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Message-ID: <8673fa43-97f8-2ad2-d784-f22b54fd7a2e@c-s.fr>
Date: Wed, 15 Jan 2020 06:58:31 +0100
From: Christophe Leroy <christophe.leroy@....fr>
To: Thomas Gleixner <tglx@...utronix.de>,
LKML <linux-kernel@...r.kernel.org>
Cc: x86@...nel.org, John Stultz <john.stultz@...aro.org>,
Vincenzo Frascino <vincenzo.frascino@....com>,
Andy Lutomirski <luto@...nel.org>,
Paolo Bonzini <pbonzini@...hat.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Juergen Gross <jgross@...e.com>,
Haiyang Zhang <haiyangz@...rosoft.com>,
Sasha Levin <sashal@...nel.org>,
Ralf Baechle <ralf@...ux-mips.org>,
Paul Burton <paulburton@...nel.org>,
James Hogan <jhogan@...nel.org>,
Russell King <linux@...linux.org.uk>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Marc Zyngier <maz@...nel.org>
Subject: Re: [patch 15/15] lib/vdso: Move VCLOCK_TIMENS to vdso_clock_modes
Le 14/01/2020 à 19:52, Thomas Gleixner a écrit :
> Move the time namespace indicator clock mode to the other ones for
> consistency sake.
>
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> ---
> include/linux/clocksource.h | 3 +++
> include/vdso/datapage.h | 2 --
> kernel/time/namespace.c | 7 ++++---
> lib/vdso/gettimeofday.c | 18 ++++++++++--------
> 4 files changed, 17 insertions(+), 13 deletions(-)
>
> --- a/include/linux/clocksource.h
> +++ b/include/linux/clocksource.h
> @@ -34,6 +34,9 @@ enum vdso_clock_mode {
> VDSO_ARCH_CLOCKMODES,
> #endif
> VDSO_CLOCKMODE_MAX,
> +
> + /* Indicator for time namespace VDSO */ > + VDSO_CLOCKMODE_TIMENS = INT_MAX
Can we shorten the names a bit in order to avoid code line splits ?
WOuldn't something like VDSO_CMODE_XXX be explicit enough ?
Christophe
> };
>
> /**
> --- a/include/vdso/datapage.h
> +++ b/include/vdso/datapage.h
> @@ -21,8 +21,6 @@
> #define CS_RAW 1
> #define CS_BASES (CS_RAW + 1)
>
> -#define VCLOCK_TIMENS UINT_MAX
> -
> /**
> * struct vdso_timestamp - basetime per clock_id
> * @sec: seconds
> --- a/kernel/time/namespace.c
> +++ b/kernel/time/namespace.c
> @@ -8,6 +8,7 @@
> #include <linux/user_namespace.h>
> #include <linux/sched/signal.h>
> #include <linux/sched/task.h>
> +#include <linux/clocksource.h>
> #include <linux/seq_file.h>
> #include <linux/proc_ns.h>
> #include <linux/export.h>
> @@ -172,8 +173,8 @@ static struct timens_offset offset_from_
> * for vdso_data->clock_mode is a non-issue. The task is spin waiting for the
> * update to finish and for 'seq' to become even anyway.
> *
> - * Timens page has vdso_data->clock_mode set to VCLOCK_TIMENS which enforces
> - * the time namespace handling path.
> + * Timens page has vdso_data->clock_mode set to VDSO_CLOCKMODE_TIMENS which
> + * enforces the time namespace handling path.
> */
> static void timens_setup_vdso_data(struct vdso_data *vdata,
> struct time_namespace *ns)
> @@ -183,7 +184,7 @@ static void timens_setup_vdso_data(struc
> struct timens_offset boottime = offset_from_ts(ns->offsets.boottime);
>
> vdata->seq = 1;
> - vdata->clock_mode = VCLOCK_TIMENS;
> + vdata->clock_mode = VDSO_CLOCKMODE_TIMENS;
> offset[CLOCK_MONOTONIC] = monotonic;
> offset[CLOCK_MONOTONIC_RAW] = monotonic;
> offset[CLOCK_MONOTONIC_COARSE] = monotonic;
> --- a/lib/vdso/gettimeofday.c
> +++ b/lib/vdso/gettimeofday.c
> @@ -116,10 +116,10 @@ static __always_inline int do_hres(const
>
> do {
> /*
> - * Open coded to handle VCLOCK_TIMENS. Time namespace
> + * Open coded to handle VDSO_CLOCKMODE_TIMENS. Time namespace
> * enabled tasks have a special VVAR page installed which
> * has vd->seq set to 1 and vd->clock_mode set to
> - * VCLOCK_TIMENS. For non time namespace affected tasks
> + * VDSO_CLOCKMODE_TIMENS. For non time namespace affected tasks
> * this does not affect performance because if vd->seq is
> * odd, i.e. a concurrent update is in progress the extra
> * check for vd->clock_mode is just a few extra
> @@ -128,7 +128,7 @@ static __always_inline int do_hres(const
> */
> while (unlikely((seq = READ_ONCE(vd->seq)) & 1)) {
> if (IS_ENABLED(CONFIG_TIME_NS) &&
> - vd->clock_mode == VCLOCK_TIMENS)
> + vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
> return do_hres_timens(vd, clk, ts);
> cpu_relax();
> }
> @@ -200,12 +200,12 @@ static __always_inline int do_coarse(con
>
> do {
> /*
> - * Open coded to handle VCLOCK_TIMENS. See comment in
> + * Open coded to handle VDSO_CLOCK_TIMENS. See comment in
> * do_hres().
> */
> while ((seq = READ_ONCE(vd->seq)) & 1) {
> if (IS_ENABLED(CONFIG_TIME_NS) &&
> - vd->clock_mode == VCLOCK_TIMENS)
> + vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
> return do_coarse_timens(vd, clk, ts);
> cpu_relax();
> }
> @@ -292,7 +292,7 @@ static __maybe_unused int
>
> if (unlikely(tz != NULL)) {
> if (IS_ENABLED(CONFIG_TIME_NS) &&
> - vd->clock_mode == VCLOCK_TIMENS)
> + vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
> vd = __arch_get_timens_vdso_data();
>
> tz->tz_minuteswest = vd[CS_HRES_COARSE].tz_minuteswest;
> @@ -308,7 +308,8 @@ static __maybe_unused __kernel_old_time_
> const struct vdso_data *vd = __arch_get_vdso_data();
> __kernel_old_time_t t;
>
> - if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VCLOCK_TIMENS)
> + if (IS_ENABLED(CONFIG_TIME_NS) &&
> + vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
> vd = __arch_get_timens_vdso_data();
>
> t = READ_ONCE(vd[CS_HRES_COARSE].basetime[CLOCK_REALTIME].sec);
> @@ -333,7 +334,8 @@ int __cvdso_clock_getres_common(clockid_
> if (unlikely((u32) clock >= MAX_CLOCKS))
> return -1;
>
> - if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VCLOCK_TIMENS)
> + if (IS_ENABLED(CONFIG_TIME_NS) &&
> + vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
> vd = __arch_get_timens_vdso_data();
>
> hrtimer_res = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res);
>
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