[kudu-CR] Fix move constructors to be noexcept

[Alexey Serbin (Code Review)]

Alexey Serbin has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/9382 )

Change subject: Fix move constructors to be noexcept
..


Patch Set 2: Code-Review+2


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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: Idd7487766be3261e3506ff9613a5d733013018b0
Gerrit-Change-Number: 9382
Gerrit-PatchSet: 2
Gerrit-Owner: Todd Lipcon 
Gerrit-Reviewer: Alexey Serbin 
Gerrit-Reviewer: Kudu Jenkins
Gerrit-Reviewer: Tidy Bot
Gerrit-Reviewer: Todd Lipcon 
Gerrit-Comment-Date: Fri, 23 Feb 2018 05:36:25 +
Gerrit-HasComments: No

[kudu-CR] Fix move constructors to be noexcept

[Alexey Serbin (Code Review)]

Alexey Serbin has submitted this change and it was merged. ( 
http://gerrit.cloudera.org:8080/9382 )

Change subject: Fix move constructors to be noexcept
..

Fix move constructors to be noexcept

I noticed while looking at a profile of a tablet server starting up that
I saw a lot of CPU used in stacks like:

  kudu::subtle::RefCountedThreadSafeBase::AddRef() const
  void std::vector::
   _M_emplace_back_aux

Digging into the source of std::vector, I saw that the emplace_back_aux
function is used when emplacing requires resizing the underlying array.
Since scoped_refptr has a move constructor I was surprised to see it
using AddRef() here during the array expansion. In fact it turns out
that std::vector<> will only use the move constructor when it is marked
'noexcept', which ours was not.

I verified this with a simple test program as well[1]. If the move
constructor is marked 'noexcept', it is called. Otherwise, it is not.

This patch corrects scoped_refptr as well as a few other spots where we
had move constructors without noexcept.

[1] https://gist.github.com/toddlipcon/c9a807c6a67037ccd1b63caa93f74c67

Change-Id: Idd7487766be3261e3506ff9613a5d733013018b0
Reviewed-on: http://gerrit.cloudera.org:8080/9382
Tested-by: Kudu Jenkins
Reviewed-by: Alexey Serbin 
---
M src/kudu/cfile/block_cache.h
M src/kudu/cfile/block_handle.h
M src/kudu/gutil/ref_counted.h
M src/kudu/tablet/lock_manager.cc
M src/kudu/tablet/lock_manager.h
M src/kudu/util/cow_object.h
M src/kudu/util/status.h
7 files changed, 17 insertions(+), 17 deletions(-)

Approvals:
  Kudu Jenkins: Verified
  Alexey Serbin: Looks good to me, approved

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To view, visit http://gerrit.cloudera.org:8080/9382
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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: merged
Gerrit-Change-Id: Idd7487766be3261e3506ff9613a5d733013018b0
Gerrit-Change-Number: 9382
Gerrit-PatchSet: 3
Gerrit-Owner: Todd Lipcon 
Gerrit-Reviewer: Alexey Serbin 
Gerrit-Reviewer: Kudu Jenkins
Gerrit-Reviewer: Tidy Bot
Gerrit-Reviewer: Todd Lipcon 

[kudu-CR] Fix move constructors to be noexcept

[Todd Lipcon (Code Review)]

Hello Tidy Bot, Alexey Serbin, Kudu Jenkins,

I'd like you to reexamine a change. Please visit

http://gerrit.cloudera.org:8080/9382

to look at the new patch set (#2).

Change subject: Fix move constructors to be noexcept
..

Fix move constructors to be noexcept

I noticed while looking at a profile of a tablet server starting up that
I saw a lot of CPU used in stacks like:

  kudu::subtle::RefCountedThreadSafeBase::AddRef() const
  void std::vector::
   _M_emplace_back_aux

Digging into the source of std::vector, I saw that the emplace_back_aux
function is used when emplacing requires resizing the underlying array.
Since scoped_refptr has a move constructor I was surprised to see it
using AddRef() here during the array expansion. In fact it turns out
that std::vector<> will only use the move constructor when it is marked
'noexcept', which ours was not.

I verified this with a simple test program as well[1]. If the move
constructor is marked 'noexcept', it is called. Otherwise, it is not.

This patch corrects scoped_refptr as well as a few other spots where we
had move constructors without noexcept.

[1] https://gist.github.com/toddlipcon/c9a807c6a67037ccd1b63caa93f74c67

Change-Id: Idd7487766be3261e3506ff9613a5d733013018b0
---
M src/kudu/cfile/block_cache.h
M src/kudu/cfile/block_handle.h
M src/kudu/gutil/ref_counted.h
M src/kudu/tablet/lock_manager.cc
M src/kudu/tablet/lock_manager.h
M src/kudu/util/cow_object.h
M src/kudu/util/status.h
7 files changed, 17 insertions(+), 17 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/82/9382/2
--
To view, visit http://gerrit.cloudera.org:8080/9382
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Idd7487766be3261e3506ff9613a5d733013018b0
Gerrit-Change-Number: 9382
Gerrit-PatchSet: 2
Gerrit-Owner: Todd Lipcon 
Gerrit-Reviewer: Alexey Serbin 
Gerrit-Reviewer: Kudu Jenkins
Gerrit-Reviewer: Tidy Bot
Gerrit-Reviewer: Todd Lipcon 

[kudu-CR] Fix move constructors to be noexcept

[Todd Lipcon (Code Review)]

Todd Lipcon has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/9382 )

Change subject: Fix move constructors to be noexcept
..


Patch Set 1:

nope, I just didn't grep well enough to find those. Will fix


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To view, visit http://gerrit.cloudera.org:8080/9382
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: Idd7487766be3261e3506ff9613a5d733013018b0
Gerrit-Change-Number: 9382
Gerrit-PatchSet: 1
Gerrit-Owner: Todd Lipcon 
Gerrit-Reviewer: Alexey Serbin 
Gerrit-Reviewer: Kudu Jenkins
Gerrit-Reviewer: Tidy Bot
Gerrit-Reviewer: Todd Lipcon 
Gerrit-Comment-Date: Thu, 22 Feb 2018 08:15:06 +
Gerrit-HasComments: No

[kudu-CR] Fix move constructors to be noexcept

[Todd Lipcon (Code Review)]

Hello Alexey Serbin,

I'd like you to do a code review. Please visit

http://gerrit.cloudera.org:8080/9382

to review the following change.


Change subject: Fix move constructors to be noexcept
..

Fix move constructors to be noexcept

I noticed while looking at a profile of a tablet server starting up that
I saw a lot of CPU used in stacks like:

  kudu::subtle::RefCountedThreadSafeBase::AddRef() const
  void std::vector::
   _M_emplace_back_aux

Digging into the source of std::vector, I saw that the emplace_back_aux
function is used when emplacing requires resizing the underlying array.
Since scoped_refptr has a move constructor I was surprised to see it
using AddRef() here during the array expansion. In fact it turns out
that std::vector<> will only use the move constructor when it is marked
'noexcept', which ours was not.

I verified this with a simple test program as well[1]. If the move
constructor is marked 'noexcept', it is called. Otherwise, it is not.

This patch corrects scoped_refptr as well as a few other spots where we
had move constructors without noexcept.

[1] https://gist.github.com/toddlipcon/c9a807c6a67037ccd1b63caa93f74c67

Change-Id: Idd7487766be3261e3506ff9613a5d733013018b0
---
M src/kudu/cfile/block_handle.h
M src/kudu/gutil/ref_counted.h
M src/kudu/tablet/lock_manager.cc
M src/kudu/tablet/lock_manager.h
M src/kudu/util/status.h
5 files changed, 12 insertions(+), 12 deletions(-)



  git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/82/9382/1
--
To view, visit http://gerrit.cloudera.org:8080/9382
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: Idd7487766be3261e3506ff9613a5d733013018b0
Gerrit-Change-Number: 9382
Gerrit-PatchSet: 1
Gerrit-Owner: Todd Lipcon 
Gerrit-Reviewer: Alexey Serbin