mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-19 00:57:49 +07:00
023e9deb51
guest_enter() doesn't call context_tracking_enabled() before calling context_tracking_enabled_this_cpu(). Therefore the guest code doesn't benefit from the static key on the fast path. Just make sure that context_tracking_enabled_*cpu() functions check the static key by themselves to propagate the optimization. Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J . Wysocki <rjw@rjwysocki.net> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Wanpeng Li <wanpengli@tencent.com> Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com> Link: https://lkml.kernel.org/r/20191016025700.31277-11-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
56 lines
1.6 KiB
C
56 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_CONTEXT_TRACKING_STATE_H
|
|
#define _LINUX_CONTEXT_TRACKING_STATE_H
|
|
|
|
#include <linux/percpu.h>
|
|
#include <linux/static_key.h>
|
|
|
|
struct context_tracking {
|
|
/*
|
|
* When active is false, probes are unset in order
|
|
* to minimize overhead: TIF flags are cleared
|
|
* and calls to user_enter/exit are ignored. This
|
|
* may be further optimized using static keys.
|
|
*/
|
|
bool active;
|
|
int recursion;
|
|
enum ctx_state {
|
|
CONTEXT_DISABLED = -1, /* returned by ct_state() if unknown */
|
|
CONTEXT_KERNEL = 0,
|
|
CONTEXT_USER,
|
|
CONTEXT_GUEST,
|
|
} state;
|
|
};
|
|
|
|
#ifdef CONFIG_CONTEXT_TRACKING
|
|
extern struct static_key_false context_tracking_key;
|
|
DECLARE_PER_CPU(struct context_tracking, context_tracking);
|
|
|
|
static inline bool context_tracking_enabled(void)
|
|
{
|
|
return static_branch_unlikely(&context_tracking_key);
|
|
}
|
|
|
|
static inline bool context_tracking_enabled_cpu(int cpu)
|
|
{
|
|
return context_tracking_enabled() && per_cpu(context_tracking.active, cpu);
|
|
}
|
|
|
|
static inline bool context_tracking_enabled_this_cpu(void)
|
|
{
|
|
return context_tracking_enabled() && __this_cpu_read(context_tracking.active);
|
|
}
|
|
|
|
static inline bool context_tracking_in_user(void)
|
|
{
|
|
return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
|
|
}
|
|
#else
|
|
static inline bool context_tracking_in_user(void) { return false; }
|
|
static inline bool context_tracking_enabled(void) { return false; }
|
|
static inline bool context_tracking_enabled_cpu(int cpu) { return false; }
|
|
static inline bool context_tracking_enabled_this_cpu(void) { return false; }
|
|
#endif /* CONFIG_CONTEXT_TRACKING */
|
|
|
|
#endif
|