1. 01 Nov, 2012 24 commits
  2. 31 Oct, 2012 15 commits
  3. 30 Oct, 2012 1 commit
    • Alex Brainman's avatar
      net: fix connection resets when closed on windows · fa3e4fc4
      Alex Brainman authored
      It is common to close network connection while another goroutine is
      blocked reading on another goroutine. This sequence corresponds to
      windows calls to WSARecv to start io, followed by GetQueuedCompletionStatus
      that blocks until io completes, and, finally, closesocket called from
      another thread. We were expecting that closesocket would unblock
      GetQueuedCompletionStatus, and it does, but not always
      (http://code.google.com/p/go/issues/detail?id=4170#c5). Also that sequence
      results in connection is being reset.
      
      This CL inserts CancelIo between GetQueuedCompletionStatus and closesocket,
      and waits for both WSARecv and GetQueuedCompletionStatus to complete before
      proceeding to closesocket.  This seems to fix both connection resets and
      issue 4170. It also makes windows code behave similar to unix version.
      
      Unfortunately, CancelIo needs to be called on the same thread as WSARecv.
      So we have to employ strategy we use for connections with deadlines to
      every connection now. It means, there are 2 unavoidable thread switches
      for every io. Some newer versions of windows have new CancelIoEx api that
      doesn't have these drawbacks, and this CL uses this capability when available.
      As time goes by, we should have less of CancelIo and more of CancelIoEx
      systems. Computers with CancelIoEx are also not affected by issue 4195 anymore.
      
      Fixes #3710
      Fixes #3746
      Fixes #4170
      Partial fix for issue 4195
      
      R=golang-dev, mikioh.mikioh, bradfitz, rsc
      CC=golang-dev
      https://golang.org/cl/6604072
      fa3e4fc4