Commit 6640b5df authored by Saurabh Sengar's avatar Saurabh Sengar Committed by Wei Liu
Browse files

Drivers: hv: vmbus: Don't assign VMbus channel interrupts to isolated CPUs 



When initially assigning a VMbus channel interrupt to a CPU, don’t choose
a managed IRQ isolated CPU (as specified on the kernel boot line with
parameter 'isolcpus=managed_irq,<#cpu>'). Also, when using sysfs to change
the CPU that a VMbus channel will interrupt, don't allow changing to a
managed IRQ isolated CPU.

Signed-off-by: default avatarSaurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1653637439-23060-1-git-send-email-ssengar@linux.microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent f2906aa8

drivers/hv/channel_mgmt.c

+12 −5
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/cpu.h>

#include <linux/hyperv.h>

#include <asm/mshyperv.h>

#include <linux/sched/isolation.h>



#include "hyperv_vmbus.h"
@@ -728,16 +729,20 @@ static void init_vp_index(struct vmbus_channel *channel) 
	u32 i, ncpu = num_online_cpus();

	cpumask_var_t available_mask;

	struct cpumask *allocated_mask;

	const struct cpumask *hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);

	u32 target_cpu;

	int numa_node;



	if (!perf_chn ||

	    !alloc_cpumask_var(&available_mask, GFP_KERNEL)) {

	    !alloc_cpumask_var(&available_mask, GFP_KERNEL) ||

	    cpumask_empty(hk_mask)) {

		/*

		 * If the channel is not a performance critical

		 * channel, bind it to VMBUS_CONNECT_CPU.

		 * In case alloc_cpumask_var() fails, bind it to

		 * VMBUS_CONNECT_CPU.

		 * If all the cpus are isolated, bind it to

		 * VMBUS_CONNECT_CPU.

		 */

		channel->target_cpu = VMBUS_CONNECT_CPU;

		if (perf_chn)
@@ -758,17 +763,19 @@ static void init_vp_index(struct vmbus_channel *channel) 
		}

		allocated_mask = &hv_context.hv_numa_map[numa_node];



		if (cpumask_equal(allocated_mask, cpumask_of_node(numa_node))) {

retry:

		cpumask_xor(available_mask, allocated_mask, cpumask_of_node(numa_node));

		cpumask_and(available_mask, available_mask, hk_mask);



		if (cpumask_empty(available_mask)) {

			/*

			 * We have cycled through all the CPUs in the node;

			 * reset the allocated map.

			 */

			cpumask_clear(allocated_mask);

			goto retry;

		}



		cpumask_xor(available_mask, allocated_mask,

			    cpumask_of_node(numa_node));



		target_cpu = cpumask_first(available_mask);

		cpumask_set_cpu(target_cpu, allocated_mask);

drivers/hv/vmbus_drv.c

+4 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/kernel_stat.h>

#include <linux/clockchips.h>

#include <linux/cpu.h>

#include <linux/sched/isolation.h>

#include <linux/sched/task_stack.h>



#include <linux/delay.h>
@@ -1770,6 +1771,9 @@ static ssize_t target_cpu_store(struct vmbus_channel *channel, 
	if (target_cpu >= nr_cpumask_bits)

		return -EINVAL;



	if (!cpumask_test_cpu(target_cpu, housekeeping_cpumask(HK_TYPE_MANAGED_IRQ)))

		return -EINVAL;



	/* No CPUs should come up or down during this. */

	cpus_read_lock();