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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2006-09-30 23:27:45 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-01 00:39:22 -0700
commit3c1fcfe229e99752c74efb945a4a3f560be04204 (patch)
tree44085d9b599e06a92426141811a6f712beac17aa /arch/s390
parentcdc39363d33506b0e067d41fc91f89d186bdf7f7 (diff)
downloadlinux-2.6.34-ux500-3c1fcfe229e99752c74efb945a4a3f560be04204.tar.gz
[PATCH] Directed yield: direct yield of spinlocks for s390.
Use the new diagnose 0x9c in the spinlock implementation for s390. It yields the remaining timeslice of the virtual cpu that tries to acquire a lock to the virtual cpu that is the current holder of the lock. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/kernel/head31.S11
-rw-r--r--arch/s390/kernel/head64.S11
-rw-r--r--arch/s390/lib/spinlock.c62
3 files changed, 61 insertions, 23 deletions
diff --git a/arch/s390/kernel/head31.S b/arch/s390/kernel/head31.S
index 1fa9fa1ca74..1b952a3664e 100644
--- a/arch/s390/kernel/head31.S
+++ b/arch/s390/kernel/head31.S
@@ -254,6 +254,16 @@ startup_continue:
oi 3(%r12),0x80 # set IDTE flag
.Lchkidte:
+#
+# find out if the diag 0x9c is available
+#
+ mvc __LC_PGM_NEW_PSW(8),.Lpcdiag9c-.LPG1(%r13)
+ stap __LC_CPUID+4 # store cpu address
+ lh %r1,__LC_CPUID+4
+ diag %r1,0,0x9c # test diag 0x9c
+ oi 2(%r12),1 # set diag9c flag
+.Lchkdiag9c:
+
lpsw .Lentry-.LPG1(13) # jump to _stext in primary-space,
# virtual and never return ...
.align 8
@@ -281,6 +291,7 @@ startup_continue:
.Lpccsp:.long 0x00080000,0x80000000 + .Lchkcsp
.Lpcmvpg:.long 0x00080000,0x80000000 + .Lchkmvpg
.Lpcidte:.long 0x00080000,0x80000000 + .Lchkidte
+.Lpcdiag9c:.long 0x00080000,0x80000000 + .Lchkdiag9c
.Lmemsize:.long memory_size
.Lmchunk:.long memory_chunk
.Lmflags:.long machine_flags
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index 48998d50b00..b30e5897cdf 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -251,6 +251,17 @@ startup_continue:
0:
#
+# find out if the diag 0x9c is available
+#
+ la %r1,0f-.LPG1(%r13) # set program check address
+ stg %r1,__LC_PGM_NEW_PSW+8
+ stap __LC_CPUID+4 # store cpu address
+ lh %r1,__LC_CPUID+4
+ diag %r1,0,0x9c # test diag 0x9c
+ oi 6(%r12),1 # set diag9c flag
+0:
+
+#
# find out if we have the MVCOS instruction
#
la %r1,0f-.LPG1(%r13) # set program check address
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index b9b7958a226..8d76403fcf8 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -24,57 +24,76 @@ static int __init spin_retry_setup(char *str)
}
__setup("spin_retry=", spin_retry_setup);
-static inline void
-_diag44(void)
+static inline void _raw_yield(void)
{
-#ifdef CONFIG_64BIT
if (MACHINE_HAS_DIAG44)
-#endif
asm volatile("diag 0,0,0x44");
}
-void
-_raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc)
+static inline void _raw_yield_cpu(int cpu)
+{
+ if (MACHINE_HAS_DIAG9C)
+ asm volatile("diag %0,0,0x9c"
+ : : "d" (__cpu_logical_map[cpu]));
+ else
+ _raw_yield();
+}
+
+void _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc)
{
int count = spin_retry;
+ unsigned int cpu = ~smp_processor_id();
while (1) {
if (count-- <= 0) {
- _diag44();
+ unsigned int owner = lp->owner_cpu;
+ if (owner != 0)
+ _raw_yield_cpu(~owner);
count = spin_retry;
}
if (__raw_spin_is_locked(lp))
continue;
- if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0)
+ if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) {
+ lp->owner_pc = pc;
return;
+ }
}
}
EXPORT_SYMBOL(_raw_spin_lock_wait);
-int
-_raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc)
+int _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc)
{
- int count = spin_retry;
+ unsigned int cpu = ~smp_processor_id();
+ int count;
- while (count-- > 0) {
+ for (count = spin_retry; count > 0; count--) {
if (__raw_spin_is_locked(lp))
continue;
- if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0)
+ if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) {
+ lp->owner_pc = pc;
return 1;
+ }
}
return 0;
}
EXPORT_SYMBOL(_raw_spin_trylock_retry);
-void
-_raw_read_lock_wait(raw_rwlock_t *rw)
+void _raw_spin_relax(raw_spinlock_t *lock)
+{
+ unsigned int cpu = lock->owner_cpu;
+ if (cpu != 0)
+ _raw_yield_cpu(~cpu);
+}
+EXPORT_SYMBOL(_raw_spin_relax);
+
+void _raw_read_lock_wait(raw_rwlock_t *rw)
{
unsigned int old;
int count = spin_retry;
while (1) {
if (count-- <= 0) {
- _diag44();
+ _raw_yield();
count = spin_retry;
}
if (!__raw_read_can_lock(rw))
@@ -86,8 +105,7 @@ _raw_read_lock_wait(raw_rwlock_t *rw)
}
EXPORT_SYMBOL(_raw_read_lock_wait);
-int
-_raw_read_trylock_retry(raw_rwlock_t *rw)
+int _raw_read_trylock_retry(raw_rwlock_t *rw)
{
unsigned int old;
int count = spin_retry;
@@ -103,14 +121,13 @@ _raw_read_trylock_retry(raw_rwlock_t *rw)
}
EXPORT_SYMBOL(_raw_read_trylock_retry);
-void
-_raw_write_lock_wait(raw_rwlock_t *rw)
+void _raw_write_lock_wait(raw_rwlock_t *rw)
{
int count = spin_retry;
while (1) {
if (count-- <= 0) {
- _diag44();
+ _raw_yield();
count = spin_retry;
}
if (!__raw_write_can_lock(rw))
@@ -121,8 +138,7 @@ _raw_write_lock_wait(raw_rwlock_t *rw)
}
EXPORT_SYMBOL(_raw_write_lock_wait);
-int
-_raw_write_trylock_retry(raw_rwlock_t *rw)
+int _raw_write_trylock_retry(raw_rwlock_t *rw)
{
int count = spin_retry;