From 6c8cd5bbda7e6be166cf2e2dd4be5890193e17ac Mon Sep 17 00:00:00 2001 From: Philipp Hachtmann Date: Mon, 7 Apr 2014 18:25:23 +0200 Subject: s390/spinlock: optimize spinlock code sequence Use lowcore constant to improve the code generated for spinlocks. [ Martin Schwidefsky: patch breakdown and code beautification ] Signed-off-by: Philipp Hachtmann Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/lowcore.h | 5 +++-- arch/s390/include/asm/spinlock.h | 15 +++++++++------ arch/s390/kernel/setup.c | 4 ++++ arch/s390/kernel/smp.c | 3 +++ arch/s390/lib/spinlock.c | 4 ++-- 5 files changed, 21 insertions(+), 10 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h index bbf8141408cd..3b476eb92f20 100644 --- a/arch/s390/include/asm/lowcore.h +++ b/arch/s390/include/asm/lowcore.h @@ -139,7 +139,7 @@ struct _lowcore { __u32 percpu_offset; /* 0x02f0 */ __u32 machine_flags; /* 0x02f4 */ __u32 ftrace_func; /* 0x02f8 */ - __u8 pad_0x02fc[0x0300-0x02fc]; /* 0x02fc */ + __u32 spinlock_lockval; /* 0x02fc */ /* Interrupt response block */ __u8 irb[64]; /* 0x0300 */ @@ -285,7 +285,8 @@ struct _lowcore { __u64 machine_flags; /* 0x0388 */ __u64 ftrace_func; /* 0x0390 */ __u64 gmap; /* 0x0398 */ - __u8 pad_0x03a0[0x0400-0x03a0]; /* 0x03a0 */ + __u32 spinlock_lockval; /* 0x03a0 */ + __u8 pad_0x03a0[0x0400-0x03a4]; /* 0x03a4 */ /* Interrupt response block. */ __u8 irb[64]; /* 0x0400 */ diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h index b60212a02d08..5a0b2882ad48 100644 --- a/arch/s390/include/asm/spinlock.h +++ b/arch/s390/include/asm/spinlock.h @@ -11,6 +11,8 @@ #include +#define SPINLOCK_LOCKVAL (S390_lowcore.spinlock_lockval) + extern int spin_retry; static inline int @@ -40,6 +42,11 @@ int arch_spin_trylock_retry(arch_spinlock_t *); void arch_spin_relax(arch_spinlock_t *); void arch_spin_lock_wait_flags(arch_spinlock_t *, unsigned long flags); +static inline u32 arch_spin_lockval(int cpu) +{ + return ~cpu; +} + static inline int arch_spin_value_unlocked(arch_spinlock_t lock) { return lock.lock == 0; @@ -52,16 +59,12 @@ static inline int arch_spin_is_locked(arch_spinlock_t *lp) static inline int arch_spin_trylock_once(arch_spinlock_t *lp) { - unsigned int new = ~smp_processor_id(); - - return _raw_compare_and_swap(&lp->lock, 0, new); + return _raw_compare_and_swap(&lp->lock, 0, SPINLOCK_LOCKVAL); } static inline int arch_spin_tryrelease_once(arch_spinlock_t *lp) { - unsigned int old = ~smp_processor_id(); - - return _raw_compare_and_swap(&lp->lock, old, 0); + return _raw_compare_and_swap(&lp->lock, SPINLOCK_LOCKVAL, 0); } static inline void arch_spin_lock(arch_spinlock_t *lp) diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index 1f5536c2fd02..7c5b05fa2194 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -373,6 +373,10 @@ static void __init setup_lowcore(void) mem_assign_absolute(S390_lowcore.restart_source, lc->restart_source); mem_assign_absolute(S390_lowcore.restart_psw, lc->restart_psw); +#ifdef CONFIG_SMP + lc->spinlock_lockval = arch_spin_lockval(0); +#endif + set_prefix((u32)(unsigned long) lc); lowcore_ptr[0] = lc; } diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 86e65ec3422b..1f0b474041c4 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -170,6 +170,7 @@ static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu) lc->panic_stack = pcpu->panic_stack + PAGE_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs); lc->cpu_nr = cpu; + lc->spinlock_lockval = arch_spin_lockval(cpu); #ifndef CONFIG_64BIT if (MACHINE_HAS_IEEE) { lc->extended_save_area_addr = get_zeroed_page(GFP_KERNEL); @@ -226,6 +227,7 @@ static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu) cpumask_set_cpu(cpu, mm_cpumask(&init_mm)); atomic_inc(&init_mm.context.attach_count); lc->cpu_nr = cpu; + lc->spinlock_lockval = arch_spin_lockval(cpu); lc->percpu_offset = __per_cpu_offset[cpu]; lc->kernel_asce = S390_lowcore.kernel_asce; lc->machine_flags = S390_lowcore.machine_flags; @@ -809,6 +811,7 @@ void __init smp_cpus_done(unsigned int max_cpus) void __init smp_setup_processor_id(void) { S390_lowcore.cpu_nr = 0; + S390_lowcore.spinlock_lockval = arch_spin_lockval(0); } /* diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c index 4a3b33b2dbb9..3ca9de4d9cb9 100644 --- a/arch/s390/lib/spinlock.c +++ b/arch/s390/lib/spinlock.c @@ -27,7 +27,7 @@ __setup("spin_retry=", spin_retry_setup); void arch_spin_lock_wait(arch_spinlock_t *lp) { int count = spin_retry; - unsigned int cpu = ~smp_processor_id(); + unsigned int cpu = SPINLOCK_LOCKVAL; unsigned int owner; while (1) { @@ -54,7 +54,7 @@ EXPORT_SYMBOL(arch_spin_lock_wait); void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) { int count = spin_retry; - unsigned int cpu = ~smp_processor_id(); + unsigned int cpu = SPINLOCK_LOCKVAL; unsigned int owner; local_irq_restore(flags); -- cgit v1.2.3