Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1396115 > unrolled thread

[PATCH BUGFIX] block: add missing group association in bio_split

Started byPaolo Valente <paolo.valente@linaro.org>
First post2016-05-06 23:30 +0200
Last post2016-05-09 17:30 +0200
Articles 2 on this page of 22 — 7 participants

Back to article view | Back to linux.kernel


Contents

  [PATCH BUGFIX] block: add missing group association in bio_split Paolo Valente <paolo.valente@linaro.org> - 2016-05-06 23:30 +0200
    Re: [PATCH BUGFIX] block: add missing group association in bio_split Jeff Moyer <jmoyer@redhat.com> - 2016-05-09 16:20 +0200
      Re: [PATCH BUGFIX] block: add missing group association in bio_split Jeff Moyer <jmoyer@redhat.com> - 2016-05-09 16:40 +0200
        Re: [PATCH BUGFIX] block: add missing group association in bio_split Paolo <paolo.valente@linaro.org> - 2016-05-09 16:40 +0200
          Re: [PATCH BUGFIX] block: add missing group association in bio_split Mark Brown <broonie@kernel.org> - 2016-05-09 17:00 +0200
            Re: [PATCH BUGFIX] block: add missing group association in bio_split Jens Axboe <axboe@kernel.dk> - 2016-05-09 20:00 +0200
              [PATCH BUGFIX] block: add missing group association in bio_split Paolo Valente <paolo.valente@linaro.org> - 2016-05-10 11:10 +0200
                Re: [PATCH BUGFIX] block: add missing group association in bio_split Jeff Moyer <jmoyer@redhat.com> - 2016-05-10 18:20 +0200
                  Re: [PATCH BUGFIX] block: add missing group association in bio_split Paolo <paolo.valente@linaro.org> - 2016-05-10 19:10 +0200
                  [PATCH BUGFIX] block: add missing group association in bio-cloning functions Paolo Valente <paolo.valente@linaro.org> - 2016-05-10 22:30 +0200
                    Re: [PATCH BUGFIX] block: add missing group association in  bio-cloning functions Tejun Heo <tj@kernel.org> - 2016-05-10 22:50 +0200
                      Re: [PATCH BUGFIX V2] block: add missing group association in  bio-cloning functions Tejun Heo <tj@kernel.org> - 2016-05-10 23:10 +0200
                      [PATCH BUGFIX V2] block: add missing group association in bio-cloning functions Paolo Valente <paolo.valente@linaro.org> - 2016-05-10 23:10 +0200
                        Re: [PATCH BUGFIX V2] block: add missing group association in bio-cloning functions Jeff Moyer <jmoyer@redhat.com> - 2016-05-10 23:40 +0200
                          Re: [PATCH BUGFIX V2] block: add missing group association in  bio-cloning functions Paolo <paolo.valente@linaro.org> - 2016-05-10 23:50 +0200
                          [PATCH BUGFIX V3] block: add missing group association in bio-cloning functions Paolo Valente <paolo.valente@linaro.org> - 2016-05-11 00:10 +0200
                            Re: [PATCH BUGFIX V3] block: add missing group association in  bio-cloning functions Nikolay Borisov <kernel@kyup.com> - 2016-05-11 08:40 +0200
                              Re: [PATCH BUGFIX V3] block: add missing group association in  bio-cloning functions Nikolay Borisov <kernel@kyup.com> - 2016-05-11 08:50 +0200
                                Re: [PATCH BUGFIX V3] block: add missing group association in  bio-cloning functions Paolo <paolo.valente@linaro.org> - 2016-05-11 11:10 +0200
                                [PATCH BUGFIX V4] block: add missing group association in bio-cloning functions Paolo Valente <paolo.valente@linaro.org> - 2016-05-11 11:30 +0200
          Re: [PATCH BUGFIX] block: add missing group association in bio_split Jens Axboe <axboe@kernel.dk> - 2016-05-09 17:00 +0200
    Re: [PATCH BUGFIX] block: add missing group association in bio_split Tejun Heo <tj@kernel.org> - 2016-05-09 17:30 +0200

Page 2 of 2 — ← Prev page 1 [2]


#1397120

FromJens Axboe <axboe@kernel.dk>
Date2016-05-09 17:00 +0200
Message-ID<rwUP9-7Fi-17@gated-at.bofh.it>
In reply to#1397101
On 05/09/2016 08:39 AM, Paolo wrote:
> Il 09/05/2016 16:35, Jeff Moyer ha scritto:
>> Jeff Moyer <jmoyer@redhat.com> writes:
>>
>>> Paolo Valente <paolo.valente@linaro.org> writes:
>>>
>>>> @@ -1811,6 +1811,11 @@ struct bio *bio_split(struct bio *bio, int
>>>> sectors,
>>>>
>>>>       bio_advance(bio, split->bi_iter.bi_size);
>>>>
>>>> +#ifdef CONFIG_BLK_CGROUP
>>>> +    if (bio->bi_css)
>>>> +        bio_associate_blkcg(split, bio->bi_css);
>>>> +#endif
>>>> +
>>>>       return split;
>>>>   }
>>>>   EXPORT_SYMBOL(bio_split);
>>>
>>> Get rid of the #ifdefery.  This should be just:
>>>
>>> bio_associate_blkcg(split, bio->bi_css);
>>
>> Gah, I see that the bi_css member is only present for CONFIG_BLK_CGROUP.
>> I guess we'll have to live with the ifdef.
>>
>
> We have already tried to remove it, but it seems it would require other
> major changes.

It'd be cleaner to have a

bio_clone_associate_blkcg(split, bio);

or similar, and then hide it in there.

-- 
Jens Axboe

[toc] | [prev] | [next] | [standalone]


#1397141

FromTejun Heo <tj@kernel.org>
Date2016-05-09 17:30 +0200
Message-ID<rwVi9-8if-1@gated-at.bofh.it>
In reply to#1396115
On Fri, May 06, 2016 at 10:45:12PM +0200, Paolo Valente wrote:
> When a bio is split, the newly created bio must be associated with the
> same blkcg as the original bio (if BLK_CGROUP is enabled). If this
> operation is not performed, then the new bio is not associated with
> any group, and the group of the current task is returned when the
> group of the bio is requested.
> 
> Depending on the frequency of splits, this may cause a large
> percentage of the bios belonging to a given group to be treated as if
> belonging to other groups (in most cases as if belonging to the root
> group). The expected group isolation may thereby be then broken.
> 
> This commit adds the missing association in bio_split.
> 
> Signed-off-by: Paolo Valente <paolo.valente@linaro.org>

Acked-by: Tejun Heo <tj@kernel.org>

> ---
>  block/bio.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/block/bio.c b/block/bio.c
> index 807d25e..c4a3834 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -1811,6 +1811,11 @@ struct bio *bio_split(struct bio *bio, int sectors,
>  
>  	bio_advance(bio, split->bi_iter.bi_size);
>  
> +#ifdef CONFIG_BLK_CGROUP
> +	if (bio->bi_css)
> +		bio_associate_blkcg(split, bio->bi_css);
> +#endif

And yeah, we need to encapsulate this better to avoid scattering
CONFIG_BLK_CGROUP but that's for another patch.

Thanks.

-- 
tejun

[toc] | [prev] | [standalone]


Page 2 of 2 — ← Prev page 1 [2]

Back to top | Article view | linux.kernel


csiph-web