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authorLinus Torvalds <torvalds@linux-foundation.org>2010-09-16 12:58:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-09-16 12:58:44 -0700
commit7bb419041bab2c0efa6e78e9e9e3d9c6ebc75fae (patch)
tree07837cf65e21d010e90288bb0d5d7aeef311d053
parent1f0ce990f0fc1bb92c28ef3f54b55cdf9a17b3a8 (diff)
parent2d2b6901649a62977452be85df53eda2412def24 (diff)
downloadlinux-7bb419041bab2c0efa6e78e9e9e3d9c6ebc75fae.tar.gz
Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
  [IA64] Optimize ticket spinlocks in fsys_rt_sigprocmask
-rw-r--r--arch/ia64/kernel/fsys.S42
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)
 	;;