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| author | John David Anglin <dave.anglin@bell.net> | 2020-10-02 21:21:41 +0200 |
|---|---|---|
| committer | Helge Deller <deller@gmx.de> | 2020-10-15 08:10:39 +0200 |
| commit | 53a42b6324b8ddce1e9d2f34da2ca68ef21c2084 (patch) | |
| tree | e56e6b487f238312f4c01b526a65aad48de475aa /arch | |
| parent | parisc: Mark pointers volatile in __xchg8(), __xchg32() and __xchg64() (diff) | |
| download | linux-53a42b6324b8ddce1e9d2f34da2ca68ef21c2084.tar.xz linux-53a42b6324b8ddce1e9d2f34da2ca68ef21c2084.zip | |
parisc: Switch to more fine grained lws locks
Increase the number of lws locks to 256 entries (instead of 16) and
choose lock entry based on bits 3-11 (instead of 4-7) of the relevant
address. With this change we archieve more fine-grained locking in
futex syscalls and thus reduce the number of possible stalls.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/parisc/include/asm/futex.h | 4 | ||||
| -rw-r--r-- | arch/parisc/kernel/syscall.S | 10 |
2 files changed, 7 insertions, 7 deletions
diff --git a/arch/parisc/include/asm/futex.h b/arch/parisc/include/asm/futex.h index c459f656c8c3..fceb9cf02fb3 100644 --- a/arch/parisc/include/asm/futex.h +++ b/arch/parisc/include/asm/futex.h @@ -16,7 +16,7 @@ static inline void _futex_spin_lock_irqsave(u32 __user *uaddr, unsigned long int *flags) { extern u32 lws_lock_start[]; - long index = ((long)uaddr & 0xf0) >> 2; + long index = ((long)uaddr & 0x3f8) >> 1; arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index]; local_irq_save(*flags); arch_spin_lock(s); @@ -26,7 +26,7 @@ static inline void _futex_spin_unlock_irqrestore(u32 __user *uaddr, unsigned long int *flags) { extern u32 lws_lock_start[]; - long index = ((long)uaddr & 0xf0) >> 2; + long index = ((long)uaddr & 0x3f8) >> 1; arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index]; arch_spin_unlock(s); local_irq_restore(*flags); diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S index 3ad61a177f5b..322503780db6 100644 --- a/arch/parisc/kernel/syscall.S +++ b/arch/parisc/kernel/syscall.S @@ -571,8 +571,8 @@ lws_compare_and_swap: ldil L%lws_lock_start, %r20 ldo R%lws_lock_start(%r20), %r28 - /* Extract four bits from r26 and hash lock (Bits 4-7) */ - extru %r26, 27, 4, %r20 + /* Extract eight bits from r26 and hash lock (Bits 3-11) */ + extru %r26, 28, 8, %r20 /* Find lock to use, the hash is either one of 0 to 15, multiplied by 16 (keep it 16-byte aligned) @@ -761,8 +761,8 @@ cas2_lock_start: ldil L%lws_lock_start, %r20 ldo R%lws_lock_start(%r20), %r28 - /* Extract four bits from r26 and hash lock (Bits 4-7) */ - extru %r26, 27, 4, %r20 + /* Extract eight bits from r26 and hash lock (Bits 3-11) */ + extru %r26, 28, 8, %r20 /* Find lock to use, the hash is either one of 0 to 15, multiplied by 16 (keep it 16-byte aligned) @@ -950,7 +950,7 @@ END(sys_call_table64) .align L1_CACHE_BYTES ENTRY(lws_lock_start) /* lws locks */ - .rept 16 + .rept 256 /* Keep locks aligned at 16-bytes */ .word 1 .word 0 |