Thank you. Now I understand.
A simple example is below:
[root@vm-dev tmp]# cat Makefile
test:
echo ${MAKEFLAGS};cd subdir; ${MAKE}
test2:
echo ${MAKEFLAGS};cd subdir; make
[root@vm-dev tmp]# cat subdir/Makefile
sub-make:
echo "this is sub-make"; echo ${MAKEFLAGS}
=== if we use make ===
# make -j2 test2
echo -j --jobserver-fds=3,4;cd subdir; make
-j --jobserver-fds=3,4
make[1]: warning: jobserver unavailable: using -j1. Add '+' to parent make
rule.
make[1]: Entering directory '/tmp/subdir'
echo "this is sub-make"; echo w
this is sub-make
w
=== if we use ${MAKE} ===
# make -j2 test
echo -j --jobserver-fds=3,4;cd subdir; make
-j --jobserver-fds=3,4
make[1]: Entering directory '/tmp/subdir'
echo "this is sub-make"; echo w -j --jobserver-fds=3,4
this is sub-make
w -j --jobserver-fds=3,4
On Tue, Feb 9, 2016 at 9:40 AM, Ben Pfaff <b...@ovn.org> wrote:
> Make automatically passes the flags through the environment in the
> MAKEFLAGS variable.
>
> On Tue, Feb 09, 2016 at 09:37:34AM -0800, William Tu wrote:
> > I'm also running "make -j2 dist-docs" but could find -j2 optioned passed
> > in. Is the correct way of using this is like this:
> >
> > # MAKE="make -j2" make dist-docs
> >
> > Thank you
> > William
> >
> > On Tue, Feb 9, 2016 at 8:59 AM, Russell Bryant <russ...@ovn.org> wrote:
> >
> > > On 02/09/2016 11:16 AM, Ben Pfaff wrote:
> > > > When GNU make sees that a command to be executed contains the string
> > > > $(MAKE), it makes the jobserver that limits parallelism available to
> > > > the command. Otherwise, any sub-make that executes sees that
> > > > parallelism is enabled but does not have access to the jobserver, so
> > > > it prints a warning and turns off parallel job execution.
> > > >
> > > > This also makes the dist-docs process run the same "make" that is
> > > > executed at the top level, in case that's different from the default
> > > > "make" found in $PATH.
> > > >
> > > > Signed-off-by: Ben Pfaff <b...@ovn.org>
> > > > ---
> > > > v1->v2: Rewrite commit message.
> > >
> > > magic, indeed...
> > >
> > > Acked-by: Russell Bryant <russ...@ovn.org>
> > >
> > > --
> > > Russell Bryant
> > > _______________________________________________
> > > dev mailing list
> > > dev@openvswitch.org
> > > http://openvswitch.org/mailman/listinfo/dev
> > >
>
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