x86/hyper-v: Use cheaper HVCALL_SEND_IPI hypercall when possible

When there is no need to send an IPI to a CPU with VP number > 64
we can do the job with fast HVCALL_SEND_IPI hypercall.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Cc: devel@linuxdriverproject.org
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tianyu Lan <Tianyu.Lan@microsoft.com>
Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
Link: https://lkml.kernel.org/r/20180622170625.30688-4-vkuznets@redhat.com
This commit is contained in:
Vitaly Kuznetsov 2018-06-22 19:06:24 +02:00 committed by Thomas Gleixner
parent d8e6b232cf
commit 4bd0606076

View File

@ -99,6 +99,9 @@ static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector)
int nr_bank = 0;
int ret = 1;
if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
return false;
local_irq_save(flags);
arg = (struct ipi_arg_ex **)this_cpu_ptr(hyperv_pcpu_input_arg);
@ -140,8 +143,18 @@ static bool __send_ipi_mask(const struct cpumask *mask, int vector)
if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
return false;
if ((ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
return __send_ipi_mask_ex(mask, vector);
/*
* From the supplied CPU set we need to figure out if we can get away
* with cheaper HVCALL_SEND_IPI hypercall. This is possible when the
* highest VP number in the set is < 64. As VP numbers are usually in
* ascending order and match Linux CPU ids, here is an optimization:
* we check the VP number for the highest bit in the supplied set first
* so we can quickly find out if using HVCALL_SEND_IPI_EX hypercall is
* a must. We will also check all VP numbers when walking the supplied
* CPU set to remain correct in all cases.
*/
if (hv_cpu_number_to_vp_number(cpumask_last(mask)) >= 64)
goto do_ex_hypercall;
ipi_arg.vector = vector;
ipi_arg.cpu_mask = 0;
@ -153,16 +166,17 @@ static bool __send_ipi_mask(const struct cpumask *mask, int vector)
* only target upto 64 CPUs.
*/
if (vcpu >= 64)
goto ipi_mask_done;
goto do_ex_hypercall;
__set_bit(vcpu, (unsigned long *)&ipi_arg.cpu_mask);
}
ret = hv_do_fast_hypercall16(HVCALL_SEND_IPI, ipi_arg.vector,
ipi_arg.cpu_mask);
ipi_mask_done:
return ((ret == 0) ? true : false);
do_ex_hypercall:
return __send_ipi_mask_ex(mask, vector);
}
static bool __send_ipi_one(int cpu, int vector)
@ -218,10 +232,7 @@ static void hv_send_ipi_self(int vector)
void __init hv_apic_init(void)
{
if (ms_hyperv.hints & HV_X64_CLUSTER_IPI_RECOMMENDED) {
if ((ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
pr_info("Hyper-V: Using ext hypercalls for IPI\n");
else
pr_info("Hyper-V: Using IPI hypercalls\n");
pr_info("Hyper-V: Using IPI hypercalls\n");
/*
* Set the IPI entry points.
*/