Line data    Source code

       1             : // Copyright 2018 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #include "src/base/bounded-page-allocator.h"
       6             : 
       7             : namespace v8 {
       8             : namespace base {
       9             : 
      10       63938 : BoundedPageAllocator::BoundedPageAllocator(v8::PageAllocator* page_allocator,
      11             :                                            Address start, size_t size,
      12             :                                            size_t allocate_page_size)
      13             :     : allocate_page_size_(allocate_page_size),
      14       63938 :       commit_page_size_(page_allocator->CommitPageSize()),
      15             :       page_allocator_(page_allocator),
      16      127876 :       region_allocator_(start, size, allocate_page_size_) {
      17       63938 :   CHECK_NOT_NULL(page_allocator);
      18      127876 :   CHECK(IsAligned(allocate_page_size, page_allocator->AllocatePageSize()));
      19      127876 :   CHECK(IsAligned(allocate_page_size_, commit_page_size_));
      20       63938 : }
      21             : 
      22           0 : BoundedPageAllocator::Address BoundedPageAllocator::begin() const {
      23           0 :   return region_allocator_.begin();
      24             : }
      25             : 
      26           0 : size_t BoundedPageAllocator::size() const { return region_allocator_.size(); }
      27             : 
      28      131637 : void* BoundedPageAllocator::AllocatePages(void* hint, size_t size,
      29             :                                           size_t alignment,
      30             :                                           PageAllocator::Permission access) {
      31      131637 :   MutexGuard guard(&mutex_);
      32      131637 :   CHECK(IsAligned(alignment, region_allocator_.page_size()));
      33             : 
      34             :   // Region allocator does not support alignments bigger than it's own
      35             :   // allocation alignment.
      36      131637 :   CHECK_LE(alignment, allocate_page_size_);
      37             : 
      38             :   // TODO(ishell): Consider using randomized version here.
      39      131637 :   Address address = region_allocator_.AllocateRegion(size);
      40      131637 :   if (address == RegionAllocator::kAllocationFailure) {
      41             :     return nullptr;
      42             :   }
      43      131637 :   CHECK(page_allocator_->SetPermissions(reinterpret_cast<void*>(address), size,
      44             :                                         access));
      45             :   return reinterpret_cast<void*>(address);
      46             : }
      47             : 
      48           1 : bool BoundedPageAllocator::AllocatePagesAt(Address address, size_t size,
      49             :                                            PageAllocator::Permission access) {
      50           2 :   CHECK(IsAligned(address, allocate_page_size_));
      51           1 :   CHECK(IsAligned(size, allocate_page_size_));
      52           1 :   CHECK(region_allocator_.contains(address, size));
      53             : 
      54           1 :   if (!region_allocator_.AllocateRegionAt(address, size)) {
      55             :     return false;
      56             :   }
      57           1 :   CHECK(page_allocator_->SetPermissions(reinterpret_cast<void*>(address), size,
      58             :                                         access));
      59             :   return true;
      60             : }
      61             : 
      62      131622 : bool BoundedPageAllocator::FreePages(void* raw_address, size_t size) {
      63      131622 :   MutexGuard guard(&mutex_);
      64             : 
      65      131622 :   Address address = reinterpret_cast<Address>(raw_address);
      66      131622 :   size_t freed_size = region_allocator_.FreeRegion(address);
      67      131622 :   if (freed_size != size) return false;
      68      131622 :   CHECK(page_allocator_->SetPermissions(raw_address, size,
      69             :                                         PageAllocator::kNoAccess));
      70             :   return true;
      71             : }
      72             : 
      73       62312 : bool BoundedPageAllocator::ReleasePages(void* raw_address, size_t size,
      74             :                                         size_t new_size) {
      75       62312 :   Address address = reinterpret_cast<Address>(raw_address);
      76      124624 :   CHECK(IsAligned(address, allocate_page_size_));
      77             : 
      78             :   DCHECK_LT(new_size, size);
      79             :   DCHECK(IsAligned(size - new_size, commit_page_size_));
      80             : 
      81             :   // Check if we freed any allocatable pages by this release.
      82       62312 :   size_t allocated_size = RoundUp(size, allocate_page_size_);
      83             :   size_t new_allocated_size = RoundUp(new_size, allocate_page_size_);
      84             : 
      85             : #ifdef DEBUG
      86             :   {
      87             :     // There must be an allocated region at given |address| of a size not
      88             :     // smaller than |size|.
      89             :     MutexGuard guard(&mutex_);
      90             :     CHECK_EQ(allocated_size, region_allocator_.CheckRegion(address));
      91             :   }
      92             : #endif
      93             : 
      94       62312 :   if (new_allocated_size < allocated_size) {
      95           0 :     MutexGuard guard(&mutex_);
      96           0 :     region_allocator_.TrimRegion(address, new_allocated_size);
      97             :   }
      98             : 
      99             :   // Keep the region in "used" state just uncommit some pages.
     100       62312 :   Address free_address = address + new_size;
     101       62312 :   size_t free_size = size - new_size;
     102      124624 :   return page_allocator_->SetPermissions(reinterpret_cast<void*>(free_address),
     103      124624 :                                          free_size, PageAllocator::kNoAccess);
     104             : }
     105             : 
     106     6648449 : bool BoundedPageAllocator::SetPermissions(void* address, size_t size,
     107             :                                           PageAllocator::Permission access) {
     108             :   DCHECK(IsAligned(reinterpret_cast<Address>(address), commit_page_size_));
     109             :   DCHECK(IsAligned(size, commit_page_size_));
     110             :   DCHECK(region_allocator_.contains(reinterpret_cast<Address>(address), size));
     111     6648449 :   return page_allocator_->SetPermissions(address, size, access);
     112             : }
     113             : 
     114        5336 : bool BoundedPageAllocator::DiscardSystemPages(void* address, size_t size) {
     115        5336 :   return page_allocator_->DiscardSystemPages(address, size);
     116             : }
     117             : 
     118             : }  // namespace base
     119      121996 : }  // namespace v8