[PATCH v6 11/11] Documentation: virtual: kvm: Support vcpu preempted check

Commit ("x86, kvm: support vcpu preempted check") add one field "__u8 preempted" into struct kvm_steal_time. This field tells if one vcpu is running or not. It is zero if 1) some old KVM deos not support this filed. 2) the vcpu is not preempted. Other values means the vcpu has been preempted.

[PATCH v6 10/11] x86, xen: support vcpu preempted check

From: Juergen Gross Support the vcpu_is_preempted() functionality under Xen. This will enhance lock performance on overcommitted hosts (more runnable vcpus than physical cpus in the system) as doing busy waits for preempted vcpus will hurt system performance far worse than early

[PATCH v6 08/11] x86, kvm/x86.c: support vcpu preempted check

Support the vcpu_is_preempted() functionality under KVM. This will enhance lock performance on overcommitted hosts (more runnable vcpus than physical cpus in the system) as doing busy waits for preempted vcpus will hurt system performance far worse than early yielding. Use one field of struct

[PATCH v6 09/11] x86, kernel/kvm.c: support vcpu preempted check

Support the vcpu_is_preempted() functionality under KVM. This will enhance lock performance on overcommitted hosts (more runnable vcpus than physical cpus in the system) as doing busy waits for preempted vcpus will hurt system performance far worse than early yielding. struct

[PATCH v6 07/11] KVM: Introduce kvm_write_guest_offset_cached

It allows us to update some status or field of one struct partially. We can also save one kvm_read_guest_cached if we just update one filed of the struct regardless of its current value. Signed-off-by: Pan Xinhui --- include/linux/kvm_host.h | 2 ++

[PATCH v6 06/11] x86, paravirt: Add interface to support kvm/xen vcpu preempted check

This is to fix some lock holder preemption issues. Some other locks implementation do a spin loop before acquiring the lock itself. Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It takes the cpu as parameter and return true if the cpu is preempted. Then kernel can break the

[PATCH v6 01/11] kernel/sched: introduce vcpu preempted check interface

This patch support to fix lock holder preemption issue. For kernel users, we could use bool vcpu_is_preempted(int cpu) to detech if one vcpu is preempted or not. The default implementation is a macro defined by false. So compiler can wrap it out if arch dose not support such vcpu pteempted

[PATCH v6 05/11] s390/spinlock: Provide vcpu_is_preempted

From: Christian Borntraeger this implements the s390 backend for commit "kernel/sched: introduce vcpu preempted check interface" by reworking the existing smp_vcpu_scheduled into arch_vcpu_is_preempted. We can then also get rid of the local cpu_is_preempted function by

[PATCH v6 04/11] powerpc/spinlock: support vcpu preempted check

This is to fix some lock holder preemption issues. Some other locks implementation do a spin loop before acquiring the lock itself. Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It takes the cpu as parameter and return true if the cpu is preempted. Then kernel can break the

[PATCH v6 03/11] kernel/locking: Drop the overload of {mutex, rwsem}_spin_on_owner

An over-committed guest with more vCPUs than pCPUs has a heavy overload in the two spin_on_owner. This blames on the lock holder preemption issue. Kernel has an interface bool vcpu_is_preempted(int cpu) to see if a vCPU is currently running or not. So break the spin loops on true condition.

[PATCH v6 02/11] locking/osq: Drop the overload of osq_lock()

An over-committed guest with more vCPUs than pCPUs has a heavy overload in osq_lock(). This is because vCPU A hold the osq lock and yield out, vCPU B wait per_cpu node->locked to be set. IOW, vCPU B wait vCPU A to run and unlock the osq lock. Kernel has an interface bool vcpu_is_preempted(int

[PATCH v6 00/11] implement vcpu preempted check

change from v5: spilt x86/kvm patch into guest/host part. introduce kvm_write_guest_offset_cached. fix some typos. rebase patch onto 4.9.2 change from v4: spilt x86 kvm vcpu preempted check into two patches. add documentation patch. add x86

Re: [RESEND PATCH 3/3] x86/vmware: Add paravirt sched clock

On Thu, 27 Oct 2016, Alexey Makhalov wrote: > Set pv_time_ops.sched_clock to vmware_sched_clock(). Please do not describe WHAT the patch does, describe why. Describe the problem you are solving. I can see from the patch > + pv_time_ops.sched_clock = vmware_sched_clock; that you

Re: [RESEND PATCH 1/3] x86/vmware: Use tsc_khz value for calibrate_cpu()

On Thu, 27 Oct 2016, Alexey Makhalov wrote: > [RESEND PATCH 1/3] x86/vmware: Use tsc_khz value for calibrate_cpu() Please don't do that. RESEND is a keyword, when the same patch (series) is sent again without any modification vs. the first patch (series). A possible reason to do so is when a

Re: [RESEND PATCH v3 kernel 6/7] virtio-balloon: define feature bit and head for misc virt queue

On Fri, Oct 21, 2016 at 02:24:39PM +0800, Liang Li wrote: > Define a new feature bit which supports a new virtual queue. This > new virtual qeuque is for information exchange between hypervisor > and guest. The VMM hypervisor can make use of this virtual queue > to request the guest do some