mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-03 15:47:36 +00:00
fafe870f31
TIF_NOHZ is used by context_tracking to force syscall slow-path on every task in order to track userspace roundtrips. As such, it must be set on all running tasks. It's currently explicitly inherited through context switches. There is no need to do it in this fast-path though. The flag could simply be set once for all on all tasks, whether they are running or not. Lets do this by setting the flag for the init task on early boot, and let it propagate through fork inheritance. While at it, mark context_tracking_cpu_set() as init code, we only need it at early boot time. Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Dave Jones <davej@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1430928266-24888-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
110 lines
2.4 KiB
C
110 lines
2.4 KiB
C
#ifndef _LINUX_CONTEXT_TRACKING_H
|
|
#define _LINUX_CONTEXT_TRACKING_H
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/vtime.h>
|
|
#include <linux/context_tracking_state.h>
|
|
#include <asm/ptrace.h>
|
|
|
|
|
|
#ifdef CONFIG_CONTEXT_TRACKING
|
|
extern void context_tracking_cpu_set(int cpu);
|
|
|
|
extern void context_tracking_enter(enum ctx_state state);
|
|
extern void context_tracking_exit(enum ctx_state state);
|
|
extern void context_tracking_user_enter(void);
|
|
extern void context_tracking_user_exit(void);
|
|
|
|
static inline void user_enter(void)
|
|
{
|
|
if (context_tracking_is_enabled())
|
|
context_tracking_user_enter();
|
|
|
|
}
|
|
static inline void user_exit(void)
|
|
{
|
|
if (context_tracking_is_enabled())
|
|
context_tracking_user_exit();
|
|
}
|
|
|
|
static inline enum ctx_state exception_enter(void)
|
|
{
|
|
enum ctx_state prev_ctx;
|
|
|
|
if (!context_tracking_is_enabled())
|
|
return 0;
|
|
|
|
prev_ctx = this_cpu_read(context_tracking.state);
|
|
if (prev_ctx != CONTEXT_KERNEL)
|
|
context_tracking_exit(prev_ctx);
|
|
|
|
return prev_ctx;
|
|
}
|
|
|
|
static inline void exception_exit(enum ctx_state prev_ctx)
|
|
{
|
|
if (context_tracking_is_enabled()) {
|
|
if (prev_ctx != CONTEXT_KERNEL)
|
|
context_tracking_enter(prev_ctx);
|
|
}
|
|
}
|
|
|
|
#else
|
|
static inline void user_enter(void) { }
|
|
static inline void user_exit(void) { }
|
|
static inline enum ctx_state exception_enter(void) { return 0; }
|
|
static inline void exception_exit(enum ctx_state prev_ctx) { }
|
|
#endif /* !CONFIG_CONTEXT_TRACKING */
|
|
|
|
|
|
#ifdef CONFIG_CONTEXT_TRACKING_FORCE
|
|
extern void context_tracking_init(void);
|
|
#else
|
|
static inline void context_tracking_init(void) { }
|
|
#endif /* CONFIG_CONTEXT_TRACKING_FORCE */
|
|
|
|
|
|
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
|
|
static inline void guest_enter(void)
|
|
{
|
|
if (vtime_accounting_enabled())
|
|
vtime_guest_enter(current);
|
|
else
|
|
current->flags |= PF_VCPU;
|
|
|
|
if (context_tracking_is_enabled())
|
|
context_tracking_enter(CONTEXT_GUEST);
|
|
}
|
|
|
|
static inline void guest_exit(void)
|
|
{
|
|
if (context_tracking_is_enabled())
|
|
context_tracking_exit(CONTEXT_GUEST);
|
|
|
|
if (vtime_accounting_enabled())
|
|
vtime_guest_exit(current);
|
|
else
|
|
current->flags &= ~PF_VCPU;
|
|
}
|
|
|
|
#else
|
|
static inline void guest_enter(void)
|
|
{
|
|
/*
|
|
* This is running in ioctl context so its safe
|
|
* to assume that it's the stime pending cputime
|
|
* to flush.
|
|
*/
|
|
vtime_account_system(current);
|
|
current->flags |= PF_VCPU;
|
|
}
|
|
|
|
static inline void guest_exit(void)
|
|
{
|
|
/* Flush the guest cputime we spent on the guest */
|
|
vtime_account_system(current);
|
|
current->flags &= ~PF_VCPU;
|
|
}
|
|
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
|
|
|
|
#endif
|