7b55e47e1d
Commitd27f1ee36e("Linux std kernel upgrade to align with CentOS 8") and commitc0fee2da8e("[kernel-rt 4.18] Upgrade kernel-rt to version 4.18.0-147.3.1 based on SRPM") uprevisioned the StarlingX kernel from v3.10 to v4.18 for migration to CentOS 8 and adapted the kernel patches accordingly. However, the CPU affinity patches' uprevisioning was made in a buggy manner: The connection between the bitmask cpu_kthread_bits and the CPU mask __cpu_kthread_mask was not kept, which made these two patches essentially inoperative, as described by bug report 1924799. This commit updates the two patches to make the kthread_cpus= kernel command line argument functional again by removing cpu_kthread_bits and making the argument parser function kthread_setup store the parsed CPU mask into __cpu_kthread_mask. This commit introduces error handling for the parsing of the kthread_cpus= argument's value as well, based on code review feedback. If a parser error occurs, then the error code is reported and the effective CPU affinity will correspond to all possible CPUs. This change was verified with the StarlingX master branch as of last week. As an example, prior to this commit, the kthreadd kernel thread (i.e., usually PID 2) had a CPU affinity of 0 on a qemu-based VM with 8 virtual CPUs despite the use of "kthread_cpus=0-1" on the kernel command line. With this patch, PID 2's CPU affinity is 0-1, as expected. Change-Id: Ica1dfe00947e4e52f19659b721958f1e1845609b Closes-Bug: 1924799 Signed-off-by: Vefa Bicakci <vefa.bicakci@windriver.com>