From 3c1fcfe229e99752c74efb945a4a3f560be04204 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Sat, 30 Sep 2006 23:27:45 -0700 Subject: [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 Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/s390/kernel/head31.S | 11 +++++++++ arch/s390/kernel/head64.S | 11 +++++++++ arch/s390/lib/spinlock.c | 62 +++++++++++++++++++++++++++++------------------ 3 files changed, 61 insertions(+), 23 deletions(-) (limited to 'arch') diff --git a/arch/s390/kernel/head31.S b/arch/s390/kernel/head31.S index 1fa9fa1c..1b952a3 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 48998d5..b30e589 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 b9b7958..8d76403 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; -- cgit v1.1