Tweak DOMStorageArea rate limit

content/browser/dom_storage/dom_storage_area.cc

Index: content/browser/dom_storage/dom_storage_area.cc
diff --git a/content/browser/dom_storage/dom_storage_area.cc b/content/browser/dom_storage/dom_storage_area.cc
index 67c7b98ac1ad2daa431256da55079eadbd02a822..a141da37b21456c6761b953a9e14abfe6bfd38af 100644
--- a/content/browser/dom_storage/dom_storage_area.cc
+++ b/content/browser/dom_storage/dom_storage_area.cc
@@ -33,12 +33,11 @@ namespace {
 
 // Delay for a moment after a value is set in anticipation
 // of other values being set, so changes are batched.
-const int kCommitDefaultDelaySecs = 5;
+const int kCommitDefaultDelaySecs = 10;

[michaeln, 2015/05/14 01:33:48]

Please don't hastily remove the commit rate limiter. You asked about Local State
and Preference files compared to DomStorage areas, one  difference is the number
of files involved. There can be a large number of areas constantly running
commit timers.

 
 // To avoid excessive IO we apply limits to the amount of data being written
 // and the frequency of writes. The specific values used are somewhat arbitrary.
-const int kMaxBytesPerDay = kPerStorageAreaQuota * 2;
-const int kMaxCommitsPerHour = 6;
+const int kMaxBytesPerMinute = kPerStorageAreaQuota;

[michaeln, 2015/05/14 01:33:48]

Adjusting the values is ok, but this adjustment goes too far.

This translates to 14Gbytes per day, 7 bad behaving apps could make for a
terabyte per week. Actually more because the limits are applied to the size of
the values provided, but due to sqlite journaling the amt of writes to disk is
about dbl.

 
 }  // namespace
 
@@ -109,8 +108,7 @@ DOMStorageArea::DOMStorageArea(const GURL& origin,
       is_shutdown_(false),
       commit_batches_in_flight_(0),
       start_time_(base::TimeTicks::Now()),
-      data_rate_limiter_(kMaxBytesPerDay, base::TimeDelta::FromHours(24)),
-      commit_rate_limiter_(kMaxCommitsPerHour, base::TimeDelta::FromHours(1)) {
+      data_rate_limiter_(kMaxBytesPerMinute, base::TimeDelta::FromMinutes(1)) {
   if (!directory.empty()) {
     base::FilePath path = directory.Append(DatabaseFileNameFromOrigin(origin_));
     backing_.reset(new LocalStorageDatabaseAdapter(path));
@@ -134,8 +132,7 @@ DOMStorageArea::DOMStorageArea(int64 namespace_id,
       is_shutdown_(false),
       commit_batches_in_flight_(0),
       start_time_(base::TimeTicks::Now()),
-      data_rate_limiter_(kMaxBytesPerDay, base::TimeDelta::FromHours(24)),
-      commit_rate_limiter_(kMaxCommitsPerHour, base::TimeDelta::FromHours(1)) {
+      data_rate_limiter_(kMaxBytesPerMinute, base::TimeDelta::FromMinutes(1)) {
   DCHECK(namespace_id != kLocalStorageNamespaceId);
   if (session_storage_backing) {
     backing_.reset(new SessionStorageDatabaseAdapter(
@@ -400,8 +397,7 @@ base::TimeDelta DOMStorageArea::ComputeCommitDelay() const {
   base::TimeDelta elapsed_time = base::TimeTicks::Now() - start_time_;
   base::TimeDelta delay = std::max(
       base::TimeDelta::FromSeconds(kCommitDefaultDelaySecs),
-      std::max(commit_rate_limiter_.ComputeDelayNeeded(elapsed_time),
-               data_rate_limiter_.ComputeDelayNeeded(elapsed_time)));
+      data_rate_limiter_.ComputeDelayNeeded(elapsed_time));
   UMA_HISTOGRAM_LONG_TIMES("LocalStorage.CommitDelay", delay);
   return delay;
 }
@@ -424,7 +420,6 @@ void DOMStorageArea::PostCommitTask() {
 
   DCHECK(backing_.get());
 
-  commit_rate_limiter_.add_samples(1);
   data_rate_limiter_.add_samples(commit_batch_->GetDataSize());
 
   // This method executes on the primary sequence, we schedule