Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu
Please note that the same issue appears to have been introduced in the recent 4.2.7 kernel. It perhaps has to do with b4ff8389ed14b849354b59ce9b360bdefcdbf99c having a matching commit e8d097151d309eb71f750bbf34e6a7ef6256da7e in linux-stable.git. The below patch to arch/x86/kernel/rtc.c was also effective for 4.2.7. Eric On 2015-12-02 18:30, Sander Eikelenboom wrote: > On 2015-12-02 15:55, David Vrabel wrote: > > On 28/11/15 15:47, Sander Eikelenboom wrote: > >> genirq: Flags mismatch irq 8. (hvc_console) vs. > >> (rtc0) > > > > We shouldn't register an rtc_cmos device because its legacy irq > > conflicts with the irq needed for hvc0. For a multi VCPU guest irq 8 > > is > > in use for the pv spinlocks and this gets requested first, preventing > > the rtc device from probing. > > > > Does this patch fix it for you? > > > > David > > It does, thanks. > > Reported-and-tested-by: Sander Eikelenboom> > -- > Sander > > > 8< > > x86: rtc_cmos platform device requires legacy irqs > > > > Adding the rtc platform device when there are no legacy irqs (no > > legacy PIC) causes a conflict with other devices that end up using the > > same irq number. > > > > In a single VCPU PV guest we should have: > > > > /proc/interrupts: > >CPU0 > > 0: 4934 xen-percpu-virq timer0 > > 1: 0 xen-percpu-ipi spinlock0 > > 2: 0 xen-percpu-ipi resched0 > > 3: 0 xen-percpu-ipi callfunc0 > > 4: 0 xen-percpu-virq debug0 > > 5: 0 xen-percpu-ipi callfuncsingle0 > > 6: 0 xen-percpu-ipi irqwork0 > > 7:321 xen-dyn-event xenbus > > 8: 90 xen-dyn-event hvc_console > > ... > > > > But hvc_console cannot get its interrupt because it is already in use > > by rtc0 and the console does not work. > > > > genirq: Flags mismatch irq 8. (hvc_console) vs. > > (rtc0) > > > > The rtc_cmos device requires a particular legacy irq so don't add it > > if there are no legacy irqs. > > > > Signed-off-by: David Vrabel > > --- > > arch/x86/kernel/rtc.c | 5 + > > 1 file changed, 5 insertions(+) > > > > diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c > > index cd96852..07c70f1 100644 > > --- a/arch/x86/kernel/rtc.c > > +++ b/arch/x86/kernel/rtc.c > > @@ -14,6 +14,7 @@ > > #include > > #include > > #include > > +#include > > > > #ifdef CONFIG_X86_32 > > /* > > @@ -200,6 +201,10 @@ static __init int add_rtc_cmos(void) > > } > > #endif > > > > + /* RTC uses legacy IRQs. */ > > + if (!nr_legacy_irqs()) > > + return -ENODEV; > > + > > platform_device_register(_device); > > dev_info(_device.dev, > >"registered platform RTC device (no PNP device found)\n"); ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu
On 2015-12-14 20:48, Eric Shelton wrote: Please note that the same issue appears to have been introduced in the recent 4.2.7 kernel. It perhaps has to do with b4ff8389ed14b849354b59ce9b360bdefcdbf99c having a matching commit e8d097151d309eb71f750bbf34e6a7ef6256da7e in linux-stable.git. The below patch to arch/x86/kernel/rtc.c was also effective for 4.2.7. Eric Hi Eric, Yeah it's unfortunate the patch patching the other patches destined for stable didn't make it in time for stable :(. Any how the chosen solution wasn't ideal so there now is a V2 patch by Boris. It hasn't been picked up yet, but hopefully will be anytime soon (for the patch see http://lkml.iu.edu/hypermail/linux/kernel/1512.1/03504.html) -- Sander On 2015-12-02 18:30, Sander Eikelenboom wrote: On 2015-12-02 15:55, David Vrabel wrote: > On 28/11/15 15:47, Sander Eikelenboom wrote: >> genirq: Flags mismatch irq 8. (hvc_console) vs. >> (rtc0) > > We shouldn't register an rtc_cmos device because its legacy irq > conflicts with the irq needed for hvc0. For a multi VCPU guest irq 8 > is > in use for the pv spinlocks and this gets requested first, preventing > the rtc device from probing. > > Does this patch fix it for you? > > David It does, thanks. Reported-and-tested-by: Sander Eikelenboom-- Sander > 8< > x86: rtc_cmos platform device requires legacy irqs > > Adding the rtc platform device when there are no legacy irqs (no > legacy PIC) causes a conflict with other devices that end up using the > same irq number. > > In a single VCPU PV guest we should have: > > /proc/interrupts: >CPU0 > 0: 4934 xen-percpu-virq timer0 > 1: 0 xen-percpu-ipi spinlock0 > 2: 0 xen-percpu-ipi resched0 > 3: 0 xen-percpu-ipi callfunc0 > 4: 0 xen-percpu-virq debug0 > 5: 0 xen-percpu-ipi callfuncsingle0 > 6: 0 xen-percpu-ipi irqwork0 > 7:321 xen-dyn-event xenbus > 8: 90 xen-dyn-event hvc_console > ... > > But hvc_console cannot get its interrupt because it is already in use > by rtc0 and the console does not work. > > genirq: Flags mismatch irq 8. (hvc_console) vs. > (rtc0) > > The rtc_cmos device requires a particular legacy irq so don't add it > if there are no legacy irqs. > > Signed-off-by: David Vrabel > --- > arch/x86/kernel/rtc.c | 5 + > 1 file changed, 5 insertions(+) > > diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c > index cd96852..07c70f1 100644 > --- a/arch/x86/kernel/rtc.c > +++ b/arch/x86/kernel/rtc.c > @@ -14,6 +14,7 @@ > #include > #include > #include > +#include > > #ifdef CONFIG_X86_32 > /* > @@ -200,6 +201,10 @@ static __init int add_rtc_cmos(void) > } > #endif > > + /* RTC uses legacy IRQs. */ > + if (!nr_legacy_irqs()) > + return -ENODEV; > + > platform_device_register(_device); > dev_info(_device.dev, >"registered platform RTC device (no PNP device found)\n"); ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 28/11/15 15:47, Sander Eikelenboom wrote: > genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) We shouldn't register an rtc_cmos device because its legacy irq conflicts with the irq needed for hvc0. For a multi VCPU guest irq 8 is in use for the pv spinlocks and this gets requested first, preventing the rtc device from probing. Does this patch fix it for you? David 8< x86: rtc_cmos platform device requires legacy irqs Adding the rtc platform device when there are no legacy irqs (no legacy PIC) causes a conflict with other devices that end up using the same irq number. In a single VCPU PV guest we should have: /proc/interrupts: CPU0 0: 4934 xen-percpu-virq timer0 1: 0 xen-percpu-ipi spinlock0 2: 0 xen-percpu-ipi resched0 3: 0 xen-percpu-ipi callfunc0 4: 0 xen-percpu-virq debug0 5: 0 xen-percpu-ipi callfuncsingle0 6: 0 xen-percpu-ipi irqwork0 7:321 xen-dyn-event xenbus 8: 90 xen-dyn-event hvc_console ... But hvc_console cannot get its interrupt because it is already in use by rtc0 and the console does not work. genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) The rtc_cmos device requires a particular legacy irq so don't add it if there are no legacy irqs. Signed-off-by: David Vrabel--- arch/x86/kernel/rtc.c | 5 + 1 file changed, 5 insertions(+) diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c index cd96852..07c70f1 100644 --- a/arch/x86/kernel/rtc.c +++ b/arch/x86/kernel/rtc.c @@ -14,6 +14,7 @@ #include #include #include +#include #ifdef CONFIG_X86_32 /* @@ -200,6 +201,10 @@ static __init int add_rtc_cmos(void) } #endif + /* RTC uses legacy IRQs. */ + if (!nr_legacy_irqs()) + return -ENODEV; + platform_device_register(_device); dev_info(_device.dev, "registered platform RTC device (no PNP device found)\n"); -- 2.1.4 ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 2015-12-02 15:55, David Vrabel wrote: On 28/11/15 15:47, Sander Eikelenboom wrote: genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) We shouldn't register an rtc_cmos device because its legacy irq conflicts with the irq needed for hvc0. For a multi VCPU guest irq 8 is in use for the pv spinlocks and this gets requested first, preventing the rtc device from probing. Does this patch fix it for you? David It does, thanks. Reported-and-tested-by: Sander Eikelenboom-- Sander 8< x86: rtc_cmos platform device requires legacy irqs Adding the rtc platform device when there are no legacy irqs (no legacy PIC) causes a conflict with other devices that end up using the same irq number. In a single VCPU PV guest we should have: /proc/interrupts: CPU0 0: 4934 xen-percpu-virq timer0 1: 0 xen-percpu-ipi spinlock0 2: 0 xen-percpu-ipi resched0 3: 0 xen-percpu-ipi callfunc0 4: 0 xen-percpu-virq debug0 5: 0 xen-percpu-ipi callfuncsingle0 6: 0 xen-percpu-ipi irqwork0 7:321 xen-dyn-event xenbus 8: 90 xen-dyn-event hvc_console ... But hvc_console cannot get its interrupt because it is already in use by rtc0 and the console does not work. genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) The rtc_cmos device requires a particular legacy irq so don't add it if there are no legacy irqs. Signed-off-by: David Vrabel --- arch/x86/kernel/rtc.c | 5 + 1 file changed, 5 insertions(+) diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c index cd96852..07c70f1 100644 --- a/arch/x86/kernel/rtc.c +++ b/arch/x86/kernel/rtc.c @@ -14,6 +14,7 @@ #include #include #include +#include #ifdef CONFIG_X86_32 /* @@ -200,6 +201,10 @@ static __init int add_rtc_cmos(void) } #endif + /* RTC uses legacy IRQs. */ + if (!nr_legacy_irqs()) + return -ENODEV; + platform_device_register(_device); dev_info(_device.dev, "registered platform RTC device (no PNP device found)\n"); ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 2015-12-02 00:41, Boris Ostrovsky wrote: On 12/01/2015 06:30 PM, Sander Eikelenboom wrote: On 2015-12-02 00:19, Boris Ostrovsky wrote: On 12/01/2015 06:00 PM, Sander Eikelenboom wrote: On 2015-12-01 23:47, Boris Ostrovsky wrote: On 11/30/2015 05:55 PM, Sander Eikelenboom wrote: On 2015-11-30 23:54, Boris Ostrovsky wrote: On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: Hi all, I have just tested a 4.4-rc2 kernel (current linus tree) + the tip tree pulled on top. Running this kernel under Xen on PV-guests with multiple vcpus goes well (on idle < 10% cpu usage), but a guest with only a single vcpu doesn't idle at all, it seems a kworker thread is stuck: root 569 98.0 0.0 0 0 ?R 16:02 12:47 [kworker/0:1] Running a 4.3 kernel works fine with a single vpcu, bisecting would probably quite painful since there were some breakages this merge window with respect to Xen pv-guests. There are some differences in the diff's from booting a 4.3, 4.4-single, 4.4-multi cpu boot: Boris has been tracking a bunch of them. I am attaching the latest set of patches I've to carry on top of v4.4-rc3. Hi Konrad, i will test those, see if it fixes all my issues and report back They shouldn't help you ;-( (and I just saw a message from you confirming this) The first one fixes a 32-bit bug (on bare metal too). The second fixes a fatal bug for 32-bit PV guests. The other two are code improvements/cleanup. One of these patches also fixes a bug i was having with a pci-passthrough device in a HVM that wasn't working (depending on which dom0-kernel i was using (4.3 or 4.4)), but didn't report yet. Fingers crossed but i think this pv-guest single vcpu issue is the last i'm troubled by for now ;) I could not reproduce this, including with your kernel config file. Hmm that's unpleasant :-\ Hmm other strange thing is it doesn't seem to affect dom0 (which is also a PV guest), but only unprivileged ones All unprivileged pv-guests seem to have the irq issue, but only with a single vcpu i see to get the stuck kworker thread that got my attention, with a 2 vcpu that doesn't seem to happen, but you still get the dmesg output and warnings about hvc) Could it be that: arch/x86/include/asm/i8259.h static inline int nr_legacy_irqs(void) { return legacy_pic->nr_legacy_irqs; } returns something different in some circumstances ? It should return 16 pre-8c058b0b9c34d8c8d7912880956543769323e2d8 and 0 after that commit. This is the last number that you see in NR_IRQS:4352 nr_irqs:48 0 line. I think you should be able to safely revert both b4ff8389ed14b849354b59ce9b360bdefcdbf99c and 8c058b0b9c34d8c8d7912880956543769323e2d8 and see if it makes any difference. -boris That was already underway compiling :) And it does reveal that reverting both fixes the issue, no stuck kworker thread .. and no: genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) hvc_open: request_irq failed with rc -16. Let me try it again tomorrow. Can you post your guest config file, Xen version and host HW (Intel or AMD)? 'xl info' maybe? -boris Hi Boris, A fresh new day .. a fresh new thought. If i look at the /proc/interrupts from a broken and a kernel with both commits the thing that catches the eye is irq8, just as the dmesg message was telling. In my PV guest rtc0 now seems to try and take irq8 that was already assigned to HVC ? Sounds like some assumptions around the legacy range are broken somewhere. What is the benefit of not just reserving the legacy range ? Attached the /proc/interrupts from both boots. -- Sander What i did get was an conflict reverting b4ff8389ed14b849354b59ce9b360bdefcdbf99c: arch/arm64/include/asm/irq.h, although that shouldn't matter because we are on x86 and not on arm. -- Sander -- Sander -boris ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel CPU0 16: 315536 xen-percpu-virq timer0 17: 0 xen-percpu-ipi spinlock0 18: 0 xen-percpu-ipi resched0 19: 0 xen-percpu-ipi callfunc0 20: 0 xen-percpu-virq debug0 21: 0 xen-percpu-ipi callfuncsingle0 22: 0 xen-percpu-ipi irqwork0 23:346 xen-dyn-event xenbus 24:134 xen-dyn-event hvc_console 25: 11464 xen-dyn-event blkif 26: 28710 xen-dyn-event eth0-q0-tx 27: 40136 xen-dyn-event eth0-q0-rx NMI: 0 Non-maskable interrupts LOC: 0 Local timer interrupts SPU: 0 Spurious interrupts PMI: 0 Performance monitoring interrupts IWI: 0 IRQ work interrupts RTR: 0 APIC ICR read retries RES: 0 Rescheduling
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 28/11/15 15:47, Sander Eikelenboom wrote: > > -rtc_cmos rtc_cmos: hctosys: unable to read the hardware clock > +hctosys: unable to open rtc device (rtc0) > > -genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) > -hvc_open: request_irq failed with rc -16. I have reproduced this issue. We really shouldn't have an RTC device in a PV guest and I think this irq conflict breaks hvc0. David ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 2015-12-01 23:47, Boris Ostrovsky wrote: On 11/30/2015 05:55 PM, Sander Eikelenboom wrote: On 2015-11-30 23:54, Boris Ostrovsky wrote: On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: Hi all, I have just tested a 4.4-rc2 kernel (current linus tree) + the tip tree pulled on top. Running this kernel under Xen on PV-guests with multiple vcpus goes well (on idle < 10% cpu usage), but a guest with only a single vcpu doesn't idle at all, it seems a kworker thread is stuck: root 569 98.0 0.0 0 0 ?R16:02 12:47 [kworker/0:1] Running a 4.3 kernel works fine with a single vpcu, bisecting would probably quite painful since there were some breakages this merge window with respect to Xen pv-guests. There are some differences in the diff's from booting a 4.3, 4.4-single, 4.4-multi cpu boot: Boris has been tracking a bunch of them. I am attaching the latest set of patches I've to carry on top of v4.4-rc3. Hi Konrad, i will test those, see if it fixes all my issues and report back They shouldn't help you ;-( (and I just saw a message from you confirming this) The first one fixes a 32-bit bug (on bare metal too). The second fixes a fatal bug for 32-bit PV guests. The other two are code improvements/cleanup. One of these patches also fixes a bug i was having with a pci-passthrough device in a HVM that wasn't working (depending on which dom0-kernel i was using (4.3 or 4.4)), but didn't report yet. Fingers crossed but i think this pv-guest single vcpu issue is the last i'm troubled by for now ;) I could not reproduce this, including with your kernel config file. Hmm that's unpleasant :-\ Hmm other strange thing is it doesn't seem to affect dom0 (which is also a PV guest), but only unprivileged ones All unprivileged pv-guests seem to have the irq issue, but only with a single vcpu i see to get the stuck kworker thread that got my attention, with a 2 vcpu that doesn't seem to happen, but you still get the dmesg output and warnings about hvc) Could it be that: arch/x86/include/asm/i8259.h static inline int nr_legacy_irqs(void) { return legacy_pic->nr_legacy_irqs; } returns something different in some circumstances ? -- Sander -boris ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 2015-11-30 23:54, Boris Ostrovsky wrote: On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: Hi all, I have just tested a 4.4-rc2 kernel (current linus tree) + the tip tree pulled on top. Running this kernel under Xen on PV-guests with multiple vcpus goes well (on idle < 10% cpu usage), but a guest with only a single vcpu doesn't idle at all, it seems a kworker thread is stuck: root 569 98.0 0.0 0 0 ?R16:02 12:47 [kworker/0:1] Running a 4.3 kernel works fine with a single vpcu, bisecting would probably quite painful since there were some breakages this merge window with respect to Xen pv-guests. There are some differences in the diff's from booting a 4.3, 4.4-single, 4.4-multi cpu boot: Boris has been tracking a bunch of them. I am attaching the latest set of patches I've to carry on top of v4.4-rc3. Hi Konrad, i will test those, see if it fixes all my issues and report back They shouldn't help you ;-( (and I just saw a message from you confirming this) The first one fixes a 32-bit bug (on bare metal too). The second fixes a fatal bug for 32-bit PV guests. The other two are code improvements/cleanup. Thanks :) -- Sander Between 4.3 and 4.4-single: -NR_IRQS:4352 nr_irqs:32 16 +Using NULL legacy PIC +NR_IRQS:4352 nr_irqs:32 0 This is fine, as long as you have b4ff8389ed14b849354b59ce9b360bdefcdbf99c. -cpu 0 spinlock event irq 17 +cpu 0 spinlock event irq 1 This is strange. I wouldn't expect spinlocks to use legacy irqs. Could it be .. that with your fixup: xen/events: Always allocate legacy interrupts on PV guests (b4ff8389ed14b849354b59ce9b360bdefcdbf99c) for commit: x86/irq: Probe for PIC presence before allocating descs for legacy IRQs (8c058b0b9c34d8c8d7912880956543769323e2d8) that we now have the situation described in the commit message of 8c058b0b9c, but now for Xen PV instead of Hyper-V ? (seems both Xen and Hyper-V want to achieve the same but have different competing implementations ?) (BTW 8c058b0b9c has a CC for stable ... so could be destined to cause more trouble). -- Sander and later on: -hctosys: unable to open rtc device (rtc0) +rtc_cmos rtc_cmos: hctosys: unable to read the hardware clock +genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) +hvc_open: request_irq failed with rc -16. +Warning: unable to open an initial console. between 4.4-single and 4.4-multi: Using NULL legacy PIC -NR_IRQS:4352 nr_irqs:32 0 +NR_IRQS:4352 nr_irqs:48 0 This is probably OK too since nr_irqs depend on number of CPUs. I think something is messed up with IRQ. I saw last week something from setup_irq() generating a stack dump (warninig) for rtc_cmos but it appeared harmless at that time and now I don't see it anymore. -boris and later on: -rtc_cmos rtc_cmos: hctosys: unable to read the hardware clock +hctosys: unable to open rtc device (rtc0) -genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) -hvc_open: request_irq failed with rc -16. -Warning: unable to open an initial console. attached: - dmesg with 4.3 kernel with 1 vcpu - dmesg with 4.4 kernel with 1 vpcu - dmesg with 4.4 kernel with 2 vpcus - .config of the 4.4 kernel is attached. -- Sander ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 2015-12-02 00:19, Boris Ostrovsky wrote: On 12/01/2015 06:00 PM, Sander Eikelenboom wrote: On 2015-12-01 23:47, Boris Ostrovsky wrote: On 11/30/2015 05:55 PM, Sander Eikelenboom wrote: On 2015-11-30 23:54, Boris Ostrovsky wrote: On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: Hi all, I have just tested a 4.4-rc2 kernel (current linus tree) + the tip tree pulled on top. Running this kernel under Xen on PV-guests with multiple vcpus goes well (on idle < 10% cpu usage), but a guest with only a single vcpu doesn't idle at all, it seems a kworker thread is stuck: root 569 98.0 0.0 0 0 ?R 16:02 12:47 [kworker/0:1] Running a 4.3 kernel works fine with a single vpcu, bisecting would probably quite painful since there were some breakages this merge window with respect to Xen pv-guests. There are some differences in the diff's from booting a 4.3, 4.4-single, 4.4-multi cpu boot: Boris has been tracking a bunch of them. I am attaching the latest set of patches I've to carry on top of v4.4-rc3. Hi Konrad, i will test those, see if it fixes all my issues and report back They shouldn't help you ;-( (and I just saw a message from you confirming this) The first one fixes a 32-bit bug (on bare metal too). The second fixes a fatal bug for 32-bit PV guests. The other two are code improvements/cleanup. One of these patches also fixes a bug i was having with a pci-passthrough device in a HVM that wasn't working (depending on which dom0-kernel i was using (4.3 or 4.4)), but didn't report yet. Fingers crossed but i think this pv-guest single vcpu issue is the last i'm troubled by for now ;) I could not reproduce this, including with your kernel config file. Hmm that's unpleasant :-\ Hmm other strange thing is it doesn't seem to affect dom0 (which is also a PV guest), but only unprivileged ones All unprivileged pv-guests seem to have the irq issue, but only with a single vcpu i see to get the stuck kworker thread that got my attention, with a 2 vcpu that doesn't seem to happen, but you still get the dmesg output and warnings about hvc) Could it be that: arch/x86/include/asm/i8259.h static inline int nr_legacy_irqs(void) { return legacy_pic->nr_legacy_irqs; } returns something different in some circumstances ? It should return 16 pre-8c058b0b9c34d8c8d7912880956543769323e2d8 and 0 after that commit. This is the last number that you see in NR_IRQS:4352 nr_irqs:48 0 line. I think you should be able to safely revert both b4ff8389ed14b849354b59ce9b360bdefcdbf99c and 8c058b0b9c34d8c8d7912880956543769323e2d8 and see if it makes any difference. -boris That was already underway compiling :) And it does reveal that reverting both fixes the issue, no stuck kworker thread .. and no: genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) hvc_open: request_irq failed with rc -16. What i did get was an conflict reverting b4ff8389ed14b849354b59ce9b360bdefcdbf99c: arch/arm64/include/asm/irq.h, although that shouldn't matter because we are on x86 and not on arm. -- Sander -- Sander -boris ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 11/30/2015 05:55 PM, Sander Eikelenboom wrote: On 2015-11-30 23:54, Boris Ostrovsky wrote: On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: Hi all, I have just tested a 4.4-rc2 kernel (current linus tree) + the tip tree pulled on top. Running this kernel under Xen on PV-guests with multiple vcpus goes well (on idle < 10% cpu usage), but a guest with only a single vcpu doesn't idle at all, it seems a kworker thread is stuck: root 569 98.0 0.0 0 0 ?R16:02 12:47 [kworker/0:1] Running a 4.3 kernel works fine with a single vpcu, bisecting would probably quite painful since there were some breakages this merge window with respect to Xen pv-guests. There are some differences in the diff's from booting a 4.3, 4.4-single, 4.4-multi cpu boot: Boris has been tracking a bunch of them. I am attaching the latest set of patches I've to carry on top of v4.4-rc3. Hi Konrad, i will test those, see if it fixes all my issues and report back They shouldn't help you ;-( (and I just saw a message from you confirming this) The first one fixes a 32-bit bug (on bare metal too). The second fixes a fatal bug for 32-bit PV guests. The other two are code improvements/cleanup. One of these patches also fixes a bug i was having with a pci-passthrough device in a HVM that wasn't working (depending on which dom0-kernel i was using (4.3 or 4.4)), but didn't report yet. Fingers crossed but i think this pv-guest single vcpu issue is the last i'm troubled by for now ;) I could not reproduce this, including with your kernel config file. -boris ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 12/01/2015 05:51 PM, Sander Eikelenboom wrote: On 2015-11-30 23:54, Boris Ostrovsky wrote: On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: Hi all, I have just tested a 4.4-rc2 kernel (current linus tree) + the tip tree pulled on top. Running this kernel under Xen on PV-guests with multiple vcpus goes well (on idle < 10% cpu usage), but a guest with only a single vcpu doesn't idle at all, it seems a kworker thread is stuck: root 569 98.0 0.0 0 0 ?R16:02 12:47 [kworker/0:1] Running a 4.3 kernel works fine with a single vpcu, bisecting would probably quite painful since there were some breakages this merge window with respect to Xen pv-guests. There are some differences in the diff's from booting a 4.3, 4.4-single, 4.4-multi cpu boot: Boris has been tracking a bunch of them. I am attaching the latest set of patches I've to carry on top of v4.4-rc3. Hi Konrad, i will test those, see if it fixes all my issues and report back They shouldn't help you ;-( (and I just saw a message from you confirming this) The first one fixes a 32-bit bug (on bare metal too). The second fixes a fatal bug for 32-bit PV guests. The other two are code improvements/cleanup. Thanks :) -- Sander Between 4.3 and 4.4-single: -NR_IRQS:4352 nr_irqs:32 16 +Using NULL legacy PIC +NR_IRQS:4352 nr_irqs:32 0 This is fine, as long as you have b4ff8389ed14b849354b59ce9b360bdefcdbf99c. -cpu 0 spinlock event irq 17 +cpu 0 spinlock event irq 1 This is strange. I wouldn't expect spinlocks to use legacy irqs. Could it be .. that with your fixup: xen/events: Always allocate legacy interrupts on PV guests (b4ff8389ed14b849354b59ce9b360bdefcdbf99c) for commit: x86/irq: Probe for PIC presence before allocating descs for legacy IRQs (8c058b0b9c34d8c8d7912880956543769323e2d8) that we now have the situation described in the commit message of 8c058b0b9c, but now for Xen PV instead of Hyper-V ? (seems both Xen and Hyper-V want to achieve the same but have different competing implementations ?) (BTW 8c058b0b9c has a CC for stable ... so could be destined to cause more trouble). You mean my statement that irq 1 looks bad? That was a red herring, it should be fine. -boris -- Sander and later on: -hctosys: unable to open rtc device (rtc0) +rtc_cmos rtc_cmos: hctosys: unable to read the hardware clock +genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) +hvc_open: request_irq failed with rc -16. +Warning: unable to open an initial console. between 4.4-single and 4.4-multi: Using NULL legacy PIC -NR_IRQS:4352 nr_irqs:32 0 +NR_IRQS:4352 nr_irqs:48 0 This is probably OK too since nr_irqs depend on number of CPUs. I think something is messed up with IRQ. I saw last week something from setup_irq() generating a stack dump (warninig) for rtc_cmos but it appeared harmless at that time and now I don't see it anymore. -boris and later on: -rtc_cmos rtc_cmos: hctosys: unable to read the hardware clock +hctosys: unable to open rtc device (rtc0) -genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) -hvc_open: request_irq failed with rc -16. -Warning: unable to open an initial console. attached: - dmesg with 4.3 kernel with 1 vcpu - dmesg with 4.4 kernel with 1 vpcu - dmesg with 4.4 kernel with 2 vpcus - .config of the 4.4 kernel is attached. -- Sander ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 2015-12-02 00:41, Boris Ostrovsky wrote: On 12/01/2015 06:30 PM, Sander Eikelenboom wrote: On 2015-12-02 00:19, Boris Ostrovsky wrote: On 12/01/2015 06:00 PM, Sander Eikelenboom wrote: On 2015-12-01 23:47, Boris Ostrovsky wrote: On 11/30/2015 05:55 PM, Sander Eikelenboom wrote: On 2015-11-30 23:54, Boris Ostrovsky wrote: On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: Hi all, I have just tested a 4.4-rc2 kernel (current linus tree) + the tip tree pulled on top. Running this kernel under Xen on PV-guests with multiple vcpus goes well (on idle < 10% cpu usage), but a guest with only a single vcpu doesn't idle at all, it seems a kworker thread is stuck: root 569 98.0 0.0 0 0 ?R 16:02 12:47 [kworker/0:1] Running a 4.3 kernel works fine with a single vpcu, bisecting would probably quite painful since there were some breakages this merge window with respect to Xen pv-guests. There are some differences in the diff's from booting a 4.3, 4.4-single, 4.4-multi cpu boot: Boris has been tracking a bunch of them. I am attaching the latest set of patches I've to carry on top of v4.4-rc3. Hi Konrad, i will test those, see if it fixes all my issues and report back They shouldn't help you ;-( (and I just saw a message from you confirming this) The first one fixes a 32-bit bug (on bare metal too). The second fixes a fatal bug for 32-bit PV guests. The other two are code improvements/cleanup. One of these patches also fixes a bug i was having with a pci-passthrough device in a HVM that wasn't working (depending on which dom0-kernel i was using (4.3 or 4.4)), but didn't report yet. Fingers crossed but i think this pv-guest single vcpu issue is the last i'm troubled by for now ;) I could not reproduce this, including with your kernel config file. Hmm that's unpleasant :-\ Hmm other strange thing is it doesn't seem to affect dom0 (which is also a PV guest), but only unprivileged ones All unprivileged pv-guests seem to have the irq issue, but only with a single vcpu i see to get the stuck kworker thread that got my attention, with a 2 vcpu that doesn't seem to happen, but you still get the dmesg output and warnings about hvc) Could it be that: arch/x86/include/asm/i8259.h static inline int nr_legacy_irqs(void) { return legacy_pic->nr_legacy_irqs; } returns something different in some circumstances ? It should return 16 pre-8c058b0b9c34d8c8d7912880956543769323e2d8 and 0 after that commit. This is the last number that you see in NR_IRQS:4352 nr_irqs:48 0 line. I think you should be able to safely revert both b4ff8389ed14b849354b59ce9b360bdefcdbf99c and 8c058b0b9c34d8c8d7912880956543769323e2d8 and see if it makes any difference. -boris That was already underway compiling :) And it does reveal that reverting both fixes the issue, no stuck kworker thread .. and no: genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) hvc_open: request_irq failed with rc -16. Let me try it again tomorrow. Can you post your guest config file, Xen version and host HW (Intel or AMD)? 'xl info' maybe? -boris Guest config file == dom0 config file == the one i send you earlier. Host is an AMD Phenom X6. # xl info host : serveerstertje release: 4.4.0-rc3-20151201-linus-doflr-boris+ version: #1 SMP Tue Dec 1 19:02:58 CET 2015 machine: x86_64 nr_cpus: 6 max_cpu_id : 5 nr_nodes : 1 cores_per_socket : 6 threads_per_core : 1 cpu_mhz: 3200 hw_caps: 178bf3ff:efd3fbff::00011300:00802001::37ff: virt_caps : hvm hvm_directio total_memory : 20479 free_memory: 7745 sharing_freed_memory : 0 sharing_used_memory: 0 outstanding_claims : 0 free_cpus : 0 xen_major : 4 xen_minor : 7 xen_extra : -unstable xen_version: 4.7-unstable xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 xen_scheduler : credit xen_pagesize : 4096 platform_params: virt_start=0x8000 xen_changeset : Thu Nov 26 20:58:13 2015 +0100 git:5252636-dirty xen_commandline: dom0_mem=1536M,max:1536M loglvl=all loglvl_guest=all console_timestamps=datems vga=gfx-1280x1024x32 cpuidle cpufreq=xen com1=38400,8n1 console=vga,com1 ivrs_ioapic[6]=00:14.0 iommu=on,verbose,debug,amd-iommu-debug conring_size=128k ucode=-1 cc_compiler: gcc-4.9.real (Debian 4.9.2-10) 4.9.2 cc_compile_by : root cc_compile_domain : dyndns.org cc_compile_date: Thu Nov 26 21:18:41 CET 2015 xend_config_format : 4 If you need and can get more info by
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 12/01/2015 06:00 PM, Sander Eikelenboom wrote: On 2015-12-01 23:47, Boris Ostrovsky wrote: On 11/30/2015 05:55 PM, Sander Eikelenboom wrote: On 2015-11-30 23:54, Boris Ostrovsky wrote: On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: Hi all, I have just tested a 4.4-rc2 kernel (current linus tree) + the tip tree pulled on top. Running this kernel under Xen on PV-guests with multiple vcpus goes well (on idle < 10% cpu usage), but a guest with only a single vcpu doesn't idle at all, it seems a kworker thread is stuck: root 569 98.0 0.0 0 0 ?R 16:02 12:47 [kworker/0:1] Running a 4.3 kernel works fine with a single vpcu, bisecting would probably quite painful since there were some breakages this merge window with respect to Xen pv-guests. There are some differences in the diff's from booting a 4.3, 4.4-single, 4.4-multi cpu boot: Boris has been tracking a bunch of them. I am attaching the latest set of patches I've to carry on top of v4.4-rc3. Hi Konrad, i will test those, see if it fixes all my issues and report back They shouldn't help you ;-( (and I just saw a message from you confirming this) The first one fixes a 32-bit bug (on bare metal too). The second fixes a fatal bug for 32-bit PV guests. The other two are code improvements/cleanup. One of these patches also fixes a bug i was having with a pci-passthrough device in a HVM that wasn't working (depending on which dom0-kernel i was using (4.3 or 4.4)), but didn't report yet. Fingers crossed but i think this pv-guest single vcpu issue is the last i'm troubled by for now ;) I could not reproduce this, including with your kernel config file. Hmm that's unpleasant :-\ Hmm other strange thing is it doesn't seem to affect dom0 (which is also a PV guest), but only unprivileged ones All unprivileged pv-guests seem to have the irq issue, but only with a single vcpu i see to get the stuck kworker thread that got my attention, with a 2 vcpu that doesn't seem to happen, but you still get the dmesg output and warnings about hvc) Could it be that: arch/x86/include/asm/i8259.h static inline int nr_legacy_irqs(void) { return legacy_pic->nr_legacy_irqs; } returns something different in some circumstances ? It should return 16 pre-8c058b0b9c34d8c8d7912880956543769323e2d8 and 0 after that commit. This is the last number that you see in NR_IRQS:4352 nr_irqs:48 0 line. I think you should be able to safely revert both b4ff8389ed14b849354b59ce9b360bdefcdbf99c and 8c058b0b9c34d8c8d7912880956543769323e2d8 and see if it makes any difference. -boris -- Sander -boris ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 12/01/2015 06:30 PM, Sander Eikelenboom wrote: On 2015-12-02 00:19, Boris Ostrovsky wrote: On 12/01/2015 06:00 PM, Sander Eikelenboom wrote: On 2015-12-01 23:47, Boris Ostrovsky wrote: On 11/30/2015 05:55 PM, Sander Eikelenboom wrote: On 2015-11-30 23:54, Boris Ostrovsky wrote: On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: Hi all, I have just tested a 4.4-rc2 kernel (current linus tree) + the tip tree pulled on top. Running this kernel under Xen on PV-guests with multiple vcpus goes well (on idle < 10% cpu usage), but a guest with only a single vcpu doesn't idle at all, it seems a kworker thread is stuck: root 569 98.0 0.0 0 0 ?R 16:02 12:47 [kworker/0:1] Running a 4.3 kernel works fine with a single vpcu, bisecting would probably quite painful since there were some breakages this merge window with respect to Xen pv-guests. There are some differences in the diff's from booting a 4.3, 4.4-single, 4.4-multi cpu boot: Boris has been tracking a bunch of them. I am attaching the latest set of patches I've to carry on top of v4.4-rc3. Hi Konrad, i will test those, see if it fixes all my issues and report back They shouldn't help you ;-( (and I just saw a message from you confirming this) The first one fixes a 32-bit bug (on bare metal too). The second fixes a fatal bug for 32-bit PV guests. The other two are code improvements/cleanup. One of these patches also fixes a bug i was having with a pci-passthrough device in a HVM that wasn't working (depending on which dom0-kernel i was using (4.3 or 4.4)), but didn't report yet. Fingers crossed but i think this pv-guest single vcpu issue is the last i'm troubled by for now ;) I could not reproduce this, including with your kernel config file. Hmm that's unpleasant :-\ Hmm other strange thing is it doesn't seem to affect dom0 (which is also a PV guest), but only unprivileged ones All unprivileged pv-guests seem to have the irq issue, but only with a single vcpu i see to get the stuck kworker thread that got my attention, with a 2 vcpu that doesn't seem to happen, but you still get the dmesg output and warnings about hvc) Could it be that: arch/x86/include/asm/i8259.h static inline int nr_legacy_irqs(void) { return legacy_pic->nr_legacy_irqs; } returns something different in some circumstances ? It should return 16 pre-8c058b0b9c34d8c8d7912880956543769323e2d8 and 0 after that commit. This is the last number that you see in NR_IRQS:4352 nr_irqs:48 0 line. I think you should be able to safely revert both b4ff8389ed14b849354b59ce9b360bdefcdbf99c and 8c058b0b9c34d8c8d7912880956543769323e2d8 and see if it makes any difference. -boris That was already underway compiling :) And it does reveal that reverting both fixes the issue, no stuck kworker thread .. and no: genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) hvc_open: request_irq failed with rc -16. Let me try it again tomorrow. Can you post your guest config file, Xen version and host HW (Intel or AMD)? 'xl info' maybe? -boris What i did get was an conflict reverting b4ff8389ed14b849354b59ce9b360bdefcdbf99c: arch/arm64/include/asm/irq.h, although that shouldn't matter because we are on x86 and not on arm. -- Sander -- Sander -boris ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 2015-11-30 23:54, Boris Ostrovsky wrote: On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: Hi all, I have just tested a 4.4-rc2 kernel (current linus tree) + the tip tree pulled on top. Running this kernel under Xen on PV-guests with multiple vcpus goes well (on idle < 10% cpu usage), but a guest with only a single vcpu doesn't idle at all, it seems a kworker thread is stuck: root 569 98.0 0.0 0 0 ?R16:02 12:47 [kworker/0:1] Running a 4.3 kernel works fine with a single vpcu, bisecting would probably quite painful since there were some breakages this merge window with respect to Xen pv-guests. There are some differences in the diff's from booting a 4.3, 4.4-single, 4.4-multi cpu boot: Boris has been tracking a bunch of them. I am attaching the latest set of patches I've to carry on top of v4.4-rc3. Hi Konrad, i will test those, see if it fixes all my issues and report back They shouldn't help you ;-( (and I just saw a message from you confirming this) The first one fixes a 32-bit bug (on bare metal too). The second fixes a fatal bug for 32-bit PV guests. The other two are code improvements/cleanup. One of these patches also fixes a bug i was having with a pci-passthrough device in a HVM that wasn't working (depending on which dom0-kernel i was using (4.3 or 4.4)), but didn't report yet. Fingers crossed but i think this pv-guest single vcpu issue is the last i'm troubled by for now ;) -- Sander Thanks :) -- Sander Between 4.3 and 4.4-single: -NR_IRQS:4352 nr_irqs:32 16 +Using NULL legacy PIC +NR_IRQS:4352 nr_irqs:32 0 This is fine, as long as you have b4ff8389ed14b849354b59ce9b360bdefcdbf99c. -cpu 0 spinlock event irq 17 +cpu 0 spinlock event irq 1 This is strange. I wouldn't expect spinlocks to use legacy irqs. and later on: -hctosys: unable to open rtc device (rtc0) +rtc_cmos rtc_cmos: hctosys: unable to read the hardware clock +genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) +hvc_open: request_irq failed with rc -16. +Warning: unable to open an initial console. between 4.4-single and 4.4-multi: Using NULL legacy PIC -NR_IRQS:4352 nr_irqs:32 0 +NR_IRQS:4352 nr_irqs:48 0 This is probably OK too since nr_irqs depend on number of CPUs. I think something is messed up with IRQ. I saw last week something from setup_irq() generating a stack dump (warninig) for rtc_cmos but it appeared harmless at that time and now I don't see it anymore. -boris and later on: -rtc_cmos rtc_cmos: hctosys: unable to read the hardware clock +hctosys: unable to open rtc device (rtc0) -genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) -hvc_open: request_irq failed with rc -16. -Warning: unable to open an initial console. attached: - dmesg with 4.3 kernel with 1 vcpu - dmesg with 4.4 kernel with 1 vpcu - dmesg with 4.4 kernel with 2 vpcus - .config of the 4.4 kernel is attached. -- Sander ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] linux 4.4 Regression: 100% cpu usage on idle pv guest under Xen with single vcpu.
On 11/30/2015 04:46 PM, Sander Eikelenboom wrote: On 2015-11-30 22:45, Konrad Rzeszutek Wilk wrote: On Sat, Nov 28, 2015 at 04:47:43PM +0100, Sander Eikelenboom wrote: Hi all, I have just tested a 4.4-rc2 kernel (current linus tree) + the tip tree pulled on top. Running this kernel under Xen on PV-guests with multiple vcpus goes well (on idle < 10% cpu usage), but a guest with only a single vcpu doesn't idle at all, it seems a kworker thread is stuck: root 569 98.0 0.0 0 0 ?R16:02 12:47 [kworker/0:1] Running a 4.3 kernel works fine with a single vpcu, bisecting would probably quite painful since there were some breakages this merge window with respect to Xen pv-guests. There are some differences in the diff's from booting a 4.3, 4.4-single, 4.4-multi cpu boot: Boris has been tracking a bunch of them. I am attaching the latest set of patches I've to carry on top of v4.4-rc3. Hi Konrad, i will test those, see if it fixes all my issues and report back They shouldn't help you ;-( (and I just saw a message from you confirming this) The first one fixes a 32-bit bug (on bare metal too). The second fixes a fatal bug for 32-bit PV guests. The other two are code improvements/cleanup. Thanks :) -- Sander Between 4.3 and 4.4-single: -NR_IRQS:4352 nr_irqs:32 16 +Using NULL legacy PIC +NR_IRQS:4352 nr_irqs:32 0 This is fine, as long as you have b4ff8389ed14b849354b59ce9b360bdefcdbf99c. -cpu 0 spinlock event irq 17 +cpu 0 spinlock event irq 1 This is strange. I wouldn't expect spinlocks to use legacy irqs. and later on: -hctosys: unable to open rtc device (rtc0) +rtc_cmos rtc_cmos: hctosys: unable to read the hardware clock +genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) +hvc_open: request_irq failed with rc -16. +Warning: unable to open an initial console. between 4.4-single and 4.4-multi: Using NULL legacy PIC -NR_IRQS:4352 nr_irqs:32 0 +NR_IRQS:4352 nr_irqs:48 0 This is probably OK too since nr_irqs depend on number of CPUs. I think something is messed up with IRQ. I saw last week something from setup_irq() generating a stack dump (warninig) for rtc_cmos but it appeared harmless at that time and now I don't see it anymore. -boris and later on: -rtc_cmos rtc_cmos: hctosys: unable to read the hardware clock +hctosys: unable to open rtc device (rtc0) -genirq: Flags mismatch irq 8. (hvc_console) vs. (rtc0) -hvc_open: request_irq failed with rc -16. -Warning: unable to open an initial console. attached: - dmesg with 4.3 kernel with 1 vcpu - dmesg with 4.4 kernel with 1 vpcu - dmesg with 4.4 kernel with 2 vpcus - .config of the 4.4 kernel is attached. -- Sander ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel