Re: [PATCH] f2fs: show more discard stat by sysfs

[Zhiguo Niu]

Dear Chao,

On Tue, Nov 28, 2023 at 10:13 AM Chao Yu <chao@xxxxxxxxxx> wrote:
>
> On 2023/11/24 9:08, Zhiguo Niu wrote:
> > The current pending_discard attr just only shows the discard_cmd_cnt
> > information, which is not very meaningful. More discard information
> > can be shown so that we can check them through sysfs when needed.
>
> What about adding this entry to /sys/fs/f2fs/<dev>/stat/?
I think it is ok!
The purpose of this patch is to obtain f2fs discard related status
when necessary.
Because sys/kernel/debug/f2fs/status cannot be used on the user version,
I will change it according to your suggestion.
>
> >
> > Signed-off-by: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>
> > ---
> >   fs/f2fs/sysfs.c | 21 +++++++++++++++------
> >   1 file changed, 15 insertions(+), 6 deletions(-)
> >
> > diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> > index 417fae96..f98e680 100644
> > --- a/fs/f2fs/sysfs.c
> > +++ b/fs/f2fs/sysfs.c
> > @@ -134,13 +134,22 @@ static ssize_t cp_status_show(struct f2fs_attr *a,
> >       return sysfs_emit(buf, "%x\n", le32_to_cpu(F2FS_CKPT(sbi)->ckpt_flags));
> >   }
> >
> > -static ssize_t pending_discard_show(struct f2fs_attr *a,
> > +static ssize_t discard_stat_show(struct f2fs_attr *a,
> >               struct f2fs_sb_info *sbi, char *buf)
> >   {
> > -     if (!SM_I(sbi)->dcc_info)
> > +     struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> > +
> > +     if (!dcc)
> >               return -EINVAL;
> > -     return sysfs_emit(buf, "%llu\n", (unsigned long long)atomic_read(
> > -                             &SM_I(sbi)->dcc_info->discard_cmd_cnt));
>
> It's better to keep the old one for any potential user.
>
> > +
> > +     return sysfs_emit(buf, "%llu, %llu, %llu, %u\n",
> > +                     (unsigned long long)atomic_read(
> > +                             &dcc->discard_cmd_cnt),
> > +                     (unsigned long long)atomic_read(
> > +                             &dcc->issued_discard),
> > +                     (unsigned long long)atomic_read(
> > +                             &dcc->queued_discard),
> > +                     dcc->undiscard_blks);
> >   }
> >
> >   static ssize_t gc_mode_show(struct f2fs_attr *a,
> > @@ -1016,7 +1025,7 @@ static ssize_t f2fs_sb_feature_show(struct f2fs_attr *a,
> >   F2FS_GENERAL_RO_ATTR(encoding);
> >   F2FS_GENERAL_RO_ATTR(mounted_time_sec);
> >   F2FS_GENERAL_RO_ATTR(main_blkaddr);
> > -F2FS_GENERAL_RO_ATTR(pending_discard);
> > +F2FS_GENERAL_RO_ATTR(discard_stat);
>
> It needs to adjust Documentation/ABI/testing/sysfs-fs-f2fs.
>
> Thanks,
>
> >   F2FS_GENERAL_RO_ATTR(gc_mode);
> >   #ifdef CONFIG_F2FS_STAT_FS
> >   F2FS_GENERAL_RO_ATTR(moved_blocks_background);
> > @@ -1074,7 +1083,7 @@ static ssize_t f2fs_sb_feature_show(struct f2fs_attr *a,
> >       ATTR_LIST(discard_urgent_util),
> >       ATTR_LIST(discard_granularity),
> >       ATTR_LIST(max_ordered_discard),
> > -     ATTR_LIST(pending_discard),
> > +     ATTR_LIST(discard_stat),
> >       ATTR_LIST(gc_mode),
> >       ATTR_LIST(ipu_policy),
> >       ATTR_LIST(min_ipu_util),