diff options
| author | Petr Tesarik <ptesarik@suse.cz> | 2010-09-16 00:35:48 +0200 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2010-09-16 00:35:48 +0200 |
| commit | 2d2b6901649a62977452be85df53eda2412def24 (patch) | |
| tree | 622553b837759352a334a350d52f1f2d7652c9c1 /arch | |
| parent | Merge branch 'sched/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/... (diff) | |
| download | linux-2d2b6901649a62977452be85df53eda2412def24.tar.xz linux-2d2b6901649a62977452be85df53eda2412def24.zip | |
[IA64] Optimize ticket spinlocks in fsys_rt_sigprocmask
Tony's fix (f574c843191728d9407b766a027f779dcd27b272) has a small bug,
it incorrectly uses "r3" as a scratch register in the first of the two
unlock paths ... it is also inefficient. Optimize the fast path again.
Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/ia64/kernel/fsys.S | 42 |
1 files changed, 11 insertions, 31 deletions
diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S index 471a1e783aca..331d42bda77a 100644 --- a/arch/ia64/kernel/fsys.S +++ b/arch/ia64/kernel/fsys.S @@ -420,34 +420,31 @@ EX(.fail_efault, ld8 r14=[r33]) // r14 <- *set ;; RSM_PSR_I(p0, r18, r19) // mask interrupt delivery - mov ar.ccv=0 andcm r14=r14,r17 // filter out SIGKILL & SIGSTOP + mov r8=EINVAL // default to EINVAL #ifdef CONFIG_SMP // __ticket_spin_trylock(r31) ld4 r17=[r31] - mov r8=EINVAL // default to EINVAL - ;; - extr r9=r17,17,15 ;; - xor r18=r17,r9 + mov.m ar.ccv=r17 + extr.u r9=r17,17,15 adds r19=1,r17 + extr.u r18=r17,0,15 ;; - extr.u r18=r18,0,15 + cmp.eq p6,p7=r9,r18 ;; - cmp.eq p0,p7=0,r18 +(p6) cmpxchg4.acq r9=[r31],r19,ar.ccv +(p6) dep.z r20=r19,1,15 // next serving ticket for unlock (p7) br.cond.spnt.many .lock_contention - mov.m ar.ccv=r17 - ;; - cmpxchg4.acq r9=[r31],r19,ar.ccv ;; cmp4.eq p0,p7=r9,r17 + adds r31=2,r31 (p7) br.cond.spnt.many .lock_contention ld8 r3=[r2] // re-read current->blocked now that we hold the lock ;; #else ld8 r3=[r2] // re-read current->blocked now that we hold the lock - mov r8=EINVAL // default to EINVAL #endif add r18=IA64_TASK_PENDING_OFFSET+IA64_SIGPENDING_SIGNAL_OFFSET,r16 add r19=IA64_TASK_SIGNAL_OFFSET,r16 @@ -503,16 +500,8 @@ EX(.fail_efault, ld8 r14=[r33]) // r14 <- *set #ifdef CONFIG_SMP // __ticket_spin_unlock(r31) - adds r31=2,r31 - ;; - ld2.bias r2=[r31] - mov r3=65534 - ;; - adds r2=2,r2 - ;; - and r3=r3,r2 - ;; - st2.rel [r31]=r3 + st2.rel [r31]=r20 + mov r20=0 // i must not leak kernel bits... #endif SSM_PSR_I(p0, p9, r31) ;; @@ -535,16 +524,7 @@ EX(.fail_efault, (p15) st8 [r34]=r3) .sig_pending: #ifdef CONFIG_SMP // __ticket_spin_unlock(r31) - adds r31=2,r31 - ;; - ld2.bias r2=[r31] - mov r3=65534 - ;; - adds r2=2,r2 - ;; - and r3=r3,r2 - ;; - st2.rel [r31]=r3 + st2.rel [r31]=r20 // release the lock #endif SSM_PSR_I(p0, p9, r17) ;; |