Re: [PATCH] f2fs: continuous counting for 'issued' in __issue_discard_cmd_orderly()

[Yuwei Guan]

在 2022/12/11 10:36, Chao Yu 写道:
> On 2022/11/22 0:11, Yuwei Guan wrote:
> > As the 'dcc->discard_granularity' and 'dcc->max_ordered_discard' can 
> > be set
> > at the user space, and if the 'dcc->max_ordered_discard' is set larger 
> > than
> > 'dcc->discard_granularity' in DPOLICY_BG mode, or it's a volume device,
> > discard_granularity can be tuned to 1 in f2fs_tuning_parameters(),
> > it will may send more requests than the number of 'dpolicy->max_requests'
> > in issue_discard_thread().
> >
> > This patch will fix the issue.
> >
> > Signed-off-by: Yuwei Guan <Yuwei.Guan@xxxxxxxxxxxxx>
> > ---
> >   fs/f2fs/segment.c | 17 ++++++++---------
> >   1 file changed, 8 insertions(+), 9 deletions(-)
> >
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 8b0b76550578..b0157bf392fb 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -1379,8 +1379,8 @@ static int __queue_discard_cmd(struct 
> > f2fs_sb_info *sbi,
> >       return 0;
> >   }
> > -static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info 
> > *sbi,
> > -                    struct discard_policy *dpolicy)
> > +static int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
> > +                    struct discard_policy *dpolicy, int *issued)
> >   {
> >       struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> >       struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
> > @@ -1388,7 +1388,6 @@ static unsigned int 
> > __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
> >       struct discard_cmd *dc;
> >       struct blk_plug plug;
> >       unsigned int pos = dcc->next_pos;
> > -    unsigned int issued = 0;
> >       bool io_interrupted = false;
> >       mutex_lock(&dcc->cmd_lock);
> > @@ -1415,9 +1414,9 @@ static unsigned int 
> > __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
> >           }
> >           dcc->next_pos = dc->lstart + dc->len;
> > -        err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> > +        err = __submit_discard_cmd(sbi, dpolicy, dc, issued);
> > -        if (issued >= dpolicy->max_requests)
> > +        if (*issued >= dpolicy->max_requests)
> >               break;
> >   next:
> >           node = rb_next(&dc->rb_node);
> > @@ -1433,10 +1432,10 @@ static unsigned int 
> > __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
> >       mutex_unlock(&dcc->cmd_lock);
> > -    if (!issued && io_interrupted)
> > -        issued = -1;
> > +    if (!(*issued) && io_interrupted)
> > +        *issued = -1;
> > -    return issued;
> > +    return *issued;
>
> A little weired that __issue_discard_cmd_orderly() will output the data
> in both return value and @issued parameter.
Got it.
> How about changing type of return value __issue_discard_cmd_orderly()
> from unsigned int to void.
I will sent a v2 patch for this.
> Thanks,
>
> >   }
> >   static unsigned int __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
> >                       struct discard_policy *dpolicy);
> > @@ -1465,7 +1464,7 @@ static int __issue_discard_cmd(struct 
> > f2fs_sb_info *sbi,
> >               break;
> >           if (i + 1 < dcc->max_ordered_discard && dpolicy->ordered)
> > -            return __issue_discard_cmd_orderly(sbi, dpolicy);
> > +            return __issue_discard_cmd_orderly(sbi, dpolicy, &issued);
> >           pend_list = &dcc->pend_list[i];