Move the SwapData class to base/process (where other system metrics data reside) and rename it to SwapInfo.

This only moves code and adds no new functionality.

This uses ScopedAllowIO. Since this is perfmon code to /proc, we have deemed that IO is acceptable.

BUG=236763
R=darin@chromium.org, nduca@chromium.org

Review URL: https://codereview.chromium.org/22780002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@220377 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 75 insertions, 64 deletions

diff --git a/base/process/process_metrics.h b/base/process/process_metrics.h
index 8a7fb13..273c8e0 100644
--- a/base/process/process_metrics.h
+++ b/base/process/process_metrics.h
@@ -263,6 +263,29 @@ struct BASE_EXPORT SystemMemoryInfoKB {
 BASE_EXPORT bool GetSystemMemoryInfo(SystemMemoryInfoKB* meminfo);
 #endif  // defined(OS_LINUX) || defined(OS_ANDROID)
 
+#if defined(OS_CHROMEOS)
+// Data from files in directory /sys/block/zram0 about ZRAM usage.
+struct BASE_EXPORT SwapInfo {
+  SwapInfo()
+      : num_reads(0),
+        num_writes(0),
+        compr_data_size(0),
+        orig_data_size(0),
+        mem_used_total(0) {
+  }
+
+  uint64 num_reads;
+  uint64 num_writes;
+  uint64 compr_data_size;
+  uint64 orig_data_size;
+  uint64 mem_used_total;
+};
+
+// In ChromeOS, reads files from /sys/block/zram0 that contain ZRAM usage data.
+// Fills in the provided |swap_data| structure.
+BASE_EXPORT void GetSwapInfo(SwapInfo* swap_info);
+#endif  // defined(OS_CHROMEOS)
+
 // Collects and holds performance metrics for system memory and disk.
 // Provides functionality to retrieve the data on various platforms and
 // to serialize the stored data.
diff --git a/base/process/process_metrics_linux.cc b/base/process/process_metrics_linux.cc
index 8d1a57c..c500459 100644
--- a/base/process/process_metrics_linux.cc
+++ b/base/process/process_metrics_linux.cc
@@ -30,6 +30,20 @@ enum ParsingState {
   KEY_VALUE
 };
 
+#ifdef OS_CHROMEOS
+// Read a file with a single number string and return the number as a uint64.
+static uint64 ReadFileToUint64(const base::FilePath file) {
+  std::string file_as_string;
+  if (!file_util::ReadFileToString(file, &file_as_string))
+    return 0;
+  TrimWhitespaceASCII(file_as_string, TRIM_ALL, &file_as_string);
+  uint64 file_as_uint64 = 0;
+  if (!base::StringToUint64(file_as_string, &file_as_uint64))
+    return 0;
+  return file_as_uint64;
+}
+#endif
+
 // Read /proc/<pid>/status and returns the value for |field|, or 0 on failure.
 // Only works for fields in the form of "Field: value kB".
 size_t ReadProcStatusAndGetFieldAsSizeT(pid_t pid, const std::string& field) {
@@ -513,4 +527,31 @@ bool GetSystemMemoryInfo(SystemMemoryInfoKB* meminfo) {
   return true;
 }
 
+#if defined(OS_CHROMEOS)
+void GetSwapInfo(SwapInfo* swap_info) {
+  // Synchronously reading files in /sys/block/zram0 is safe.
+  ThreadRestrictions::ScopedAllowIO allow_io;
+
+  base::FilePath zram_path("/sys/block/zram0");
+  uint64 orig_data_size = ReadFileToUint64(zram_path.Append("orig_data_size"));
+  if (orig_data_size <= 4096) {
+    // A single page is compressed at startup, and has a high compression
+    // ratio. We ignore this as it doesn't indicate any real swapping.
+    swap_info->orig_data_size = 0;
+    swap_info->num_reads = 0;
+    swap_info->num_writes = 0;
+    swap_info->compr_data_size = 0;
+    swap_info->mem_used_total = 0;
+    return;
+  }
+  swap_info->orig_data_size = orig_data_size;
+  swap_info->num_reads = ReadFileToUint64(zram_path.Append("num_reads"));
+  swap_info->num_writes = ReadFileToUint64(zram_path.Append("num_writes"));
+  swap_info->compr_data_size =
+      ReadFileToUint64(zram_path.Append("compr_data_size"));
+  swap_info->mem_used_total =
+      ReadFileToUint64(zram_path.Append("mem_used_total"));
+}
+#endif  // defined(OS_CHROMEOS)
+
 }  // namespace base
diff --git a/chrome/browser/memory_details.cc b/chrome/browser/memory_details.cc
index c589ef2..643e211 100644
--- a/chrome/browser/memory_details.cc
+++ b/chrome/browser/memory_details.cc
@@ -501,8 +501,8 @@ void MemoryDetails::UpdateHistograms() {
 
 #if defined(OS_CHROMEOS)
 void MemoryDetails::UpdateSwapHistograms() {
-  UMA_HISTOGRAM_BOOLEAN("Memory.Swap.HaveSwapped", swap_data_.num_writes > 0);
-  if (swap_data_.num_writes == 0)
+  UMA_HISTOGRAM_BOOLEAN("Memory.Swap.HaveSwapped", swap_info_.num_writes > 0);
+  if (swap_info_.num_writes == 0)
     return;
 
   // Only record swap info when any swaps have happened, to give us more
@@ -575,25 +575,25 @@ void MemoryDetails::UpdateSwapHistograms() {
   UMA_HISTOGRAM_MEMORY_MB("Memory.Swap.Total", total_sample);
 
   UMA_HISTOGRAM_CUSTOM_COUNTS("Memory.Swap.CompressedDataSize",
-                              swap_data_.compr_data_size / (1024 * 1024),
+                              swap_info_.compr_data_size / (1024 * 1024),
                               1, 4096, 50);
   UMA_HISTOGRAM_CUSTOM_COUNTS("Memory.Swap.OriginalDataSize",
-                              swap_data_.orig_data_size / (1024 * 1024),
+                              swap_info_.orig_data_size / (1024 * 1024),
                               1, 4096, 50);
   UMA_HISTOGRAM_CUSTOM_COUNTS("Memory.Swap.MemUsedTotal",
-                              swap_data_.mem_used_total / (1024 * 1024),
+                              swap_info_.mem_used_total / (1024 * 1024),
                               1, 4096, 50);
   UMA_HISTOGRAM_CUSTOM_COUNTS("Memory.Swap.NumReads",
-                              swap_data_.num_reads,
+                              swap_info_.num_reads,
                               1, 100000000, 100);
   UMA_HISTOGRAM_CUSTOM_COUNTS("Memory.Swap.NumWrites",
-                              swap_data_.num_writes,
+                              swap_info_.num_writes,
                               1, 100000000, 100);
 
-  if (swap_data_.orig_data_size > 0 && swap_data_.compr_data_size > 0) {
+  if (swap_info_.orig_data_size > 0 && swap_info_.compr_data_size > 0) {
     UMA_HISTOGRAM_CUSTOM_COUNTS(
         "Memory.Swap.CompressionRatio",
-        swap_data_.orig_data_size / swap_data_.compr_data_size,
+        swap_info_.orig_data_size / swap_info_.compr_data_size,
         1, 20, 20);
   }
 }
diff --git a/chrome/browser/memory_details.h b/chrome/browser/memory_details.h
index cfbd68e..fb2ebb3 100644
--- a/chrome/browser/memory_details.h
+++ b/chrome/browser/memory_details.h
@@ -87,24 +87,6 @@ struct ProcessData {
 class ProcessInfoSnapshot;
 #endif
 
-#if defined(OS_CHROMEOS)
-struct SwapData {
-  SwapData()
-      : num_reads(0),
-        num_writes(0),
-        compr_data_size(0),
-        orig_data_size(0),
-        mem_used_total(0) {
-  }
-
-  uint64 num_reads;
-  uint64 num_writes;
-  uint64 compr_data_size;
-  uint64 orig_data_size;
-  uint64 mem_used_total;
-};
-#endif
-
 // MemoryDetails fetches memory details about current running browsers.
 // Because this data can only be fetched asynchronously, callers use
 // this class via a callback.
@@ -206,7 +188,7 @@ class MemoryDetails : public base::RefCountedThreadSafe<MemoryDetails> {
   UserMetricsMode user_metrics_mode_;
 
 #if defined(OS_CHROMEOS)
-  SwapData swap_data_;
+  base::SwapInfo swap_info_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(MemoryDetails);
diff --git a/chrome/browser/memory_details_linux.cc b/chrome/browser/memory_details_linux.cc
index ec149da..03f000e 100644
--- a/chrome/browser/memory_details_linux.cc
+++ b/chrome/browser/memory_details_linux.cc
@@ -163,41 +163,6 @@ static std::vector<pid_t> GetAllChildren(const ProcessMap& processes,
   return children;
 }
 
-#if defined(OS_CHROMEOS)
-static uint64 ReadFileToUint64(const base::FilePath file) {
-  std::string file_as_string;
-  if (!file_util::ReadFileToString(file, &file_as_string))
-    return 0;
-  TrimWhitespaceASCII(file_as_string, TRIM_ALL, &file_as_string);
-  uint64 file_as_uint64 = 0;
-  if (!base::StringToUint64(file_as_string, &file_as_uint64))
-    return 0;
-  return file_as_uint64;
-}
-
-static void GetSwapData(SwapData* swap_data) {
-  base::FilePath zram_path("/sys/block/zram0");
-  uint64 orig_data_size = ReadFileToUint64(zram_path.Append("orig_data_size"));
-  if (orig_data_size <= 4096) {
-    // A single page is compressed at startup, and has a high compression
-    // ratio. We ignore this as it doesn't indicate any real swapping.
-    swap_data->orig_data_size = 0;
-    swap_data->num_reads = 0;
-    swap_data->num_writes = 0;
-    swap_data->compr_data_size = 0;
-    swap_data->mem_used_total = 0;
-    return;
-  }
-  swap_data->orig_data_size = orig_data_size;
-  swap_data->num_reads = ReadFileToUint64(zram_path.Append("num_reads"));
-  swap_data->num_writes = ReadFileToUint64(zram_path.Append("num_writes"));
-  swap_data->compr_data_size =
-      ReadFileToUint64(zram_path.Append("compr_data_size"));
-  swap_data->mem_used_total =
-      ReadFileToUint64(zram_path.Append("mem_used_total"));
-}
-#endif
-
 void MemoryDetails::CollectProcessData(
     const std::vector<ProcessMemoryInformation>& child_info) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
@@ -269,7 +234,7 @@ void MemoryDetails::CollectProcessData(
   }
 
 #if defined(OS_CHROMEOS)
-  GetSwapData(&swap_data_);
+  base::GetSwapInfo(&swap_info_);
 #endif
 
   // Finally return to the browser thread.