Disk cache: Track evictions of ga.js.

The purpose is to understand the cache behavior with very popular resources.

BUG=147383
TEST=none

Review URL: https://chromiumcodereview.appspot.com/11000062

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@161468 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 19 insertions, 3 deletions

diff --git a/net/disk_cache/backend_impl.cc b/net/disk_cache/backend_impl.cc
index 2de5952..e7fd5d6 100644
--- a/net/disk_cache/backend_impl.cc
+++ b/net/disk_cache/backend_impl.cc
@@ -1538,6 +1538,7 @@ void BackendImpl::RestartCache(bool failure) {
   int64 errors = stats_.GetCounter(Stats::FATAL_ERROR);
   int64 full_dooms = stats_.GetCounter(Stats::DOOM_CACHE);
   int64 partial_dooms = stats_.GetCounter(Stats::DOOM_RECENT);
+  int64 ga_evictions = stats_.GetCounter(Stats::GAJS_EVICTED);
   int64 last_report = stats_.GetCounter(Stats::LAST_REPORT);
 
   PrepareForRestart();
@@ -1557,6 +1558,7 @@ void BackendImpl::RestartCache(bool failure) {
     stats_.SetCounter(Stats::FATAL_ERROR, errors);
     stats_.SetCounter(Stats::DOOM_CACHE, full_dooms);
     stats_.SetCounter(Stats::DOOM_RECENT, partial_dooms);
+    stats_.SetCounter(Stats::GAJS_EVICTED, ga_evictions);
     stats_.SetCounter(Stats::LAST_REPORT, last_report);
   }
 }
@@ -2013,9 +2015,12 @@ void BackendImpl::ReportStats() {
             static_cast<int>(stats_.GetCounter(Stats::DOOM_CACHE)));
   CACHE_UMA(COUNTS_10000, "TotalDoomRecentEntries", 0,
             static_cast<int>(stats_.GetCounter(Stats::DOOM_RECENT)));
+  CACHE_UMA(COUNTS_10000, "TotalEvictionsGaJs", 0,
+            static_cast<int>(stats_.GetCounter(Stats::GAJS_EVICTED)));
   stats_.SetCounter(Stats::FATAL_ERROR, 0);
   stats_.SetCounter(Stats::DOOM_CACHE, 0);
   stats_.SetCounter(Stats::DOOM_RECENT, 0);
+  stats_.SetCounter(Stats::GAJS_EVICTED, 0);
 
   int64 total_hours = stats_.GetCounter(Stats::TIMER) / 120;
   if (!data_->header.create_time || !data_->header.lru.filled) {
diff --git a/net/disk_cache/eviction.cc b/net/disk_cache/eviction.cc
index 7a33479..1a4a0f1 100644
--- a/net/disk_cache/eviction.cc
+++ b/net/disk_cache/eviction.cc
@@ -281,8 +281,6 @@ bool Eviction::EvictEntry(CacheRankingsBlock* node, bool empty,
   ReportTrimTimes(entry);
   if (empty || !new_eviction_) {
     entry->DoomImpl();
-    if (!empty)
-      backend_->OnEvent(Stats::TRIM_ENTRY);
   } else {
     entry->DeleteEntryData(false);
     EntryStore* info = entry->entry()->Data();
@@ -292,7 +290,13 @@ bool Eviction::EvictEntry(CacheRankingsBlock* node, bool empty,
     info->state = ENTRY_EVICTED;
     entry->entry()->Store();
     rankings_->Insert(entry->rankings(), true, Rankings::DELETED);
+  }
+  if (!empty) {
     backend_->OnEvent(Stats::TRIM_ENTRY);
+
+    static const char gajs[] = "http://www.google-analytics.com/ga.js";
+    if (!entry->GetKey().compare(gajs))
+      backend_->OnEvent(Stats::GAJS_EVICTED);
   }
   entry->Release();
 
diff --git a/net/disk_cache/stats.cc b/net/disk_cache/stats.cc
index 62d228c..c77f7f9 100644
--- a/net/disk_cache/stats.cc
+++ b/net/disk_cache/stats.cc
@@ -61,7 +61,8 @@ static const char* kCounterNames[] = {
   "Fatal error",
   "Last report",
   "Last report timer",
-  "Doom recent entries"
+  "Doom recent entries",
+  "ga.js evicted"
 };
 COMPILE_ASSERT(arraysize(kCounterNames) == disk_cache::Stats::MAX_COUNTER,
                update_the_names);
@@ -88,6 +89,11 @@ bool LoadStats(BackendImpl* backend, Addr address, OnDiskStats* stats) {
   // counter; we keep old data if we can.
   if (static_cast<unsigned int>(stats->size) > sizeof(*stats)) {
     memset(stats, 0, sizeof(*stats));
+    stats->signature = kDiskSignature;
+  } else if (static_cast<unsigned int>(stats->size) != sizeof(*stats)) {
+    size_t delta = sizeof(*stats) - static_cast<unsigned int>(stats->size);
+    memset(reinterpret_cast<char*>(stats) + stats->size, 0, delta);
+    stats->size = sizeof(*stats);
   }
 
   return true;
diff --git a/net/disk_cache/stats.h b/net/disk_cache/stats.h
index 94b9d68..845aa18 100644
--- a/net/disk_cache/stats.h
+++ b/net/disk_cache/stats.h
@@ -48,6 +48,7 @@ class Stats {
     LAST_REPORT,  // Time of the last time we sent a report.
     LAST_REPORT_TIMER,  // Timer count of the last time we sent a report.
     DOOM_RECENT,  // The cache was partially cleared.
+    GAJS_EVICTED,  // ga.js was evicted from the cache.
     MAX_COUNTER
   };