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| author | David S. Miller | 2007-10-16 01:41:44 +0200 |
|---|---|---|
| committer | David S. Miller | 2007-10-18 01:24:55 +0200 |
| commit | 24f287e412ae90de8d281543c8b1043b6ed6c019 (patch) | |
| tree | eb69803d187d35fd9e90c1428952c0ed5a0970c1 /arch/sparc64/lib/bitops.S | |
| parent | Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/... (diff) | |
| download | kernel-qcow2-linux-24f287e412ae90de8d281543c8b1043b6ed6c019.tar.gz kernel-qcow2-linux-24f287e412ae90de8d281543c8b1043b6ed6c019.tar.xz kernel-qcow2-linux-24f287e412ae90de8d281543c8b1043b6ed6c019.zip | |
[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/sparc64/lib/bitops.S')
| -rw-r--r-- | arch/sparc64/lib/bitops.S | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/arch/sparc64/lib/bitops.S b/arch/sparc64/lib/bitops.S index 892431a82131..6b015a6eefb5 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 |