mirror of
https://github.com/torvalds/linux.git
synced 2025-12-07 20:06:24 +00:00
0d30dae38f
During suspend/resume tests with S2IDLE, some ISH functional failures were observed because of delay in executing ISH resume handler. Here schedule_work() is used from resume handler to do actual work. schedule_work() uses system_wq, which is a per CPU work queue. Although the queuing is not bound to a CPU, but it prefers local CPU of the caller, unless prohibited. Users of this work queue are not supposed to queue long running work. But in practice, there are scenarios where long running work items are queued on other unbound workqueues, occupying the CPU. As a result, the ISH resume handler may not get a chance to execute in a timely manner. In one scenario, one of the ish_resume_handler() executions was delayed nearly 1 second because another work item on an unbound workqueue occupied the same CPU. This delay causes ISH functionality failures. A similar issue was previously observed where the ISH HID driver timed out while getting the HID descriptor during S4 resume in the recovery kernel, likely caused by the same workqueue contention problem. Create dedicated unbound workqueues for all ISH operations to allow work items to execute on any available CPU, eliminating CPU-specific bottlenecks and improving resume reliability under varying system loads. Also ISH has three different components, a bus driver which implements ISH protocols, a PCI interface layer and HID interface. Use one dedicated work queue for all of them. Signed-off-by: Zhang Lixu <lixu.zhang@intel.com> Signed-off-by: Jiri Kosina <jkosina@suse.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 reStructuredText 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.