New disk cache eviction algorithm.

net/disk_cache/entry_impl.cc

 // Copyright (c) 2006-2008 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 "net/disk_cache/entry_impl.h"
 
 #include "base/histogram.h"
 #include "base/message_loop.h"
 #include "base/string_util.h"
 #include "net/base/io_buffer.h"
@@ skipping 74 matching lines @@
 }
 
 // When an entry is deleted from the cache, we clean up all the data associated
 // with it for two reasons: to simplify the reuse of the block (we know that any
 // unused block is filled with zeros), and to simplify the handling of write /
 // read partial information from an entry (don't have to worry about returning
 // data related to a previous cache entry because the range was not fully
 // 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++) {
       if (user_buffers_[index].get()) {
         if (!(ret = Flush(index, entry_.Data()->data_size[index], false)))
           LOG(ERROR) << "Failed to save user data";
       } else if (unreported_size_[index]) {
         backend_->ModifyStorageSize(
             entry_.Data()->data_size[index] - unreported_size_[index],
             entry_.Data()->data_size[index]);
@@ skipping 341 matching lines @@
 
 void EntryImpl::InternalDoom() {
   DCHECK(node_.HasData());
   if (!node_.Data()->dirty) {
     node_.Data()->dirty = backend_->GetCurrentEntryId();
     node_.Store();
   }
   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;
 }
 
 void EntryImpl::SetNextAddress(Addr address) {
   entry_.Data()->next = address.value();
   bool success = entry_.Store();
   DCHECK(success);
 }
 
@@ skipping 342 matching lines @@
   Trace("%s 0x%p 0x%x 0x%x", msg, reinterpret_cast<void*>(this),
         entry_.address().value(), node_.address().value());
 
   Trace("  data: 0x%x 0x%x 0x%x", entry_.Data()->data_addr[0],
         entry_.Data()->data_addr[1], entry_.Data()->long_key);
 
   Trace("  doomed: %d 0x%p 0x%x", doomed_, pointer, dirty);
 }
 
 }  // namespace disk_cache