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Commit f24ade3a authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86, sched_clock(): mark variables read-mostly 



Impact: micro-optimization

There's a number of variables in the sched_clock() path that are
in .data/.bss - but not marked __read_mostly. This creates the
danger of accidental false cacheline sharing with some other,
write-often variable.

So mark them __read_mostly.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 8325d9c0

arch/x86/kernel/tsc.c

+5 −4
Original line number Diff line number Diff line
@@ -17,20 +17,21 @@ 
#include <asm/delay.h>

#include <asm/hypervisor.h>



unsigned int cpu_khz;           /* TSC clocks / usec, not used here */

unsigned int __read_mostly cpu_khz;	/* TSC clocks / usec, not used here */

EXPORT_SYMBOL(cpu_khz);

unsigned int tsc_khz;



unsigned int __read_mostly tsc_khz;

EXPORT_SYMBOL(tsc_khz);



/*

 * TSC can be unstable due to cpufreq or due to unsynced TSCs

 */

static int tsc_unstable;

static int __read_mostly tsc_unstable;



/* native_sched_clock() is called before tsc_init(), so

   we must start with the TSC soft disabled to prevent

   erroneous rdtsc usage on !cpu_has_tsc processors */

static int tsc_disabled = -1;

static int __read_mostly tsc_disabled = -1;



static int tsc_clocksource_reliable;

/*