commit 99afb75b979b2641da7f8ec2222d0f4e0b93c39d
author Vikram Auradkar <auradkar@google.com> Fri May 22 23:20:48 2020 +0000
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> Fri May 22 23:20:48 2020 +0000
tree d95ab1e180928ddce5c74dc4b3e3855fd3c58f32
parent 5f54e1cdc713459e55fe1f63450b5952bbecc196

[blobfs] Change container size and reorder member fields

Saves 8 bytes per blobfs::Blob instance
Before:
[zxdb] p sizeof(blobfs::Blob)
344

After:
[zxdb] p sizeof(blobfs::Blob)
336

TEST: Built

Change-Id: I3bbbcfce66441aa6fbaa84a1738975c1a442b21f
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/392353
Reviewed-by: Brett Wilson <brettw@google.com>
Testability-Review: Brett Wilson <brettw@google.com>
Commit-Queue: Vikram Auradkar <auradkar@google.com>

zircon/system/ulib/blobfs/blob.cc

diff --git a/zircon/system/ulib/blobfs/blob.cc b/zircon/system/ulib/blobfs/blob.cc
index bdd7410..bc64988 100644
--- a/zircon/system/ulib/blobfs/blob.cc
+++ b/zircon/system/ulib/blobfs/blob.cc
@@ -111,8 +111,8 @@
       blobfs_(bs),
       flags_(kBlobStateReadable),
       syncing_state_(SyncingState::kDone),
-      clone_watcher_(this),
       map_index_(node_index),
+      clone_watcher_(this),
       inode_(inode) {}
 
 zx_status_t Blob::SpaceAllocate(uint64_t size_data) {

zircon/system/ulib/blobfs/blob.h

diff --git a/zircon/system/ulib/blobfs/blob.h b/zircon/system/ulib/blobfs/blob.h
index 2730fa2..722c95c 100644
--- a/zircon/system/ulib/blobfs/blob.h
+++ b/zircon/system/ulib/blobfs/blob.h
@@ -50,7 +50,7 @@
 using digest::Digest;
 using digest::MerkleTreeVerifier;
 
-typedef uint32_t BlobFlags;
+typedef uint16_t BlobFlags;
 
 // clang-format off
 
@@ -252,11 +252,9 @@
   Blobfs* const blobfs_;
   BlobFlags flags_ = {};
 
-  // This object is not generally threadsafe but a few small things are done on the journal thread.
-  // This mutex protects such data.
-  std::mutex mutex_;
+  bool tearing_down_ = false;
 
-  enum class SyncingState {
+  enum class SyncingState : char {
     // The Blob is being streamed and it is not possible to generate the merkle root and metadata at
     // this point.
     kDataIncomplete,
@@ -272,6 +270,12 @@
   // is protected by the mutex.
   SyncingState syncing_state_ __TA_GUARDED(mutex_) = SyncingState::kDataIncomplete;
 
+  uint32_t map_index_ = 0;
+
+  // This object is not generally threadsafe but a few small things are done on the journal thread.
+  // This mutex protects such data.
+  std::mutex mutex_;
+
   // VMO mappings for the blob's merkle tree and data.
   // Data is stored in a separate VMO from the merkle tree for several reasons:
   //   - While data may be paged, the merkle tree (i.e. verification metadata) should always be
@@ -296,8 +300,6 @@
   zx::event readable_event_ = {};
 
   uint32_t fd_count_ = 0;
-  uint32_t map_index_ = 0;
-  bool tearing_down_ = false;
 
   // TODO(smklein): We are only using a few of these fields, such as:
   // - blob_size