cvs commit: src/sys/kern sys_pipe.c

David Xu davidxu at
Thu Nov 22 18:48:25 PST 2007

Jean-Sebastien Pedron wrote:
> dumbbell    2007-11-19 15:05:20 UTC
>   FreeBSD src repository
>   Modified files:
>     sys/kern             sys_pipe.c 
>   Log:
>   The kernel uses two ways to write data on a pipe:
>       o  buffered write, for chunks smaller than PIPE_MINDIRECT bytes
>       o  direct write, for everything else
>   A call to writev(2) may receive struct iov of various size and the
>   kernel may have to switch from one solution to the other. Before doing
>   this, it must wake reader processes and any select/poll/kqueue up.
>   This commit fixes a bug where select/poll/kqueue are not triggered
>   when switching from buffered write to direct write. It adds calls to
>   pipeselwakeup().
>   I give more details on freebsd-arch@:
>   This should fix issues with Erlang (lang/erlang) and kqueue.
>   Reported by:    Rickard Green (Erlang)
>   Revision  Changes    Path
>   1.193     +4 -0      src/sys/kern/sys_pipe.c

This is an important fix, would you MFC it to RELENG_7 and maybe

David Xu

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