aboutsummaryrefslogtreecommitdiffstats
path: root/arch/ia64/mm/tlb.c
diff options
context:
space:
mode:
authorTony Luck <tony.luck@intel.com>2009-10-09 13:52:39 -0400
committerTony Luck <tony.luck@intel.com>2009-10-09 13:52:39 -0400
commit883a3acf5b0d4782ac35981227a0d094e8b44850 (patch)
treea5ad44c09e36298749f0b37dbd5695bad040620c /arch/ia64/mm/tlb.c
parent36a07902c2134649c4af7f07980413ffb1a56085 (diff)
[IA64] Re-implement spinaphores using ticket lock concepts
Bound the wait time for the ptcg_sem by using similar idea to the ticket spin locks. In this case we have only one instance of a spinaphore, so make it 8 bytes rather than try to squeeze it into 4-bytes to keep the code simpler (and shorter). Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/mm/tlb.c')
-rw-r--r--arch/ia64/mm/tlb.c24
1 files changed, 18 insertions, 6 deletions
diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c
index f426dc78d959..ee09d261f2e6 100644
--- a/arch/ia64/mm/tlb.c
+++ b/arch/ia64/mm/tlb.c
@@ -100,24 +100,36 @@ wrap_mmu_context (struct mm_struct *mm)
100 * this primitive it can be moved up to a spinaphore.h header. 100 * this primitive it can be moved up to a spinaphore.h header.
101 */ 101 */
102struct spinaphore { 102struct spinaphore {
103 atomic_t cur; 103 unsigned long ticket;
104 unsigned long serve;
104}; 105};
105 106
106static inline void spinaphore_init(struct spinaphore *ss, int val) 107static inline void spinaphore_init(struct spinaphore *ss, int val)
107{ 108{
108 atomic_set(&ss->cur, val); 109 ss->ticket = 0;
110 ss->serve = val;
109} 111}
110 112
111static inline void down_spin(struct spinaphore *ss) 113static inline void down_spin(struct spinaphore *ss)
112{ 114{
113 while (unlikely(!atomic_add_unless(&ss->cur, -1, 0))) 115 unsigned long t = ia64_fetchadd(1, &ss->ticket, acq), serve;
114 while (atomic_read(&ss->cur) == 0) 116
115 cpu_relax(); 117 if (time_before(t, ss->serve))
118 return;
119
120 ia64_invala();
121
122 for (;;) {
123 asm volatile ("ld4.c.nc %0=[%1]" : "=r"(serve) : "r"(&ss->serve) : "memory");
124 if (time_before(t, serve))
125 return;
126 cpu_relax();
127 }
116} 128}
117 129
118static inline void up_spin(struct spinaphore *ss) 130static inline void up_spin(struct spinaphore *ss)
119{ 131{
120 atomic_add(1, &ss->cur); 132 ia64_fetchadd(1, &ss->serve, rel);
121} 133}
122 134
123static struct spinaphore ptcg_sem; 135static struct spinaphore ptcg_sem;