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authorIngo Molnar <mingo@elte.hu>2005-09-10 03:25:56 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-10 13:06:21 -0400
commitfb1c8f93d869b34cacb8b8932e2b83d96a19d720 (patch)
treea006d078aa02e421a7dc4793c335308204859d36 /include/asm-ppc64
parent4327edf6b8a7ac7dce144313947995538842d8fd (diff)
[PATCH] spinlock consolidation
This patch (written by me and also containing many suggestions of Arjan van de Ven) does a major cleanup of the spinlock code. It does the following things: - consolidates and enhances the spinlock/rwlock debugging code - simplifies the asm/spinlock.h files - encapsulates the raw spinlock type and moves generic spinlock features (such as ->break_lock) into the generic code. - cleans up the spinlock code hierarchy to get rid of the spaghetti. Most notably there's now only a single variant of the debugging code, located in lib/spinlock_debug.c. (previously we had one SMP debugging variant per architecture, plus a separate generic one for UP builds) Also, i've enhanced the rwlock debugging facility, it will now track write-owners. There is new spinlock-owner/CPU-tracking on SMP builds too. All locks have lockup detection now, which will work for both soft and hard spin/rwlock lockups. The arch-level include files now only contain the minimally necessary subset of the spinlock code - all the rest that can be generalized now lives in the generic headers: include/asm-i386/spinlock_types.h | 16 include/asm-x86_64/spinlock_types.h | 16 I have also split up the various spinlock variants into separate files, making it easier to see which does what. The new layout is: SMP | UP ----------------------------|----------------------------------- asm/spinlock_types_smp.h | linux/spinlock_types_up.h linux/spinlock_types.h | linux/spinlock_types.h asm/spinlock_smp.h | linux/spinlock_up.h linux/spinlock_api_smp.h | linux/spinlock_api_up.h linux/spinlock.h | linux/spinlock.h /* * here's the role of the various spinlock/rwlock related include files: * * on SMP builds: * * asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the * initializers * * linux/spinlock_types.h: * defines the generic type and initializers * * asm/spinlock.h: contains the __raw_spin_*()/etc. lowlevel * implementations, mostly inline assembly code * * (also included on UP-debug builds:) * * linux/spinlock_api_smp.h: * contains the prototypes for the _spin_*() APIs. * * linux/spinlock.h: builds the final spin_*() APIs. * * on UP builds: * * linux/spinlock_type_up.h: * contains the generic, simplified UP spinlock type. * (which is an empty structure on non-debug builds) * * linux/spinlock_types.h: * defines the generic type and initializers * * linux/spinlock_up.h: * contains the __raw_spin_*()/etc. version of UP * builds. (which are NOPs on non-debug, non-preempt * builds) * * (included on UP-non-debug builds:) * * linux/spinlock_api_up.h: * builds the _spin_*() APIs. * * linux/spinlock.h: builds the final spin_*() APIs. */ All SMP and UP architectures are converted by this patch. arm, i386, ia64, ppc, ppc64, s390/s390x, x64 was build-tested via crosscompilers. m32r, mips, sh, sparc, have not been tested yet, but should be mostly fine. From: Grant Grundler <grundler@parisc-linux.org> Booted and lightly tested on a500-44 (64-bit, SMP kernel, dual CPU). Builds 32-bit SMP kernel (not booted or tested). I did not try to build non-SMP kernels. That should be trivial to fix up later if necessary. I converted bit ops atomic_hash lock to raw_spinlock_t. Doing so avoids some ugly nesting of linux/*.h and asm/*.h files. Those particular locks are well tested and contained entirely inside arch specific code. I do NOT expect any new issues to arise with them. If someone does ever need to use debug/metrics with them, then they will need to unravel this hairball between spinlocks, atomic ops, and bit ops that exist only because parisc has exactly one atomic instruction: LDCW (load and clear word). From: "Luck, Tony" <tony.luck@intel.com> ia64 fix Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjanv@infradead.org> Signed-off-by: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Mikael Pettersson <mikpe@csd.uu.se> Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/asm-ppc64')
-rw-r--r--include/asm-ppc64/spinlock.h191
-rw-r--r--include/asm-ppc64/spinlock_types.h20
2 files changed, 106 insertions, 105 deletions
diff --git a/include/asm-ppc64/spinlock.h b/include/asm-ppc64/spinlock.h
index acd11564dd75..14cb895bb607 100644
--- a/include/asm-ppc64/spinlock.h
+++ b/include/asm-ppc64/spinlock.h
@@ -15,36 +15,42 @@
15 * modify it under the terms of the GNU General Public License 15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version 16 * as published by the Free Software Foundation; either version
17 * 2 of the License, or (at your option) any later version. 17 * 2 of the License, or (at your option) any later version.
18 *
19 * (the type definitions are in asm/spinlock_types.h)
18 */ 20 */
19#include <linux/config.h> 21#include <linux/config.h>
20#include <asm/paca.h> 22#include <asm/paca.h>
21#include <asm/hvcall.h> 23#include <asm/hvcall.h>
22#include <asm/iSeries/HvCall.h> 24#include <asm/iSeries/HvCall.h>
23 25
24typedef struct { 26#define __raw_spin_is_locked(x) ((x)->slock != 0)
25 volatile unsigned int lock;
26#ifdef CONFIG_PREEMPT
27 unsigned int break_lock;
28#endif
29} spinlock_t;
30 27
31typedef struct { 28/*
32 volatile signed int lock; 29 * This returns the old value in the lock, so we succeeded
33#ifdef CONFIG_PREEMPT 30 * in getting the lock if the return value is 0.
34 unsigned int break_lock; 31 */
35#endif 32static __inline__ unsigned long __spin_trylock(raw_spinlock_t *lock)
36} rwlock_t; 33{
34 unsigned long tmp, tmp2;
37 35
38#ifdef __KERNEL__ 36 __asm__ __volatile__(
39#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 } 37" lwz %1,%3(13) # __spin_trylock\n\
381: lwarx %0,0,%2\n\
39 cmpwi 0,%0,0\n\
40 bne- 2f\n\
41 stwcx. %1,0,%2\n\
42 bne- 1b\n\
43 isync\n\
442:" : "=&r" (tmp), "=&r" (tmp2)
45 : "r" (&lock->slock), "i" (offsetof(struct paca_struct, lock_token))
46 : "cr0", "memory");
40 47
41#define spin_is_locked(x) ((x)->lock != 0) 48 return tmp;
42#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0) 49}
43 50
44static __inline__ void _raw_spin_unlock(spinlock_t *lock) 51static int __inline__ __raw_spin_trylock(raw_spinlock_t *lock)
45{ 52{
46 __asm__ __volatile__("lwsync # spin_unlock": : :"memory"); 53 return __spin_trylock(lock) == 0;
47 lock->lock = 0;
48} 54}
49 55
50/* 56/*
@@ -64,44 +70,15 @@ static __inline__ void _raw_spin_unlock(spinlock_t *lock)
64#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES) 70#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
65/* We only yield to the hypervisor if we are in shared processor mode */ 71/* We only yield to the hypervisor if we are in shared processor mode */
66#define SHARED_PROCESSOR (get_paca()->lppaca.shared_proc) 72#define SHARED_PROCESSOR (get_paca()->lppaca.shared_proc)
67extern void __spin_yield(spinlock_t *lock); 73extern void __spin_yield(raw_spinlock_t *lock);
68extern void __rw_yield(rwlock_t *lock); 74extern void __rw_yield(raw_rwlock_t *lock);
69#else /* SPLPAR || ISERIES */ 75#else /* SPLPAR || ISERIES */
70#define __spin_yield(x) barrier() 76#define __spin_yield(x) barrier()
71#define __rw_yield(x) barrier() 77#define __rw_yield(x) barrier()
72#define SHARED_PROCESSOR 0 78#define SHARED_PROCESSOR 0
73#endif 79#endif
74extern void spin_unlock_wait(spinlock_t *lock);
75
76/*
77 * This returns the old value in the lock, so we succeeded
78 * in getting the lock if the return value is 0.
79 */
80static __inline__ unsigned long __spin_trylock(spinlock_t *lock)
81{
82 unsigned long tmp, tmp2;
83
84 __asm__ __volatile__(
85" lwz %1,%3(13) # __spin_trylock\n\
861: lwarx %0,0,%2\n\
87 cmpwi 0,%0,0\n\
88 bne- 2f\n\
89 stwcx. %1,0,%2\n\
90 bne- 1b\n\
91 isync\n\
922:" : "=&r" (tmp), "=&r" (tmp2)
93 : "r" (&lock->lock), "i" (offsetof(struct paca_struct, lock_token))
94 : "cr0", "memory");
95
96 return tmp;
97}
98
99static int __inline__ _raw_spin_trylock(spinlock_t *lock)
100{
101 return __spin_trylock(lock) == 0;
102}
103 80
104static void __inline__ _raw_spin_lock(spinlock_t *lock) 81static void __inline__ __raw_spin_lock(raw_spinlock_t *lock)
105{ 82{
106 while (1) { 83 while (1) {
107 if (likely(__spin_trylock(lock) == 0)) 84 if (likely(__spin_trylock(lock) == 0))
@@ -110,12 +87,12 @@ static void __inline__ _raw_spin_lock(spinlock_t *lock)
110 HMT_low(); 87 HMT_low();
111 if (SHARED_PROCESSOR) 88 if (SHARED_PROCESSOR)
112 __spin_yield(lock); 89 __spin_yield(lock);
113 } while (unlikely(lock->lock != 0)); 90 } while (unlikely(lock->slock != 0));
114 HMT_medium(); 91 HMT_medium();
115 } 92 }
116} 93}
117 94
118static void __inline__ _raw_spin_lock_flags(spinlock_t *lock, unsigned long flags) 95static void __inline__ __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
119{ 96{
120 unsigned long flags_dis; 97 unsigned long flags_dis;
121 98
@@ -128,12 +105,20 @@ static void __inline__ _raw_spin_lock_flags(spinlock_t *lock, unsigned long flag
128 HMT_low(); 105 HMT_low();
129 if (SHARED_PROCESSOR) 106 if (SHARED_PROCESSOR)
130 __spin_yield(lock); 107 __spin_yield(lock);
131 } while (unlikely(lock->lock != 0)); 108 } while (unlikely(lock->slock != 0));
132 HMT_medium(); 109 HMT_medium();
133 local_irq_restore(flags_dis); 110 local_irq_restore(flags_dis);
134 } 111 }
135} 112}
136 113
114static __inline__ void __raw_spin_unlock(raw_spinlock_t *lock)
115{
116 __asm__ __volatile__("lwsync # __raw_spin_unlock": : :"memory");
117 lock->slock = 0;
118}
119
120extern void __raw_spin_unlock_wait(raw_spinlock_t *lock);
121
137/* 122/*
138 * Read-write spinlocks, allowing multiple readers 123 * Read-write spinlocks, allowing multiple readers
139 * but only one writer. 124 * but only one writer.
@@ -144,24 +129,15 @@ static void __inline__ _raw_spin_lock_flags(spinlock_t *lock, unsigned long flag
144 * irq-safe write-lock, but readers can get non-irqsafe 129 * irq-safe write-lock, but readers can get non-irqsafe
145 * read-locks. 130 * read-locks.
146 */ 131 */
147#define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
148 132
149#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0) 133#define __raw_read_can_lock(rw) ((rw)->lock >= 0)
150 134#define __raw_write_can_lock(rw) (!(rw)->lock)
151#define read_can_lock(rw) ((rw)->lock >= 0)
152#define write_can_lock(rw) (!(rw)->lock)
153
154static __inline__ void _raw_write_unlock(rwlock_t *rw)
155{
156 __asm__ __volatile__("lwsync # write_unlock": : :"memory");
157 rw->lock = 0;
158}
159 135
160/* 136/*
161 * This returns the old value in the lock + 1, 137 * This returns the old value in the lock + 1,
162 * so we got a read lock if the return value is > 0. 138 * so we got a read lock if the return value is > 0.
163 */ 139 */
164static long __inline__ __read_trylock(rwlock_t *rw) 140static long __inline__ __read_trylock(raw_rwlock_t *rw)
165{ 141{
166 long tmp; 142 long tmp;
167 143
@@ -180,45 +156,11 @@ static long __inline__ __read_trylock(rwlock_t *rw)
180 return tmp; 156 return tmp;
181} 157}
182 158
183static int __inline__ _raw_read_trylock(rwlock_t *rw)
184{
185 return __read_trylock(rw) > 0;
186}
187
188static void __inline__ _raw_read_lock(rwlock_t *rw)
189{
190 while (1) {
191 if (likely(__read_trylock(rw) > 0))
192 break;
193 do {
194 HMT_low();
195 if (SHARED_PROCESSOR)
196 __rw_yield(rw);
197 } while (unlikely(rw->lock < 0));
198 HMT_medium();
199 }
200}
201
202static void __inline__ _raw_read_unlock(rwlock_t *rw)
203{
204 long tmp;
205
206 __asm__ __volatile__(
207 "eieio # read_unlock\n\
2081: lwarx %0,0,%1\n\
209 addic %0,%0,-1\n\
210 stwcx. %0,0,%1\n\
211 bne- 1b"
212 : "=&r"(tmp)
213 : "r"(&rw->lock)
214 : "cr0", "memory");
215}
216
217/* 159/*
218 * This returns the old value in the lock, 160 * This returns the old value in the lock,
219 * so we got the write lock if the return value is 0. 161 * so we got the write lock if the return value is 0.
220 */ 162 */
221static __inline__ long __write_trylock(rwlock_t *rw) 163static __inline__ long __write_trylock(raw_rwlock_t *rw)
222{ 164{
223 long tmp, tmp2; 165 long tmp, tmp2;
224 166
@@ -237,12 +179,21 @@ static __inline__ long __write_trylock(rwlock_t *rw)
237 return tmp; 179 return tmp;
238} 180}
239 181
240static int __inline__ _raw_write_trylock(rwlock_t *rw) 182static void __inline__ __raw_read_lock(raw_rwlock_t *rw)
241{ 183{
242 return __write_trylock(rw) == 0; 184 while (1) {
185 if (likely(__read_trylock(rw) > 0))
186 break;
187 do {
188 HMT_low();
189 if (SHARED_PROCESSOR)
190 __rw_yield(rw);
191 } while (unlikely(rw->lock < 0));
192 HMT_medium();
193 }
243} 194}
244 195
245static void __inline__ _raw_write_lock(rwlock_t *rw) 196static void __inline__ __raw_write_lock(raw_rwlock_t *rw)
246{ 197{
247 while (1) { 198 while (1) {
248 if (likely(__write_trylock(rw) == 0)) 199 if (likely(__write_trylock(rw) == 0))
@@ -256,5 +207,35 @@ static void __inline__ _raw_write_lock(rwlock_t *rw)
256 } 207 }
257} 208}
258 209
259#endif /* __KERNEL__ */ 210static int __inline__ __raw_read_trylock(raw_rwlock_t *rw)
211{
212 return __read_trylock(rw) > 0;
213}
214
215static int __inline__ __raw_write_trylock(raw_rwlock_t *rw)
216{
217 return __write_trylock(rw) == 0;
218}
219
220static void __inline__ __raw_read_unlock(raw_rwlock_t *rw)
221{
222 long tmp;
223
224 __asm__ __volatile__(
225 "eieio # read_unlock\n\
2261: lwarx %0,0,%1\n\
227 addic %0,%0,-1\n\
228 stwcx. %0,0,%1\n\
229 bne- 1b"
230 : "=&r"(tmp)
231 : "r"(&rw->lock)
232 : "cr0", "memory");
233}
234
235static __inline__ void __raw_write_unlock(raw_rwlock_t *rw)
236{
237 __asm__ __volatile__("lwsync # write_unlock": : :"memory");
238 rw->lock = 0;
239}
240
260#endif /* __ASM_SPINLOCK_H */ 241#endif /* __ASM_SPINLOCK_H */
diff --git a/include/asm-ppc64/spinlock_types.h b/include/asm-ppc64/spinlock_types.h
new file mode 100644
index 000000000000..a37c8eabb9f2
--- /dev/null
+++ b/include/asm-ppc64/spinlock_types.h
@@ -0,0 +1,20 @@
1#ifndef __ASM_SPINLOCK_TYPES_H
2#define __ASM_SPINLOCK_TYPES_H
3
4#ifndef __LINUX_SPINLOCK_TYPES_H
5# error "please don't include this file directly"
6#endif
7
8typedef struct {
9 volatile unsigned int slock;
10} raw_spinlock_t;
11
12#define __RAW_SPIN_LOCK_UNLOCKED { 0 }
13
14typedef struct {
15 volatile signed int lock;
16} raw_rwlock_t;
17
18#define __RAW_RW_LOCK_UNLOCKED { 0 }
19
20#endif