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From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org, mathias.nyman@linux.intel.com,
	gregkh@linuxfoundation.org
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
	rdunlap@infradead.org, linux-usb@vger.kernel.org
Subject: [PATCH 1/3] x86/tsc: Be consistent about use_tsc_delay()
Date: Fri, 04 Mar 2022 16:19:54 +0100	[thread overview]
Message-ID: <20220304152135.914397165@infradead.org> (raw)
In-Reply-To: 20220304151953.830111479@infradead.org

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) <peterz@infradead.org>
---
 arch/x86/kernel/tsc.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- 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();
 



  reply	other threads:[~2022-03-04 15:22 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-04 15:19 [PATCH 0/3] x86: Make XDBC work Peter Zijlstra
2022-03-04 15:19 ` Peter Zijlstra [this message]
2022-03-04 15:19 ` [PATCH 2/3] usb: early: xhci-dbc: Remove duplicate keep parsing Peter Zijlstra
2022-03-04 15:19 ` [PATCH 3/3] usb: early: xhci-dbc: Fix xdbc number parsing Peter Zijlstra
2022-03-08 10:01   ` Mathias Nyman
2022-04-20  3:14 ` [PATCH 0/3] x86: Make XDBC work Randy Dunlap

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