diff options
| author | Suresh E. Warrier <warrier@linux.vnet.ibm.com> | 2015-12-21 23:33:57 +0100 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2016-02-29 06:25:06 +0100 |
| commit | 520fe9c607d3acea96391aad27e17518bd7d39bd (patch) | |
| tree | ee3c420760c8d739bfe2cfa9d928c40622545c69 /arch | |
| parent | KVM: PPC: Book3S HV: Send IPI to host core to wake VCPU (diff) | |
| download | linux-520fe9c607d3acea96391aad27e17518bd7d39bd.tar.xz linux-520fe9c607d3acea96391aad27e17518bd7d39bd.zip | |
KVM: PPC: Book3S HV: Add tunable to control H_IPI redirection
Redirecting the wakeup of a VCPU from the H_IPI hypercall to
a core running in the host is usually a good idea, most workloads
seemed to benefit. However, in one heavily interrupt-driven SMT1
workload, some regression was observed. This patch adds a kvm_hv
module parameter called h_ipi_redirect to control this feature.
The default value for this tunable is 1 - that is enable the feature.
Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/include/asm/kvm_ppc.h | 1 | ||||
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv.c | 11 | ||||
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_rm_xics.c | 5 |
3 files changed, 16 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index bc14e9e0e4fe..197a8aca2871 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -464,6 +464,7 @@ extern int kvmppc_xics_set_icp(struct kvm_vcpu *vcpu, u64 icpval); extern int kvmppc_xics_connect_vcpu(struct kvm_device *dev, struct kvm_vcpu *vcpu, u32 cpu); extern void kvmppc_xics_ipi_action(void); +extern int h_ipi_redirect; #else static inline void kvmppc_alloc_host_rm_ops(void) {}; static inline void kvmppc_free_host_rm_ops(void) {}; diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index c3c731085c1f..f47fffefadc1 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -81,6 +81,17 @@ static int target_smt_mode; module_param(target_smt_mode, int, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(target_smt_mode, "Target threads per core (0 = max)"); +#ifdef CONFIG_KVM_XICS +static struct kernel_param_ops module_param_ops = { + .set = param_set_int, + .get = param_get_int, +}; + +module_param_cb(h_ipi_redirect, &module_param_ops, &h_ipi_redirect, + S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(h_ipi_redirect, "Redirect H_IPI wakeup to a free host core"); +#endif + static void kvmppc_end_cede(struct kvm_vcpu *vcpu); static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu); diff --git a/arch/powerpc/kvm/book3s_hv_rm_xics.c b/arch/powerpc/kvm/book3s_hv_rm_xics.c index e673fb9fee98..980d8a6f7284 100644 --- a/arch/powerpc/kvm/book3s_hv_rm_xics.c +++ b/arch/powerpc/kvm/book3s_hv_rm_xics.c @@ -24,6 +24,9 @@ #define DEBUG_PASSUP +int h_ipi_redirect = 1; +EXPORT_SYMBOL(h_ipi_redirect); + static void icp_rm_deliver_irq(struct kvmppc_xics *xics, struct kvmppc_icp *icp, u32 new_irq); @@ -148,7 +151,7 @@ static void icp_rm_set_vcpu_irq(struct kvm_vcpu *vcpu, cpu = vcpu->arch.thread_cpu; if (cpu < 0 || cpu >= nr_cpu_ids) { hcore = -1; - if (kvmppc_host_rm_ops_hv) + if (kvmppc_host_rm_ops_hv && h_ipi_redirect) hcore = find_available_hostcore(XICS_RM_KICK_VCPU); if (hcore != -1) { icp_send_hcore_msg(hcore, vcpu); |