[v2] Drivers: hv: vmbus: Don't assign VMbus channel interrupts to isolated CPUs

[RESEND PATCH v2] Drivers: hv: vmbus: Don't assign VMbus channel interrupts to isolated CPUs

Posted by Saurabh Sengar 3 years, 11 months ago

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: Saurabh Sengar <ssengar@linux.microsoft.com>
---
v2: * Resending v2 with minor correction, please discard the earlier v2
    * better commit message
    * Added back empty line, removed by mistake
    * Removed error print for sysfs error

 drivers/hv/channel_mgmt.c | 17 ++++++++++++-----
 drivers/hv/vmbus_drv.c    |  4 ++++
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 97d8f56..127a05b 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -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);
 
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 714d549..547ae33 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -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();
 
-- 
1.8.3.1

RE: [RESEND PATCH v2] Drivers: hv: vmbus: Don't assign VMbus channel interrupts to isolated CPUs

Posted by Michael Kelley (LINUX) 3 years, 11 months ago

From: Saurabh Sengar <ssengar@linux.microsoft.com> Sent: Friday, May 27, 2022 12:44 AM
> 
> 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: Saurabh Sengar <ssengar@linux.microsoft.com>
> ---
> v2: * Resending v2 with minor correction, please discard the earlier v2
>     * better commit message
>     * Added back empty line, removed by mistake
>     * Removed error print for sysfs error
> 
>  drivers/hv/channel_mgmt.c | 17 ++++++++++++-----
>  drivers/hv/vmbus_drv.c    |  4 ++++
>  2 files changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
> index 97d8f56..127a05b 100644
> --- a/drivers/hv/channel_mgmt.c
> +++ b/drivers/hv/channel_mgmt.c
> @@ -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);
> 
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 714d549..547ae33 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -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();
> 
> --
> 1.8.3.1

Reviewed-by: Michael Kelley <mikelley@microsoft.com>

Re: [RESEND PATCH v2] Drivers: hv: vmbus: Don't assign VMbus channel interrupts to isolated CPUs

Posted by Wei Liu 3 years, 10 months ago

On Sat, May 28, 2022 at 01:11:21PM +0000, Michael Kelley (LINUX) wrote:
> From: Saurabh Sengar <ssengar@linux.microsoft.com> Sent: Friday, May 27, 2022 12:44 AM
> > 
> > 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: Saurabh Sengar <ssengar@linux.microsoft.com>
> > ---
[...]
> Reviewed-by: Michael Kelley <mikelley@microsoft.com>

Applied to hyperv-fixes. Thanks.