New disk cache eviction algorithm (partial implementation).

Disabled by a #def. When enabled, file format 2.1 is used,
with a possible update from ver 2.0. If a version with this
code disabled is run after the upgrade, it will just
discard the file and go back to 2.0.

We now put some of those extra list to use! Entries are
separated into various lists depending on how often are
used, and we keep track of previously evicted entries.

If the new algorithm is not enabled, most of the code just
goes through a different path (with the old code instead of
the new one). One notable exception is OpenFollowingEntry,
used to enumerate the entries on the cache; the code changed
significantly to support the new version of the "cache
iterator", but functionally should do the same as the current
code.


Review URL: http://codereview.chromium.org/27345

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@11145 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 34 insertions, 21 deletions

diff --git a/net/disk_cache/entry_impl.cc b/net/disk_cache/entry_impl.cc
index 9db5647..361a7ee 100644
--- a/net/disk_cache/entry_impl.cc
+++ b/net/disk_cache/entry_impl.cc
@@ -92,27 +92,7 @@ EntryImpl::EntryImpl(BackendImpl* backend, Addr address)
 // written before).
 EntryImpl::~EntryImpl() {
   if (doomed_) {
-    UMA_HISTOGRAM_COUNTS("DiskCache.DeleteHeader", GetDataSize(0));
-    UMA_HISTOGRAM_COUNTS("DiskCache.DeleteData", GetDataSize(1));
-    for (int index = 0; index < NUM_STREAMS; index++) {
-      Addr address(entry_.Data()->data_addr[index]);
-      if (address.is_initialized()) {
-        DeleteData(address, index);
-        backend_->ModifyStorageSize(entry_.Data()->data_size[index] -
-                                        unreported_size_[index], 0);
-      }
-    }
-    Addr address(entry_.Data()->long_key);
-    DeleteData(address, kKeyFileIndex);
-    backend_->ModifyStorageSize(entry_.Data()->key_len, 0);
-
-    memset(node_.buffer(), 0, node_.size());
-    memset(entry_.buffer(), 0, entry_.size());
-    node_.Store();
-    entry_.Store();
-
-    backend_->DeleteBlock(node_.address(), false);
-    backend_->DeleteBlock(entry_.address(), false);
+    DeleteEntryData(true);
   } else {
     bool ret = true;
     for (int index = 0; index < NUM_STREAMS; index++) {
@@ -474,6 +454,39 @@ void EntryImpl::InternalDoom() {
   doomed_ = true;
 }
 
+void EntryImpl::DeleteEntryData(bool everything) {
+  DCHECK(doomed_ || !everything);
+
+  UMA_HISTOGRAM_COUNTS("DiskCache.DeleteHeader", GetDataSize(0));
+  UMA_HISTOGRAM_COUNTS("DiskCache.DeleteData", GetDataSize(1));
+  for (int index = 0; index < NUM_STREAMS; index++) {
+    Addr address(entry_.Data()->data_addr[index]);
+    if (address.is_initialized()) {
+      DeleteData(address, index);
+      backend_->ModifyStorageSize(entry_.Data()->data_size[index] -
+                                      unreported_size_[index], 0);
+    }
+  }
+
+  if (!everything)
+    return;
+
+  // Remove all traces of this entry.
+  backend_->RemoveEntry(this);
+
+  Addr address(entry_.Data()->long_key);
+  DeleteData(address, kKeyFileIndex);
+  backend_->ModifyStorageSize(entry_.Data()->key_len, 0);
+
+  memset(node_.buffer(), 0, node_.size());
+  memset(entry_.buffer(), 0, entry_.size());
+  node_.Store();
+  entry_.Store();
+
+  backend_->DeleteBlock(node_.address(), false);
+  backend_->DeleteBlock(entry_.address(), false);
+}
+
 CacheAddr EntryImpl::GetNextAddress() {
   return entry_.Data()->next;
 }