1 files changed, 206 insertions, 0 deletions
diff --git a/src/rocksdb/memory/jemalloc_nodump_allocator.cc b/src/rocksdb/memory/jemalloc_nodump_allocator.cc
new file mode 100644
index 000000000..980b08b95
--- /dev/null
+++ b/src/rocksdb/memory/jemalloc_nodump_allocator.cc
@@ -0,0 +1,206 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#include "memory/jemalloc_nodump_allocator.h"
+
+#include <string>
+#include <thread>
+
+#include "port/likely.h"
+#include "port/port.h"
+#include "util/string_util.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+#ifdef ROCKSDB_JEMALLOC_NODUMP_ALLOCATOR
+
+std::atomic<extent_alloc_t*> JemallocNodumpAllocator::original_alloc_{nullptr};
+
+JemallocNodumpAllocator::JemallocNodumpAllocator(
+    JemallocAllocatorOptions& options,
+    std::unique_ptr<extent_hooks_t>&& arena_hooks, unsigned arena_index)
+    : options_(options),
+      arena_hooks_(std::move(arena_hooks)),
+      arena_index_(arena_index),
+      tcache_(&JemallocNodumpAllocator::DestroyThreadSpecificCache) {}
+
+int JemallocNodumpAllocator::GetThreadSpecificCache(size_t size) {
+  // We always enable tcache. The only corner case is when there are a ton of
+  // threads accessing with low frequency, then it could consume a lot of
+  // memory (may reach # threads * ~1MB) without bringing too much benefit.
+  if (options_.limit_tcache_size && (size <= options_.tcache_size_lower_bound ||
+                                     size > options_.tcache_size_upper_bound)) {
+    return MALLOCX_TCACHE_NONE;
+  }
+  unsigned* tcache_index = reinterpret_cast<unsigned*>(tcache_.Get());
+  if (UNLIKELY(tcache_index == nullptr)) {
+    // Instantiate tcache.
+    tcache_index = new unsigned(0);
+    size_t tcache_index_size = sizeof(unsigned);
+    int ret =
+        mallctl("tcache.create", tcache_index, &tcache_index_size, nullptr, 0);
+    if (ret != 0) {
+      // No good way to expose the error. Silently disable tcache.
+      delete tcache_index;
+      return MALLOCX_TCACHE_NONE;
+    }
+    tcache_.Reset(static_cast<void*>(tcache_index));
+  }
+  return MALLOCX_TCACHE(*tcache_index);
+}
+
+void* JemallocNodumpAllocator::Allocate(size_t size) {
+  int tcache_flag = GetThreadSpecificCache(size);
+  return mallocx(size, MALLOCX_ARENA(arena_index_) | tcache_flag);
+}
+
+void JemallocNodumpAllocator::Deallocate(void* p) {
+  // Obtain tcache.
+  size_t size = 0;
+  if (options_.limit_tcache_size) {
+    size = malloc_usable_size(p);
+  }
+  int tcache_flag = GetThreadSpecificCache(size);
+  // No need to pass arena index to dallocx(). Jemalloc will find arena index
+  // from its own metadata.
+  dallocx(p, tcache_flag);
+}
+
+void* JemallocNodumpAllocator::Alloc(extent_hooks_t* extent, void* new_addr,
+                                     size_t size, size_t alignment, bool* zero,
+                                     bool* commit, unsigned arena_ind) {
+  extent_alloc_t* original_alloc =
+      original_alloc_.load(std::memory_order_relaxed);
+  assert(original_alloc != nullptr);
+  void* result = original_alloc(extent, new_addr, size, alignment, zero, commit,
+                                arena_ind);
+  if (result != nullptr) {
+    int ret = madvise(result, size, MADV_DONTDUMP);
+    if (ret != 0) {
+      fprintf(
+          stderr,
+          "JemallocNodumpAllocator failed to set MADV_DONTDUMP, error code: %d",
+          ret);
+      assert(false);
+    }
+  }
+  return result;
+}
+
+Status JemallocNodumpAllocator::DestroyArena(unsigned arena_index) {
+  assert(arena_index != 0);
+  std::string key = "arena." + ToString(arena_index) + ".destroy";
+  int ret = mallctl(key.c_str(), nullptr, 0, nullptr, 0);
+  if (ret != 0) {
+    return Status::Incomplete("Failed to destroy jemalloc arena, error code: " +
+                              ToString(ret));
+  }
+  return Status::OK();
+}
+
+void JemallocNodumpAllocator::DestroyThreadSpecificCache(void* ptr) {
+  assert(ptr != nullptr);
+  unsigned* tcache_index = static_cast<unsigned*>(ptr);
+  size_t tcache_index_size = sizeof(unsigned);
+  int ret __attribute__((__unused__)) =
+      mallctl("tcache.destroy", nullptr, 0, tcache_index, tcache_index_size);
+  // Silently ignore error.
+  assert(ret == 0);
+  delete tcache_index;
+}
+
+JemallocNodumpAllocator::~JemallocNodumpAllocator() {
+  // Destroy tcache before destroying arena.
+  autovector<void*> tcache_list;
+  tcache_.Scrape(&tcache_list, nullptr);
+  for (void* tcache_index : tcache_list) {
+    DestroyThreadSpecificCache(tcache_index);
+  }
+  // Destroy arena. Silently ignore error.
+  Status s __attribute__((__unused__)) = DestroyArena(arena_index_);
+  assert(s.ok());
+}
+
+size_t JemallocNodumpAllocator::UsableSize(void* p,
+                                           size_t /*allocation_size*/) const {
+  return malloc_usable_size(static_cast<void*>(p));
+}
+#endif  // ROCKSDB_JEMALLOC_NODUMP_ALLOCATOR
+
+Status NewJemallocNodumpAllocator(
+    JemallocAllocatorOptions& options,
+    std::shared_ptr<MemoryAllocator>* memory_allocator) {
+  *memory_allocator = nullptr;
+  Status unsupported = Status::NotSupported(
+      "JemallocNodumpAllocator only available with jemalloc version >= 5 "
+      "and MADV_DONTDUMP is available.");
+#ifndef ROCKSDB_JEMALLOC_NODUMP_ALLOCATOR
+  (void)options;
+  return unsupported;
+#else
+  if (!HasJemalloc()) {
+    return unsupported;
+  }
+  if (memory_allocator == nullptr) {
+    return Status::InvalidArgument("memory_allocator must be non-null.");
+  }
+  if (options.limit_tcache_size &&
+      options.tcache_size_lower_bound >= options.tcache_size_upper_bound) {
+    return Status::InvalidArgument(
+        "tcache_size_lower_bound larger or equal to tcache_size_upper_bound.");
+  }
+
+  // Create arena.
+  unsigned arena_index = 0;
+  size_t arena_index_size = sizeof(arena_index);
+  int ret =
+      mallctl("arenas.create", &arena_index, &arena_index_size, nullptr, 0);
+  if (ret != 0) {
+    return Status::Incomplete("Failed to create jemalloc arena, error code: " +
+                              ToString(ret));
+  }
+  assert(arena_index != 0);
+
+  // Read existing hooks.
+  std::string key = "arena." + ToString(arena_index) + ".extent_hooks";
+  extent_hooks_t* hooks;
+  size_t hooks_size = sizeof(hooks);
+  ret = mallctl(key.c_str(), &hooks, &hooks_size, nullptr, 0);
+  if (ret != 0) {
+    JemallocNodumpAllocator::DestroyArena(arena_index);
+    return Status::Incomplete("Failed to read existing hooks, error code: " +
+                              ToString(ret));
+  }
+
+  // Store existing alloc.
+  extent_alloc_t* original_alloc = hooks->alloc;
+  extent_alloc_t* expected = nullptr;
+  bool success =
+      JemallocNodumpAllocator::original_alloc_.compare_exchange_strong(
+          expected, original_alloc);
+  if (!success && original_alloc != expected) {
+    JemallocNodumpAllocator::DestroyArena(arena_index);
+    return Status::Incomplete("Original alloc conflict.");
+  }
+
+  // Set the custom hook.
+  std::unique_ptr<extent_hooks_t> new_hooks(new extent_hooks_t(*hooks));
+  new_hooks->alloc = &JemallocNodumpAllocator::Alloc;
+  extent_hooks_t* hooks_ptr = new_hooks.get();
+  ret = mallctl(key.c_str(), nullptr, nullptr, &hooks_ptr, sizeof(hooks_ptr));
+  if (ret != 0) {
+    JemallocNodumpAllocator::DestroyArena(arena_index);
+    return Status::Incomplete("Failed to set custom hook, error code: " +
+                              ToString(ret));
+  }
+
+  // Create cache allocator.
+  memory_allocator->reset(
+      new JemallocNodumpAllocator(options, std::move(new_hooks), arena_index));
+  return Status::OK();
+#endif  // ROCKSDB_JEMALLOC_NODUMP_ALLOCATOR
+}
+
+}  // namespace ROCKSDB_NAMESPACE