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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2015-01-14 17:52:33 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2015-01-23 15:17:04 +0100 |
| commit | 2c72a44ecdf2a7ceac73844226e97ed2d5dd1e82 (patch) | |
| tree | a8475e1252115402a27b4c9a822943782085b151 /arch/s390/include | |
| parent | 55b5eb75e7ccdfe94b6ea1be6bba0c21149abecf (diff) | |
| download | linux-2c72a44ecdf2a7ceac73844226e97ed2d5dd1e82.tar.bz2 | |
s390/spinlock: add compare-and-delay to lock wait loops
Add the compare-and-delay instruction to the spin-lock and rw-lock
retry loops. A CPU executing the compare-and-delay instruction stops
until the lock value has changed. This is done to make the locking
code for contended locks to behave better in regard to the multi-
hreading facility. A thread of a core executing a compare-and-delay
will allow the other threads of a core to get a larger share of the
core resources.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include')
| -rw-r--r-- | arch/s390/include/asm/setup.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h index 7736fdd72595..b8d1e54b4733 100644 --- a/arch/s390/include/asm/setup.h +++ b/arch/s390/include/asm/setup.h @@ -57,6 +57,7 @@ extern void detect_memory_memblock(void); #define MACHINE_FLAG_TE (1UL << 15) #define MACHINE_FLAG_TLB_LC (1UL << 17) #define MACHINE_FLAG_VX (1UL << 18) +#define MACHINE_FLAG_CAD (1UL << 19) #define MACHINE_IS_VM (S390_lowcore.machine_flags & MACHINE_FLAG_VM) #define MACHINE_IS_KVM (S390_lowcore.machine_flags & MACHINE_FLAG_KVM) @@ -80,6 +81,7 @@ extern void detect_memory_memblock(void); #define MACHINE_HAS_TE (0) #define MACHINE_HAS_TLB_LC (0) #define MACHINE_HAS_VX (0) +#define MACHINE_HAS_CAD (0) #else /* CONFIG_64BIT */ #define MACHINE_HAS_IEEE (1) #define MACHINE_HAS_CSP (1) @@ -93,6 +95,7 @@ extern void detect_memory_memblock(void); #define MACHINE_HAS_TE (S390_lowcore.machine_flags & MACHINE_FLAG_TE) #define MACHINE_HAS_TLB_LC (S390_lowcore.machine_flags & MACHINE_FLAG_TLB_LC) #define MACHINE_HAS_VX (S390_lowcore.machine_flags & MACHINE_FLAG_VX) +#define MACHINE_HAS_CAD (S390_lowcore.machine_flags & MACHINE_FLAG_CAD) #endif /* CONFIG_64BIT */ /* |