Re: [PATCH] btrfs-progs: Add dependencies explicitly to fix a parallel build issue

[Rongqing Li <rongqing.li@windriver.com>]

On 09/18/2013 10:51 PM, David Sterba wrote:
> On Wed, Sep 18, 2013 at 09:11:01AM +0800, rongqing.li@windriver.com wrote:
>> From: Roy Li <rongqing.li@windriver.com>
>>
>> The dependencies of "all: version.h" or other similar ones can not
>> fix the parallel build failure, only reduce the times; In fact,
>> many *.o files require version.h file.
>>
>> 	#grep '#include "version.h"' ./ -r
>> 	./btrfs-corrupt-block.c:#include "version.h"
>> 	./btrfs.c:#include "version.h"
>> 	./btrfs-image.c:#include "version.h"
>> 	./cmds-filesystem.c:#include "version.h"
>> 	./btrfs-show-super.c:#include "version.h"
>> 	./btrfs-select-super.c:#include "version.h"
>> 	./cmds-restore.c:#include "version.h"
>> 	./btrfs-find-root.c:#include "version.h"
>> 	./mkfs.c:#include "version.h"
>> 	./btrfs-zero-log.c:#include "version.h"
>> 	./btrfs-defrag.c:#include "version.h"
>> 	./cmds-chunk.c:#include "version.h"
>> 	./btrfstune.c:#include "version.h"
>> 	./btrfs-calc-size.c:#include "version.h"
>> 	./btrfs-map-logical.c:#include "version.h"
>> 	./cmds-check.c:#include "version.h"
>> 	./btrfs-debug-tree.c:#include "version.h"
>>
>> Signed-off-by: Roy Li <rongqing.li@windriver.com>
>> ---
>>   Sorry, The patch [btrfs-progs: fix parallel build] sent by me on Sep 3
>> can not fix the build failure, when build enough times on a 16 core cpu,
>> the build failure happens again, so I refix it again.
>
> I'm running make -j all the time but haven't seen the build fail due to
> missing version.h for a long time. With this patch or the previous one
> or with Eric's, all fine. The generated dependency files contain
> version.h so make has complete information how to order the rules.
>

I want to know how many cores your cpu has? I can not reproduce it on
my 2 cores cpu, but it always happens when run on a server which is
a 16 cores cpu and "make -j20"


> The dependency files are generated by an implicit rule .c -> .o.d, so
> there should be no problem for any of the files listed above.
>

Do you means the below:

.c.o:
         $(Q)$(check) $<
         @echo "    [CC]     $@"
         $(Q)$(CC) $(DEPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c $<


-Roy



> If you think the patch "btrfs-progs: fix parallel build" does not help
> much I'll drop it.
>
>
> david
>
>

-- 
Best Reagrds,
Roy | RongQing Li