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Revision 783e391b7b5b273cd20856d8f6f4878da8ec31b3 authored by Venki Pallipadi on 10 April 2008, 16:49:58 UTC, committed by Linus Torvalds on 10 April 2008, 22:38:29 UTC 
x86: Simplify cpu_idle_wait
 
This patch also resolves hangs on boot:
	http://lkml.org/lkml/2008/2/23/263
	http://bugzilla.kernel.org/show_bug.cgi?id=10093

The bug was causing once-in-few-reboots 10-15 sec wait during boot on
certain laptops.

Earlier commit 40d6a146629b98d8e322b6f9332b182c7cbff3df added
smp_call_function in cpu_idle_wait() to kick cpus that are in tickless
idle.  Looking at cpu_idle_wait code at that time, code seemed to be
over-engineered for a case which is rarely used (while changing idle
handler).

Below is a simplified version of cpu_idle_wait, which just makes a dummy
smp_call_function to all cpus, to make them come out of old idle handler
and start using the new idle handler.  It eliminates code in the idle
loop to handle cpu_idle_wait.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent a1e58bb
Raw File
segment.h 
#ifndef _M68K_SEGMENT_H
#define _M68K_SEGMENT_H

/* define constants */
/* Address spaces (FC0-FC2) */
#define USER_DATA     (1)
#ifndef __USER_DS
#define __USER_DS     (USER_DATA)
#endif
#define USER_PROGRAM  (2)
#define SUPER_DATA    (5)
#ifndef __KERNEL_DS
#define __KERNEL_DS   (SUPER_DATA)
#endif
#define SUPER_PROGRAM (6)
#define CPU_SPACE     (7)

#ifndef __ASSEMBLY__

typedef struct {
	unsigned long seg;
} mm_segment_t;

#define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })
#define USER_DS		MAKE_MM_SEG(__USER_DS)
#define KERNEL_DS	MAKE_MM_SEG(__KERNEL_DS)

/*
 * Get/set the SFC/DFC registers for MOVES instructions
 */

static inline mm_segment_t get_fs(void)
{
    return USER_DS;
}

static inline mm_segment_t get_ds(void)
{
    /* return the supervisor data space code */
    return KERNEL_DS;
}

static inline void set_fs(mm_segment_t val)
{
}

#define segment_eq(a,b)	((a).seg == (b).seg)

#endif /* __ASSEMBLY__ */

#endif /* _M68K_SEGMENT_H */
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