Re: [PATCH BUGFIX] block, bfq: update wr_busy_queues if needed on a queue split

Il giorno 19 giu 2017, alle ore 09:38, kbuild test robot =

[off-list ref] ha scritto:

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Hi Paolo,
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[auto build test WARNING on v4.12-rc5]
[also build test WARNING on next-20170616]
[cannot apply to block/for-next]
[if your patch is applied to the wrong git tree, please drop us a note =

to help improve the system]

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url:    =

https://github.com/0day-ci/linux/commits/Paolo-Valente/block-bfq-update-wr=
_busy_queues-if-needed-on-a-queue-split/20170619-145003

config: i386-randconfig-x000-201725 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
       # save the attached .config to linux build tree
       make ARCH=3Di386=20
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Note: it may well be a FALSE warning. FWIW you are at least aware of =

it now.

http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
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All warnings (new ones prefixed by >>):
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  block/bfq-iosched.c: In function 'bfq_get_rq_private':

quoted

quoted

block/bfq-iosched.c:770:10: warning: 'old_wr_coeff' may be used =

uninitialized in this function [-Wmaybe-uninitialized]

    else if (old_wr_coeff > 1 && bfqq->wr_coeff =3D=3D 1)
            ^
  block/bfq-iosched.c:731:15: note: 'old_wr_coeff' was declared here
    unsigned int old_wr_coeff;
                 ^~~~~~~~~~~~
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I'm sending a V2, (probably imperceptibly) slower on average, but not
confusing the compiler.

Thanks,
Paolo

vim +/old_wr_coeff +770 block/bfq-iosched.c
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  754		    time_is_before_jiffies(bfqq->last_wr_start_finish +
  755					   bfqq->wr_cur_max_time))) {
  756			bfq_log_bfqq(bfqq->bfqd, bfqq,
  757			    "resume state: switching off wr");
  758=09
  759			bfqq->wr_coeff =3D 1;
  760		}
  761=09
  762		/* make sure weight will be updated, however we got here =

*/

  763		bfqq->entity.prio_changed =3D 1;
  764=09
  765		if (likely(!busy))
  766			return;
  767=09
  768		if (old_wr_coeff =3D=3D 1 && bfqq->wr_coeff > 1)
  769			bfqd->wr_busy_queues++;

quoted

770		else if (old_wr_coeff > 1 && bfqq->wr_coeff =3D=3D 1)

  771			bfqd->wr_busy_queues--;
  772	}
  773=09
  774	static int bfqq_process_refs(struct bfq_queue *bfqq)
  775	{
  776		return bfqq->ref - bfqq->allocated - bfqq->entity.on_st;
  777	}
  778=09
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