| Greg Thelen | 623fd80 | 2013-11-12 15:08:34 -0800 | [diff] [blame] | 1 | #include <linux/module.h> |
| 2 | |
| 3 | /* validate @native and @pcp counter values match @expected */ |
| 4 | #define CHECK(native, pcp, expected) \ |
| 5 | do { \ |
| 6 | WARN((native) != (expected), \ |
| 7 | "raw %ld (0x%lx) != expected %lld (0x%llx)", \ |
| 8 | (native), (native), \ |
| 9 | (long long)(expected), (long long)(expected)); \ |
| 10 | WARN(__this_cpu_read(pcp) != (expected), \ |
| 11 | "pcp %ld (0x%lx) != expected %lld (0x%llx)", \ |
| 12 | __this_cpu_read(pcp), __this_cpu_read(pcp), \ |
| 13 | (long long)(expected), (long long)(expected)); \ |
| 14 | } while (0) |
| 15 | |
| 16 | static DEFINE_PER_CPU(long, long_counter); |
| 17 | static DEFINE_PER_CPU(unsigned long, ulong_counter); |
| 18 | |
| 19 | static int __init percpu_test_init(void) |
| 20 | { |
| 21 | /* |
| 22 | * volatile prevents compiler from optimizing it uses, otherwise the |
| 23 | * +ul_one/-ul_one below would replace with inc/dec instructions. |
| 24 | */ |
| 25 | volatile unsigned int ui_one = 1; |
| 26 | long l = 0; |
| 27 | unsigned long ul = 0; |
| 28 | |
| 29 | pr_info("percpu test start\n"); |
| 30 | |
| 31 | preempt_disable(); |
| 32 | |
| 33 | l += -1; |
| 34 | __this_cpu_add(long_counter, -1); |
| 35 | CHECK(l, long_counter, -1); |
| 36 | |
| 37 | l += 1; |
| 38 | __this_cpu_add(long_counter, 1); |
| 39 | CHECK(l, long_counter, 0); |
| 40 | |
| 41 | ul = 0; |
| 42 | __this_cpu_write(ulong_counter, 0); |
| 43 | |
| 44 | ul += 1UL; |
| 45 | __this_cpu_add(ulong_counter, 1UL); |
| 46 | CHECK(ul, ulong_counter, 1); |
| 47 | |
| 48 | ul += -1UL; |
| 49 | __this_cpu_add(ulong_counter, -1UL); |
| 50 | CHECK(ul, ulong_counter, 0); |
| 51 | |
| 52 | ul += -(unsigned long)1; |
| 53 | __this_cpu_add(ulong_counter, -(unsigned long)1); |
| 54 | CHECK(ul, ulong_counter, -1); |
| 55 | |
| 56 | ul = 0; |
| 57 | __this_cpu_write(ulong_counter, 0); |
| 58 | |
| 59 | ul -= 1; |
| 60 | __this_cpu_dec(ulong_counter); |
| 61 | CHECK(ul, ulong_counter, -1); |
| 62 | CHECK(ul, ulong_counter, ULONG_MAX); |
| 63 | |
| 64 | l += -ui_one; |
| 65 | __this_cpu_add(long_counter, -ui_one); |
| 66 | CHECK(l, long_counter, 0xffffffff); |
| 67 | |
| 68 | l += ui_one; |
| 69 | __this_cpu_add(long_counter, ui_one); |
| 70 | CHECK(l, long_counter, (long)0x100000000LL); |
| 71 | |
| 72 | |
| 73 | l = 0; |
| 74 | __this_cpu_write(long_counter, 0); |
| 75 | |
| 76 | l -= ui_one; |
| 77 | __this_cpu_sub(long_counter, ui_one); |
| 78 | CHECK(l, long_counter, -1); |
| 79 | |
| 80 | l = 0; |
| 81 | __this_cpu_write(long_counter, 0); |
| 82 | |
| 83 | l += ui_one; |
| 84 | __this_cpu_add(long_counter, ui_one); |
| 85 | CHECK(l, long_counter, 1); |
| 86 | |
| 87 | l += -ui_one; |
| 88 | __this_cpu_add(long_counter, -ui_one); |
| 89 | CHECK(l, long_counter, (long)0x100000000LL); |
| 90 | |
| 91 | l = 0; |
| 92 | __this_cpu_write(long_counter, 0); |
| 93 | |
| 94 | l -= ui_one; |
| 95 | this_cpu_sub(long_counter, ui_one); |
| 96 | CHECK(l, long_counter, -1); |
| 97 | CHECK(l, long_counter, ULONG_MAX); |
| 98 | |
| 99 | ul = 0; |
| 100 | __this_cpu_write(ulong_counter, 0); |
| 101 | |
| 102 | ul += ui_one; |
| 103 | __this_cpu_add(ulong_counter, ui_one); |
| 104 | CHECK(ul, ulong_counter, 1); |
| 105 | |
| 106 | ul = 0; |
| 107 | __this_cpu_write(ulong_counter, 0); |
| 108 | |
| 109 | ul -= ui_one; |
| 110 | __this_cpu_sub(ulong_counter, ui_one); |
| 111 | CHECK(ul, ulong_counter, -1); |
| 112 | CHECK(ul, ulong_counter, ULONG_MAX); |
| 113 | |
| 114 | ul = 3; |
| 115 | __this_cpu_write(ulong_counter, 3); |
| 116 | |
| 117 | ul = this_cpu_sub_return(ulong_counter, ui_one); |
| 118 | CHECK(ul, ulong_counter, 2); |
| 119 | |
| 120 | ul = __this_cpu_sub_return(ulong_counter, ui_one); |
| 121 | CHECK(ul, ulong_counter, 1); |
| 122 | |
| 123 | preempt_enable(); |
| 124 | |
| 125 | pr_info("percpu test done\n"); |
| 126 | return -EAGAIN; /* Fail will directly unload the module */ |
| 127 | } |
| 128 | |
| 129 | static void __exit percpu_test_exit(void) |
| 130 | { |
| 131 | } |
| 132 | |
| 133 | module_init(percpu_test_init) |
| 134 | module_exit(percpu_test_exit) |
| 135 | |
| 136 | MODULE_LICENSE("GPL"); |
| 137 | MODULE_AUTHOR("Greg Thelen"); |
| 138 | MODULE_DESCRIPTION("percpu operations test"); |