I am currently receiving the following error whenever I go to adjust the smp_affinity/smp_affinity_list files for IRQ's associated the Samsung NVMe SDD PM1725a installed in a Dell PowerEdge R7425 server:

echo: write error: Input/output error

I have stopped/disabled irqbalance using the following:

systemctl stop irqbalance
systemctl disable irqbalance

However, I still get the Input/output error when I try and echo any values into either the smp_affinity or smp_affinity_list files. What is really peculiar about this, is I have no issues updating the values in these files as long as I am on the stock kernel 3.10.0-514 that came with CentOS 7.3; however, whenever I get this error on the following kernels 3.10.0-862.11.6, 4.4.153-1, and 4.18.5-1. Since I am only experiencing this issue in these newer kernels, I imagine there is some setting I do not have set that is preventing me from updating the SMP affinity values for the NVMe SDD's IRQ's. Has anyone else experienced this issue and possibly know how to correct it?

Are the non-stock kernels built with the same config?

For the non-stock kernels, the 3.10.0-862 kernel was acquired using yum update, and the version 4 kernels were installed using base RPM's. Looking at the configuration files for 3.10.0-514 and 3.10.0-862, I did notice the following two variables were defined as 'y'/present in the 3.10.0-862 kernel:

CONFIG_REGMAP_IRQ=y
CONFIG_GPIO_IRQCHIP=y

Neither of these variables appear in the 3.10.0-514 kernel config file. Are you aware of any specific kernel variables in the config file that would cause the issue of not being able to write the smp_affinity, smp_affinity_list files, or do these to variables stand out as issues, for NVMe SDD devices?