Re: [PATCH V3 00/16] Introduce the BFQ I/O scheduler

[Paolo Valente]

> Il giorno 11 apr 2017, alle ore 20:31, Bart Van Assche <bart.vanassche@xxxxxxxxxxx> ha scritto:
> 
> On Tue, 2017-04-11 at 19:37 +0200, Paolo Valente wrote:
>> Just pushed:
>> https://github.com/Algodev-github/bfq-mq/tree/add-bfq-mq-logical
> 
> Thanks!
> 
> But are you aware that the code on that branch doesn't build?
> 
> $ make all
> [ ... ]
> ERROR: "bfq_mark_bfqq_busy" [block/bfq-wf2q.ko] undefined!
> ERROR: "bfqg_stats_update_dequeue" [block/bfq-wf2q.ko] undefined!
> [ ... ]
> 
> $ PAGER= git grep bfq_mark_bfqq_busy
> block/bfq-wf2q.c:       bfq_mark_bfqq_busy(bfqq);
> 

That's exactly the complain of the kbuild test robot.  As I wrote,
build completes with no problem in my test system (Ubuntu 16.04, gcc
5.4.0), even with the exact offending tree and .config that the robot
reports.

I didn't understand what is going on.  In your case, as well as for
the test robot, the compilation of the file block/bfq-wf2q.c as a
module component fails, because that file does not contain the
definition of the reported functions.  But that definition is
(uniquely) in the file block/bfq-iosched.c, which is to be compiled
with the former file, according to the following rule in
block/Makefile:
obj-$(CONFIG_IOSCHED_BFQ)       += bfq-iosched.o bfq-wf2q.o bfq-cgroup.o

I have tried all combinations of configurations for bfq (builti-in or
module, with or without cgrousp support), always successfully.  If it
makes any sense to share this information, these are the exact
commands I used to test al combinations (in addition to make full
builds in some cases, and try make all as in your case):

make O=builddir M=block

and

make O=builddir M=block modules

Where is my mistake?

Thanks,
Paolo

> Bart.