Re: [RFH] plumber's puzzle

From: Junio C Hamano <junkio@cox.net>
Date: Apr 22, 2007, 23:52 UTC
Message-ID: <7vejmcklv0.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <alpine.LFD.0.98.0704221546160.9964@woody.linux-foundation.org>

Linus Torvalds <torvalds@linux-foundation.org> writes:

Show 18 quoted lines

> On Sun, 22 Apr 2007, Junio C Hamano wrote:
>> 
>> I should be happy that I figured out what is going on, but I am
>> not very happy with this patch.
>
> That actually looks like the right patch.
>
> The "fflush() before fork()" thing is a real issue, and a real bug. Stdio 
> is buffered, and yes, fork() will duplicate the buffer if not flushed.
>
> Of course, I'm not 100% sure that is the right _place_ for the fflush() 
> call. I wonder if we should just do the fflush() closer to the place that 
> generates the data. As it is, we may have other things like that lurking.
>
> Of course, delaying the fflush as long as possible is likely good for 
> performance, so doing it just before the fork() (even if it may be ugly 
> and somewhat unexpected at that point to have to do it) may just be the 
> right thing regardless...

Another possibility I considered is to call low-level _exit so that we bypass not just stdio flushing but also atexit(). But I think "fflush() before fork()" is cleaner.