sched: Provide cant_migrate()

Some code pathes rely on preempt_disable() to prevent migration on a non RT
enabled kernel. These preempt_disable/enable() pairs are substituted by
migrate_disable/enable() pairs or other forms of RT specific protection. On
RT these protections prevent migration but not preemption. Obviously a
cant_sleep() check in such a section will trigger on RT because preemption
is not disabled.

Provide a cant_migrate() macro which maps to cant_sleep() on a non RT
kernel and an empty placeholder for RT for now. The placeholder will be
changed to a proper debug check along with the RT specific migration
protection mechanism.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200214161503.070487511@linutronix.de
This commit is contained in:
Thomas Gleixner 2020-02-14 14:39:19 +01:00
parent 66630058e5
commit 4e139c7711

View File

@ -257,6 +257,13 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset);
#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
#ifndef CONFIG_PREEMPT_RT
# define cant_migrate() cant_sleep()
#else
/* Placeholder for now */
# define cant_migrate() do { } while (0)
#endif
/**
* abs - return absolute value of an argument
* @x: the value. If it is unsigned type, it is converted to signed type first.