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linux-next/include/asm-sparc64/backoff.h
David S. Miller 4cfea5a7df [SPARC64]: Fix atomic backoff limit.
4096 will not fit into the immediate field of a compare instruction,
in fact it will end up being -4096 causing the check to fail every
time and thus disabling backoff.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-19 01:04:48 -07:00

32 lines
514 B
C

#ifndef _SPARC64_BACKOFF_H
#define _SPARC64_BACKOFF_H
#define BACKOFF_LIMIT (4 * 1024)
#ifdef CONFIG_SMP
#define BACKOFF_SETUP(reg) \
mov 1, reg
#define BACKOFF_SPIN(reg, tmp, label) \
mov reg, tmp; \
88: brnz,pt tmp, 88b; \
sub tmp, 1, tmp; \
set BACKOFF_LIMIT, tmp; \
cmp reg, tmp; \
bg,pn %xcc, label; \
nop; \
ba,pt %xcc, label; \
sllx reg, 1, reg;
#else
#define BACKOFF_SETUP(reg)
#define BACKOFF_SPIN(reg, tmp, label) \
ba,pt %xcc, label; \
nop;
#endif
#endif /* _SPARC64_BACKOFF_H */