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sparc64: Use pause instruction when available.

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In atomic backoff and cpu_relax(), use the pause instruction
found on SPARC-T4 and later.

It makes the cpu strand unselectable for the given number of
cycles, unless an intervening disrupting trap occurs.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2012-10-27 23:00:41 -07:00
parent 270c10e00a
commit e9b9eb59ff
5 changed files with 62 additions and 16 deletions
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7
arch/sparc/kernel/entry.h
View file

@ -59,6 +59,13 @@ struct popc_6insn_patch_entry {
extern struct popc_6insn_patch_entry __popc_6insn_patch,
__popc_6insn_patch_end;
struct pause_patch_entry {
unsigned int addr;
unsigned int insns[3];
};
extern struct pause_patch_entry __pause_patch,
__pause_patch_end;
extern void __init per_cpu_patch(void);
extern void sun4v_patch_1insn_range(struct sun4v_1insn_patch_entry *,
struct sun4v_1insn_patch_entry *);