linux-kernel - [RFC PATCH v3 03/12] lib: vdso: mark __cvdso_clock

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Message-Id: <9f0f72424a8f0260470ecd50d5803db685285ba5.1578934751.git.christophe.leroy@c-s.fr>
Date:   Mon, 13 Jan 2020 17:08:41 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, arnd@...db.de,
        tglx@...utronix.de, vincenzo.frascino@....com, luto@...nel.org
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-arm-kernel@...ts.infradead.org, linux-mips@...r.kernel.org,
        x86@...nel.org
Subject: [RFC PATCH v3 03/12] lib: vdso: mark __cvdso_clock_getres() as static

When __cvdso_clock_getres() became __cvdso_clock_getres_common()
and a new __cvdso_clock_getres() was added, static qualifier was
forgotten.

This change allows the compiler to inline __cvdso_clock_getres_common(),
and the performance improvement is significant:

Before:
clock-getres-realtime-coarse:    vdso: 984 nsec/call
clock-getres-realtime:    vdso: 922 nsec/call
clock-getres-monotonic-raw:    vdso: 968 nsec/call

After:
clock-getres-realtime-coarse:    vdso: 753 nsec/call
clock-getres-realtime:    vdso: 691 nsec/call
clock-getres-monotonic-raw:    vdso: 737 nsec/call

Fixes: 502a590a170b ("lib/vdso: Move fallback invocation to the callers")
Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 lib/vdso/gettimeofday.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index 9ecfd3b547ba..42bd8ab955fa 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -221,6 +221,7 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res)
 	return 0;
 }
 
+static __maybe_unused
 int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
 {
 	int ret = __cvdso_clock_getres_common(clock, res);
-- 
2.13.3