Move GetHandleLimit from SharedMemory to process_metrics.h.

base::SharedMemory, which is being deprecated, exposes a utilty
method GetHandleLimit() which needs to be moved somewhere.
process_metrics.h seems to be a more appropriate place for this
anyway over base::SharedMemory.

Bug: 795291
Change-Id: I1562cca6445c362654ba4a52195c0ec4d53757ff
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1695284
Commit-Queue: Matthew Cary (CET) <mattcary@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Charlie Harrison <csharrison@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676546}

base/memory/shared_memory.h

@@ -98,9 +98,6 @@ class BASE_EXPORT SharedMemory {
   // Closes a shared memory handle.
   static void CloseHandle(const SharedMemoryHandle& handle);
 
-  // Returns the maximum number of handles that can be open at once per process.
-  static size_t GetHandleLimit();
-
   // Duplicates The underlying OS primitive. Returns an invalid handle on
   // failure. The caller is responsible for destroying the duplicated OS
   // primitive.

base/memory/shared_memory_fuchsia.cc

@@ -38,13 +38,6 @@ void SharedMemory::CloseHandle(const SharedMemoryHandle& handle) {
   handle.Close();
 }
 
-// static
-size_t SharedMemory::GetHandleLimit() {
-  // Duplicated from the internal Magenta kernel constant kMaxHandleCount
-  // (kernel/lib/zircon/zircon.cpp).
-  return 256 * 1024u;
-}
-
 bool SharedMemory::CreateAndMapAnonymous(size_t size) {
   return CreateAnonymous(size) && Map(size);
 }

base/memory/shared_memory_mac.cc

@@ -98,11 +98,6 @@ void SharedMemory::CloseHandle(const SharedMemoryHandle& handle) {
   handle.Close();
 }
 
-// static
-size_t SharedMemory::GetHandleLimit() {
-  return GetMaxFds();
-}
-
 // static
 SharedMemoryHandle SharedMemory::DuplicateHandle(
     const SharedMemoryHandle& handle) {

base/memory/shared_memory_posix.cc

@@ -59,11 +59,6 @@ void SharedMemory::CloseHandle(const SharedMemoryHandle& handle) {
   handle.Close();
 }
 
-// static
-size_t SharedMemory::GetHandleLimit() {
-  return GetMaxFds();
-}
-
 // static
 SharedMemoryHandle SharedMemory::DuplicateHandle(
     const SharedMemoryHandle& handle) {

base/memory/shared_memory_win.cc

@@ -162,13 +162,6 @@ void SharedMemory::CloseHandle(const SharedMemoryHandle& handle) {
   handle.Close();
 }
 
-// static
-size_t SharedMemory::GetHandleLimit() {
-  // Rounded down from value reported here:
-  // http://blogs.technet.com/b/markrussinovich/archive/2009/09/29/3283844.aspx
-  return static_cast<size_t>(1 << 23);
-}
-
 // static
 SharedMemoryHandle SharedMemory::DuplicateHandle(
     const SharedMemoryHandle& handle) {

base/process/process_metrics.h

@@ -254,6 +254,9 @@ BASE_EXPORT size_t GetPageSize();
 // at once. If the number is unavailable, a conservative best guess is returned.
 BASE_EXPORT size_t GetMaxFds();
 
+// Returns the maximum number of handles that can be open at once per process.
+BASE_EXPORT size_t GetHandleLimit();
+
 #if defined(OS_POSIX)
 // Increases the file descriptor soft limit to |max_descriptors| or the OS hard
 // limit, whichever is lower. If the limit is already higher than

base/process/process_metrics_fuchsia.cc

@@ -12,6 +12,12 @@ size_t GetMaxFds() {
   return FDIO_MAX_FD;
 }
 
+size_t GetHandleLimit() {
+  // Duplicated from the internal Magenta kernel constant kMaxHandleCount
+  // (zircon/kernel/object/handle.cc).
+  return 256 * 1024u;
+}
+
 size_t GetSystemCommitCharge() {
   // TODO(https://crbug.com/926581): Fuchsia does not support this.
   return 0;

base/process/process_metrics_posix.cc

@@ -71,6 +71,15 @@ size_t GetMaxFds() {
   return static_cast<size_t>(max_fds);
 }
 
+size_t GetHandleLimit() {
+#if defined(OS_MACOSX)
+  // Taken from a small test that allocated ports in a loop.
+  return static_cast<size_t>(1 << 18);
+#else
+  return GetMaxFds();
+#endif
+}
+
 void IncreaseFdLimitTo(unsigned int max_descriptors) {
   struct rlimit limits;
   if (getrlimit(RLIMIT_NOFILE, &limits) == 0) {

base/process/process_metrics_win.cc

@@ -129,6 +129,12 @@ size_t GetMaxFds() {
   return std::numeric_limits<size_t>::max();
 }
 
+size_t GetHandleLimit() {
+  // Rounded down from value reported here:
+  // http://blogs.technet.com/b/markrussinovich/archive/2009/09/29/3283844.aspx
+  return static_cast<size_t>(1 << 23);
+}
+
 // static
 std::unique_ptr<ProcessMetrics> ProcessMetrics::CreateProcessMetrics(
     ProcessHandle process) {

content/browser/loader/resource_dispatcher_host_impl.cc

@@ -26,6 +26,7 @@
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/process/process_metrics.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/task/post_task.h"
@@ -362,7 +363,7 @@ ResourceDispatcherHostImpl::ResourceDispatcherHostImpl(
       is_shutdown_(false),
       enable_resource_scheduler_(enable_resource_scheduler),
       num_in_flight_requests_(0),
-      max_num_in_flight_requests_(base::SharedMemory::GetHandleLimit()),
+      max_num_in_flight_requests_(base::GetHandleLimit()),
       max_num_in_flight_requests_per_process_(static_cast<int>(
           max_num_in_flight_requests_ * kMaxRequestsPerProcessRatio)),
       max_outstanding_requests_cost_per_process_(