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lib/vdso: Avoid highres update if clocksource is not VDSO capable

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If the current clocksource is not VDSO capable there is no point in
updating the high resolution parts of the VDSO data.

Replace the architecture specific check with a check for a VDSO capable
clocksource and skip the update if there is none.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lkml.kernel.org/r/20200207124403.563379423@linutronix.de
This commit is contained in:
Thomas Gleixner 2020-02-07 13:39:00 +01:00
parent f86fd32db7
commit c7a18100bd
3 changed files with 3 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/arm/include/asm/vdso/vsyscall.h
View File

@ -21,13 +21,6 @@ struct vdso_data *__arm_get_k_vdso_data(void)
}
#define __arch_get_k_vdso_data __arm_get_k_vdso_data
static __always_inline
bool __arm_update_vdso_data(void)
{
return cntvct_ok;
}
#define __arch_update_vdso_data __arm_update_vdso_data
static __always_inline
void __arm_sync_vdso_data(struct vdso_data *vdata)
{

7
include/asm-generic/vdso/vsyscall.h
View File

@ -11,13 +11,6 @@ static __always_inline struct vdso_data *__arch_get_k_vdso_data(void)
}
#endif /* __arch_get_k_vdso_data */
#ifndef __arch_update_vdso_data
static __always_inline bool __arch_update_vdso_data(void)
{
return true;
}
#endif /* __arch_update_vdso_data */
#ifndef __arch_update_vsyscall
static __always_inline void __arch_update_vsyscall(struct vdso_data *vdata,
struct timekeeper *tk)

6
kernel/time/vsyscall.c
View File

@ -105,10 +105,10 @@ void update_vsyscall(struct timekeeper *tk)
WRITE_ONCE(vdata[CS_HRES_COARSE].hrtimer_res, hrtimer_resolution);
/*
* Architectures can opt out of updating the high resolution part
* of the VDSO.
* If the current clocksource is not VDSO capable, then spare the
* update of the high reolution parts.
*/
if (__arch_update_vdso_data())
if (clock_mode != VDSO_CLOCKMODE_NONE)
update_vdso_data(vdata, tk);
__arch_update_vsyscall(vdata, tk);