android 4.X上偶尔出现的多个system_server进程的解决办法

在android 4.X中有时候会出现多个system_server进程，会导致系统内存占用急速增加，系统性能下降的情况，可以尝试如下修正方法：

--- java_lang_ProcessManager.cpp 

+++ java_lang_ProcessManager_new.cpp 

@@ -23,7 +23,7 @@

 #include <stdlib.h>

 #include <string.h>

 #include <errno.h>

-

+#include <sys/wait.h>

 #include "jni.h"

 #include "JNIHelp.h"

 #include "JniConstants.h"

@@ -60,6 +60,19 @@

     }

 }

 

+#define TEMP_FAILURE_RETRY(exp) ({ \

+ typeof (exp) _rc; \

+ do { \

+ _rc = (exp); \

+ } while (_rc == -1 && errno == EINTR); \

+ _rc; })

+

+static void AbortChild(int status_pipe_fd) {

+ int error = errno;

+ TEMP_FAILURE_RETRY(write(status_pipe_fd, &error, sizeof(int)));

+ close(status_pipe_fd); 

+ _exit(127);

+}

 /** Executes a command in a child process. */

 static pid_t executeProcess(JNIEnv* env, char** commands, char** environment,

         const char* workingDirectory, jobject inDescriptor,

@@ -129,7 +142,7 @@

         // Switch to working directory.

         if (workingDirectory != NULL) {

             if (chdir(workingDirectory) == -1) {

- goto execFailed;

+ AbortChild(statusOut);

             }

         }

 

@@ -143,13 +156,7 @@

         // should be the command itself. In fact, I get segfaults when this

         // isn't the case.

         execvp(commands[0], commands);

-

- // If we got here, execvp() failed or the working dir was invalid.

-execFailed:

- int error = errno;

- write(statusOut, &error, sizeof(int));

- close(statusOut);

- exit(error);

+ AbortChild(statusOut);

     }

 

     // This is the parent process.

@@ -163,16 +170,22 @@

     // Check status pipe for an error code. If execvp() succeeds, the other

     // end of the pipe should automatically close, in which case, we'll read

     // nothing.

- int result;

- int count = read(statusIn, &result, sizeof(int));

+ int child_errno;

+ ssize_t count = TEMP_FAILURE_RETRY(read(statusIn, &child_errno, sizeof(int)));

     close(statusIn);

     if (count > 0) {

- jniThrowIOException(env, result);

+ jniThrowIOException(env, child_errno);

 

         close(stdoutIn);

         close(stdinOut);

         close(stderrIn);

 

+ // Reap our zombie child right away

+ int status;

+ int rc = TEMP_FAILURE_RETRY(waitpid(childPid, &status, 0));

+ if(rc == -1) {

+ ALOGW("waitpid on failed exec failed: %s", strerror(errno));

+ }

         return -1;

     }