diff --git a/compiler-rt/lib/scudo/standalone/primary32.h b/compiler-rt/lib/scudo/standalone/primary32.h
--- a/compiler-rt/lib/scudo/standalone/primary32.h
+++ b/compiler-rt/lib/scudo/standalone/primary32.h
@@ -467,28 +467,33 @@
       }
     }
 
-    // TODO(kostyak): currently not ideal as we loop over all regions and
-    // iterate multiple times over the same freelist if a ClassId spans multiple
-    // regions. But it will have to do for now.
-    uptr TotalReleasedBytes = 0;
-    const uptr MaxSize = (RegionSize / BlockSize) * BlockSize;
+    DCHECK_GT(MinRegionIndex, 0U);
+    uptr First = 0;
     for (uptr I = MinRegionIndex; I <= MaxRegionIndex; I++) {
       if (PossibleRegions[I] - 1U == ClassId) {
-        const uptr Region = I * RegionSize;
-        // If the region is the one currently associated to the size-class, we
-        // only need to release up to CurrentRegionAllocated, MaxSize otherwise.
-        const uptr Size = (Region == Sci->CurrentRegion)
-                              ? Sci->CurrentRegionAllocated
-                              : MaxSize;
-        ReleaseRecorder Recorder(Region);
-        releaseFreeMemoryToOS(Sci->FreeList, Region, Size, BlockSize,
-                              &Recorder);
-        if (Recorder.getReleasedRangesCount() > 0) {
-          Sci->ReleaseInfo.PushedBlocksAtLastRelease = Sci->Stats.PushedBlocks;
-          Sci->ReleaseInfo.RangesReleased += Recorder.getReleasedRangesCount();
-          Sci->ReleaseInfo.LastReleasedBytes = Recorder.getReleasedBytes();
-          TotalReleasedBytes += Sci->ReleaseInfo.LastReleasedBytes;
-        }
+        First = I;
+        break;
+      }
+    }
+    uptr Last = 0;
+    for (uptr I = MaxRegionIndex; I >= MinRegionIndex; I--) {
+      if (PossibleRegions[I] - 1U == ClassId) {
+        Last = I;
+        break;
+      }
+    }
+    uptr TotalReleasedBytes = 0;
+    if (First && Last) {
+      const uptr Base = First * RegionSize;
+      const uptr NumberOfRegions = Last - First + 1U;
+      ReleaseRecorder Recorder(Base);
+      releaseFreeMemoryToOS(Sci->FreeList, Base, RegionSize, NumberOfRegions,
+                            BlockSize, &Recorder);
+      if (Recorder.getReleasedRangesCount() > 0) {
+        Sci->ReleaseInfo.PushedBlocksAtLastRelease = Sci->Stats.PushedBlocks;
+        Sci->ReleaseInfo.RangesReleased += Recorder.getReleasedRangesCount();
+        Sci->ReleaseInfo.LastReleasedBytes = Recorder.getReleasedBytes();
+        TotalReleasedBytes += Sci->ReleaseInfo.LastReleasedBytes;
       }
     }
     Sci->ReleaseInfo.LastReleaseAtNs = getMonotonicTime();
diff --git a/compiler-rt/lib/scudo/standalone/primary64.h b/compiler-rt/lib/scudo/standalone/primary64.h
--- a/compiler-rt/lib/scudo/standalone/primary64.h
+++ b/compiler-rt/lib/scudo/standalone/primary64.h
@@ -481,7 +481,7 @@
 
     ReleaseRecorder Recorder(Region->RegionBeg, &Region->Data);
     releaseFreeMemoryToOS(Region->FreeList, Region->RegionBeg,
-                          Region->AllocatedUser, BlockSize, &Recorder);
+                          Region->AllocatedUser, 1U, BlockSize, &Recorder);
 
     if (Recorder.getReleasedRangesCount() > 0) {
       Region->ReleaseInfo.PushedBlocksAtLastRelease =
diff --git a/compiler-rt/lib/scudo/standalone/release.h b/compiler-rt/lib/scudo/standalone/release.h
--- a/compiler-rt/lib/scudo/standalone/release.h
+++ b/compiler-rt/lib/scudo/standalone/release.h
@@ -49,7 +49,10 @@
 // incremented past MaxValue.
 class PackedCounterArray {
 public:
-  PackedCounterArray(uptr NumCounters, uptr MaxValue) : N(NumCounters) {
+  PackedCounterArray(uptr NumberOfRegions, uptr CountersPerRegion,
+                     uptr MaxValue)
+      : Regions(NumberOfRegions), NumCounters(CountersPerRegion) {
+    CHECK_GT(Regions, 0);
     CHECK_GT(NumCounters, 0);
     CHECK_GT(MaxValue, 0);
     constexpr uptr MaxCounterBits = sizeof(*Buffer) * 8UL;
@@ -66,9 +69,10 @@
     PackingRatioLog = getLog2(PackingRatio);
     BitOffsetMask = PackingRatio - 1;
 
-    BufferSize = (roundUpTo(N, static_cast<uptr>(1U) << PackingRatioLog) >>
-                  PackingRatioLog) *
-                 sizeof(*Buffer);
+    SizePerRegion =
+        roundUpTo(NumCounters, static_cast<uptr>(1U) << PackingRatioLog) >>
+        PackingRatioLog;
+    BufferSize = SizePerRegion * sizeof(*Buffer) * Regions;
     if (BufferSize <= (StaticBufferCount * sizeof(Buffer[0])) &&
         Mutex.tryLock()) {
       Buffer = &StaticBuffer[0];
@@ -89,41 +93,45 @@
 
   bool isAllocated() const { return !!Buffer; }
 
-  uptr getCount() const { return N; }
+  uptr getCount() const { return NumCounters; }
 
-  uptr get(uptr I) const {
-    DCHECK_LT(I, N);
+  uptr get(uptr Region, uptr I) const {
+    DCHECK_LT(Region, Regions);
+    DCHECK_LT(I, NumCounters);
     const uptr Index = I >> PackingRatioLog;
     const uptr BitOffset = (I & BitOffsetMask) << CounterSizeBitsLog;
-    return (Buffer[Index] >> BitOffset) & CounterMask;
+    return (Buffer[Region * SizePerRegion + Index] >> BitOffset) & CounterMask;
   }
 
-  void inc(uptr I) const {
-    DCHECK_LT(get(I), CounterMask);
+  void inc(uptr Region, uptr I) const {
+    DCHECK_LT(get(Region, I), CounterMask);
     const uptr Index = I >> PackingRatioLog;
     const uptr BitOffset = (I & BitOffsetMask) << CounterSizeBitsLog;
     DCHECK_LT(BitOffset, SCUDO_WORDSIZE);
-    Buffer[Index] += static_cast<uptr>(1U) << BitOffset;
+    Buffer[Region * SizePerRegion + Index] += static_cast<uptr>(1U)
+                                              << BitOffset;
   }
 
-  void incRange(uptr From, uptr To) const {
+  void incRange(uptr Region, uptr From, uptr To) const {
     DCHECK_LE(From, To);
-    const uptr Top = Min(To + 1, N);
+    const uptr Top = Min(To + 1, NumCounters);
     for (uptr I = From; I < Top; I++)
-      inc(I);
+      inc(Region, I);
   }
 
   uptr getBufferSize() const { return BufferSize; }
 
-  static const uptr StaticBufferCount = 1024U;
+  static const uptr StaticBufferCount = 2048U;
 
 private:
-  const uptr N;
+  const uptr Regions;
+  const uptr NumCounters;
   uptr CounterSizeBitsLog;
   uptr CounterMask;
   uptr PackingRatioLog;
   uptr BitOffsetMask;
 
+  uptr SizePerRegion;
   uptr BufferSize;
   uptr *Buffer;
 
@@ -169,7 +177,8 @@
 template <class TransferBatchT, class ReleaseRecorderT>
 NOINLINE void
 releaseFreeMemoryToOS(const IntrusiveList<TransferBatchT> &FreeList, uptr Base,
-                      uptr Size, uptr BlockSize, ReleaseRecorderT *Recorder) {
+                      uptr RegionSize, uptr NumberOfRegions, uptr BlockSize,
+                      ReleaseRecorderT *Recorder) {
   const uptr PageSize = getPageSizeCached();
 
   // Figure out the number of chunks per page and whether we can take a fast
@@ -206,13 +215,15 @@
     }
   }
 
-  const uptr PagesCount = roundUpTo(Size, PageSize) / PageSize;
-  PackedCounterArray Counters(PagesCount, FullPagesBlockCountMax);
+  const uptr PagesCount = roundUpTo(RegionSize, PageSize) / PageSize;
+  PackedCounterArray Counters(NumberOfRegions, PagesCount,
+                              FullPagesBlockCountMax);
   if (!Counters.isAllocated())
     return;
 
   const uptr PageSizeLog = getLog2(PageSize);
-  const uptr RoundedSize = PagesCount << PageSizeLog;
+  const uptr RoundedRegionSize = PagesCount << PageSizeLog;
+  const uptr RoundedSize = NumberOfRegions * RoundedRegionSize;
 
   // Iterate over free chunks and count how many free chunks affect each
   // allocated page.
@@ -228,14 +239,17 @@
       for (u32 I = IsTransferBatch ? 1 : 0; I < It.getCount(); I++) {
         const uptr P = reinterpret_cast<uptr>(It.get(I)) - Base;
         // This takes care of P < Base and P >= Base + RoundedSize.
-        if (P < RoundedSize)
-          Counters.inc(P >> PageSizeLog);
+        if (P < RoundedSize) {
+          const uptr RegionIndex = NumberOfRegions == 1U ? 0 : P / RegionSize;
+          const uptr PInRegion = P - RegionIndex * RegionSize;
+          Counters.inc(RegionIndex, PInRegion >> PageSizeLog);
+        }
       }
     }
-    for (uptr P = Size; P < RoundedSize; P += BlockSize)
-      Counters.inc(P >> PageSizeLog);
   } else {
     // In all other cases chunks might affect more than one page.
+    DCHECK_GE(RegionSize, BlockSize);
+    const uptr LastBlockInRegion = ((RegionSize / BlockSize) - 1U) * BlockSize;
     for (const auto &It : FreeList) {
       // See TransferBatch comment above.
       const bool IsTransferBatch =
@@ -244,13 +258,24 @@
       for (u32 I = IsTransferBatch ? 1 : 0; I < It.getCount(); I++) {
         const uptr P = reinterpret_cast<uptr>(It.get(I)) - Base;
         // This takes care of P < Base and P >= Base + RoundedSize.
-        if (P < RoundedSize)
-          Counters.incRange(P >> PageSizeLog,
-                            (P + BlockSize - 1) >> PageSizeLog);
+        if (P < RoundedSize) {
+          const uptr RegionIndex = NumberOfRegions == 1U ? 0 : P / RegionSize;
+          uptr PInRegion = P - RegionIndex * RegionSize;
+          Counters.incRange(RegionIndex, PInRegion >> PageSizeLog,
+                            (PInRegion + BlockSize - 1) >> PageSizeLog);
+          // The last block in a region might straddle a page, so if it's
+          // free, we mark the following "pretend" memory block(s) as free.
+          if (PInRegion == LastBlockInRegion) {
+            PInRegion += BlockSize;
+            while (PInRegion < RoundedRegionSize) {
+              Counters.incRange(RegionIndex, PInRegion >> PageSizeLog,
+                                (PInRegion + BlockSize - 1) >> PageSizeLog);
+              PInRegion += BlockSize;
+            }
+          }
+        }
       }
     }
-    for (uptr P = Size; P < RoundedSize; P += BlockSize)
-      Counters.incRange(P >> PageSizeLog, (P + BlockSize - 1) >> PageSizeLog);
   }
 
   // Iterate over pages detecting ranges of pages with chunk Counters equal
@@ -258,8 +283,10 @@
   FreePagesRangeTracker<ReleaseRecorderT> RangeTracker(Recorder);
   if (SameBlockCountPerPage) {
     // Fast path, every page has the same number of chunks affecting it.
-    for (uptr I = 0; I < Counters.getCount(); I++)
-      RangeTracker.processNextPage(Counters.get(I) == FullPagesBlockCountMax);
+    for (uptr I = 0; I < NumberOfRegions; I++)
+      for (uptr J = 0; J < PagesCount; J++)
+        RangeTracker.processNextPage(Counters.get(I, J) ==
+                                     FullPagesBlockCountMax);
   } else {
     // Slow path, go through the pages keeping count how many chunks affect
     // each page.
@@ -270,23 +297,25 @@
     // except the first and the last one) and then the last chunk size, adding
     // up the number of chunks on the current page and checking on every step
     // whether the page boundary was crossed.
-    uptr PrevPageBoundary = 0;
-    uptr CurrentBoundary = 0;
-    for (uptr I = 0; I < Counters.getCount(); I++) {
-      const uptr PageBoundary = PrevPageBoundary + PageSize;
-      uptr BlocksPerPage = Pn;
-      if (CurrentBoundary < PageBoundary) {
-        if (CurrentBoundary > PrevPageBoundary)
-          BlocksPerPage++;
-        CurrentBoundary += Pnc;
+    for (uptr I = 0; I < NumberOfRegions; I++) {
+      uptr PrevPageBoundary = 0;
+      uptr CurrentBoundary = 0;
+      for (uptr J = 0; J < PagesCount; J++) {
+        const uptr PageBoundary = PrevPageBoundary + PageSize;
+        uptr BlocksPerPage = Pn;
         if (CurrentBoundary < PageBoundary) {
-          BlocksPerPage++;
-          CurrentBoundary += BlockSize;
+          if (CurrentBoundary > PrevPageBoundary)
+            BlocksPerPage++;
+          CurrentBoundary += Pnc;
+          if (CurrentBoundary < PageBoundary) {
+            BlocksPerPage++;
+            CurrentBoundary += BlockSize;
+          }
         }
-      }
-      PrevPageBoundary = PageBoundary;
+        PrevPageBoundary = PageBoundary;
 
-      RangeTracker.processNextPage(Counters.get(I) == BlocksPerPage);
+        RangeTracker.processNextPage(Counters.get(I, J) == BlocksPerPage);
+      }
     }
   }
   RangeTracker.finish();
diff --git a/compiler-rt/lib/scudo/standalone/tests/release_test.cpp b/compiler-rt/lib/scudo/standalone/tests/release_test.cpp
--- a/compiler-rt/lib/scudo/standalone/tests/release_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/release_test.cpp
@@ -21,14 +21,14 @@
 TEST(ScudoReleaseTest, PackedCounterArray) {
   for (scudo::uptr I = 0; I < SCUDO_WORDSIZE; I++) {
     // Various valid counter's max values packed into one word.
-    scudo::PackedCounterArray Counters2N(1, 1UL << I);
+    scudo::PackedCounterArray Counters2N(1U, 1U, 1UL << I);
     EXPECT_EQ(sizeof(scudo::uptr), Counters2N.getBufferSize());
     // Check the "all bit set" values too.
-    scudo::PackedCounterArray Counters2N1_1(1, ~0UL >> I);
+    scudo::PackedCounterArray Counters2N1_1(1U, 1U, ~0UL >> I);
     EXPECT_EQ(sizeof(scudo::uptr), Counters2N1_1.getBufferSize());
     // Verify the packing ratio, the counter is Expected to be packed into the
     // closest power of 2 bits.
-    scudo::PackedCounterArray Counters(SCUDO_WORDSIZE, 1UL << I);
+    scudo::PackedCounterArray Counters(1U, SCUDO_WORDSIZE, 1UL << I);
     EXPECT_EQ(sizeof(scudo::uptr) * scudo::roundUpToPowerOfTwo(I + 1),
               Counters.getBufferSize());
   }
@@ -38,19 +38,20 @@
     // Make sure counters request one memory page for the buffer.
     const scudo::uptr NumCounters =
         (scudo::getPageSizeCached() / 8) * (SCUDO_WORDSIZE >> I);
-    scudo::PackedCounterArray Counters(NumCounters, 1UL << ((1UL << I) - 1));
-    Counters.inc(0);
+    scudo::PackedCounterArray Counters(1U, NumCounters,
+                                       1UL << ((1UL << I) - 1));
+    Counters.inc(0U, 0U);
     for (scudo::uptr C = 1; C < NumCounters - 1; C++) {
-      EXPECT_EQ(0UL, Counters.get(C));
-      Counters.inc(C);
-      EXPECT_EQ(1UL, Counters.get(C - 1));
+      EXPECT_EQ(0UL, Counters.get(0U, C));
+      Counters.inc(0U, C);
+      EXPECT_EQ(1UL, Counters.get(0U, C - 1));
     }
-    EXPECT_EQ(0UL, Counters.get(NumCounters - 1));
-    Counters.inc(NumCounters - 1);
+    EXPECT_EQ(0UL, Counters.get(0U, NumCounters - 1));
+    Counters.inc(0U, NumCounters - 1);
     if (I > 0) {
-      Counters.incRange(0, NumCounters - 1);
+      Counters.incRange(0u, 0U, NumCounters - 1);
       for (scudo::uptr C = 0; C < NumCounters; C++)
-        EXPECT_EQ(2UL, Counters.get(C));
+        EXPECT_EQ(2UL, Counters.get(0U, C));
     }
   }
 }
@@ -190,7 +191,7 @@
 
     // Release the memory.
     ReleasedPagesRecorder Recorder;
-    releaseFreeMemoryToOS(FreeList, 0, MaxBlocks * BlockSize, BlockSize,
+    releaseFreeMemoryToOS(FreeList, 0, MaxBlocks * BlockSize, 1U, BlockSize,
                           &Recorder);
 
     // Verify that there are no released pages touched by used chunks and all