[1/3] x86/tsc: Be consistent about use_tsc_delay()

Commit Message

Peter Zijlstra March 4, 2022, 3:19 p.m. UTC

Currently loops_per_jiffy is set in tsc_early_init(), but then don't
switch to delay_tsc, with the result that delay_loop is used with
loops_per_jiffy set for delay_tsc.

Then in (late) tsc_init() lpj_fine is set (which is mostly unused) and
after which use_tsc_delay() is finally called.

Move both loops_per_jiffy and use_tsc_delay() into
tsc_enable_sched_clock() which is called the moment tsc_khz is
determined, be it early or late. Keeping the lot consistent.

Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
---
 arch/x86/kernel/tsc.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Patch

--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1487,6 +1487,9 @@  static unsigned long __init get_loops_pe
 
 static void __init tsc_enable_sched_clock(void)
 {
+	loops_per_jiffy = get_loops_per_jiffy();
+	use_tsc_delay();
+
 	/* Sanitize TSC ADJUST before cyc2ns gets initialized */
 	tsc_store_and_check_tsc_adjust(true);
 	cyc2ns_init_boot_cpu();
@@ -1502,8 +1505,6 @@  void __init tsc_early_init(void)
 		return;
 	if (!determine_cpu_tsc_frequencies(true))
 		return;
-	loops_per_jiffy = get_loops_per_jiffy();
-
 	tsc_enable_sched_clock();
 }
 
@@ -1537,7 +1538,6 @@  void __init tsc_init(void)
 		enable_sched_clock_irqtime();
 
 	lpj_fine = get_loops_per_jiffy();
-	use_tsc_delay();
 
 	check_system_tsc_reliable();