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nexedi
linux
Commits
dc647a63
Commit
dc647a63
authored
Jul 24, 2003
by
David Mosberger
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ia64: Drop ".bias" in spinlocks as it caused more harm than good. Pointed
out by Jesse Barnes. Also, drop the old lock code.
parent
63aa95fe
Changes
2
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2 changed files
with
2 additions
and
30 deletions
+2
-30
arch/ia64/kernel/head.S
arch/ia64/kernel/head.S
+2
-2
include/asm-ia64/spinlock.h
include/asm-ia64/spinlock.h
+0
-28
No files found.
arch/ia64/kernel/head.S
View file @
dc647a63
...
...
@@ -863,7 +863,7 @@ GLOBAL_ENTRY(ia64_spinlock_contention_pre3_4)
.
wait
:
//
exponential
backoff
,
kdb
,
lockmeter
etc
.
go
in
here
hint
@
pause
ld4
.bias
r30
=[
r31
]
ld4
r30
=[
r31
]
//
don
't use ld4.bias; if it'
s
contended
,
we
won
't write the word
nop
0
;;
cmp4.eq
p14
,
p0
=
r30
,
r0
...
...
@@ -880,7 +880,7 @@ GLOBAL_ENTRY(ia64_spinlock_contention)
.
wait
:
//
exponential
backoff
,
kdb
,
lockmeter
etc
.
go
in
here
hint
@
pause
ld4
.bias
r30
=[
r31
]
ld4
r30
=[
r31
]
//
don
't use ld4.bias; if it'
s
contended
,
we
won
't write the word
;;
cmp4.ne
p14
,
p0
=
r30
,
r0
mov
r30
=
1
...
...
include/asm-ia64/spinlock.h
View file @
dc647a63
...
...
@@ -22,9 +22,6 @@ typedef struct {
#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
#define spin_lock_init(x) ((x)->lock = 0)
#define NEW_LOCK
#ifdef NEW_LOCK
/*
* Try to get the lock. If we fail to get the lock, make a non-standard call to
* ia64_spinlock_contention(). We do not use a normal call because that would force all
...
...
@@ -87,31 +84,6 @@ _raw_spin_lock (spinlock_t *lock)
#endif
}
#else
/* !NEW_LOCK */
/*
* Streamlined test_and_set_bit(0, (x)). We use test-and-test-and-set
* rather than a simple xchg to avoid writing the cache-line when
* there is contention.
*/
#define _raw_spin_lock(x) __asm__ __volatile__ ( \
"mov ar.ccv = r0\n" \
"mov r29 = 1\n" \
";;\n" \
"1:\n" \
"ld4.bias r2 = [%0]\n" \
";;\n" \
"cmp4.eq p0,p7 = r0,r2\n" \
"(p7) br.cond.spnt.few 1b \n" \
"cmpxchg4.acq r2 = [%0], r29, ar.ccv\n" \
";;\n" \
"cmp4.eq p0,p7 = r0, r2\n" \
"(p7) br.cond.spnt.few 1b\n" \
";;\n" \
:: "r"(&(x)->lock) : "ar.ccv", "p7", "r2", "r29", "memory")
#endif
/* !NEW_LOCK */
#define spin_is_locked(x) ((x)->lock != 0)
#define _raw_spin_unlock(x) do { barrier(); ((spinlock_t *) x)->lock = 0; } while (0)
#define _raw_spin_trylock(x) (cmpxchg_acq(&(x)->lock, 0, 1) == 0)
...
...
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