Add code to enforce the paralleism count (-j N) for the entire tree

of submakes spawned during processing.

We create a fifo and stuff one character into it for each job we are
allowed to run.  The name of the fifo is passed to child processes
in the MAKE_JOBS_FIFO environment variable.

A make which finds this variable on startup will open the fifo and
only spawn jobs when it managed to read a token from the fifo.
When the job completes a token is writen back to the fifo.

Slave make processes get one token for free: the one their parent
make got in order to run them.  This makes the make processes
themselves invisible in the process counts.

The net effect is that "make -j 12 -s buildworld" will start at
most 12 jobs at the same time, instead of as previously up to
65 jobs would get started.

1 files changed, 1 insertions, 1 deletions

diff --git a/usr.bin/make/job.h b/usr.bin/make/job.h
index 09fe8fe..25aa511 100644
--- a/usr.bin/make/job.h
+++ b/usr.bin/make/job.h
@@ -209,7 +209,7 @@ void Shell_Init(void);
 void Job_Touch(GNode *, Boolean);
 Boolean Job_CheckCommands(GNode *, void (*abortProc)(const char *, ...));
 void Job_CatchChildren(Boolean);
-void Job_CatchOutput(void);
+void Job_CatchOutput(int flag);
 void Job_Make(GNode *);
 void Job_Init(int);
 Boolean Job_Full(void);