175cc3ab28
A timer deletion only dequeues the timer but it doesn't shutdown
the related costly process wide cputimer counter and the tick dependency.
The following code snippet keeps this overhead around for one week after
the timer deletion:
void trigger_process_counter(void)
{
timer_t id;
struct itimerspec val = { };
val.it_value.tv_sec = 604800;
timer_create(CLOCK_PROCESS_CPUTIME_ID, NULL, &id);
timer_settime(id, 0, &val, NULL);
timer_delete(id);
}
Make sure the next target's tick recalculates the nearest expiration and
clears the process wide counter and tick dependency if necessary.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210726125513.271824-3-frederic@kernel.org
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.