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authorPavel Tatashin <pasha.tatashin@oracle.com>2018-07-19 23:55:40 +0300
committerThomas Gleixner <tglx@linutronix.de>2018-07-20 01:02:42 +0300
commit4763f03d3d186ce8a1125844790152d76804ad60 (patch)
treee9167caff8aa0890284c184ebc3952ec8329d6c9 /arch/x86/kernel/tsc.c
parente2a9ca29b5edc89da2fddeae30e1070b272395c5 (diff)
downloadlinux-4763f03d3d186ce8a1125844790152d76804ad60.tar.xz
x86/tsc: Use TSC as sched clock early
All prerequesites for enabling TSC as sched clock early in the boot process are available now: - Early attempt of TSC calibration - Early availablity of static branch patching If TSC frequency can be established in the early calibration, enable the static key which switches sched clock to use TSC. [ tglx: Massaged changelog ] Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: steven.sistare@oracle.com Cc: daniel.m.jordan@oracle.com Cc: linux@armlinux.org.uk Cc: schwidefsky@de.ibm.com Cc: heiko.carstens@de.ibm.com Cc: john.stultz@linaro.org Cc: sboyd@codeaurora.org Cc: hpa@zytor.com Cc: douly.fnst@cn.fujitsu.com Cc: peterz@infradead.org Cc: prarit@redhat.com Cc: feng.tang@intel.com Cc: pmladek@suse.com Cc: gnomes@lxorguk.ukuu.org.uk Cc: linux-s390@vger.kernel.org Cc: boris.ostrovsky@oracle.com Cc: jgross@suse.com Cc: pbonzini@redhat.com Link: https://lkml.kernel.org/r/20180719205545.16512-22-pasha.tatashin@oracle.com
Diffstat (limited to 'arch/x86/kernel/tsc.c')
-rw-r--r--arch/x86/kernel/tsc.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 7ea0718a4c75..9277ae9b68b3 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1408,6 +1408,7 @@ void __init tsc_early_init(void)
/* Sanitize TSC ADJUST before cyc2ns gets initialized */
tsc_store_and_check_tsc_adjust(true);
cyc2ns_init_boot_cpu();
+ static_branch_enable(&__use_tsc);
}
void __init tsc_init(void)