Mean          1100us          |   1021us
Deviation       59us          |    149us
Here the results on a 150000 times 1ms timer with a cpu-z stress test:
	  Before 8003c9ae204e | After 8003c9ae204e
Max          32000us          | 140000us
Mean          1006us          |   1997us
Deviation      140us          |  11095us

The root cause of the problem is starting hrtimer with an expiry time
already in the past can take more than 20 milliseconds to trigger the
timer function.  It can be solved by forward such past timers
immediately, rather than submitting them to hrtimer_start().
In case the timer is periodic, update the target expiration and call
hrtimer_start with it.

v2: Check if the tsc deadline is already expired. Thank you Mika.
v3: Execute the past timers immediately rather than submitting them to
hrtimer_start().
v4: Rearm the periodic timer with advance_periodic_target_expiration() a
simpler version of set_target_expiration(). Thank you Paolo.

Cc: Mika Penttilä <mika.penttila@nextfour.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Anthoine Bourgeois <anthoine.bourgeois@blade-group.com>
8003c9ae204e ("KVM: LAPIC: add APIC Timer periodic/oneshot mode VMX preemption timer support")
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


---
 arch/x86/kvm/lapic.c |   37 ++++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 17 deletions(-)

--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1418,23 +1418,6 @@ static void start_sw_tscdeadline(struct
 	local_irq_restore(flags);
 }
 
-static void start_sw_period(struct kvm_lapic *apic)
-{
-	if (!apic->lapic_timer.period)
-		return;
-
-	if (apic_lvtt_oneshot(apic) &&
-	    ktime_after(ktime_get(),
-			apic->lapic_timer.target_expiration)) {
-		apic_timer_expired(apic);
-		return;
-	}
-
-	hrtimer_start(&apic->lapic_timer.timer,
-		apic->lapic_timer.target_expiration,
-		HRTIMER_MODE_ABS_PINNED);
-}
-
 static bool set_target_expiration(struct kvm_lapic *apic)
 {
 	ktime_t now;
@@ -1491,6 +1474,26 @@ static void advance_periodic_target_expi
 				apic->lapic_timer.period);
 }
 
+static void start_sw_period(struct kvm_lapic *apic)
+{
+	if (!apic->lapic_timer.period)
+		return;
+
+	if (ktime_after(ktime_get(),
+			apic->lapic_timer.target_expiration)) {
+		apic_timer_expired(apic);
+
+		if (apic_lvtt_oneshot(apic))
+			return;
+
+		advance_periodic_target_expiration(apic);
+	}
+
+	hrtimer_start(&apic->lapic_timer.timer,
+		apic->lapic_timer.target_expiration,
+		HRTIMER_MODE_ABS_PINNED);
+}
+
 bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu)
 {
 	if (!lapic_in_kernel(vcpu))

  parent reply	other threads:[~2018-05-14  6:49 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-14  6:48 [PATCH 4.14 00/62] 4.14.41-stable review Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 01/62] ipvs: fix rtnl_lock lockups caused by start_sync_thread Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 02/62] netfilter: ebtables: dont attempt to allocate 0-sized compat array Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 03/62] kcm: Call strp_stop before strp_done in kcm_attach Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 04/62] crypto: af_alg - fix possible uninit-value in alg_bind() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 05/62] netlink: fix uninit-value in netlink_sendmsg Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 06/62] net: fix rtnh_ok() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 07/62] net: initialize skb->peeked when cloning Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 08/62] net: fix uninit-value in __hw_addr_add_ex() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 09/62] dccp: initialize ireq->ir_mark Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 10/62] ipv4: fix uninit-value in ip_route_output_key_hash_rcu() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 11/62] soreuseport: initialise timewait reuseport field Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 12/62] inetpeer: fix uninit-value in inet_getpeer Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 13/62] memcg: fix per_node_info cleanup Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 14/62] perf: Remove superfluous allocation error check Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 15/62] tcp: fix TCP_REPAIR_QUEUE bound checking Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 16/62] bdi: wake up concurrent wb_shutdown() callers Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 17/62] bdi: Fix oops in wb_workfn() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 18/62] KVM: PPC: Book3S HV: Fix trap number return from __kvmppc_vcore_entry Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 19/62] KVM: PPC: Book3S HV: Fix guest time accounting with VIRT_CPU_ACCOUNTING_GEN Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 20/62] KVM: PPC: Book3S HV: Fix VRMA initialization with 2MB or 1GB memory backing Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 21/62] arm64: Add work around for Arm Cortex-A55 Erratum 1024718 Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 22/62] compat: fix 4-byte infoleak via uninitialized struct field Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 23/62] gpioib: do not free unrequested descriptors Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 24/62] gpio: fix aspeed_gpio unmask irq Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 25/62] gpio: fix error path in lineevent_create Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 26/62] rfkill: gpio: fix memory leak in probe error path Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 27/62] libata: Apply NOLPM quirk for SanDisk SD7UB3Q*G1001 SSDs Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 28/62] dm integrity: use kvfree for kvmallocd memory Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 29/62] tracing: Fix regex_match_front() to not over compare the test string Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 30/62] z3fold: fix reclaim lock-ups Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 31/62] mm: sections are not offlined during memory hotremove Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 32/62] mm, oom: fix concurrent munlock and oom reaper unmap, v3 Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 33/62] ceph: fix rsize/wsize capping in ceph_direct_read_write() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 34/62] can: kvaser_usb: Increase correct stats counter in kvaser_usb_rx_can_msg() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 35/62] can: hi311x: Acquire SPI lock on ->do_get_berr_counter Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 36/62] can: hi311x: Work around TX complete interrupt erratum Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 37/62] drm/vc4: Fix scaling of uni-planar formats Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 38/62] drm/i915: Fix drm:intel_enable_lvds ERROR message in kernel log Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 39/62] drm/nouveau: Fix deadlock in nv50_mstm_register_connector() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 40/62] drm/atomic: Clean old_state/new_state in drm_atomic_state_default_clear() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 41/62] drm/atomic: Clean private obj " Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 42/62] net: atm: Fix potential Spectre v1 Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.14 43/62] atm: zatm: " Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 44/62] PCI / PM: Always check PME wakeup capability for runtime wakeup support Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 45/62] PCI / PM: Check device_may_wakeup() in pci_enable_wake() Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 46/62] cpufreq: schedutil: Avoid using invalid next_freq Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 47/62] Revert "Bluetooth: btusb: Fix quirk for Atheros 1525/QCA6174" Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 48/62] Bluetooth: btusb: Add Dell XPS 13 9360 to btusb_needs_reset_resume_table Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 49/62] Bluetooth: btusb: Only check needs_reset_resume DMI table for QCA rome chipsets Greg Kroah-Hartman
2018-05-15 17:07   ` Brian Norris
2018-05-15 19:42     ` Guenter Roeck
2018-05-16  7:57       ` gregkh
2018-05-14  6:49 ` [PATCH 4.14 50/62] thermal: exynos: Reading temperature makes sense only when TMU is turned on Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 51/62] thermal: exynos: Propagate error value from tmu_read() Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 52/62] nvme: add quirk to force medium priority for SQ creation Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 53/62] smb3: directory sync should not return an error Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 54/62] sched/autogroup: Fix possible Spectre-v1 indexing for sched_prio_to_weight[] Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 55/62] tracing/uprobe_event: Fix strncpy corner case Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 56/62] perf/x86: Fix possible Spectre-v1 indexing for hw_perf_event cache_* Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 57/62] perf/x86/cstate: Fix possible Spectre-v1 indexing for pkg_msr Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 58/62] perf/x86/msr: Fix possible Spectre-v1 indexing in the MSR driver Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 59/62] perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[] Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 60/62] perf/x86: Fix possible Spectre-v1 indexing for x86_pmu::event_map() Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.14 61/62] KVM: PPC: Book3S HV: Fix handling of large pages in radix page fault handler Greg Kroah-Hartman
2018-05-14  6:49 ` Greg Kroah-Hartman [this message]
2018-05-14  8:28 ` [PATCH 4.14 00/62] 4.14.41-stable review Nathan Chancellor
2018-05-14 12:45 ` kernelci.org bot
2018-05-14 16:21 ` Guenter Roeck
2018-05-14 22:02 ` Shuah Khan
2018-05-15  5:36 ` Naresh Kamboju

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