Changeset 179823 in webkit

Timestamp:

Feb 9, 2015, 3:03:06 AM (12 years ago)

Author:

Antti Koivisto

Message:

Measure cache size more accurately
​https://bugs.webkit.org/show_bug.cgi?id=141378
<rdar://problem/19760224>

Reviewed by Chris Dumez.

Estimate the cache disk space usage from the actual entry sizes instead of the item count.
This prevents large cache items from making the cache grow beyond its bounds.

• NetworkProcess/cache/NetworkCacheStorage.h:
• NetworkProcess/cache/NetworkCacheStorageCocoa.mm:

(WebKit::NetworkCacheStorage::initialize):
(WebKit::NetworkCacheStorage::removeEntry):
(WebKit::NetworkCacheStorage::store):
(WebKit::NetworkCacheStorage::clear):
(WebKit::NetworkCacheStorage::shrinkIfNeeded):

Location:

trunk/Source/WebKit2

Files:

• ChangeLog (modified) (1 diff)
• NetworkProcess/cache/NetworkCacheStorage.h (modified) (3 diffs)
• NetworkProcess/cache/NetworkCacheStorageCocoa.mm (modified) (11 diffs)

trunk/Source/WebKit2/ChangeLog

@@ +1 @@
+2015-02-08  Antti Koivisto  <antti@apple.com>
+
+        Measure cache size more accurately
+        https://bugs.webkit.org/show_bug.cgi?id=141378
+        <rdar://problem/19760224>
+
+        Reviewed by Chris Dumez.
+
+        Estimate the cache disk space usage from the actual entry sizes instead of the item count.
+        This prevents large cache items from making the cache grow beyond its bounds.
+
+        * NetworkProcess/cache/NetworkCacheStorage.h:
+        * NetworkProcess/cache/NetworkCacheStorageCocoa.mm:
+        (WebKit::NetworkCacheStorage::initialize):
+        (WebKit::NetworkCacheStorage::removeEntry):
+        (WebKit::NetworkCacheStorage::store):
+        (WebKit::NetworkCacheStorage::clear):
+        (WebKit::NetworkCacheStorage::shrinkIfNeeded):
+
 2015-02-09  Carlos Garcia Campos  <cgarcia@igalia.com>
 

trunk/Source/WebKit2/NetworkProcess/cache/NetworkCacheStorage.h

@@ -30 +30 @@
 
 #include "NetworkCacheKey.h"
-#include <WebCore/ResourceResponse.h>
 #include <wtf/BloomFilter.h>
 #include <wtf/Deque.h>
@@ -46 +45 @@
 
 namespace WebKit {
-
-class ShareableResource;
 
 #if PLATFORM(COCOA)
@@ -193 +190 @@
 
     BloomFilter<20> m_contentsFilter;
-    std::atomic<size_t> m_approximateEntryCount { 0 };
+    std::atomic<size_t> m_approximateSize { 0 };
     std::atomic<bool> m_shrinkInProgress { false };
 

trunk/Source/WebKit2/NetworkProcess/cache/NetworkCacheStorageCocoa.mm

@@ -35 +35 @@
 #include <sys/mman.h>
 #include <sys/stat.h>
+#include <wtf/RandomNumber.h>
 #include <wtf/RunLoop.h>
 #include <wtf/text/CString.h>
@@ -110 +111 @@
 
     StringCapture cachePathCapture(m_directoryPath);
-    auto& entryCount = m_approximateEntryCount;
-
-    dispatch_async(m_backgroundIOQueue.get(), [this, cachePathCapture, &entryCount] {
+
+    dispatch_async(m_backgroundIOQueue.get(), [this, cachePathCapture] {
         String cachePath = cachePathCapture.string();
-        traverseCacheFiles(cachePath, [this, &entryCount](const String& fileName, const String&) {
+        traverseCacheFiles(cachePath, [this](const String& fileName, const String& partitionPath) {
             NetworkCacheKey::HashType hash;
             if (!NetworkCacheKey::stringToHash(fileName, hash))
@@ -122 +122 @@
                 m_contentsFilter.add(shortHash);
             });
-            ++entryCount;
+            auto filePath = WebCore::pathByAppendingComponent(partitionPath, fileName);
+            long long fileSize = 0;
+            WebCore::getFileSize(filePath, fileSize);
+            m_approximateSize += fileSize;
         });
     });
@@ -324 +327 @@
     ASSERT(RunLoop::isMain());
 
+    // For simplicity we don't reduce m_approximateSize on removals caused by load or decode errors.
+    // The next cache shrink will update the size.
+
     if (m_contentsFilter.mayContain(key.shortHash()))
         m_contentsFilter.remove(key.shortHash());
 
     StringCapture filePathCapture(filePathForKey(key, m_directoryPath));
-    dispatch_async(m_ioQueue.get(), [this, filePathCapture] {
+    dispatch_async(m_backgroundIOQueue.get(), [this, filePathCapture] {
         WebCore::deleteFile(filePathCapture.string());
-        if (m_approximateEntryCount)
-            --m_approximateEntryCount;
     });
 }
@@ -430 +434 @@
 
     m_contentsFilter.add(key.shortHash());
-    ++m_approximateEntryCount;
 
     auto storeOperation = std::make_unique<StoreOperation>(StoreOperation { key, entry, WTF::move(completionHandler) });
@@ -442 +445 @@
 
         size_t bodyOffset = dispatch_data_get_size(encodedHeader.get());
-        size_t bodySize = store.entry.body.size();
 
         int fd;
         auto channel = openFileForKey(store.key, FileOpenType::Create, cachePathCapture.string(), fd);
-        dispatch_io_write(channel.get(), 0, writeData.get(), dispatch_get_main_queue(), [this, &store, fd, bodyOffset, bodySize](bool done, dispatch_data_t, int error) {
+        dispatch_io_write(channel.get(), 0, writeData.get(), dispatch_get_main_queue(), [this, &store, fd, bodyOffset](bool done, dispatch_data_t, int error) {
             ASSERT_UNUSED(done, done);
             LOG(NetworkCacheStorage, "(NetworkProcess) write complete error=%d", error);
@@ -452 +454 @@
                 if (m_contentsFilter.mayContain(store.key.shortHash()))
                     m_contentsFilter.remove(store.key.shortHash());
-                if (m_approximateEntryCount)
-                    --m_approximateEntryCount;
             }
+            size_t bodySize = store.entry.body.size();
+            size_t totalSize = bodyOffset + bodySize;
+
+            m_approximateSize += totalSize;
 
             bool shouldMapBody = !error && bodySize >= vm_page_size;
@@ -532 +536 @@
 
     m_contentsFilter.clear();
-    m_approximateEntryCount = 0;
+    m_approximateSize = 0;
 
     StringCapture directoryPathCapture(m_directoryPath);
@@ -550 +554 @@
 void NetworkCacheStorage::shrinkIfNeeded()
 {
-    const size_t assumedAverageResourceSize { 48 * 1024 };
-    const size_t everyNthResourceToDelete { 4 };
-
-    size_t estimatedCacheSize = assumedAverageResourceSize * m_approximateEntryCount;
-
-    if (estimatedCacheSize <= m_maximumSize)
+    ASSERT(RunLoop::isMain());
+
+    static const double deletionProbability { 0.25 };
+
+    if (m_approximateSize <= m_maximumSize)
         return;
     if (m_shrinkInProgress)
@@ -561 +564 @@
     m_shrinkInProgress = true;
 
-    LOG(NetworkCacheStorage, "(NetworkProcess) shrinking cache m_approximateEntryCount=%d estimatedCacheSize=%d, m_maximumSize=%d", static_cast<size_t>(m_approximateEntryCount), estimatedCacheSize, m_maximumSize);
+    LOG(NetworkCacheStorage, "(NetworkProcess) shrinking cache approximateSize=%d, m_maximumSize=%d", static_cast<size_t>(m_approximateSize), m_maximumSize);
+
+    m_approximateSize = 0;
 
     StringCapture cachePathCapture(m_directoryPath);
     dispatch_async(m_backgroundIOQueue.get(), [this, cachePathCapture] {
         String cachePath = cachePathCapture.string();
-        size_t foundEntryCount = 0;
-        size_t deletedCount = 0;
-        traverseCacheFiles(cachePath, [this, &foundEntryCount, &deletedCount](const String& fileName, const String& partitionPath) {
-            ++foundEntryCount;
-            if (foundEntryCount % everyNthResourceToDelete)
+        traverseCacheFiles(cachePath, [this](const String& fileName, const String& partitionPath) {
+            auto filePath = WebCore::pathByAppendingComponent(partitionPath, fileName);
+
+            bool shouldDelete = randomNumber() < deletionProbability;
+            if (!shouldDelete) {
+                long long fileSize = 0;
+                WebCore::getFileSize(filePath, fileSize);
+                m_approximateSize += fileSize;
                 return;
-            ++deletedCount;
-
-            WebCore::deleteFile(WebCore::pathByAppendingComponent(partitionPath, fileName));
-
+            }
+
+            WebCore::deleteFile(filePath);
             NetworkCacheKey::HashType hash;
             if (!NetworkCacheKey::stringToHash(fileName, hash))
@@ -585 +592 @@
             });
         });
-        m_approximateEntryCount = foundEntryCount - deletedCount;
         m_shrinkInProgress = false;
 
-        LOG(NetworkCacheStorage, "(NetworkProcess) cache shrink completed m_approximateEntryCount=%d", static_cast<size_t>(m_approximateEntryCount));
+        LOG(NetworkCacheStorage, "(NetworkProcess) cache shrink completed approximateSize=%d", static_cast<size_t>(m_approximateSize));
     });
 }