x86: udelay: Use this_cpu_read to avoid address calculation

Christoph Lameter · htejun · commit 357089fca91f · 2011-01-04T06:08:55.000+01:00
The code will use a segment prefix instead of doing the lookup and
calculation.

Signed-off-by: Christoph Lameter &lt;cl@linux.com&gt;
Acked-by: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
diff --git a/arch/x86/lib/delay.c b/arch/x86/lib/delay.c
@@ -121,7 +121,7 @@ inline void __const_udelay(unsigned long xloops)
 	asm("mull %%edx"
 		:"=d" (xloops), "=&a" (d0)
 		:"1" (xloops), "0"
-		(cpu_data(raw_smp_processor_id()).loops_per_jiffy * (HZ/4)));
+		(this_cpu_read(cpu_info.loops_per_jiffy) * (HZ/4)));
 
 	__delay(++xloops);
 }

Original file line number	Diff line number	Diff line change
`@@ -121,7 +121,7 @@ inline void __const_udelay(unsigned long xloops)`
`121`	`121`	`asm("mull %%edx"`
`122`	`122`	`:"=d" (xloops), "=&a" (d0)`
`123`	`123`	`:"1" (xloops), "0"`
`124`		`- (cpu_data(raw_smp_processor_id()).loops_per_jiffy * (HZ/4)));`
	`124`	`+ (this_cpu_read(cpu_info.loops_per_jiffy) * (HZ/4)));`
`125`	`125`
`126`	`126`	`__delay(++xloops);`
`127`	`127`	`}`