Changeset 28727 in webkit

Timestamp:

Dec 14, 2007, 4:25:45 PM (18 years ago)

Author:

[email protected]

Message:

Add logic for TCMalloc to release memory to the system

Reviewed by Maciej and Oliver.

Add final changes to make TCMalloc release memory to the system.
This results in a 0.4% regression against ToT, but this is offset
against the gains made by the original TCMalloc r38 merge - in fact
we retain around 0.3-0.4% progression overall.

Location:

trunk/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• wtf/FastMalloc.cpp (modified) (6 diffs)
• wtf/TCSystemAlloc.cpp (modified) (2 diffs)

trunk/JavaScriptCore/ChangeLog

@@ +1 @@
+2007-12-14  Mark Rowe <[email protected]>
+
+        Reviewed by Maciej and Oliver.
+
+        Add final changes to make TCMalloc release memory to the system.
+        This results in a 0.4% regression against ToT, but this is offset
+        against the gains made by the original TCMalloc r38 merge - in fact
+        we retain around 0.3-0.4% progression overall.
+
+        * wtf/FastMalloc.cpp:
+        (WTF::InitSizeClasses):
+        (WTF::TCMalloc_PageHeap::IncrementalScavenge):
+        * wtf/TCSystemAlloc.cpp:
+        (TCMalloc_SystemRelease):
+
 2007-12-14  Darin Adler  <[email protected]>
 

trunk/JavaScriptCore/wtf/FastMalloc.cpp

@@ -236 +236 @@
 #endif
 
+#ifndef PRIuS
+#define PRIuS "zu"
+#endif
+
 // Calling pthread_getspecific through a global function pointer is faster than a normal
 // call to the function on Mac OS X, and it's used in performance-critical code. So we
@@ -672 +676 @@
   }
   if (sc != kNumClasses) {
-    MESSAGE("wrong number of size classes: found %d instead of %d\n",
+    MESSAGE("wrong number of size classes: found %" PRIuS " instead of %d\n",
             sc, int(kNumClasses));
     abort();
@@ -691 +695 @@
     const size_t sc = SizeClass(size);
     if (sc == 0) {
-      MESSAGE("Bad size class %d for %" PRIuS "\n", sc, size);
+      MESSAGE("Bad size class %" PRIuS " for %" PRIuS "\n", sc, size);
       abort();
     }
     if (sc > 1 && size <= class_to_size[sc-1]) {
-      MESSAGE("Allocating unnecessarily large class %d for %" PRIuS
+      MESSAGE("Allocating unnecessarily large class %" PRIuS " for %" PRIuS
               "\n", sc, size);
       abort();
     }
     if (sc >= kNumClasses) {
-      MESSAGE("Bad size class %d for %" PRIuS "\n", sc, size);
+      MESSAGE("Bad size class %" PRIuS " for %" PRIuS "\n", sc, size);
       abort();
     }
     const size_t s = class_to_size[sc];
     if (size > s) {
-      MESSAGE("Bad size %" PRIuS " for %" PRIuS " (sc = %d)\n", s, size, sc);
+     MESSAGE("Bad size %" PRIuS " for %" PRIuS " (sc = %" PRIuS ")\n", s, size, sc);
       abort();
     }
     if (s == 0) {
-      MESSAGE("Bad size %" PRIuS " for %" PRIuS " (sc = %d)\n", s, size, sc);
+      MESSAGE("Bad size %" PRIuS " for %" PRIuS " (sc = %" PRIuS ")\n", s, size, sc);
       abort();
     }
@@ -1329 +1333 @@
   if (scavenge_counter_ >= 0) return;  // Not yet time to scavenge
 
-  // Never delay scavenging for more than the following number of
-  // deallocated pages.  With 4K pages, this comes to 4GB of
-  // deallocation.
-  static const int kMaxReleaseDelay = 1 << 20;
-
   // If there is nothing to release, wait for so many pages before
-  // scavenging again.  With 4K pages, this comes to 1GB of memory.
-  static const int kDefaultReleaseDelay = 1 << 18;
-
-  const double rate = FLAGS_tcmalloc_release_rate;
-  if (rate <= 1e-6) {
-    // Tiny release rate means that releasing is disabled.
-    scavenge_counter_ = kDefaultReleaseDelay;
-    return;
-  }
+  // scavenging again.  With 4K pages, this comes to 16MB of memory.
+  static const size_t kDefaultReleaseDelay = 1 << 8;
 
   // Find index of free list to scavenge
@@ -1358 +1350 @@
       DLL_Prepend(&slist->returned, s);
 
-      // Compute how long to wait until we return memory.
-      // FLAGS_tcmalloc_release_rate==1 means wait for 1000 pages
-      // after releasing one page.
-      const double mult = 1000.0 / rate;
-      double wait = mult * static_cast<double>(s->length);
-      if (wait > kMaxReleaseDelay) {
-        // Avoid overflow and bound to reasonable range
-        wait = kMaxReleaseDelay;
-      }
-      scavenge_counter_ = static_cast<int64_t>(wait);
-
-      scavenge_index_ = index;  // Scavenge at index+1 next time
+      scavenge_counter_ = max(64UL, min(kDefaultReleaseDelay, kDefaultReleaseDelay - (free_pages_ / kDefaultReleaseDelay)));
+//      fprintf(stderr, "Released %zu pages at 0x%08zx to the system from index %zu.  Delaying for %lld pages before scavenging next.\n", s->length, s->start << kPageShift, index, scavenge_counter_);
+
+      if (index == kMaxPages && !DLL_IsEmpty(&slist->normal))
+        scavenge_index_ = index - 1;
+      else
+        scavenge_index_ = index;
       return;
     }
@@ -1377 +1364 @@
   // Nothing to scavenge, delay for a while
   scavenge_counter_ = kDefaultReleaseDelay;
+//  fprintf(stderr, "Nothing to scavenge.  Delaying for %lld pages before scavenging next.\n", scavenge_counter_);
 }
 

trunk/JavaScriptCore/wtf/TCSystemAlloc.cpp

@@ -381 +381 @@
 }
 
-#ifndef MADV_DONTNEED
-void TCMalloc_SystemRelease(void*, size_t) {}
-#else
 void TCMalloc_SystemRelease(void* start, size_t length) {
+#ifdef MADV_DONTNEED
   if (FLAGS_malloc_devmem_start) {
     // It's not safe to use MADV_DONTNEED if we've been mapping
@@ -416 +414 @@
     }
   }
-}
-#endif
+#endif
+
+#if HAVE(MMAP)
+  void *newAddress = mmap(start, length, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, -1, 0);
+  UNUSED_PARAM(newAddress);
+  // If the mmap failed then that's ok, we just won't return the memory to the system.
+  ASSERT(newAddress == start || newAddress == reinterpret_cast<void*>(MAP_FAILED));
+#endif
+}