Use MemoryChunk-based allocation for deoptimization entry code

src/spaces.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 189 matching lines @@
     if (requested <= allocation_list_[current_allocation_block_index_].size) {
       return;  // Found a large enough allocation block.
     }
   }
 
   // Code range is full or too fragmented.
   V8::FatalProcessOutOfMemory("CodeRange::GetNextAllocationBlock");
 }
 
 
-
 Address CodeRange::AllocateRawMemory(const size_t requested,
-                                     size_t* allocated) {
+                                     size_t* allocated,
+                                     size_t initial_commit_size) {
+  ASSERT(initial_commit_size <= requested);
   ASSERT(current_allocation_block_index_ < allocation_list_.length());
   if (requested > allocation_list_[current_allocation_block_index_].size) {
     // Find an allocation block large enough.  This function call may
     // call V8::FatalProcessOutOfMemory if it cannot find a large enough block.
     GetNextAllocationBlock(requested);
   }
   // Commit the requested memory at the start of the current allocation block.
   size_t aligned_requested = RoundUp(requested, MemoryChunk::kAlignment);
   FreeBlock current = allocation_list_[current_allocation_block_index_];
   if (aligned_requested >= (current.size - Page::kPageSize)) {
     // Don't leave a small free block, useless for a large object or chunk.
     *allocated = current.size;
   } else {
     *allocated = aligned_requested;
   }
   ASSERT(*allocated <= current.size);
   ASSERT(IsAddressAligned(current.start, MemoryChunk::kAlignment));
   if (!MemoryAllocator::CommitCodePage(code_range_,
                                        current.start,
-                                       *allocated)) {
+                                       initial_commit_size)) {
     *allocated = 0;
     return NULL;
   }
   allocation_list_[current_allocation_block_index_].start += *allocated;
   allocation_list_[current_allocation_block_index_].size -= *allocated;
   if (*allocated == current.size) {
     GetNextAllocationBlock(0);  // This block is used up, get the next one.
   }
   return current.start;
 }
 
 
+bool CodeRange::RecommitRawMemory(Address start, size_t size) {

[danno, 2013/01/16 14:48:54]

If you make the changes in MemoryChunk to support committed_body_size_, then
this method too can just be called CommitRawMemory, and be used to just commit
the delta of uncommitted pages. 

[haitao.feng, 2013/01/17 05:34:01]

Done.

+  ASSERT(reinterpret_cast<int64_t>(start) % MemoryChunk::kAlignment ==
+         MemoryAllocator::CodePageAreaStartOffset());
+
+  // Recommit page body (executable).
+  if (!code_range_->Commit(start, size, true)) return false;
+  // Append a guard page.
+  if (!code_range_->Guard(start + size)) return false;

[danno, 2013/01/16 14:48:54]

Guard pages are managed by the MemoryChunk (not here), and it should always be
allocated in a fixed position at the end of the MemoryChunk. If there are
uncommitted pages between the currently "active" committed region, that's OK.

[haitao.feng, 2013/01/17 05:34:01]

Done.

+
+  return true;
+}
+
+
 void CodeRange::FreeRawMemory(Address address, size_t length) {
   ASSERT(IsAddressAligned(address, MemoryChunk::kAlignment));
   free_list_.Add(FreeBlock(address, length));
   code_range_->Uncommit(address, length);
 }
 
 
 void CodeRange::TearDown() {
     delete code_range_;  // Frees all memory in the virtual memory range.
     code_range_ = NULL;
@@ skipping 84 matching lines @@
 }
 
 
 Address MemoryAllocator::ReserveAlignedMemory(size_t size,
                                               size_t alignment,
                                               VirtualMemory* controller) {
   VirtualMemory reservation(size, alignment);
 
   if (!reservation.IsReserved()) return NULL;
   size_ += reservation.size();
-  Address base = RoundUp(static_cast<Address>(reservation.address()),
-                         alignment);
+  Address base = static_cast<Address>(reservation.address());
   controller->TakeControl(&reservation);
   return base;
 }
 
 
 Address MemoryAllocator::AllocateAlignedMemory(size_t size,
                                                size_t alignment,
+                                               size_t initial_commit_size,
                                                Executability executable,
                                                VirtualMemory* controller) {
+  ASSERT(initial_commit_size <= size);
   VirtualMemory reservation;
   Address base = ReserveAlignedMemory(size, alignment, &reservation);
   if (base == NULL) return NULL;
 
   if (executable == EXECUTABLE) {
-    if (!CommitCodePage(&reservation, base, size)) {
+    if (!CommitCodePage(&reservation, base, initial_commit_size)) {

[danno, 2013/01/16 14:48:54]

CommitCodePage should take both size and initial_commit_size. If should create
the guard pages using size, but commit using initial_commit_size.

[haitao.feng, 2013/01/17 05:34:01]

Done.

       base = NULL;
     }
   } else {
-    if (!reservation.Commit(base, size, false)) {
+    if (!reservation.Commit(base, initial_commit_size, false)) {
       base = NULL;
     }
   }
 
   if (base == NULL) {
     // Failed to commit the body. Release the mapping and any partially
     // commited regions inside it.
     reservation.Release();
     return NULL;
   }
@@ skipping 83 matching lines @@
   }
 
   if (owner == heap->old_data_space()) {
     chunk->SetFlag(CONTAINS_ONLY_DATA);
   }
 
   return chunk;
 }
 
 
+bool MemoryChunk::RecommitBody(size_t body_size, Executability executable) {

[danno, 2013/01/16 14:48:54]

I think I'd prefer that the MemoryChunk remembered "committed_body_size_", and
that this method just be called CommitBody, ASSERTing that body_size >=
committed_body_size_ and only explicitly committing the pages between
committed_body_size_ and body_size

[haitao.feng, 2013/01/17 05:34:01]

I am using area_end_ - area_start_ to remember "committed_body_size". If the
body_size <= area_end_ - area_start_, the function just returns true and no
uncommitment happens.

+  ASSERT(area_start_ + body_size <= area_end_);
+  if (reservation_.IsReserved()) {
+    if (executable == EXECUTABLE) {
+      // Recommit page body (executable).
+      if (!reservation_.Commit(area_start_, body_size, true)) return false;
+      // Append a guard page.
+      if (!reservation_.Guard(area_start_ + body_size)) return false;

[danno, 2013/01/16 14:48:54]

As mentioned above, the guard page should always be created at the end of the
MemoryChunk already, so you shouldn't have to always re-create it here. That
also simplified the logic, which is in both cases:

if (!reservation_.Commit(area_start_, body_size, true)) return false;

[haitao.feng, 2013/01/17 05:34:01]

Done.

+    } else {
+      if (!reservation_.Commit(area_start_, body_size, false)) return false;
+    }
+  } else {
+    ASSERT(heap_->isolate()->code_range()->exists() &&
+           (executable == EXECUTABLE));
+    // Recommit page body (executable).
+    if (!heap_->isolate()->code_range()->RecommitRawMemory(area_start_,

[danno, 2013/01/16 14:48:54]

If you change this method to be called "CommitBody", then RecommitRawMemory can
be CommitRawMemory:

CommitRawMemory(area_start_ + committed_body_size_, body_size -
committed_body_size_);

[haitao.feng, 2013/01/17 05:34:01]

Done.

+                                                           body_size)) {
+      return false;
+    }
+  }
+
+  if (Heap::ShouldZapGarbage()) {

[danno, 2013/01/16 14:48:54]

Just zap the delta of uncommitted pages.

[haitao.feng, 2013/01/17 05:34:01]

Done.

+    heap_->isolate()->memory_allocator()->ZapBlock(area_start_, body_size);
+  }
+
+  return true;
+}
+
+
 void MemoryChunk::InsertAfter(MemoryChunk* other) {
   next_chunk_ = other->next_chunk_;
   prev_chunk_ = other;
   other->next_chunk_->prev_chunk_ = this;
   other->next_chunk_ = this;
 }
 
 
 void MemoryChunk::Unlink() {
   if (!InNewSpace() && IsFlagSet(SCAN_ON_SCAVENGE)) {
     heap_->decrement_scan_on_scavenge_pages();
     ClearFlag(SCAN_ON_SCAVENGE);
   }
   next_chunk_->prev_chunk_ = prev_chunk_;
   prev_chunk_->next_chunk_ = next_chunk_;
   prev_chunk_ = NULL;
   next_chunk_ = NULL;
 }
 
 
 MemoryChunk* MemoryAllocator::AllocateChunk(intptr_t body_size,
+                                            intptr_t commit_size,
                                             Executability executable,
                                             Space* owner) {
-  size_t chunk_size;
+  ASSERT(commit_size <= body_size);
+
+  size_t chunk_size, initial_commit_size;

[danno, 2013/01/16 14:48:54]

nit: declare initial_commit_size in the scope that it's used in.

   Heap* heap = isolate_->heap();
   Address base = NULL;
   VirtualMemory reservation;
   Address area_start = NULL;
   Address area_end = NULL;
 
   if (executable == EXECUTABLE) {
     chunk_size = RoundUp(CodePageAreaStartOffset() + body_size,
                          OS::CommitPageSize()) + CodePageGuardSize();
 
     // Check executable memory limit.
     if (size_executable_ + chunk_size > capacity_executable_) {
       LOG(isolate_,
           StringEvent("MemoryAllocator::AllocateRawMemory",
                       "V8 Executable Allocation capacity exceeded"));
       return NULL;
     }
 
+    initial_commit_size = RoundUp(CodePageAreaStartOffset() + commit_size,

[danno, 2013/01/16 14:48:54]

I don't think you need to round this up if you make sure the guard page is only
allocated once and stays at the end.

[danno, 2013/01/16 14:48:54]

As noted above:

size_t initial_commit_size = ...

[haitao.feng, 2013/01/17 05:34:01]

Done.

[haitao.feng, 2013/01/17 05:34:01]

Done.

+                                  OS::CommitPageSize()) + CodePageGuardSize();
+
     // Allocate executable memory either from code range or from the
     // OS.
     if (isolate_->code_range()->exists()) {
-      base = isolate_->code_range()->AllocateRawMemory(chunk_size, &chunk_size);
+      base = isolate_->code_range()->AllocateRawMemory(chunk_size,
+                                                       &chunk_size,
+                                                       initial_commit_size);
       ASSERT(IsAligned(reinterpret_cast<intptr_t>(base),
                        MemoryChunk::kAlignment));
       if (base == NULL) return NULL;
       size_ += chunk_size;
       // Update executable memory size.
       size_executable_ += chunk_size;
     } else {
       base = AllocateAlignedMemory(chunk_size,
                                    MemoryChunk::kAlignment,
+                                   initial_commit_size,
                                    executable,
                                    &reservation);
       if (base == NULL) return NULL;
       // Update executable memory size.
       size_executable_ += reservation.size();
     }
 
     if (Heap::ShouldZapGarbage()) {
       ZapBlock(base, CodePageGuardStartOffset());
-      ZapBlock(base + CodePageAreaStartOffset(), body_size);
+      ZapBlock(base + CodePageAreaStartOffset(), commit_size);
     }
 
     area_start = base + CodePageAreaStartOffset();
     area_end = area_start + body_size;
   } else {
     chunk_size = MemoryChunk::kObjectStartOffset + body_size;
+    initial_commit_size = MemoryChunk::kObjectStartOffset + commit_size;

[danno, 2013/01/16 14:48:54]

As noted above:

size_t initial_commit_size = ...

[haitao.feng, 2013/01/17 05:34:01]

Done.

     base = AllocateAlignedMemory(chunk_size,
                                  MemoryChunk::kAlignment,
+                                 initial_commit_size,
                                  executable,
                                  &reservation);
 
     if (base == NULL) return NULL;
 
     if (Heap::ShouldZapGarbage()) {
-      ZapBlock(base, chunk_size);
+      ZapBlock(base, commit_size);
     }
 
     area_start = base + Page::kObjectStartOffset;
     area_end = base + chunk_size;
   }
 
   isolate_->counters()->memory_allocated()->
       Increment(static_cast<int>(chunk_size));
 
   LOG(isolate_, NewEvent("MemoryChunk", base, chunk_size));
@@ skipping 10 matching lines @@
                                                 executable,
                                                 owner);
   result->set_reserved_memory(&reservation);
   return result;
 }
 
 
 Page* MemoryAllocator::AllocatePage(intptr_t size,
                                     PagedSpace* owner,
                                     Executability executable) {
-  MemoryChunk* chunk = AllocateChunk(size, executable, owner);
+  MemoryChunk* chunk = AllocateChunk(size, size, executable, owner);
 
   if (chunk == NULL) return NULL;
 
   return Page::Initialize(isolate_->heap(), chunk, executable, owner);
 }
 
 
 LargePage* MemoryAllocator::AllocateLargePage(intptr_t object_size,
                                               Space* owner,
                                               Executability executable) {
-  MemoryChunk* chunk = AllocateChunk(object_size, executable, owner);
+  MemoryChunk* chunk = AllocateChunk(object_size,
+                                     object_size,
+                                     executable,
+                                     owner);
   if (chunk == NULL) return NULL;
   return LargePage::Initialize(isolate_->heap(), chunk);
 }
 
 
 void MemoryAllocator::Free(MemoryChunk* chunk) {
   LOG(isolate_, DeleteEvent("MemoryChunk", chunk));
   if (chunk->owner() != NULL) {
     ObjectSpace space =
         static_cast<ObjectSpace>(1 << chunk->owner()->identity());
@@ skipping 2381 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal