Re: [PATCH] Makefile: fix use of -j without an argument

[Matheus Tavares Bernardino]

Hi, Philippe

On Thu, 11 Apr 2024 17:29:58 +0200 =?UTF-8?Q?Philippe_Mathieu-Daud=C3=A9?= 
<philmd@linaro.org> wrote:
>
> Hi Matheus,
> 
> On 11/4/24 17:09, Matheus Tavares Bernardino wrote:
> > Our Makefile massages the given make arguments to invoke ninja
> > accordingly. One key difference is that ninja will parallelize by
> > default, whereas make only does so with -j<n> or -j. The make man page
> > says that "if the -j option is given without an argument, make will not
> > limit the number of jobs that can run simultaneously". We use to support
> > that by replacing -j with "" (empty string) when calling ninja, so that
> > it would do its auto-parallelization based on the number of CPU cores.
> > 
> > This was accidentally broken at d1ce2cc95b (Makefile: preserve
> > --jobserver-auth argument when calling ninja, 2024-04-02),
> > causing `make -j` to fail:
> > 
> > $ make -j V=1
> >    /usr/bin/ninja -v   -j -d keepdepfile all | cat
> >    make  -C contrib/plugins/ V="1" TARGET_DIR="contrib/plugins/" all
> >    ninja: fatal: invalid -j parameter
> >    make: *** [Makefile:161: run-ninja] Error
> > 
> > Let's fix that and indent the touched code for better readability.
> > 
> > Signed-off-by: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
> > ---
> >   Makefile | 8 ++++++--
> >   1 file changed, 6 insertions(+), 2 deletions(-)
> > 
> > diff --git a/Makefile b/Makefile
> > index 183756018f..d299c14dab 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -142,8 +142,12 @@ MAKE.k = $(findstring k,$(firstword $(filter-out 
> > --%,$(MAKEFLAGS))))
> >   MAKE.q = $(findstring q,$(firstword $(filter-out --%,$(MAKEFLAGS))))
> >   MAKE.nq = $(if $(word 2, $(MAKE.n) $(MAKE.q)),nq)
> >   NINJAFLAGS = $(if $V,-v) $(if $(MAKE.n), -n) $(if $(MAKE.k), -k0) \
> > -        $(or $(filter -l% -j%, $(MAKEFLAGS)), $(if $(filter 
> > --jobserver-auth=%, $(MAKEFLAGS)),, -j1)) \
> > -        -d keepdepfile
> > +        $(if $(filter -j, $(MAKEFLAGS)) \
> > +        ,, \
> > +        $(or \
> > +             $(filter -l% -j%, $(MAKEFLAGS)), \
> > +             $(if $(filter --jobserver-auth=%, $(MAKEFLAGS)),, -j1)) \
> > +        ) -d keepdepfile
> >   ninja-cmd-goals = $(or $(MAKECMDGOALS), all)
> >   ninja-cmd-goals += $(foreach g, $(MAKECMDGOALS), $(.ninja-goals.$g))
> >   
> 
> Apparently Martin sent the same patch (although not as nicely
> indented) and Paolo queued it:
> 20240402081738.1051560-1-martin@geanix.com/">https://lore.kernel.org/qemu-devel/20240402081738.1051560-1-martin@geanix.com/

Actually, this patch is a follow-up to that one, fixing a feature that was
accidentally broken.