From: Christophe Leroy <christophe.leroy@c-s.fr> To: Benjamin Herrenschmidt <benh@kernel.crashing.org>, Paul Mackerras <paulus@samba.org>, Michael Ellerman <mpe@ellerman.id.au>, nathanl@linux.ibm.com, arnd@arndb.de, tglx@linutronix.de, vincenzo.frascino@arm.com, luto@kernel.org Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, x86@kernel.org Subject: [RFC PATCH v4 03/11] lib: vdso: only read hrtimer_res when needed in __cvdso_clock_getres() Date: Thu, 16 Jan 2020 17:58:27 +0000 (UTC) Message-ID: <7ac2f0d21652f95e2bbdfa6bd514ae6c7caf53ab.1579196675.git.christophe.leroy@c-s.fr> (raw) In-Reply-To: <cover.1579196675.git.christophe.leroy@c-s.fr> Only perform READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res) for HRES and RAW clocks. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- lib/vdso/gettimeofday.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index 9563be3cb5fa..8b3084d9a3ec 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -326,7 +326,6 @@ static __maybe_unused int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) { const struct vdso_data *vd = __arch_get_vdso_data(); - u64 hrtimer_res; u32 msk; u64 ns; @@ -338,7 +337,6 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) vd->clock_mode == VDSO_CLOCKMODE_TIMENS) vd = __arch_get_timens_vdso_data(); - hrtimer_res = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res); /* * Convert the clockid to a bitmask and use it to check which * clocks are handled in the VDSO directly. @@ -348,7 +346,7 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) /* * Preserves the behaviour of posix_get_hrtimer_res(). */ - ns = hrtimer_res; + ns = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res); } else if (msk & VDSO_COARSE) { /* * Preserves the behaviour of posix_get_coarse_res(). -- 2.13.3
next prev parent reply index Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-16 17:58 [RFC PATCH v4 00/11] powerpc: switch VDSO to C implementation Christophe Leroy 2020-01-16 17:58 ` [RFC PATCH v4 01/11] powerpc/64: Don't provide time functions in compat VDSO32 Christophe Leroy 2020-01-16 17:58 ` [RFC PATCH v4 02/11] powerpc/vdso: Switch VDSO to generic C implementation Christophe Leroy 2020-01-16 17:58 ` Christophe Leroy [this message] 2020-01-16 17:58 ` [RFC PATCH v4 04/11] powerpc/vdso: simplify __get_datapage() Christophe Leroy 2020-01-16 17:58 ` [RFC PATCH v4 05/11] lib: vdso: allow arches to provide vdso data pointer Christophe Leroy 2020-01-16 17:58 ` [RFC PATCH v4 06/11] powerpc/vdso: provide inline alternative to __get_datapage() Christophe Leroy 2020-01-16 17:58 ` [RFC PATCH v4 07/11] powerpc/vdso: provide vdso data pointer from the ASM caller Christophe Leroy 2020-01-16 17:58 ` [RFC PATCH v4 08/11] lib: vdso: allow fixed clock mode Christophe Leroy 2020-01-16 20:13 ` Thomas Gleixner 2020-01-16 20:19 ` Andy Lutomirski 2020-01-16 21:07 ` Thomas Gleixner 2020-01-16 17:58 ` [RFC PATCH v4 09/11] powerpc/vdso: override __arch_vdso_capable() Christophe Leroy 2020-01-16 17:58 ` [RFC PATCH v4 10/11] lib: vdso: Allow arches to override the ns shift operation Christophe Leroy 2020-01-16 19:47 ` Andy Lutomirski 2020-01-16 19:57 ` Thomas Gleixner 2020-01-16 20:20 ` Andy Lutomirski 2020-01-29 7:14 ` Thomas Gleixner 2020-01-29 7:26 ` Christophe Leroy 2020-01-16 17:58 ` [RFC PATCH v4 11/11] powerpc/32: provide vdso_shift_ns() Christophe Leroy 2020-01-17 8:58 ` [RFC PATCH v4 00/11] powerpc: switch VDSO to C implementation Segher Boessenkool 2020-01-17 9:26 ` Christophe Leroy 2020-01-20 14:56 ` Christophe Leroy 2020-01-20 15:19 ` Segher Boessenkool 2020-01-20 17:08 ` Christophe Leroy 2020-01-20 17:27 ` Segher Boessenkool
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