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

Differential Revision: https://phabricator.services.mozilla.com/D37192

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

modules/libpref/init/StaticPrefList.h

@@ -823,6 +823,16 @@ VARCACHE_PREF(
   RelaxedAtomicUint32, 40 * 1024
 )
 
+// Number of seconds the cache spends writing pending data and closing files
+// after shutdown has been signalled. Past that time data is not written and
+// files are left open for the OS to clean up.
+VARCACHE_PREF(
+  Live,
+  "browser.cache.max_shutdown_io_lag",
+   browser_cache_max_shutdown_io_lag,
+  RelaxedAtomicUint32, 2
+)
+
 // Whether Content Blocking Third-Party Cookies UI has been enabled.
 VARCACHE_PREF(
   Live,

modules/libpref/init/all.js

@@ -37,11 +37,6 @@ pref("browser.cache.check_doc_frequency",   3);
 // The half life used to re-compute cache entries frecency in hours.
 pref("browser.cache.frecency_half_life_hours", 6);
 
-// Number of seconds the cache spends writting pending data and closing files
-// after the shutdown has been signalled.  Past that time data are never written
-// and files are left open given up to the OS to do the cleanup.
-pref("browser.cache.max_shutdown_io_lag", 2);
-
 // AppCache over insecure connection is disabled by default
 pref("browser.cache.offline.insecure.enable",  false);
 

netwerk/cache2/CacheObserver.cpp

@@ -45,10 +45,6 @@ bool CacheObserver::sCacheFSReported = kDefaultCacheFSReported;
 static bool kDefaultHashStatsReported = false;
 bool CacheObserver::sHashStatsReported = kDefaultHashStatsReported;
 
-static uint32_t const kDefaultMaxShutdownIOLag = 2;  // seconds
-Atomic<uint32_t, Relaxed> CacheObserver::sMaxShutdownIOLag(
-    kDefaultMaxShutdownIOLag);
-
 Atomic<PRIntervalTime> CacheObserver::sShutdownDemandedTime(
     PR_INTERVAL_NO_TIMEOUT);
 
@@ -122,10 +118,6 @@ void CacheObserver::AttachToPreferences() {
                                         "privacy.clearOnShutdown.cache",
                                         kDefaultClearCacheOnShutdown);
 
-  mozilla::Preferences::AddAtomicUintVarCache(
-      &sMaxShutdownIOLag, "browser.cache.max_shutdown_io_lag",
-      kDefaultMaxShutdownIOLag);
-
   mozilla::Preferences::AddAtomicUintVarCache(
       &sTelemetryReportID, "browser.cache.disk.telemetry_report_ID",
       kDefaultTelemetryReportID);
@@ -375,12 +367,12 @@ bool CacheObserver::IsPastShutdownIOLag() {
 #endif
 
   if (sShutdownDemandedTime == PR_INTERVAL_NO_TIMEOUT ||
-      sMaxShutdownIOLag == UINT32_MAX) {
+      MaxShutdownIOLag() == UINT32_MAX) {
     return false;
   }
 
   static const PRIntervalTime kMaxShutdownIOLag =
-      PR_SecondsToInterval(sMaxShutdownIOLag);
+      PR_SecondsToInterval(MaxShutdownIOLag());
 
   if ((PR_IntervalNow() - sShutdownDemandedTime) > kMaxShutdownIOLag) {
     return true;

netwerk/cache2/CacheObserver.h

@@ -91,7 +91,9 @@ class CacheObserver : public nsIObserver, public nsSupportsWeakReference {
 
   static bool EntryIsTooBig(int64_t aSize, bool aUsingDisk);
 
-  static uint32_t MaxShutdownIOLag() { return sMaxShutdownIOLag; }
+  static uint32_t MaxShutdownIOLag() {
+    return StaticPrefs::browser_cache_max_shutdown_io_lag();
+  }
   static bool IsPastShutdownIOLag();
 
   static bool ShuttingDown() {
@@ -115,7 +117,6 @@ class CacheObserver : public nsIObserver, public nsSupportsWeakReference {
   static bool sClearCacheOnShutdown;
   static bool sCacheFSReported;
   static bool sHashStatsReported;
-  static Atomic<uint32_t, Relaxed> sMaxShutdownIOLag;
   static Atomic<PRIntervalTime> sShutdownDemandedTime;
   static Atomic<uint32_t, Relaxed> sTelemetryReportID;
   static Atomic<uint32_t, Relaxed> sCacheAmountWritten;