[xpu] add XPU_L3_LOCK_REQUIRED to support multi-process run

test=develop test=xpu

lite/core/program.cc

@@ -23,6 +23,9 @@
 #ifdef LITE_WITH_PRECISION_PROFILE
 #include "lite/core/profile/precision_profiler.h"
 #endif
+#ifdef LITE_WITH_XPU
+#include <fcntl.h>
+#endif
 
 namespace paddle {
 namespace lite {
@@ -439,7 +442,44 @@ void Instruction::Run() {
     CHECK(op_->CheckShape());
   }
 
-  if (op_->run_once() && has_run_) {
+#ifdef LITE_WITH_XPU
+  static int reentrant = 0;
+  int xpu_l3_lock_fd;
+  auto need_lock_l3 = std::getenv("XPU_L3_LOCK_REQUIRED");
+  struct flock f_lock;
+  f_lock.l_whence = 0;
+  f_lock.l_len = 0;
+
+  if (reentrant == 0) {
+    if (need_lock_l3) {
+      int pd = 0;  // TODO(luohang): need get from lite api
+      std::string buf = "/opt/xpu_lock" + std::to_string(pd);
+      xpu_l3_lock_fd = open(buf.c_str(), O_RDWR);
+      CHECK(xpu_l3_lock_fd > 0) << "open " << buf
+                                << " failed: " << xpu_l3_lock_fd;
+
+      // lock
+      f_lock.l_type = F_WRLCK;
+      fcntl(xpu_l3_lock_fd, F_SETLKW, &f_lock);
+    } else {
+      xpu_l3_lock_fd = -1;
+    }
+  }
+  reentrant++;
+#endif
+
+  bool run_res = op_->run_once() && has_run_;
+
+#ifdef LITE_WITH_XPU
+  if (need_lock_l3 && reentrant == 1) {
+    f_lock.l_type = F_UNLCK;
+    fcntl(xpu_l3_lock_fd, F_SETLKW, &f_lock);
+    close(xpu_l3_lock_fd);
+  }
+  reentrant--;
+#endif
+
+  if (run_res) {
     return;
   }