[patch V2 06/11] x86/vdso: Collapse high resolution functions

From: Thomas Gleixner
Date: Mon Sep 17 2018 - 09:09:20 EST


do_realtime() and do_monotonic() are now the same except for the storage
array index. Hand the index in as an argument and collapse the functions.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/entry/vdso/vclock_gettime.c | 35 +++++++----------------------------
1 file changed, 7 insertions(+), 28 deletions(-)

--- a/arch/x86/entry/vdso/vclock_gettime.c
+++ b/arch/x86/entry/vdso/vclock_gettime.c
@@ -203,35 +203,12 @@ notrace static inline u64 vgetsns(int *m
return v * gtod->mult;
}

-/* Code size doesn't matter (vdso is 4k anyway) and this is faster. */
-notrace static int __always_inline do_realtime(struct timespec *ts)
+notrace static int do_hres(clockid_t clk, struct timespec *ts)
{
- struct vgtod_ts *base = &gtod->basetime[CLOCK_REALTIME];
+ struct vgtod_ts *base = &gtod->basetime[clk];
unsigned int seq;
- u64 ns;
int mode;
-
- do {
- seq = gtod_read_begin(gtod);
- mode = gtod->vclock_mode;
- ts->tv_sec = base->sec;
- ns = base->nsec;
- ns += vgetsns(&mode);
- ns >>= gtod->shift;
- } while (unlikely(gtod_read_retry(gtod, seq)));
-
- ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
- ts->tv_nsec = ns;
-
- return mode;
-}
-
-notrace static int __always_inline do_monotonic(struct timespec *ts)
-{
- struct vgtod_ts *base = &gtod->basetime[CLOCK_MONOTONIC];
- unsigned int seq;
u64 ns;
- int mode;

do {
seq = gtod_read_begin(gtod);
@@ -276,11 +253,11 @@ notrace int __vdso_clock_gettime(clockid
{
switch (clock) {
case CLOCK_REALTIME:
- if (do_realtime(ts) == VCLOCK_NONE)
+ if (do_hres(CLOCK_REALTIME, ts) == VCLOCK_NONE)
goto fallback;
break;
case CLOCK_MONOTONIC:
- if (do_monotonic(ts) == VCLOCK_NONE)
+ if (do_hres(CLOCK_MONOTONIC, ts) == VCLOCK_NONE)
goto fallback;
break;
case CLOCK_REALTIME_COARSE:
@@ -303,7 +280,9 @@ int clock_gettime(clockid_t, struct time
notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
{
if (likely(tv != NULL)) {
- if (unlikely(do_realtime((struct timespec *)tv) == VCLOCK_NONE))
+ struct timespec *ts = (struct timespec *) tv;
+
+ if (unlikely(do_hres(CLOCK_REALTIME, ts) == VCLOCK_NONE))
return vdso_fallback_gtod(tv, tz);
tv->tv_usec /= 1000;
}