From: Thomas Gleixner <tglx@linutronix.de>
To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Tony Luck <tony.luck@intel.com>, Ashok Raj <ashok.raj@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Jan Kiszka <jan.kiszka@siemens.com>, x86 <x86@kernel.org>,
Ricardo Neri <ricardo.neri@intel.com>,
Stephane Eranian <eranian@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Juergen Gross <jgross@suse.com>,
Bjorn Helgaas <bhelgaas@google.com>,
iommu@lists.linux-foundation.org,
Randy Dunlap <rdunlap@infradead.org>,
Jacob Pan <jacob.jun.pan@intel.com>,
Philippe Ombredanne <pombredanne@nexb.com>,
Andi Kleen <andi.kleen@intel.com>, Borislav Petkov <bp@suse.de>,
Ingo Molnar <mingo@kernel.org>,
Wincy Van <fanwenyi0529@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [RFC PATCH v4 20/21] iommu/vt-d: hpet: Reserve an interrupt remampping table entry for watchdog
Date: Sat, 22 Jun 2019 09:21:33 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1906220920270.5503@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190621235541.GA25773@ranerica-svr.sc.intel.com>
On Fri, 21 Jun 2019, Ricardo Neri wrote:
> On Fri, Jun 21, 2019 at 10:05:01PM +0200, Thomas Gleixner wrote:
> > On Fri, 21 Jun 2019, Jacob Pan wrote:
> > > >
> > > I looked at the code again, seems the per cpu HPET code already taken
> > > care of HPET MSI management. Why can't we use IR-HPET-MSI chip and
> > > domain to allocate and set affinity etc.?
> > > Most APIC timer has ARAT not enough per cpu HPET, so per cpu HPET is
> > > not used mostly.
> >
> > Sure, we can use that, but that does not allow to move the affinity from
> > NMI context either. Same issue with the IOMMU as with the other hack.
>
> If I understand Thomas' point correctly, the problem is having to take
> lock in NMI context to update the IRTE for the HPET; both as in my hack
> and in the generic irq code. The problem is worse when using the generic
> irq code as there are several layers and several locks that need to be
> handled.
It does not matter how many locks are involved. One is enough to wedge the
machine.
Thanks,
tglx
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next prev parent reply other threads:[~2019-06-22 7:23 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-24 1:16 [RFC PATCH v4 00/21] Implement an HPET-based hardlockup detector Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 01/21] x86/msi: Add definition for NMI delivery mode Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 02/21] x86/hpet: Expose hpet_writel() in header Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 03/21] x86/hpet: Calculate ticks-per-second in a separate function Ricardo Neri
2019-06-14 15:54 ` Thomas Gleixner
2019-06-14 15:59 ` Thomas Gleixner
2019-06-18 22:48 ` Ricardo Neri
2019-06-18 23:13 ` Thomas Gleixner
2019-05-24 1:16 ` [RFC PATCH v4 04/21] x86/hpet: Add hpet_set_comparator() for periodic and one-shot modes Ricardo Neri
2019-06-14 18:17 ` Thomas Gleixner
2019-06-18 22:48 ` Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 05/21] x86/hpet: Reserve timer for the HPET hardlockup detector Ricardo Neri
2019-06-11 19:54 ` Thomas Gleixner
2019-06-14 1:14 ` Ricardo Neri
2019-06-14 16:10 ` Thomas Gleixner
2019-06-18 22:48 ` Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 06/21] x86/hpet: Configure the timer used by the " Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 07/21] watchdog/hardlockup: Define a generic function to detect hardlockups Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 08/21] watchdog/hardlockup: Decouple the hardlockup detector from perf Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 09/21] x86/nmi: Add a NMI_WATCHDOG NMI handler category Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 10/21] watchdog/hardlockup: Add function to enable NMI watchdog on all allowed CPUs at once Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 11/21] x86/watchdog/hardlockup: Add an HPET-based hardlockup detector Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 12/21] watchdog/hardlockup/hpet: Adjust timer expiration on the number of monitored CPUs Ricardo Neri
2019-06-11 20:11 ` Thomas Gleixner
2019-06-18 22:46 ` Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 13/21] x86/watchdog/hardlockup/hpet: Determine if HPET timer caused NMI Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 14/21] watchdog/hardlockup: Use parse_option_str() to handle "nmi_watchdog" Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 15/21] watchdog/hardlockup/hpet: Only enable the HPET watchdog via a boot parameter Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 16/21] x86/watchdog: Add a shim hardlockup detector Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 17/21] x86/tsc: Switch to perf-based hardlockup detector if TSC become unstable Ricardo Neri
2019-06-07 0:35 ` Stephane Eranian via iommu
2019-06-07 14:14 ` Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 18/21] x86/apic: Add a parameter for the APIC delivery mode Ricardo Neri
2019-06-16 9:55 ` Thomas Gleixner
2019-06-18 22:47 ` Ricardo Neri
2019-06-18 23:15 ` Thomas Gleixner
2019-05-24 1:16 ` [RFC PATCH v4 19/21] iommu/vt-d: Rework prepare_irte() to support per-irq " Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 20/21] iommu/vt-d: hpet: Reserve an interrupt remampping table entry for watchdog Ricardo Neri
2019-06-16 18:42 ` Thomas Gleixner
2019-06-16 19:21 ` Thomas Gleixner
2019-06-17 8:25 ` Thomas Gleixner
2019-06-17 21:38 ` Stephane Eranian via iommu
2019-06-17 23:08 ` Thomas Gleixner
2019-06-19 15:43 ` Jacob Pan
2019-06-21 15:33 ` Thomas Gleixner
2019-06-21 17:31 ` Jacob Pan
2019-06-21 18:39 ` Jacob Pan
2019-06-21 20:05 ` Thomas Gleixner
2019-06-21 23:55 ` Ricardo Neri
2019-06-22 7:21 ` Thomas Gleixner [this message]
2019-10-18 2:48 ` Ricardo Neri
2019-06-18 22:45 ` Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 21/21] x86/watchdog/hardlockup/hpet: Support interrupt remapping Ricardo Neri
2019-06-16 8:44 ` Thomas Gleixner
2019-06-16 8:53 ` Thomas Gleixner
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