From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, John Stultz <john.stultz@linaro.org>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Andy Lutomirski <luto@kernel.org>,
Christophe Leroy <christophe.leroy@c-s.fr>,
Paolo Bonzini <pbonzini@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Sasha Levin <sashal@kernel.org>,
Ralf Baechle <ralf@linux-mips.org>,
Paul Burton <paulburton@kernel.org>,
James Hogan <jhogan@kernel.org>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Marc Zyngier <maz@kernel.org>
Subject: [patch 14/15] lib/vdso: Avoid highres update if clocksource is not VDSO capable
Date: Tue, 14 Jan 2020 19:52:51 +0100 [thread overview]
Message-ID: <20200114185947.996078385@linutronix.de> (raw)
In-Reply-To: 20200114185237.273005683@linutronix.de
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>
---
arch/arm/include/asm/vdso/vsyscall.h | 7 -------
include/asm-generic/vdso/vsyscall.h | 7 -------
kernel/time/vsyscall.c | 14 +++++++-------
3 files changed, 7 insertions(+), 21 deletions(-)
--- a/arch/arm/include/asm/vdso/vsyscall.h
+++ b/arch/arm/include/asm/vdso/vsyscall.h
@@ -22,13 +22,6 @@ struct vdso_data *__arm_get_k_vdso_data(
#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)
{
flush_dcache_page(virt_to_page(vdata));
--- a/include/asm-generic/vdso/vsyscall.h
+++ b/include/asm-generic/vdso/vsyscall.h
@@ -11,13 +11,6 @@ static __always_inline struct vdso_data
}
#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)
--- a/kernel/time/vsyscall.c
+++ b/kernel/time/vsyscall.c
@@ -71,15 +71,15 @@ void update_vsyscall(struct timekeeper *
{
struct vdso_data *vdata = __arch_get_k_vdso_data();
struct vdso_timestamp *vdso_ts;
+ s32 clock_mode;
u64 nsec;
- s32 mode;
/* copy vsyscall data */
vdso_write_begin(vdata);
- mode = tk->tkr_mono.clock->vdso_clock_mode;
- vdata[CS_HRES_COARSE].clock_mode = mode;
- vdata[CS_RAW].clock_mode = mode;
+ clock_mode = tk->tkr_mono.clock->vdso_clock_mode;
+ vdata[CS_HRES_COARSE].clock_mode = clock_mode;
+ vdata[CS_RAW].clock_mode = clock_mode;
/* CLOCK_REALTIME also required for time() */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME];
@@ -105,10 +105,10 @@ void update_vsyscall(struct timekeeper *
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);
next prev parent reply other threads:[~2020-01-14 19:49 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 18:52 [patch 00/15] lib/vdso: Bugfix and consolidation Thomas Gleixner
2020-01-14 18:52 ` [patch 01/15] lib/vdso: Make __arch_update_vdso_data() logic understandable Thomas Gleixner
2020-01-17 15:07 ` [tip: timers/urgent] " tip-bot2 for Thomas Gleixner
2020-01-14 18:52 ` [patch 02/15] lib/vdso: Update coarse timekeeper unconditionally Thomas Gleixner
2020-01-17 15:07 ` [tip: timers/urgent] " tip-bot2 for Thomas Gleixner
2020-01-14 18:52 ` [patch 03/15] ARM: vdso: Remove unused function Thomas Gleixner
2020-01-14 18:52 ` [patch 04/15] lib/vdso: Allow the high resolution parts to be compiled out Thomas Gleixner
2020-01-14 18:52 ` [patch 05/15] ARM: vdso: Compile high resolution parts conditionally Thomas Gleixner
2020-01-14 18:52 ` [patch 06/15] MIPS: " Thomas Gleixner
2020-01-14 18:52 ` [patch 07/15] clocksource: Cleanup struct clocksource and documentation Thomas Gleixner
2020-01-14 18:52 ` [patch 08/15] x86/vdso: Move VDSO clocksource state tracking to callback Thomas Gleixner
2020-01-15 5:56 ` Jürgen Groß
2020-01-20 1:42 ` Michael Kelley
2020-01-14 18:52 ` [patch 09/15] clocksource: Add common vdso clock mode storage Thomas Gleixner
2020-01-15 5:50 ` Christophe Leroy
2020-01-15 7:59 ` Thomas Gleixner
2020-01-14 18:52 ` [patch 10/15] x86/vdso: Use generic VDSO " Thomas Gleixner
2020-01-15 5:57 ` Jürgen Groß
2020-01-14 18:52 ` [patch 11/15] mips: vdso: " Thomas Gleixner
2020-01-14 18:52 ` [patch 12/15] ARM/arm64: vdso: Use common vdso " Thomas Gleixner
2020-01-14 18:52 ` [patch 13/15] lib/vdso: Cleanup clock mode storage leftovers Thomas Gleixner
2020-01-14 18:52 ` Thomas Gleixner [this message]
2020-01-15 5:54 ` [patch 14/15] lib/vdso: Avoid highres update if clocksource is not VDSO capable Christophe Leroy
2020-01-14 18:52 ` [patch 15/15] lib/vdso: Move VCLOCK_TIMENS to vdso_clock_modes Thomas Gleixner
2020-01-15 5:58 ` Christophe Leroy
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