Add access count and time-since-accessed histograms to temp storage eviction.

storage/browser/quota/quota_manager.cc

 // Copyright 2013 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 "storage/browser/quota/quota_manager.h"
 
 #include <algorithm>
 #include <functional>
 
 #include "base/bind.h"
@@ skipping 58 matching lines @@
 // TODO(kinuko): This should be like 10% of the actual disk space.
 // For now we simply use a constant as getting the disk size needs
 // platform-dependent code. (http://crbug.com/178976)
 int64 QuotaManager::kMinimumPreserveForSystem = 1024 * kMBytes;
 
 const int QuotaManager::kEvictionIntervalInMilliSeconds =
     30 * kMinutesInMilliSeconds;
 
 const char QuotaManager::kTimeBetweenRepeatedOriginEvictionsHistogram[] =
     "Quota.TimeBetweenRepeatedOriginEvictions";
+const char QuotaManager::kEvictedOriginAccessedCountHistogram[] =
+    "Quota.EvictedOriginAccessCount";
+const char QuotaManager::kEvictedOriginTimeSinceAccessHistogram[] =
+    "Quota.EvictedOriginTimeSinceAccess";
 
 // Heuristics: assuming average cloud server allows a few Gigs storage
 // on the server side and the storage needs to be shared for user data
 // and by multiple apps.
 int64 QuotaManager::kSyncableStorageDefaultHostQuota = 500 * kMBytes;
 
 namespace {
 
 void CountOriginType(const std::set<GURL>& origins,
                      SpecialStoragePolicy* policy,
@@ skipping 63 matching lines @@
   DCHECK(database);
   database->GetLRUOrigin(type, exceptions, policy, url);
   return true;
 }
 
 bool DeleteOriginInfoOnDBThread(const GURL& origin,
                                 StorageType type,
                                 bool is_eviction,
                                 QuotaDatabase* database) {
   DCHECK(database);
+
+  QuotaDatabase::OriginInfoTableEntry entry;
+
+  base::Time now = base::Time::Now();

[michaeln, 2015/10/30 00:49:02]

maybe swap  lines |now| and |entry| are declared on since entry is only used
within the new block below and now is used in the new block and in existing code
at the end of the method

[calamity, 2015/11/02 06:27:44]

Done.

+  if (database->GetOriginInfo(origin, type, &entry)) {

[michaeln, 2015/10/30 00:49:02]

please add |is_eviction| to this condition too

[calamity, 2015/11/02 06:27:44]

Done. Nice catch.

+    UMA_HISTOGRAM_COUNTS(QuotaManager::kEvictedOriginAccessedCountHistogram,
+                         entry.used_count);
+    UMA_HISTOGRAM_LONG_TIMES(
+        QuotaManager::kEvictedOriginTimeSinceAccessHistogram,
+        now - entry.last_access_time);
+  }
+
   if (!database->DeleteOriginInfo(origin, type))
     return false;
 
   // If the deletion is not due to an eviction, delete the entry in the eviction
   // table as well due to privacy concerns.
   if (!is_eviction)
     return database->DeleteOriginLastEvictionTime(origin, type);
 
   base::Time last_eviction_time;
   if (!database->GetOriginLastEvictionTime(origin, type, &last_eviction_time))
     return false;
 
-  base::Time now = base::Time::Now();
   if (last_eviction_time != base::Time()) {
     UMA_HISTOGRAM_LONG_TIMES(
         QuotaManager::kTimeBetweenRepeatedOriginEvictionsHistogram,
         now - last_eviction_time);
   }
 
   return database->SetOriginLastEvictionTime(origin, type, now);
 }
 
 bool InitializeTemporaryOriginsInfoOnDBThread(const std::set<GURL>* origins,
@@ skipping 1547 matching lines @@
   // |database_|, therefore we can be sure that database_ is alive when this
   // task runs.
   base::PostTaskAndReplyWithResult(
       db_thread_.get(),
       from_here,
       base::Bind(task, base::Unretained(database_.get())),
       reply);
 }
 
 }  // namespace storage