Files
Peter Zijlstra 676e8cf70c sched,livepatch: Untangle cond_resched() and live-patching
With the goal of deprecating / removing VOLUNTARY preempt, live-patch
needs to stop relying on cond_resched() to make forward progress.

Instead, rely on schedule() with TASK_FREEZABLE set. Just like
live-patching, the freezer needs to be able to stop tasks in a safe /
known state.

[bigeasy: use likely() in __klp_sched_try_switch() and update comments]

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Tested-by: Petr Mladek <[email protected]>
Tested-by: Miroslav Benes <[email protected]>
Acked-by: Miroslav Benes <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
2025-05-14 13:16:24 +02:00

26 lines
670 B
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
#ifndef _LINUX_LIVEPATCH_SCHED_H_
#define _LINUX_LIVEPATCH_SCHED_H_
#include <linux/jump_label.h>
#include <linux/sched.h>
#ifdef CONFIG_LIVEPATCH
void __klp_sched_try_switch(void);
DECLARE_STATIC_KEY_FALSE(klp_sched_try_switch_key);
static __always_inline void klp_sched_try_switch(struct task_struct *curr)
{
if (static_branch_unlikely(&klp_sched_try_switch_key) &&
READ_ONCE(curr->__state) & TASK_FREEZABLE)
__klp_sched_try_switch();
}
#else /* !CONFIG_LIVEPATCH */
static inline void klp_sched_try_switch(struct task_struct *curr) {}
#endif /* CONFIG_LIVEPATCH */
#endif /* _LINUX_LIVEPATCH_SCHED_H_ */