diff options
author | Chen, Kenneth W <kenneth.w.chen@intel.com> | 2006-01-11 20:11:09 -0500 |
---|---|---|
committer | Tony Luck <tony.luck@intel.com> | 2006-01-26 16:10:19 -0500 |
commit | a454c2f3d1fd1cab7073b53c6c14d6d4b61f4e09 (patch) | |
tree | a1240c5b420adb94dd5c952a089f0326ee0060fe /include/asm-ia64/mutex.h | |
parent | 3ee68c4af3fd7228c1be63254b9f884614f9ebb2 (diff) |
[IA64] implement ia64 specific mutex primitives
Implement ia64 optimized mutex primitives. It properly uses
acquire/release memory ordering semantics in lock/unlock path.
2nd version making them all static inline functions.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'include/asm-ia64/mutex.h')
-rw-r--r-- | include/asm-ia64/mutex.h | 93 |
1 files changed, 88 insertions, 5 deletions
diff --git a/include/asm-ia64/mutex.h b/include/asm-ia64/mutex.h index 458c1f7fbc18..5a3224f6af38 100644 --- a/include/asm-ia64/mutex.h +++ b/include/asm-ia64/mutex.h | |||
@@ -1,9 +1,92 @@ | |||
1 | /* | 1 | /* |
2 | * Pull in the generic implementation for the mutex fastpath. | 2 | * ia64 implementation of the mutex fastpath. |
3 | * | 3 | * |
4 | * TODO: implement optimized primitives instead, or leave the generic | 4 | * Copyright (C) 2006 Ken Chen <kenneth.w.chen@intel.com> |
5 | * implementation in place, or pick the atomic_xchg() based generic | 5 | * |
6 | * implementation. (see asm-generic/mutex-xchg.h for details) | 6 | */ |
7 | |||
8 | #ifndef _ASM_MUTEX_H | ||
9 | #define _ASM_MUTEX_H | ||
10 | |||
11 | /** | ||
12 | * __mutex_fastpath_lock - try to take the lock by moving the count | ||
13 | * from 1 to a 0 value | ||
14 | * @count: pointer of type atomic_t | ||
15 | * @fail_fn: function to call if the original value was not 1 | ||
16 | * | ||
17 | * Change the count from 1 to a value lower than 1, and call <fail_fn> if | ||
18 | * it wasn't 1 originally. This function MUST leave the value lower than | ||
19 | * 1 even when the "1" assertion wasn't true. | ||
20 | */ | ||
21 | static inline void | ||
22 | __mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *)) | ||
23 | { | ||
24 | if (unlikely(ia64_fetchadd4_acq(count, -1) != 1)) | ||
25 | fail_fn(count); | ||
26 | } | ||
27 | |||
28 | /** | ||
29 | * __mutex_fastpath_lock_retval - try to take the lock by moving the count | ||
30 | * from 1 to a 0 value | ||
31 | * @count: pointer of type atomic_t | ||
32 | * @fail_fn: function to call if the original value was not 1 | ||
33 | * | ||
34 | * Change the count from 1 to a value lower than 1, and call <fail_fn> if | ||
35 | * it wasn't 1 originally. This function returns 0 if the fastpath succeeds, | ||
36 | * or anything the slow path function returns. | ||
37 | */ | ||
38 | static inline int | ||
39 | __mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *)) | ||
40 | { | ||
41 | if (unlikely(ia64_fetchadd4_acq(count, -1) != 1)) | ||
42 | return fail_fn(count); | ||
43 | return 0; | ||
44 | } | ||
45 | |||
46 | /** | ||
47 | * __mutex_fastpath_unlock - try to promote the count from 0 to 1 | ||
48 | * @count: pointer of type atomic_t | ||
49 | * @fail_fn: function to call if the original value was not 0 | ||
50 | * | ||
51 | * Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>. | ||
52 | * In the failure case, this function is allowed to either set the value to | ||
53 | * 1, or to set it to a value lower than 1. | ||
54 | * | ||
55 | * If the implementation sets it to a value of lower than 1, then the | ||
56 | * __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs | ||
57 | * to return 0 otherwise. | ||
58 | */ | ||
59 | static inline void | ||
60 | __mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *)) | ||
61 | { | ||
62 | int ret = ia64_fetchadd4_rel(count, 1); | ||
63 | if (unlikely(ret < 0)) | ||
64 | fail_fn(count); | ||
65 | } | ||
66 | |||
67 | #define __mutex_slowpath_needs_to_unlock() 1 | ||
68 | |||
69 | /** | ||
70 | * __mutex_fastpath_trylock - try to acquire the mutex, without waiting | ||
71 | * | ||
72 | * @count: pointer of type atomic_t | ||
73 | * @fail_fn: fallback function | ||
74 | * | ||
75 | * Change the count from 1 to a value lower than 1, and return 0 (failure) | ||
76 | * if it wasn't 1 originally, or return 1 (success) otherwise. This function | ||
77 | * MUST leave the value lower than 1 even when the "1" assertion wasn't true. | ||
78 | * Additionally, if the value was < 0 originally, this function must not leave | ||
79 | * it to 0 on failure. | ||
80 | * | ||
81 | * If the architecture has no effective trylock variant, it should call the | ||
82 | * <fail_fn> spinlock-based trylock variant unconditionally. | ||
7 | */ | 83 | */ |
84 | static inline int | ||
85 | __mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *)) | ||
86 | { | ||
87 | if (likely(cmpxchg_acq(count, 1, 0)) == 1) | ||
88 | return 1; | ||
89 | return 0; | ||
90 | } | ||
8 | 91 | ||
9 | #include <asm-generic/mutex-dec.h> | 92 | #endif |