This adds periodic OOM score adjustment, based on the last access time

chrome/browser/zygote_host_linux.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/zygote_host_linux.h"
 
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ skipping 218 matching lines @@
   pid_t pid;
   {
     AutoLock lock(control_lock_);
     if (!base::SendMsg(control_fd_, pickle.data(), pickle.size(), fds))
       return base::kNullProcessHandle;
 
     if (ReadReply(&pid, sizeof(pid)) != sizeof(pid))
       return base::kNullProcessHandle;
   }
 
+  const int kRendererScore = 5;
+  AdjustRendererOOMScore(pid, kRendererScore);
+
+  return pid;
+}
+
+void ZygoteHost::AdjustRendererOOMScore(base::ProcessHandle pid, int score) {
   // 1) You can't change the oom_adj of a non-dumpable process (EPERM) unless
   //    you're root. Because of this, we can't set the oom_adj from the browser
   //    process.
   //
   // 2) We can't set the oom_adj before entering the sandbox because the
   //    zygote is in the sandbox and the zygote is as critical as the browser
   //    process. Its oom_adj value shouldn't be changed.
   //
   // 3) A non-dumpable process can't even change its own oom_adj because it's
   //    root owned 0644. The sandboxed processes don't even have /proc, but one
@@ skipping 12 matching lines @@
   // and it's easy.
 
   static bool selinux;
   static bool selinux_valid = false;
 
   if (!selinux_valid) {
     selinux = access("/selinux", X_OK) == 0;
     selinux_valid = true;
   }
 
-  const int kRendererScore = 5;
   if (using_suid_sandbox_ && !selinux) {
     base::ProcessHandle sandbox_helper_process;
-    base::file_handle_mapping_vector dummy_map;
     std::vector<std::string> adj_oom_score_cmdline;
 
     adj_oom_score_cmdline.push_back(sandbox_binary_);
     adj_oom_score_cmdline.push_back(base::kAdjustOOMScoreSwitch);
     adj_oom_score_cmdline.push_back(base::Int64ToString(pid));
-    adj_oom_score_cmdline.push_back(base::IntToString(kRendererScore));
+    adj_oom_score_cmdline.push_back(base::IntToString(score));
     CommandLine adj_oom_score_cmd(adj_oom_score_cmdline);
-    if (base::LaunchApp(adj_oom_score_cmdline, dummy_map, false,
+    if (base::LaunchApp(adj_oom_score_cmd, false, true,
                         &sandbox_helper_process)) {
       ProcessWatcher::EnsureProcessGetsReaped(sandbox_helper_process);
     }
   } else if (!using_suid_sandbox_) {
-    if (!base::AdjustOOMScore(pid, kRendererScore))
-      LOG(ERROR) << "Failed to adjust OOM score of renderer";
+    if (!base::AdjustOOMScore(pid, score))
+      LOG(ERROR) << "Failed to adjust OOM score of renderer with pid " << pid;
   }
-
-  return pid;
 }
 
 void ZygoteHost::EnsureProcessTerminated(pid_t process) {
   DCHECK(init_);
   Pickle pickle;
 
   pickle.WriteInt(kCmdReap);
   pickle.WriteInt(process);
 
   if (HANDLE_EINTR(write(control_fd_, pickle.data(), pickle.size())) < 0)
@@ skipping 33 matching lines @@
       !read_pickle.ReadBool(&iter, &tmp_child_exited)) {
     LOG(WARNING) << "Error parsing DidProcessCrash response from zygote.";
     return false;
   }
 
   if (child_exited)
     *child_exited = tmp_child_exited;
 
   return did_crash;
 }