{"id":1809,"date":"2010-10-20T17:20:42","date_gmt":"2010-10-20T09:20:42","guid":{"rendered":"http:\/\/edsionte.com\/techblog\/?p=1809"},"modified":"2010-10-24T13:56:30","modified_gmt":"2010-10-24T05:56:30","slug":"%e5%86%85%e6%a0%b8%e5%90%8c%e6%ad%a5%e6%96%b9%e6%b3%95-%e5%8e%9f%e5%ad%90%e6%93%8d%e4%bd%9c","status":"publish","type":"post","link":"http:\/\/edsionte.com\/techblog\/archives\/1809","title":{"rendered":"\u5185\u6838\u540c\u6b65\u65b9\u6cd5-\u539f\u5b50\u64cd\u4f5c"},"content":{"rendered":"<p><strong><em><span style=\"color: #ff0000;\">Latest Update:2010\/10\/23<\/span><\/em><\/strong><\/p>\n<p><strong><em><\/em><\/strong><strong>\u539f\u5b50\u64cd\u4f5c<\/strong><\/p>\n<p>\u539f\u5b50\u64cd\u4f5c\u7528\u4e8e\u6267\u884c\u8f7b\u91cf\u7ea7\u3001\u4ec5\u6267\u884c\u4e00\u6b21\u7684\u64cd\u4f5c\uff0c\u6bd4\u5982\u4fee\u6539\u8ba1\u6570\u5668\uff0c\u67d0\u4e9b\u6761\u4ef6\u4e0b\u7684\u589e\u52a0\u503c\u6216\u8bbe\u7f6e\u4f4d\u7b49\u3002\u539f\u5b50\u64cd\u4f5c\u6307\u7684\u662f\u6307\u4ee4\u4ee5\u539f\u5b50\u7684\u65b9\u5f0f\u6267\u884c\u3002\u4e4b\u6240\u4ee5\u7528\u539f\u5b50\u6765\u4fee\u9970\u8fd9\u79cd\u64cd\u4f5c\u65b9\u5f0f\u662f\u56e0\u4e3a\u5b83\u4eec\u5747\u4e0d\u53ef\u518d\u5206\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u539f\u5b50\u64cd\u4f5c\u8981\u4e48\u4e00\u6b21\u6027\u6267\u884c\u5b8c\u6bd5\uff0c\u8981\u4e48\u5c31\u4e0d\u6267\u884c\uff0c\u8fd9\u4e9b\u64cd\u4f5c\u7684\u6267\u884c\u8fc7\u7a0b\u662f\u4e0d\u53ef\u88ab\u6253\u65ad\u7684\u3002<span style=\"font-size: 13.3333px;\">\u539f\u5b50\u64cd\u4f5c\u7684\u5177\u4f53\u5b9e\u73b0\u53d6\u51b3\u4e8e\u4f53\u7cfb\u67b6\u6784\uff0c\u4ee5\u4e0b\u4ee3\u7801\u5982\u65e0\u7279\u522b\u58f0\u660e\uff0c\u5747\u6765\u81ealinux\/arch\/x86\/include\/asm\/atomic.h\u4e2d<\/span><\/p>\n<p>\u5185\u6838\u4e2d\u63d0\u4f9b\u4e86\u4e24\u7ec4\u539f\u5b50\u64cd\u4f5c\u7684\u63a5\u53e3\uff1a\u539f\u5b50\u6574\u5f62\u64cd\u4f5c\u548c\u539f\u5b50\u4f4d\u64cd\u4f5c\u3002\u524d\u8005\u662f\u4e00\u7ec4\u5bf9\u6574\u5f62\u6570\u636e\u7684\u64cd\u4f5c\uff0c\u540e\u8005\u5219\u662f\u9488\u5bf9\u5355\u72ec\u7684\u4f4d\u64cd\u4f5c\u3002\u901a\u8fc7\u4e0a\u9762\u7684\u53d9\u8ff0\u6211\u4eec\u53ef\u4ee5\u77e5\u9053\uff0c\u8fd9\u5199\u64cd\u4f5c\u63a5\u53e3\u5b8c\u6210\u7684\u52a8\u4f5c\u90fd\u662f\u539f\u5b50\u7684\u3002<\/p>\n<h4>\u539f\u5b50\u6574\u5f62\u64cd\u4f5c<\/h4>\n<p><strong>0.\u6570\u636e\u7ed3\u6784<\/strong><\/p>\n<p>\u5728linux\/include\/linux\/types.h\u4e2d\u6709\u5982\u4e0b\u5b9a\u4e49\uff1a<\/p>\n<pre class=\"brush:c\"> 190typedef struct {\r\n 191        int counter;\r\n 192} atomic_t;<\/pre>\n<p>\u539f\u5b50\u7c7b\u578b\u5185\u90e8\u53ea\u6709\u4e00\u4e2a\u6574\u578b\u7684\u6210\u5458counter\u3002<\/p>\n<p><strong>1.\u521d\u59cb\u5316\/\u8bbe\u7f6e\u539f\u5b50\u53d8\u91cf\u7684\u503c<\/strong><\/p>\n<pre class=\"brush:c\">  15#define ATOMIC_INIT(i)  { (i) }\r\n\r\n  35static inline void atomic_set(atomic_t *v, int i)\r\n  36{\r\n  37        v-&gt;counter = i;\r\n  38}<\/pre>\n<p>\u521d\u59cb\u5316\u5b8f\u7684\u6e90\u7801\u5f88\u660e\u663e\u7684\u8bf4\u660e\u4e86\u5982\u4f55\u521d\u59cb\u5316\u4e00\u4e2a\u539f\u5b50\u53d8\u91cf\u3002\u6211\u4eec\u5728\u5b9a\u4e49\u4e00\u4e2a\u539f\u5b50\u53d8\u91cf\u65f6\u53ef\u4ee5\u8fd9\u6837\u7684\u4f7f\u7528\u5b83\uff1a<\/p>\n<pre class=\"brush:c\">  atomic_t v=ATOMIC_INIT(0);<\/pre>\n<p>atomic_set\u51fd\u6570\u53ef\u4ee5\u539f\u5b50\u7684\u8bbe\u7f6e\u4e00\u4e2a\u53d8\u91cf\u7684\u503c\u3002<\/p>\n<p><strong>2.\u83b7\u53d6\u539f\u5b50\u53d8\u91cf\u7684\u503c<\/strong><\/p>\n<pre class=\"brush:c\">  23static inline int atomic_read(const atomic_t *v)\r\n  24{\r\n  25        return (*(volatile int *)&amp;(v)-&gt;counter);\r\n  26}<\/pre>\n<p>\u8fd4\u56de\u539f\u5b50\u578b\u53d8\u91cfv\u4e2d\u7684counter\u503c\u3002\u5173\u952e\u5b57volatile\u4fdd\u8bc1&amp;(v-&gt;counter)\u7684\u503c\u56fa\u5b9a\u4e0d\u53d8\uff0c\u4ee5\u786e\u4fdd\u8fd9\u4e2a\u51fd\u6570\u6bcf\u6b21\u8bfb\u5165\u7684\u90fd\u662f\u539f\u59cb\u5730\u5740\u4e2d\u7684\u503c\u3002<\/p>\n<p><strong>3.\u539f\u5b50\u53d8\u91cf\u7684\u52a0\u4e0e\u51cf<\/strong><\/p>\n<pre class=\"brush:c\">   47static inline void atomic_add(int i, atomic_t *v)\r\n  48{\r\n  49        asm volatile(LOCK_PREFIX \"addl %1,%0\"\r\n  50                     : \"+m\" (v-&gt;counter)\r\n  51                     : \"ir\" (i));\r\n  52}\r\n\r\n  61static inline void atomic_sub(int i, atomic_t *v)\r\n  62{\r\n  63        asm volatile(LOCK_PREFIX \"subl %1,%0\"\r\n  64                     : \"+m\" (v-&gt;counter)\r\n  65                     : \"ir\" (i));\r\n  66}<\/pre>\n<p>\u52a0\u51cf\u64cd\u4f5c\u4e2d\u4f7f\u7528\u4e86\u5185\u8054\u6c47\u7f16\u8bed\u53e5\u3002<\/p>\n<p>linux\u4e2d\u7684\u6c47\u7f16\u8bed\u53e5\u90fd\u91c7\u7528AT&amp;T\u6307\u4ee4\u683c\u5f0f\u3002\u5e26\u6709C\u8868\u8fbe\u5f0f\u7684\u5185\u8054\u6c47\u7f16\u683c\u5f0f\u4e3a\uff1a__asm__ __volatile__(&#8220;InstructionList&#8221; :Output :Input :Clobber\/Modify);\u5176\u4e2dasm\uff08\u6216__asm__\uff09\u7528\u6765\u58f0\u660e\u4e00\u4e2a\u5185\u8054\u6c47\u7f16\u8bed\u53e5\uff1b\u5173\u952e\u5b57volatile\u662f\u53ef\u9009\u7684\uff0c\u9009\u62e9\u6b64\u5173\u952e\u5b57\u610f\u5473\u7740\u5411\u7f16\u8bd1\u5668\u58f0\u660e\u201c\u4e0d\u8981\u52a8\u6211\u6240\u5199\u7684\u6307\u4ee4\uff0c\u6211\u9700\u8981\u539f\u5c01\u4e0d\u52a8\u7684\u4fdd\u7559\u6bcf\u4e00\u6761\u6307\u4ee4\u201d\uff0c\u5426\u5219\uff0c\u7f16\u8bd1\u5668\u53ef\u80fd\u4f1a\u5bf9\u6307\u4ee4\u8fdb\u884c\u4f18\u5316\u3002InstructionList\u5373\u6211\u4eec\u6240\u52a0\u7684\u6c47\u7f16\u8bed\u53e5\u3002\u6307\u4ee4\u540e\u9762\u76843\u4e2a\u90e8\u5206(Output\uff0c Input\uff0cClobber\/Modify)\u662f\u53ef\u9009\u7684\uff0c\u5206\u522b\u6307\u8f93\u51fa\u64cd\u4f5c\u6570\uff0c\u8f93\u5165\u64cd\u4f5c\u6570\uff0c\u4fee\u6539\u4f4d\u3002<\/p>\n<p>\u4e0b\u9762\u6211\u4eec\u9488\u5bf9\u4e0a\u8ff0\u52a0\u51cf\u64cd\u4f5c\u5bf9\u4e0a\u8ff0\u5185\u8054\u6c47\u7f16\u8bed\u53e5\u505a\u7b80\u5355\u7684\u89e3\u91ca\u3002<\/p>\n<p>\u5728\u52a0\u51fd\u6570\u4e2d\uff0c\u5bf9\u53d8\u91cf\u52a0\u64cd\u4f5c\u7684\u539f\u5b50\u578b\u8868\u73b0\u5728\u4f7f\u7528\u5355\u6761\u7684\u6c47\u7f16\u8bed\u53e5\u5b8c\u6210\u3002\u6307\u4ee4\u4e2d\u7684%1\uff0c%0\u5206\u522b\u4ee3\u8868\u8f93\u5165\u64cd\u4f5c\u6570\u548c\u8f93\u51fa\u64cd\u4f5c\u6570\uff0c\u5b83\u4eec\u7528\u6765\u6807\u793a\u53d8\u91cf\u3002\u5185\u8054\u6c47\u7f16\u8bed\u53e5\u4e2d\u7684\u64cd\u4f5c\u6570\u4ece0\u5f00\u59cb\u8fdb\u884c\u7f16\u53f7\uff0c\u5e76\u4e14\u4f18\u5148\u4e3a\u8f93\u51fa\u64cd\u4f5c\u6570\u7f16\u53f7\uff0c\u7136\u540e\u518d\u4f9d\u6b21\u4e3a\u8f93\u5165\u64cd\u4f5c\u6570\u7f16\u53f7\u3002\u5728\u6307\u4ee4\u540e\u7684\u8f93\u51fa\u90e8\u5206\uff0c\u201c+m\u201d\u4e2d\u7684+\u8868\u793a\u8f93\u51fa\u53d8\u91cf\u662f\u53ef\u8bfb\u53ef\u5199\u7684\uff0cm\u8868\u793a\u8f93\u51fa\u64cd\u4f5c\u6570\u5b58\u50a8\u4e8e\u5185\u5b58\u5355\u5143\u4e2d\uff0c\u800c\u4e0d\u662f\u5728\u5bc4\u5b58\u5668\u4e2d\u3002\u5728\u8f93\u5165\u90e8\u5206\uff0c\u201cir\u201d\u4e2d\u7684i\u8868\u793a\u8f93\u5165\u64cd\u4f5c\u6570\u662f\u4e00\u4e2a\u76f4\u63a5\u64cd\u4f5c\u6570\uff0cr\u8868\u793a\u5b58\u50a8\u4e0e\u5bc4\u5b58\u5668\u4e2d\u3002\u8f93\u5165\u90e8\u5206\u548c\u8f93\u51fa\u90e8\u5206\u4e2d\u7684\u62ec\u53f7\u5185\u7684C\u8bed\u8a00\u683c\u5f0f\u7684\u53d8\u91cf\u5206\u522b\u5bf9\u5e94\u6c47\u7f16\u8bed\u53e5\u4e2d\u7684\u8f93\u5165\u64cd\u4f5c\u6570\u548c\u8f93\u51fa\u64cd\u4f5c\u6570\u3002<\/p>\n<p>\u6c47\u7f16\u8bed\u53e5addl %1,%0\u5c31\u662f\u5c06i\u52a0\u81f3v-&gt;counter\u4e0a\uff0c\u8fd9\u4e2a\u52a0\u7684\u8fc7\u7a0b\u662f\u539f\u5b50\u7684\u3002<\/p>\n<p>\u4e86\u89e3\u4e86\u52a0\u64cd\u4f5c\uff0c\u90a3\u4e48\u51cf\u64cd\u4f5c\u4e5f\u5c31\u4e0d\u96be\u7406\u89e3\u4e86\uff0c\u8fd9\u91cc\u4e0d\u518d\u8d58\u8ff0\u3002<\/p>\n<p><strong>4.\u539f\u5b50\u53d8\u91cf\u7684\u81ea\u52a0\u81ea\u51cf<\/strong><\/p>\n<pre class=\"brush:c\">  93static inline void atomic_inc(atomic_t *v)\r\n  94{\r\n  95        asm volatile(LOCK_PREFIX \"incl %0\"\r\n  96                     : \"+m\" (v-&gt;counter));\r\n  97}\r\n\r\n 105static inline void atomic_dec(atomic_t *v)\r\n 106{\r\n 107        asm volatile(LOCK_PREFIX \"decl %0\"\r\n 108                     : \"+m\" (v-&gt;counter));\r\n 109}<\/pre>\n<p>\u4ece\u5185\u8054\u7684\u6c47\u7f16\u8bed\u53e5\u4e2d\u53ef\u4ee5\u770b\u5230\uff0c\u81ea\u52a0\u81ea\u51cf\u5747\u91c7\u7528\u5355\u6761\u6c47\u7f16\u6307\u4ee4\uff0c\u76f4\u63a5\u5728\u8f93\u51fa\u6570%0\u4e0a\u52a01\u6216\u51cf1\u3002\u8fd9\u91cc\u7684\u8f93\u51fa\u6570%0\u7684\u503c\u5373\u662fv-&gt;counter\u53d8\u91cf\u7684\u503c\u3002<\/p>\n<p><strong>5.\u64cd\u4f5c\u5e76\u6d4b\u8bd5<\/strong><\/p>\n<p>atomic_sub_and_test\u51fd\u6570\u5b9e\u73b0\u7684\u529f\u80fd\u662f\u539f\u5b50\u7684\u4ecev\u51cf\u53bbi\uff0c\u5982\u679c\u7ed3\u679c\u7b49\u4e8e0\uff0c\u5219\u8fd4\u56de1\uff1b\u5426\u5219\u8fd4\u56de0\u3002<\/p>\n<pre class=\"brush:c\"> 77static inline int atomic_sub_and_test(int i, atomic_t *v)\r\n  78{\r\n  79        unsigned char c;\r\n  80\r\n  81        asm volatile(LOCK_PREFIX \"subl %2,%0; sete %1\"\r\n  82                     : \"+m\" (v-&gt;counter), \"=qm\" (c)\r\n  83                     : \"ir\" (i) : \"memory\");\r\n  84        return c;\r\n  85}<\/pre>\n<p>\u901a\u8fc7\u4e0a\u8ff0\u6e90\u7801\u53ef\u4ee5\u770b\u5230\uff0c\u7b2c\u4e00\u6761\u6307\u4ee4\u5b9e\u73b0\u51cf\u64cd\u4f5c\uff1b\u63a5\u7740\u6839\u636eZF\u7684\u503c\u8bbe\u7f6ec\u53d8\u91cf\u7684\u503c\u3002sete\u547d\u4ee4\u7684\u4f5c\u7528\u662f\uff0c\u5982\u679cZF=1\uff0c\u4e5f\u5c31\u662f\u8bf4\u51cf\u7684\u7ed3\u679c\u4e3a0\uff0c\u5c06\u8bbe\u7f6ec\u53d8\u91cf\u4e3a1\uff1b\u5426\u5219c\u7684\u503c\u4e3a0\u3002\u6267\u884c\u5b8c\u6bd5\u540e\u8fd4\u56de\u76f8\u5e94\u7684c\u503c\u3002<\/p>\n<pre class=\"brush:c\"> 119static inline int atomic_dec_and_test(atomic_t *v)\r\n 120{\r\n 121        unsigned char c;\r\n 122\r\n 123        asm volatile(LOCK_PREFIX \"decl %0; sete %1\"\r\n 124                     : \"+m\" (v-&gt;counter), \"=qm\" (c)\r\n 125                     : : \"memory\");\r\n 126        return c != 0;\r\n 127}\r\n\r\n 137static inline int atomic_inc_and_test(atomic_t *v)\r\n 138{\r\n 139        unsigned char c;\r\n 140\r\n 141        asm volatile(LOCK_PREFIX \"incl %0; sete %1\"\r\n 142                     : \"+m\" (v-&gt;counter), \"=qm\" (c)\r\n 143                     : : \"memory\");\r\n 144        return c != 0;\r\n 145}<\/pre>\n<p>\u4e0a\u6570\u4e24\u4e2a\u51fd\u6570\u7684\u4f5c\u7528\u662f\u81ea\u51cf1\u6216\u81ea\u52a01\u540e\uff0c\u518d\u6d4b\u8bd5v\u503c\u662f\u5426\u4e3a0\uff0c\u5982\u679c\u662f0\uff0c\u5219\u8fd4\u56de1\uff1b\u5426\u5219\u8fd4\u56de0\u3002<\/p>\n<p>\u4e5f\u8bb8\u4f60\u4f1a\u8ba4\u4e3a\u4e0a\u8ff0\u7684\u52a0\/\u51cf\u5e76\u6d4b\u8bd5\u5e76\u4e0d\u662f\u539f\u5b50\u7684\u3002\u6211\u4e2a\u4eba\u7684\u8ba4\u4e3a\u662f\uff1a\u7b2c\u4e00\u6761\u52a0\/\u51cf\u64cd\u4f5c\u7684\u786e\u662f\u539f\u5b50\u7684\uff0c\u5f53\u6b64\u6761\u8bed\u53e5\u6267\u884c\u5b8c\u6bd5\u540e\uff0c\u4f1a\u4ea7\u751f\u76f8\u5e94\u7684ZF\u503c\u3002\u5982\u679c\u6b64\u65f6\u5728\u6267\u884csete\u4e4b\u524d\u4ea7\u751f\u4e86\u4e2d\u65ad\uff0c\u90a3\u4e48\u80af\u5b9a\u4f1a\u4fdd\u5b58\u5f53\u524d\u5bc4\u5b58\u5668\u7b49\u503c\u3002\u56e0\u6b64\uff0c\u5373\u4fbf\u4e2d\u95f4\u4ea7\u751f\u4e86\u4e2d\u65ad\uff0c\u8fd4\u56de\u7684\u4e5f\u662f\u4e2d\u65ad\u524d\u52a0\/\u51cf\u540e\u7684\u7ed3\u679c\u3002<\/p>\n<p><strong>6.\u64cd\u4f5c\u5e76\u8fd4\u56de<\/strong><\/p>\n<pre class=\"brush:c\"> 173static inline int atomic_add_return(int i, atomic_t *v)\r\n 174{\r\n 175        int __i;\r\n 176#ifdef CONFIG_M386\r\n 177        unsigned long flags;\r\n 178        if (unlikely(boot_cpu_data.x86 &lt;= 3))\r\n 179                goto no_xadd;\r\n 180#endif\r\n 181        \/* Modern 486+ processor *\/\r\n 182        __i = i;\r\n 183        asm volatile(LOCK_PREFIX \"xaddl %0, %1\"\r\n 184                     : \"+r\" (i), \"+m\" (v-&gt;counter)\r\n 185                     : : \"memory\");\r\n 186        return i + __i;\r\n 187\r\n 188#ifdef CONFIG_M386\r\n 189no_xadd: \/* Legacy 386 processor *\/\r\n 190        raw_local_irq_save(flags);\r\n 191        __i = atomic_read(v);\r\n 192        atomic_set(v, i + __i);\r\n 193        raw_local_irq_restore(flags);\r\n 194        return i + __i;\r\n 195#endif\r\n 196}<\/pre>\n<p>\u9996\u5148if\u5224\u65ad\u8bed\u53e5\u5224\u65ad\u5f53\u524d\u7684\u5904\u7406\u5668\u662f\u5426\u4e3a386\u6216386\u4ee5\u4e0b\uff0c\u5982\u679c\u662f\u5219\u76f4\u63a5\u6267\u884cno_xadd\u5904\u5f00\u59cb\u7684\u4ee3\u7801\uff1b\u5426\u5219\u7d27\u63a5\u7740\u5224\u65ad\u8bed\u53e5\u6267\u884c\u3002\u6b64\u5904\u7684unlikely\u8868\u793a\u201d\u7ecf\u5e38\u4e0d\u201c\u3002\u56e0\u4e3a\u73b0\u5728\u7684\u5904\u7406\u5668\u5927\u90fd\u9ad8\u4e8e386\uff0c\u6240\u4ee5\u7f16\u8bd1\u5668\u4e00\u822c\u90fd\u6309\u7167\u9ad8\u4e8e386\u6765\u5904\u7406\uff0c\u4ee5\u8fbe\u5230\u4f18\u5316\u6e90\u4ee3\u7801\u7684\u76ee\u7684\u3002\u641e\u6e05\u695a\u8fd9\u6bb5\u4ee3\u7801\u7684\u903b\u8f91\u5173\u7cfb\uff0c\u90a3\u4e48\u63a5\u4e0b\u6765\u7684\u5de5\u4f5c\u5c31\u4e0d\u56f0\u96be\u4e86\u3002<\/p>\n<p>\u5982\u679cCPU\u9ad8\u4e8e386\uff0c\u5219\u5b83\u5c06\u6267\u884cxaddl\u547d\u4ee4\uff0c\u8be5\u547d\u4ee4\u7684\u4f5c\u7528\u662f\u5148\u4ea4\u6362\u6e90\u548c\u76ee\u7684\u64cd\u4f5c\u6570\uff0c\u518d\u76f8\u52a0\u3002\u8fd9\u91cc%0\uff0c%1\u5206\u522b\u4ee3\u8868i\u548cv-&gt;counter\u3002\u9996\u5148\u5c06i\u503c\u7528__i\u4fdd\u5b58\uff1b\u64cd\u4f5c\u6570\u4ea4\u6362\u540e\uff0c%0\uff0c%1\u7684\u503c\u4f9d\u6b21\u4e3av-&gt;counter\u548ci\uff1b\u76f8\u52a0\u5e76\u4fdd\u5b58\u5230%1\uff1b\u6700\u540e%0\uff0c%1\u7684\u7ed3\u679c\u5c31\u662fv-&gt;counter\uff0ci+v-&gt;counter\uff0c\u8fd4\u56de\u7684\u7ed3\u679ci+__i\u7684\u7ed3\u679c\u5c31\u662fi+v-&gt;counter\u3002\u8fd9\u91cc\u6d89\u53ca\u5230i\u548cv-&gt;counter\u7684\u503c\u65f6\u5747\u6307\u521d\u503c\u3002<\/p>\n<p>\u7406\u89e3\u4e86\u4e0a\u8ff0\u8fc7\u7a0b\uff0c\u518d\u770b\u5176\u4ed6\u7684\u64cd\u4f5c\u8fd4\u56de\u51fd\u6570\uff1a<\/p>\n<pre class=\"brush:c\"> 205static inline int atomic_sub_return(int i, atomic_t *v)\r\n 206{\r\n 207        return atomic_add_return(-i, v);\r\n 208}<\/pre>\n<p>\u53ef\u4ee5\u770b\u5230\uff0catomic_sub_return\u51fd\u6570\u662f\u5bf9atomic_add_return\u51fd\u6570\u7684\u5c01\u88c5\u3002\u800c\u4e0b\u9762\u4e24\u4e2a\u51fd\u6570\u5219\u53c8\u662f\u5bf9\u4e0a\u8ff0\u4e24\u4e2a\u51fd\u6570\u7684\u5c01\u88c5\u3002<\/p>\n<pre class=\"brush:c\"> 210#define atomic_inc_return(v)  (atomic_add_return(1, v))\r\n 211#define atomic_dec_return(v)  (atomic_sub_return(1, v))<\/pre>\n<p>\u4e0a\u8ff0\u5c31\u662f\u5bf9\u6574\u5f62\u539f\u5b50\u64cd\u4f5c\u7684\u5206\u6790\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Latest Update:2010\/10\/23 \u539f\u5b50\u64cd\u4f5c \u539f\u5b50\u64cd\u4f5c\u7528\u4e8e\u6267\u884c\u8f7b\u91cf\u7ea7\u3001\u4ec5\u6267\u884c\u4e00\u6b21\u7684\u64cd\u4f5c\uff0c\u6bd4\u5982\u4fee\u6539 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[110],"tags":[108,147,167,168],"class_list":["post-1809","post","type-post","status-publish","format-standard","hentry","category-linux","tag-linux","tag-147","tag-167","tag-168"],"views":22121,"_links":{"self":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts\/1809","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/comments?post=1809"}],"version-history":[{"count":0,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts\/1809\/revisions"}],"wp:attachment":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/media?parent=1809"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/categories?post=1809"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/tags?post=1809"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}