Re: [PATCH v2 0/6] forking and threading
- Date: Thu, 13 Apr 2017 13:50:08 -0700
- From: Jonathan Nieder <jrnieder@xxxxxxxxx>
- Subject: Re: [PATCH v2 0/6] forking and threading
Brandon Williams wrote:
> From what I can see, there are now no calls in the child process (after fork
> and before exec/_exit) which are not Async-Signal-Safe. This means that
> fork/exec in a threaded context should work without deadlock
I don't see why the former implies the latter. Can you explain
You already know my opinions about fork+threads by now. I continue to
think this is heading in a direction of decreased maintainability that
That's not to say that this is wasted work. I would prefer an approach
like the following:
1. First, make grep work without running fork() from threads.
Jonathan Tan's approach would be one way to do this. Another way
would be to simply disable threads in --recurse-submodules mode.
This would be the first thing to do because it would make tests
reliable again, without having to wait for deeper changes.
2. Then, teaching run_command to prepare the environment and do $PATH
lookup before forking. This might make it possible for run_command
to use vfork or might not.
3. Teaching run_command to delegate chdir to the child, using -C for
git commands and 'cd' for shell commands, and using a shell where
necessary where it didn't before.
4. Switching run_command to use posix_spawn on platforms where it is
available, which would make it possible to use in a threaded
context on those platforms.