93a4d6f401
The recent affinitization didn't address cpu offlining/onlining. If an interrupt vector is shared and the low order cpu owning the vector is offlined, as interrupts are managed, the vector is taken offline. This causes the other CPUs sharing the vector will hang as they can't get io completions. Correct by registering callbacks with the system for Offline/Online events. When a cpu is taken offline, its eq, which is tied to an interrupt vector is found. If the cpu is the "owner" of the vector and if the eq/vector is shared by other CPUs, the eq is placed into a polled mode. Additionally, code paths that perform io submission on the "sharing CPUs" will check the eq state and poll for completion after submission of new io to a wq that uses the eq. Similarly, when a cpu comes back online and owns an offlined vector, the eq is taken out of polled mode and rearmed to start driving interrupts for eq. Link: https://lore.kernel.org/r/20191105005708.7399-9-jsmart2021@gmail.com Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com> Signed-off-by: James Smart <jsmart2021@gmail.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.