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locking/spinlocks, s390: Implement vcpu_is_preempted(cpu)

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This implements the s390 version for vcpu_is_preempted(cpu),
by reworking the existing smp_vcpu_scheduled() function into
arch_vcpu_is_preempted().

We can then also get rid of the local cpu_is_preempted()
function by moving the CIF_ENABLED_WAIT test into
arch_vcpu_is_preempted().

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: benh@kernel.crashing.org
Cc: boqun.feng@gmail.com
Cc: bsingharora@gmail.com
Cc: dave@stgolabs.net
Cc: jgross@suse.com
Cc: kernellwp@gmail.com
Cc: konrad.wilk@oracle.com
Cc: linuxppc-dev@lists.ozlabs.org
Cc: mpe@ellerman.id.au
Cc: paulmck@linux.vnet.ibm.com
Cc: paulus@samba.org
Cc: pbonzini@redhat.com
Cc: rkrcmar@redhat.com
Cc: virtualization@lists.linux-foundation.org
Cc: will.deacon@arm.com
Cc: xen-devel-request@lists.xenproject.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1478077718-37424-6-git-send-email-xinhui.pan@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Christian Borntraeger 2016-11-02 05:08:32 -04:00 committed by Ingo Molnar
parent 41946c8687
commit 760928c0da
3 changed files with 23 additions and 19 deletions
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8
arch/s390/include/asm/spinlock.h
View File

@ -23,6 +23,14 @@ _raw_compare_and_swap(unsigned int *lock, unsigned int old, unsigned int new)
return __sync_bool_compare_and_swap(lock, old, new);
}
#ifndef CONFIG_SMP
static inline bool arch_vcpu_is_preempted(int cpu) { return false; }
#else
bool arch_vcpu_is_preempted(int cpu);
#endif
#define vcpu_is_preempted arch_vcpu_is_preempted
/*
* Simple spin lock operations. There are two variants, one clears IRQ's
* on the local processor, one does not.

9
arch/s390/kernel/smp.c
View File

@ -368,10 +368,15 @@ int smp_find_processor_id(u16 address)
return -1;
}
int smp_vcpu_scheduled(int cpu)
bool arch_vcpu_is_preempted(int cpu)
{
return pcpu_running(pcpu_devices + cpu);
if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
return false;
if (pcpu_running(pcpu_devices + cpu))
return false;
return true;
}
EXPORT_SYMBOL(arch_vcpu_is_preempted);
void smp_yield_cpu(int cpu)
{

25
arch/s390/lib/spinlock.c
View File

@ -37,15 +37,6 @@ static inline void _raw_compare_and_delay(unsigned int *lock, unsigned int old)
asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock));
}
static inline int cpu_is_preempted(int cpu)
{
if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
return 0;
if (smp_vcpu_scheduled(cpu))
return 0;
return 1;
}
void arch_spin_lock_wait(arch_spinlock_t *lp)
{
unsigned int cpu = SPINLOCK_LOCKVAL;
@ -62,7 +53,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp)
continue;
}
/* First iteration: check if the lock owner is running. */
if (first_diag && cpu_is_preempted(~owner)) {
if (first_diag && arch_vcpu_is_preempted(~owner)) {
smp_yield_cpu(~owner);
first_diag = 0;
continue;
@ -81,7 +72,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp)
* yield the CPU unconditionally. For LPAR rely on the
* sense running status.
*/
if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) {
if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) {
smp_yield_cpu(~owner);
first_diag = 0;
}
@ -108,7 +99,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
continue;
}
/* Check if the lock owner is running. */
if (first_diag && cpu_is_preempted(~owner)) {
if (first_diag && arch_vcpu_is_preempted(~owner)) {
smp_yield_cpu(~owner);
first_diag = 0;
continue;
@ -127,7 +118,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
* yield the CPU unconditionally. For LPAR rely on the
* sense running status.
*/
if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) {
if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) {
smp_yield_cpu(~owner);
first_diag = 0;
}
@ -165,7 +156,7 @@ void _raw_read_lock_wait(arch_rwlock_t *rw)
owner = 0;
while (1) {
if (count-- <= 0) {
if (owner && cpu_is_preempted(~owner))
if (owner && arch_vcpu_is_preempted(~owner))
smp_yield_cpu(~owner);
count = spin_retry;
}
@ -211,7 +202,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev)
owner = 0;
while (1) {
if (count-- <= 0) {
if (owner && cpu_is_preempted(~owner))
if (owner && arch_vcpu_is_preempted(~owner))
smp_yield_cpu(~owner);
count = spin_retry;
}
@ -241,7 +232,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw)
owner = 0;
while (1) {
if (count-- <= 0) {
if (owner && cpu_is_preempted(~owner))
if (owner && arch_vcpu_is_preempted(~owner))
smp_yield_cpu(~owner);
count = spin_retry;
}
@ -285,7 +276,7 @@ void arch_lock_relax(unsigned int cpu)
{
if (!cpu)
return;
if (MACHINE_IS_LPAR && !cpu_is_preempted(~cpu))
if (MACHINE_IS_LPAR && !arch_vcpu_is_preempted(~cpu))
return;
smp_yield_cpu(~cpu);
}