The patch titled
Directed yield: direct yield of spinlocks for s390.
has been added to the -mm tree. Its filename is
directed-yield-direct-yield-of-spinlocks-for-s390.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Directed yield: direct yield of spinlocks for s390.
From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
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 <schwidefsky@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/s390/kernel/head31.S | 11 ++++
arch/s390/kernel/head64.S | 11 ++++
arch/s390/lib/spinlock.c | 62 +++++++++++++++++-----------
include/asm-s390/setup.h | 1
include/asm-s390/spinlock.h | 31 +++++++++-----
include/asm-s390/spinlock_types.h | 6 +-
6 files changed, 87 insertions(+), 35 deletions(-)
diff -puN arch/s390/kernel/head31.S~directed-yield-direct-yield-of-spinlocks-for-s390 arch/s390/kernel/head31.S
--- a/arch/s390/kernel/head31.S~directed-yield-direct-yield-of-spinlocks-for-s390
+++ a/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 -puN arch/s390/kernel/head64.S~directed-yield-direct-yield-of-spinlocks-for-s390 arch/s390/kernel/head64.S
--- a/arch/s390/kernel/head64.S~directed-yield-direct-yield-of-spinlocks-for-s390
+++ a/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 -puN arch/s390/lib/spinlock.c~directed-yield-direct-yield-of-spinlocks-for-s390 arch/s390/lib/spinlock.c
--- a/arch/s390/lib/spinlock.c~directed-yield-direct-yield-of-spinlocks-for-s390
+++ a/arch/s390/lib/spinlock.c
@@ -24,57 +24,76 @@ static int __init spin_retry_setup(char
}
__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;
diff -puN include/asm-s390/setup.h~directed-yield-direct-yield-of-spinlocks-for-s390 include/asm-s390/setup.h
--- a/include/asm-s390/setup.h~directed-yield-direct-yield-of-spinlocks-for-s390
+++ a/include/asm-s390/setup.h
@@ -39,6 +39,7 @@ extern unsigned long machine_flags;
#define MACHINE_IS_P390 (machine_flags & 4)
#define MACHINE_HAS_MVPG (machine_flags & 16)
#define MACHINE_HAS_IDTE (machine_flags & 128)
+#define MACHINE_HAS_DIAG9C (machine_flags & 256)
#ifndef __s390x__
#define MACHINE_HAS_IEEE (machine_flags & 2)
diff -puN include/asm-s390/spinlock.h~directed-yield-direct-yield-of-spinlocks-for-s390 include/asm-s390/spinlock.h
--- a/include/asm-s390/spinlock.h~directed-yield-direct-yield-of-spinlocks-for-s390
+++ a/include/asm-s390/spinlock.h
@@ -11,6 +11,8 @@
#ifndef __ASM_SPINLOCK_H
#define __ASM_SPINLOCK_H
+#include <linux/smp.h>
+
static inline int
_raw_compare_and_swap(volatile unsigned int *lock,
unsigned int old, unsigned int new)
@@ -31,34 +33,46 @@ _raw_compare_and_swap(volatile unsigned
* (the type definitions are in asm/spinlock_types.h)
*/
-#define __raw_spin_is_locked(x) ((x)->lock != 0)
+#define __raw_spin_is_locked(x) ((x)->owner_cpu != 0)
#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
#define __raw_spin_unlock_wait(lock) \
- do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0)
+ do { while (__raw_spin_is_locked(lock)) \
+ _raw_spin_relax(lock); } while (0)
-extern void _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc);
-extern int _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc);
+extern void _raw_spin_lock_wait(raw_spinlock_t *, unsigned int pc);
+extern int _raw_spin_trylock_retry(raw_spinlock_t *, unsigned int pc);
+extern void _raw_spin_relax(raw_spinlock_t *lock);
static inline void __raw_spin_lock(raw_spinlock_t *lp)
{
unsigned long pc = 1 | (unsigned long) __builtin_return_address(0);
+ int old;
- if (unlikely(_raw_compare_and_swap(&lp->lock, 0, pc) != 0))
- _raw_spin_lock_wait(lp, pc);
+ old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
+ if (likely(old == 0)) {
+ lp->owner_pc = pc;
+ return;
+ }
+ _raw_spin_lock_wait(lp, pc);
}
static inline int __raw_spin_trylock(raw_spinlock_t *lp)
{
unsigned long pc = 1 | (unsigned long) __builtin_return_address(0);
+ int old;
- if (likely(_raw_compare_and_swap(&lp->lock, 0, pc) == 0))
+ old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
+ if (likely(old == 0)) {
+ lp->owner_pc = pc;
return 1;
+ }
return _raw_spin_trylock_retry(lp, pc);
}
static inline void __raw_spin_unlock(raw_spinlock_t *lp)
{
- _raw_compare_and_swap(&lp->lock, lp->lock, 0);
+ lp->owner_pc = 0;
+ _raw_compare_and_swap(&lp->owner_cpu, lp->owner_cpu, 0);
}
/*
@@ -135,7 +149,6 @@ static inline int __raw_write_trylock(ra
return _raw_write_trylock_retry(rw);
}
-#define _raw_spin_relax(lock) cpu_relax()
#define _raw_read_relax(lock) cpu_relax()
#define _raw_write_relax(lock) cpu_relax()
diff -puN include/asm-s390/spinlock_types.h~directed-yield-direct-yield-of-spinlocks-for-s390 include/asm-s390/spinlock_types.h
--- a/include/asm-s390/spinlock_types.h~directed-yield-direct-yield-of-spinlocks-for-s390
+++ a/include/asm-s390/spinlock_types.h
@@ -6,16 +6,16 @@
#endif
typedef struct {
- volatile unsigned int lock;
+ volatile unsigned int owner_cpu;
+ volatile unsigned int owner_pc;
} __attribute__ ((aligned (4))) raw_spinlock_t;
#define __RAW_SPIN_LOCK_UNLOCKED { 0 }
typedef struct {
volatile unsigned int lock;
- volatile unsigned int owner_pc;
} raw_rwlock_t;
-#define __RAW_RW_LOCK_UNLOCKED { 0, 0 }
+#define __RAW_RW_LOCK_UNLOCKED { 0 }
#endif
_
Patches currently in -mm which might be from schwidefsky@xxxxxxxxxx are
origin.patch
git-s390.patch
reduce-max_nr_zones-remove-display-of-counters-for-unconfigured-zones-s390-fix.patch
reduce-max_nr_zones-remove-display-of-counters-for-unconfigured-zones-s390-fix-fix.patch
out-of-memory-notifier.patch
out-of-memory-notifier-tidy.patch
bootmem-use-max_dma_address-instead-of-low32limit.patch
own-header-file-for-struct-page.patch
convert-s390-page-handling-macros-to-functions.patch
convert-s390-page-handling-macros-to-functions-fix.patch
s390-fix-cmm-kernel-thread-handling.patch
make-touch_nmi_watchdog-imply-touch_softlockup_watchdog-on-fix.patch
simplify-update_times-avoid-jiffies-jiffies_64-aliasing-problem-2.patch
directed-yield-cpu_relax-variants-for-spinlocks-and-rw-locks.patch
directed-yield-direct-yield-of-spinlocks-for-powerpc.patch
directed-yield-direct-yield-of-spinlocks-for-s390.patch
kill-wall_jiffies.patch
generic-ioremap_page_range-implementation.patch
generic-ioremap_page_range-flush_cache_vmap.patch
generic-ioremap_page_range-s390-conversion.patch
s390-update-fs3270-to-use-a-struct-pid.patch
add-regs_return_value-helper.patch
introduce-kernel_execve.patch
rename-the-provided-execve-functions-to-kernel_execve.patch
provide-kernel_execve-on-all-architectures.patch
provide-kernel_execve-on-all-architectures-fix.patch
remove-the-use-of-_syscallx-macros-in-uml.patch
sh64-remove-the-use-of-kernel-syscalls.patch
remove-remaining-errno-and-__kernel_syscalls__-references.patch
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