Revert "base/allocator: Report the size of mapped PageAllocator space when crashing."

This reverts commit 402cee70.

Reason for revert: PageAllocatorTest.MappedPagesAccounting is failing on lollipop; see https://ci.chromium.org/p/chromium/builders/ci/Lollipop%20Phone%20Tester/25868 and https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=base_unittests&tests=PageAllocatorTest.MappedPagesAccounting

Original change's description:
> base/allocator: Report the size of mapped PageAllocator space when crashing.
> 
> PartitionAllocator can occupy a lot of address space, as freed pages for
> normal buckets are never unmapped, and these are not shared across
> buckets. This is a known issue, tracked in the linked bug.
> 
> However the reporting currently in place only looks at a single
> partition when reporting that an OOM is likely due to too many mapped
> pages. It does not look at all PageAllocator allocations. This commit
> adds a crash key reporting the total amount of mapped PageAllocator
> pages to crash reports, to allow distinguishing between "true" OOM and
> address space exhaustion.
> 
> For instance, on Windows 32, an address space exhaustion crash would
> happen with a reasonable committed set, remaining system commit limit,
> and a large amount of mapped pages. All these data points are available
> in crash reports, except for the last one, which this commit adds.
> 
> Bug: 421387
> Change-Id: If3eac64489b61297cb5da6da328cfc70fecc4c8c
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2264438
> Reviewed-by: Kentaro Hara <haraken@chromium.org>
> Commit-Queue: Benoit L <lizeb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#782459}

TBR=haraken@chromium.org,lizeb@chromium.org

Change-Id: Ib18a3623e09c3c278f355ffd4cc63aee47aeacce
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 421387
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2267425Reviewed-by: Patrick Noland <pnoland@chromium.org>
Commit-Queue: Patrick Noland <pnoland@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782528}

base/allocator/partition_allocator/page_allocator.cc

@@ -42,8 +42,6 @@ Lock& GetReserveLock() {
   return *lock;
 }
 
-std::atomic<size_t> g_total_mapped_address_space;
-
 // We only support a single block of reserved address space.
 void* s_reservation_address GUARDED_BY(GetReserveLock()) = nullptr;
 size_t s_reservation_size GUARDED_BY(GetReserveLock()) = 0;
@@ -99,12 +97,8 @@ void* SystemAllocPages(void* hint,
   PA_DCHECK(!(reinterpret_cast<uintptr_t>(hint) &
               kPageAllocationGranularityOffsetMask));
   PA_DCHECK(commit || accessibility == PageInaccessible);
-  void* ptr =
-      SystemAllocPagesInternal(hint, length, accessibility, page_tag, commit);
-  if (ptr)
-    g_total_mapped_address_space.fetch_add(length, std::memory_order_relaxed);
-
-  return ptr;
+  return SystemAllocPagesInternal(hint, length, accessibility, page_tag,
+                                  commit);
 }
 
 void* AllocPages(void* address,
@@ -194,8 +188,6 @@ void FreePages(void* address, size_t length) {
               kPageAllocationGranularityOffsetMask));
   PA_DCHECK(!(length & kPageAllocationGranularityOffsetMask));
   FreePagesInternal(address, length);
-  PA_DCHECK(g_total_mapped_address_space.load(std::memory_order_relaxed) > 0);
-  g_total_mapped_address_space.fetch_sub(length, std::memory_order_relaxed);
 }
 
 bool TrySetSystemPagesAccess(void* address,
@@ -269,8 +261,4 @@ uint32_t GetAllocPageErrorCode() {
   return s_allocPageErrorCode;
 }
 
-size_t GetTotalMappedSize() {
-  return g_total_mapped_address_space;
-}
-
 }  // namespace base

base/allocator/partition_allocator/page_allocator.h

@@ -193,11 +193,6 @@ BASE_EXPORT bool HasReservationForTesting();
 // (POSIX) or |VirtualAlloc| (Windows) fails.
 BASE_EXPORT uint32_t GetAllocPageErrorCode();
 
-// Returns the total amount of mapped pages from all clients of
-// PageAllocator. These pages may or may not be committed. This is mostly useful
-// to assess address space pressure.
-BASE_EXPORT size_t GetTotalMappedSize();
-
 }  // namespace base
 
 #endif  // BASE_ALLOCATOR_PARTITION_ALLOCATOR_PAGE_ALLOCATOR_H_

base/allocator/partition_allocator/page_allocator_unittest.cc

@@ -270,31 +270,10 @@ TEST(PageAllocatorTest, DecommitErasesMemory) {
     sum += recommitted_buffer[i];
   }
   EXPECT_EQ(0u, sum) << "Data was not erased";
-
-  FreePages(buffer, size);
 }
 
 #endif  // defined(OS_MACOSX)
 
-TEST(PageAllocatorTest, MappedPagesAccounting) {
-  size_t size = kPageAllocationGranularity;
-  size_t mapped_size_before = GetTotalMappedSize();
-
-  // Ask for a large alignment to make sure that trimming doesn't change the
-  // accounting.
-  void* data = AllocPages(nullptr, size, 128 * kPageAllocationGranularity,
-                          PageInaccessible, PageTag::kChromium, true);
-  ASSERT_TRUE(data);
-
-  EXPECT_EQ(mapped_size_before + size, GetTotalMappedSize());
-
-  DecommitSystemPages(data, size);
-  EXPECT_EQ(mapped_size_before + size, GetTotalMappedSize());
-
-  FreePages(data, size);
-  EXPECT_EQ(mapped_size_before, GetTotalMappedSize());
-}
-
 }  // namespace base
 
 #endif  // !defined(MEMORY_TOOL_REPLACES_ALLOCATOR)

third_party/blink/renderer/platform/wtf/BUILD.gn

@@ -207,7 +207,6 @@ jumbo_component("wtf") {
   public_deps = [
     "//base",
     "//base/third_party/double_conversion",
-    "//components/crash/core/common:crash_key",
     "//third_party/icu",
   ]
 

third_party/blink/renderer/platform/wtf/allocator/partitions.cc

@@ -34,8 +34,6 @@
 #include "base/allocator/partition_allocator/oom.h"
 #include "base/allocator/partition_allocator/page_allocator.h"
 #include "base/debug/alias.h"
-#include "base/strings/safe_sprintf.h"
-#include "components/crash/core/common/crash_key.h"
 #include "third_party/blink/renderer/platform/wtf/allocator/partition_allocator.h"
 #include "third_party/blink/renderer/platform/wtf/wtf.h"
 
@@ -247,21 +245,6 @@ void Partitions::HandleOutOfMemory(size_t size) {
   uint32_t alloc_page_error_code = base::GetAllocPageErrorCode();
   base::debug::Alias(&alloc_page_error_code);
 
-  // Report the total mapped size from PageAllocator. This is intended to
-  // distinguish better between address space exhaustion and out of memory on 32
-  // bit platforms. PartitionAlloc can use a lot of address space, as free pages
-  // are not shared between buckets (see crbug.com/421387). There is already
-  // reporting for this, however it only looks at the address space usage of a
-  // single partition. This allows to look across all the partitions, and other
-  // users such as V8.
-  char value[24];
-  // %d works for 64 bit types as well with SafeSPrintf(), see its unit tests
-  // for an example.
-  base::strings::SafeSPrintf(value, "%d", base::GetTotalMappedSize());
-  static crash_reporter::CrashKeyString<24> g_page_allocator_mapped_size(
-      "page-allocator-mapped-size");
-  g_page_allocator_mapped_size.Set(value);
-
   if (total_usage >= 2UL * 1024 * 1024 * 1024)
     PartitionsOutOfMemoryUsing2G(size);
   if (total_usage >= 1UL * 1024 * 1024 * 1024)