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authorLinus Torvalds <torvalds@linux-foundation.org>2015-02-11 17:42:32 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-11 17:42:32 -0800
commitb3d6524ff7956c5a898d51a18eaecb62a60a2b84 (patch)
treecc049e7ec9edd9f5a76f286e04d8db9a1caa516a /arch/s390/lib/spinlock.c
parent07f80d41cf24b7e6e76cd97d420167932c9a7f82 (diff)
parent6a039eab53c01a58bfff95c78fc800ca7de27c77 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Martin Schwidefsky: - The remaining patches for the z13 machine support: kernel build option for z13, the cache synonym avoidance, SMT support, compare-and-delay for spinloops and the CES5S crypto adapater. - The ftrace support for function tracing with the gcc hotpatch option. This touches common code Makefiles, Steven is ok with the changes. - The hypfs file system gets an extension to access diagnose 0x0c data in user space for performance analysis for Linux running under z/VM. - The iucv hvc console gets wildcard spport for the user id filtering. - The cacheinfo code is converted to use the generic infrastructure. - Cleanup and bug fixes. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (42 commits) s390/process: free vx save area when releasing tasks s390/hypfs: Eliminate hypfs interval s390/hypfs: Add diagnose 0c support s390/cacheinfo: don't use smp_processor_id() in preemptible context s390/zcrypt: fixed domain scanning problem (again) s390/smp: increase maximum value of NR_CPUS to 512 s390/jump label: use different nop instruction s390/jump label: add sanity checks s390/mm: correct missing space when reporting user process faults s390/dasd: cleanup profiling s390/dasd: add locking for global_profile access s390/ftrace: hotpatch support for function tracing ftrace: let notrace function attribute disable hotpatching if necessary ftrace: allow architectures to specify ftrace compile options s390: reintroduce diag 44 calls for cpu_relax() s390/zcrypt: Add support for new crypto express (CEX5S) adapter. s390/zcrypt: Number of supported ap domains is not retrievable. s390/spinlock: add compare-and-delay to lock wait loops s390/tape: remove redundant if statement s390/hvc_iucv: add simple wildcard matches to the iucv allow filter ...
Diffstat (limited to 'arch/s390/lib/spinlock.c')
-rw-r--r--arch/s390/lib/spinlock.c52
1 files changed, 45 insertions, 7 deletions
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index 034a35a3e9c1..d6c9991f7797 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -12,7 +12,15 @@
#include <linux/smp.h>
#include <asm/io.h>
-int spin_retry = 1000;
+int spin_retry = -1;
+
+static int __init spin_retry_init(void)
+{
+ if (spin_retry < 0)
+ spin_retry = MACHINE_HAS_CAD ? 10 : 1000;
+ return 0;
+}
+early_initcall(spin_retry_init);
/**
* spin_retry= parameter
@@ -24,6 +32,11 @@ static int __init spin_retry_setup(char *str)
}
__setup("spin_retry=", spin_retry_setup);
+static inline void _raw_compare_and_delay(unsigned int *lock, unsigned int old)
+{
+ asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock));
+}
+
void arch_spin_lock_wait(arch_spinlock_t *lp)
{
unsigned int cpu = SPINLOCK_LOCKVAL;
@@ -46,6 +59,8 @@ void arch_spin_lock_wait(arch_spinlock_t *lp)
/* Loop for a while on the lock value. */
count = spin_retry;
do {
+ if (MACHINE_HAS_CAD)
+ _raw_compare_and_delay(&lp->lock, owner);
owner = ACCESS_ONCE(lp->lock);
} while (owner && count-- > 0);
if (!owner)
@@ -84,6 +99,8 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
/* Loop for a while on the lock value. */
count = spin_retry;
do {
+ if (MACHINE_HAS_CAD)
+ _raw_compare_and_delay(&lp->lock, owner);
owner = ACCESS_ONCE(lp->lock);
} while (owner && count-- > 0);
if (!owner)
@@ -100,11 +117,19 @@ EXPORT_SYMBOL(arch_spin_lock_wait_flags);
int arch_spin_trylock_retry(arch_spinlock_t *lp)
{
+ unsigned int cpu = SPINLOCK_LOCKVAL;
+ unsigned int owner;
int count;
- for (count = spin_retry; count > 0; count--)
- if (arch_spin_trylock_once(lp))
- return 1;
+ for (count = spin_retry; count > 0; count--) {
+ owner = ACCESS_ONCE(lp->lock);
+ /* Try to get the lock if it is free. */
+ if (!owner) {
+ if (_raw_compare_and_swap(&lp->lock, 0, cpu))
+ return 1;
+ } else if (MACHINE_HAS_CAD)
+ _raw_compare_and_delay(&lp->lock, owner);
+ }
return 0;
}
EXPORT_SYMBOL(arch_spin_trylock_retry);
@@ -126,8 +151,11 @@ void _raw_read_lock_wait(arch_rwlock_t *rw)
}
old = ACCESS_ONCE(rw->lock);
owner = ACCESS_ONCE(rw->owner);
- if ((int) old < 0)
+ if ((int) old < 0) {
+ if (MACHINE_HAS_CAD)
+ _raw_compare_and_delay(&rw->lock, old);
continue;
+ }
if (_raw_compare_and_swap(&rw->lock, old, old + 1))
return;
}
@@ -141,8 +169,11 @@ int _raw_read_trylock_retry(arch_rwlock_t *rw)
while (count-- > 0) {
old = ACCESS_ONCE(rw->lock);
- if ((int) old < 0)
+ if ((int) old < 0) {
+ if (MACHINE_HAS_CAD)
+ _raw_compare_and_delay(&rw->lock, old);
continue;
+ }
if (_raw_compare_and_swap(&rw->lock, old, old + 1))
return 1;
}
@@ -173,6 +204,8 @@ void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev)
}
if ((old & 0x7fffffff) == 0 && (int) prev >= 0)
break;
+ if (MACHINE_HAS_CAD)
+ _raw_compare_and_delay(&rw->lock, old);
}
}
EXPORT_SYMBOL(_raw_write_lock_wait);
@@ -201,6 +234,8 @@ void _raw_write_lock_wait(arch_rwlock_t *rw)
smp_rmb();
if ((old & 0x7fffffff) == 0 && (int) prev >= 0)
break;
+ if (MACHINE_HAS_CAD)
+ _raw_compare_and_delay(&rw->lock, old);
}
}
EXPORT_SYMBOL(_raw_write_lock_wait);
@@ -214,8 +249,11 @@ int _raw_write_trylock_retry(arch_rwlock_t *rw)
while (count-- > 0) {
old = ACCESS_ONCE(rw->lock);
- if (old)
+ if (old) {
+ if (MACHINE_HAS_CAD)
+ _raw_compare_and_delay(&rw->lock, old);
continue;
+ }
if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000))
return 1;
}