From 50628893711fd5dc3fdbe8cb95e685f2fe75b662 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= Date: Mon, 21 Sep 2026 11:45:58 +0200 Subject: [PATCH] vdso/gettimeofday: Avoid runtime conditional in do_hres_timens() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently the derivation of the non-namespaced clock from its namespaced sibling uses a runtime conditional. This conditional mirrors the VDSO_RAW check in __cvdso_clock_gettime_common(), in a non-obvious way. Replace the runtime conditional with unconditional pointer arithmetic, which removes the duplication of logic and also is smaller and faster. Also get rid of the weird double use of the 'vc' variable, pointing both to the array of clocks and later to one specific one. This saves 31 bytes of .text on x86_64. Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20260921-vdso-timens-conditional-v1-1-eac173f8bd92@weissschuh.net --- lib/vdso/gettimeofday.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index 728fed1ae52f..c0e81996532d 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -139,22 +139,23 @@ const struct vdso_time_data *vdso_timens_data(const struct vdso_time_data *vd) return (void *)vd + PAGE_SIZE; } +static __always_inline +const struct vdso_clock *vdso_timens_clock(const struct vdso_clock *vc) +{ + return (void *)vc + PAGE_SIZE; +} + static __always_inline bool do_hres_timens(const struct vdso_time_data *vdns, const struct vdso_clock *vcns, clockid_t clk, struct __kernel_timespec *ts) { const struct vdso_time_data *vd = vdso_timens_data(vdns); + const struct vdso_clock *vc = vdso_timens_clock(vcns); const struct timens_offset *offs = &vcns->offset[clk]; - const struct vdso_clock *vc = vd->clock_data; u32 seq; s64 sec; u64 ns; - if (clk != CLOCK_MONOTONIC_RAW) - vc = &vc[CS_HRES_COARSE]; - else - vc = &vc[CS_RAW]; - do { seq = vdso_read_begin(vc);