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authorDavid S. Miller <davem@sunset.davemloft.net>2007-10-15 16:41:44 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-10-17 16:24:55 -0700
commit24f287e412ae90de8d281543c8b1043b6ed6c019 (patch)
treeeb69803d187d35fd9e90c1428952c0ed5a0970c1 /arch
parentd85714d81cc0408daddb68c10f7fd69eafe7c213 (diff)
downloadop-kernel-dev-24f287e412ae90de8d281543c8b1043b6ed6c019.zip
op-kernel-dev-24f287e412ae90de8d281543c8b1043b6ed6c019.tar.gz
[SPARC64]: Implement atomic backoff.
When the cpu count is high and contention hits an atomic object, the processors can synchronize such that some cpus continually get knocked out and cannot complete the atomic update. So implement an exponential backoff when SMP. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch')
-rw-r--r--arch/sparc64/lib/atomic.S38
-rw-r--r--arch/sparc64/lib/bitops.S30
2 files changed, 48 insertions, 20 deletions
diff --git a/arch/sparc64/lib/atomic.S b/arch/sparc64/lib/atomic.S
index 9633750..70ac418 100644
--- a/arch/sparc64/lib/atomic.S
+++ b/arch/sparc64/lib/atomic.S
@@ -1,10 +1,10 @@
-/* $Id: atomic.S,v 1.4 2001/11/18 00:12:56 davem Exp $
- * atomic.S: These things are too big to do inline.
+/* atomic.S: These things are too big to do inline.
*
- * Copyright (C) 1999 David S. Miller (davem@redhat.com)
+ * Copyright (C) 1999, 2007 David S. Miller (davem@davemloft.net)
*/
#include <asm/asi.h>
+#include <asm/backoff.h>
.text
@@ -16,27 +16,31 @@
.globl atomic_add
.type atomic_add,#function
atomic_add: /* %o0 = increment, %o1 = atomic_ptr */
+ BACKOFF_SETUP(%o2)
1: lduw [%o1], %g1
add %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %icc, 1b
+ bne,pn %icc, 2f
nop
retl
nop
+2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic_add, .-atomic_add
.globl atomic_sub
.type atomic_sub,#function
atomic_sub: /* %o0 = decrement, %o1 = atomic_ptr */
+ BACKOFF_SETUP(%o2)
1: lduw [%o1], %g1
sub %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %icc, 1b
+ bne,pn %icc, 2f
nop
retl
nop
+2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic_sub, .-atomic_sub
/* On SMP we need to use memory barriers to ensure
@@ -60,89 +64,101 @@ atomic_sub: /* %o0 = decrement, %o1 = atomic_ptr */
.globl atomic_add_ret
.type atomic_add_ret,#function
atomic_add_ret: /* %o0 = increment, %o1 = atomic_ptr */
+ BACKOFF_SETUP(%o2)
ATOMIC_PRE_BARRIER
1: lduw [%o1], %g1
add %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %icc, 1b
+ bne,pn %icc, 2f
add %g7, %o0, %g7
sra %g7, 0, %o0
ATOMIC_POST_BARRIER
retl
nop
+2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic_add_ret, .-atomic_add_ret
.globl atomic_sub_ret
.type atomic_sub_ret,#function
atomic_sub_ret: /* %o0 = decrement, %o1 = atomic_ptr */
+ BACKOFF_SETUP(%o2)
ATOMIC_PRE_BARRIER
1: lduw [%o1], %g1
sub %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %icc, 1b
+ bne,pn %icc, 2f
sub %g7, %o0, %g7
sra %g7, 0, %o0
ATOMIC_POST_BARRIER
retl
nop
+2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic_sub_ret, .-atomic_sub_ret
.globl atomic64_add
.type atomic64_add,#function
atomic64_add: /* %o0 = increment, %o1 = atomic_ptr */
+ BACKOFF_SETUP(%o2)
1: ldx [%o1], %g1
add %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %xcc, 1b
+ bne,pn %xcc, 2f
nop
retl
nop
+2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic64_add, .-atomic64_add
.globl atomic64_sub
.type atomic64_sub,#function
atomic64_sub: /* %o0 = decrement, %o1 = atomic_ptr */
+ BACKOFF_SETUP(%o2)
1: ldx [%o1], %g1
sub %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %xcc, 1b
+ bne,pn %xcc, 2f
nop
retl
nop
+2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic64_sub, .-atomic64_sub
.globl atomic64_add_ret
.type atomic64_add_ret,#function
atomic64_add_ret: /* %o0 = increment, %o1 = atomic_ptr */
+ BACKOFF_SETUP(%o2)
ATOMIC_PRE_BARRIER
1: ldx [%o1], %g1
add %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %xcc, 1b
+ bne,pn %xcc, 2f
add %g7, %o0, %g7
mov %g7, %o0
ATOMIC_POST_BARRIER
retl
nop
+2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic64_add_ret, .-atomic64_add_ret
.globl atomic64_sub_ret
.type atomic64_sub_ret,#function
atomic64_sub_ret: /* %o0 = decrement, %o1 = atomic_ptr */
+ BACKOFF_SETUP(%o2)
ATOMIC_PRE_BARRIER
1: ldx [%o1], %g1
sub %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %xcc, 1b
+ bne,pn %xcc, 2f
sub %g7, %o0, %g7
mov %g7, %o0
ATOMIC_POST_BARRIER
retl
nop
+2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic64_sub_ret, .-atomic64_sub_ret
diff --git a/arch/sparc64/lib/bitops.S b/arch/sparc64/lib/bitops.S
index 892431a..6b015a6 100644
--- a/arch/sparc64/lib/bitops.S
+++ b/arch/sparc64/lib/bitops.S
@@ -1,10 +1,10 @@
-/* $Id: bitops.S,v 1.3 2001/11/18 00:12:56 davem Exp $
- * bitops.S: Sparc64 atomic bit operations.
+/* bitops.S: Sparc64 atomic bit operations.
*
- * Copyright (C) 2000 David S. Miller (davem@redhat.com)
+ * Copyright (C) 2000, 2007 David S. Miller (davem@davemloft.net)
*/
#include <asm/asi.h>
+#include <asm/backoff.h>
.text
@@ -29,6 +29,7 @@
.globl test_and_set_bit
.type test_and_set_bit,#function
test_and_set_bit: /* %o0=nr, %o1=addr */
+ BACKOFF_SETUP(%o3)
BITOP_PRE_BARRIER
srlx %o0, 6, %g1
mov 1, %o2
@@ -40,18 +41,20 @@ test_and_set_bit: /* %o0=nr, %o1=addr */
or %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 1b
+ bne,pn %xcc, 2f
and %g7, %o2, %g2
clr %o0
movrne %g2, 1, %o0
BITOP_POST_BARRIER
retl
nop
+2: BACKOFF_SPIN(%o3, %o4, 1b)
.size test_and_set_bit, .-test_and_set_bit
.globl test_and_clear_bit
.type test_and_clear_bit,#function
test_and_clear_bit: /* %o0=nr, %o1=addr */
+ BACKOFF_SETUP(%o3)
BITOP_PRE_BARRIER
srlx %o0, 6, %g1
mov 1, %o2
@@ -63,18 +66,20 @@ test_and_clear_bit: /* %o0=nr, %o1=addr */
andn %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 1b
+ bne,pn %xcc, 2f
and %g7, %o2, %g2
clr %o0
movrne %g2, 1, %o0
BITOP_POST_BARRIER
retl
nop
+2: BACKOFF_SPIN(%o3, %o4, 1b)
.size test_and_clear_bit, .-test_and_clear_bit
.globl test_and_change_bit
.type test_and_change_bit,#function
test_and_change_bit: /* %o0=nr, %o1=addr */
+ BACKOFF_SETUP(%o3)
BITOP_PRE_BARRIER
srlx %o0, 6, %g1
mov 1, %o2
@@ -86,18 +91,20 @@ test_and_change_bit: /* %o0=nr, %o1=addr */
xor %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 1b
+ bne,pn %xcc, 2f
and %g7, %o2, %g2
clr %o0
movrne %g2, 1, %o0
BITOP_POST_BARRIER
retl
nop
+2: BACKOFF_SPIN(%o3, %o4, 1b)
.size test_and_change_bit, .-test_and_change_bit
.globl set_bit
.type set_bit,#function
set_bit: /* %o0=nr, %o1=addr */
+ BACKOFF_SETUP(%o3)
srlx %o0, 6, %g1
mov 1, %o2
sllx %g1, 3, %g3
@@ -108,15 +115,17 @@ set_bit: /* %o0=nr, %o1=addr */
or %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 1b
+ bne,pn %xcc, 2f
nop
retl
nop
+2: BACKOFF_SPIN(%o3, %o4, 1b)
.size set_bit, .-set_bit
.globl clear_bit
.type clear_bit,#function
clear_bit: /* %o0=nr, %o1=addr */
+ BACKOFF_SETUP(%o3)
srlx %o0, 6, %g1
mov 1, %o2
sllx %g1, 3, %g3
@@ -127,15 +136,17 @@ clear_bit: /* %o0=nr, %o1=addr */
andn %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 1b
+ bne,pn %xcc, 2f
nop
retl
nop
+2: BACKOFF_SPIN(%o3, %o4, 1b)
.size clear_bit, .-clear_bit
.globl change_bit
.type change_bit,#function
change_bit: /* %o0=nr, %o1=addr */
+ BACKOFF_SETUP(%o3)
srlx %o0, 6, %g1
mov 1, %o2
sllx %g1, 3, %g3
@@ -146,8 +157,9 @@ change_bit: /* %o0=nr, %o1=addr */
xor %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 1b
+ bne,pn %xcc, 2f
nop
retl
nop
+2: BACKOFF_SPIN(%o3, %o4, 1b)
.size change_bit, .-change_bit
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