If sysconfig fails, fallback to sysinfo

base/sys_info_linux.cc

 // Copyright (c) 2011 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 "base/sys_info.h"
 
 #include <limits>
+#include <sys/sysinfo.h>
 
 #include "base/files/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/sys_info_internal.h"
 
 namespace {
 
 int64 AmountOfMemory(int pages_name) {
   long pages = sysconf(pages_name);

[danakj, 2015/04/02 19:05:47]

can you DCHECK up here that pages_name is _SC_PHYS_PAGES or _SC_ACPHYS_PAGES?

[smcgruer2, 2015/04/07 21:25:43]

Done.

   long page_size = sysconf(_SC_PAGESIZE);
   if (pages == -1 || page_size == -1) {
+    struct sysinfo si;
+    if (sysinfo(&si)) {

[danakj, 2015/04/02 19:05:47]

on success 0 is returned. so this won't work right now. are there unit tests for
this code? can you run them on the target system and make sure they pass? if not
can you add some?

[smcgruer2, 2015/04/07 21:25:43]

Whoops! Good eye, the original code was checking '== 0' but I accidentally
dropped it when making this cl. That issue is fixed by your DCHECK_EQ
suggestion, but a unittest is probably a good idea.

Is there a nice way to add a unittest given that this code is part of a
platform-specific implementation (so can't add it to a header file), and it
calls into system functions? I'm unfamiliar with Chromium's unittest setup.

+      if (pages_name == _SC_PHYS_PAGES) {
+        return si.totalram * si.mem_unit;

[danakj, 2015/04/02 19:05:47]

can you cast the totalram to an int64 before multiplying?

[smcgruer2, 2015/04/07 21:25:43]

Done.

+      } else if (pages_name == _SC_AVPHYS_PAGES) {

[danakj, 2015/04/02 19:05:47]

just else should be sufficient? (can leave ..AVPHYS.. in a comment)

[smcgruer2, 2015/04/07 21:25:43]

Done.

+        return si.freeram * si.mem_unit;

[danakj, 2015/04/02 19:05:47]

dittos

[smcgruer2, 2015/04/07 21:25:43]

Done.

+      }
+    }
     NOTREACHED();

[danakj, 2015/04/02 19:05:47]

can you restructure this code so we don't have NOTREACHED(); return; anymore?

int ret = sysinfo(&si);
DCHECK_EQ(ret, 0);
...

would work.

[smcgruer2, 2015/04/07 21:25:43]

Done.

     return 0;
   }
   return static_cast<int64>(pages) * page_size;
 }
 
 int64 AmountOfPhysicalMemory() {
   return AmountOfMemory(_SC_PHYS_PAGES);
 }
 
 size_t MaxSharedMemorySize() {
@@ skipping 65 matching lines @@
       if (line.compare(0, strlen(kCpuModelPrefix), kCpuModelPrefix) == 0) {
         size_t pos = line.find(": ");
         return line.substr(pos + 2);
       }
     }
   }
   return std::string();
 }
 
 }  // namespace base