| Message ID | 20210503111822.758423-1-npiggin@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | powerpc/pseries: Enable hardlockup watchdog for PowerVM partitions | expand |
| Related | show |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (e3a9b9d6a03f5fbf99b540e863b001d46ba1735c) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | fail | Build failed! |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 20 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
On Mon, 3 May 2021 21:18:22 +1000, Nicholas Piggin wrote: > PowerVM will not arbitrarily oversubscribe or stop guests, page out the > guest kernel text to a NFS volume connected by carrier pigeon to abacus > based storage, etc., as a KVM host might. So PowerVM guests are not > likely to be killed by the hard lockup watchdog in normal operation, > even with shared processor LPARs which still get a minimum allotment of > CPU time. > > [...] Applied to powerpc/next. [1/1] powerpc/pseries: Enable hardlockup watchdog for PowerVM partitions https://git.kernel.org/powerpc/c/633c8e9800f3884a26b2af59be8ce27696ad6ebf cheers
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index b779d25761cf..c0e234456863 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -939,15 +939,17 @@ u64 hw_nmi_get_sample_period(int watchdog_thresh) * disable it by default. Book3S has a soft-nmi hardlockup detector based * on the decrementer interrupt, so it does not suffer from this problem. * - * It is likely to get false positives in VM guests, so disable it there - * by default too. + * It is likely to get false positives in KVM guests, so disable it there + * by default too. PowerVM will not stop or arbitrarily oversubscribe + * CPUs, but give a minimum regular allotment even with SPLPAR, so enable + * the detector for non-KVM guests, assume PowerVM. */ static int __init disable_hardlockup_detector(void) { #ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF hardlockup_detector_disable(); #else - if (firmware_has_feature(FW_FEATURE_LPAR)) + if (is_kvm_guest()) hardlockup_detector_disable(); #endif
PowerVM will not arbitrarily oversubscribe or stop guests, page out the guest kernel text to a NFS volume connected by carrier pigeon to abacus based storage, etc., as a KVM host might. So PowerVM guests are not likely to be killed by the hard lockup watchdog in normal operation, even with shared processor LPARs which still get a minimum allotment of CPU time. Enable the hard lockup detector by default on !KVM guests, which we will assume is PowerVM. It has been useful in finding problems on bare metal kernels. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/kernel/setup_64.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)