Bug 1562305 - Make browser.cache.disk.preload_chunk_count a static pref. r=michal

Differential Revision: https://phabricator.services.mozilla.com/D37186

--HG--
extra : moz-landing-system : lando

modules/libpref/init/StaticPrefList.h

@@ -775,6 +775,15 @@ VARCACHE_PREF(
   RelaxedAtomicUint32, 1024  // 1MB
 )
 
+// The number of chunks we preload ahead of read. One chunk currently has
+// 256kB.
+VARCACHE_PREF(
+  Live,
+  "browser.cache.disk.preload_chunk_count",
+   browser_cache_disk_preload_chunk_count,
+  RelaxedAtomicUint32, 4  // 1 MB of read ahead
+)
+
 // Whether Content Blocking Third-Party Cookies UI has been enabled.
 VARCACHE_PREF(
   Live,

modules/libpref/init/all.js

@@ -50,8 +50,6 @@ pref("browser.cache.disk.max_priority_chunks_memory_usage", 40960);
 pref("browser.cache.disk_cache_ssl",        true);
 // 0 = once-per-session, 1 = each-time, 2 = never, 3 = when-appropriate/automatically
 pref("browser.cache.check_doc_frequency",   3);
-// The number of chunks we preload ahead of read.  One chunk has currently 256kB.
-pref("browser.cache.disk.preload_chunk_count", 4); // 1 MB of read ahead
 // The half life used to re-compute cache entries frecency in hours.
 pref("browser.cache.frecency_half_life_hours", 6);
 

netwerk/cache2/CacheObserver.cpp

@@ -33,9 +33,6 @@ static uint32_t const kDefaultDiskCacheCapacity = 250 * 1024;  // 250 MB
 Atomic<uint32_t, Relaxed> CacheObserver::sDiskCacheCapacity(
     kDefaultDiskCacheCapacity);
 
-static uint32_t const kDefaultPreloadChunkCount = 4;
-uint32_t CacheObserver::sPreloadChunkCount = kDefaultPreloadChunkCount;
-
 static int32_t const kDefaultMaxMemoryEntrySize = 4 * 1024;  // 4 MB
 int32_t CacheObserver::sMaxMemoryEntrySize = kDefaultMaxMemoryEntrySize;
 
@@ -127,10 +124,6 @@ void CacheObserver::AttachToPreferences() {
                                               "browser.cache.disk.capacity",
                                               kDefaultDiskCacheCapacity);
 
-  mozilla::Preferences::AddUintVarCache(
-      &sPreloadChunkCount, "browser.cache.disk.preload_chunk_count",
-      kDefaultPreloadChunkCount);
-
   mozilla::Preferences::AddIntVarCache(&sMaxDiskEntrySize,
                                        "browser.cache.disk.max_entry_size",
                                        kDefaultMaxDiskEntrySize);

netwerk/cache2/CacheObserver.h

@@ -53,7 +53,9 @@ class CacheObserver : public nsIObserver, public nsSupportsWeakReference {
   static bool SmartCacheSizeEnabled() {
     return StaticPrefs::browser_cache_disk_smart_size_enabled();
   }
-  static uint32_t PreloadChunkCount() { return sPreloadChunkCount; }
+  static uint32_t PreloadChunkCount() {
+    return StaticPrefs::browser_cache_disk_preload_chunk_count();
+  }
   static uint32_t MaxMemoryEntrySize()  // result in kilobytes.
   {
     return sMaxMemoryEntrySize;
@@ -107,7 +109,6 @@ class CacheObserver : public nsIObserver, public nsSupportsWeakReference {
 
   static int32_t sAutoMemoryCacheCapacity;
   static Atomic<uint32_t, Relaxed> sDiskCacheCapacity;
-  static uint32_t sPreloadChunkCount;
   static int32_t sMaxMemoryEntrySize;
   static int32_t sMaxDiskEntrySize;
   static uint32_t sMaxDiskChunksMemoryUsage;