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From: Zhiguo Niu <niuzhiguo84@gmail.com>
Date: Wed, 5 Jun 2024 15:14:58 +0800
Message-ID: <CAHJ8P3K-LOMDU0udwXj__qRpozNmv2tvvA4BRdktcOaK4OB7Bw@mail.gmail.com>
Subject: Re: [PATCH] f2fs: enable atgc if atgc_age_threshold from user is less
 than elapsed_time
To: Chao Yu <chao@kernel.org>
Cc: Zhiguo Niu <zhiguo.niu@unisoc.com>, jaegeuk@kernel.org, 
	linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, 
	ke.wang@unisoc.com
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On Wed, Jun 5, 2024 at 2:26=E2=80=AFPM Chao Yu <chao@kernel.org> wrote:
>
> On 2024/6/5 13:59, Zhiguo Niu wrote:
> > On Wed, Jun 5, 2024 at 11:48=E2=80=AFAM Chao Yu <chao@kernel.org> wrote=
:
> >>
> >> On 2024/6/3 17:05, Zhiguo Niu wrote:
> >>> On Mon, Jun 3, 2024 at 3:41=E2=80=AFPM Chao Yu <chao@kernel.org> wrot=
e:
> >>>>
> >>>> On 2024/5/20 19:36, Zhiguo Niu wrote:
> >>>>> Now atgc can be enabled based on the following conditions:
> >>>>> -ATGC mount option is set
> >>>>> -elapsed_time is more than atgc_age_threshold already
> >>>>> but these conditions are check when umounted->mounted device again.
> >>>>> If the device has not be umounted->mounted for a long time, atgc ca=
n
> >>>>> not work even the above conditions met.
> >>>>>
> >>>>> It is better to enable atgc dynamiclly when user change atgc_age_th=
reshold
> >>>>> meanwhile this vale is less than elapsed_time and ATGC mount option=
 is on.
> >>>>>
> >>>>> Signed-off-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
> >>>>> ---
> >>>>>     fs/f2fs/f2fs.h    |  1 +
> >>>>>     fs/f2fs/segment.c |  9 ++++-----
> >>>>>     fs/f2fs/sysfs.c   | 16 ++++++++++++++++
> >>>>>     3 files changed, 21 insertions(+), 5 deletions(-)
> >>>>>
> >>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> >>>>> index 1974b6a..e441d2d 100644
> >>>>> --- a/fs/f2fs/f2fs.h
> >>>>> +++ b/fs/f2fs/f2fs.h
> >>>>> @@ -3694,6 +3694,7 @@ void f2fs_clear_prefree_segments(struct f2fs_=
sb_info *sbi,
> >>>>>     int f2fs_init_inmem_curseg(struct f2fs_sb_info *sbi);
> >>>>>     void f2fs_save_inmem_curseg(struct f2fs_sb_info *sbi);
> >>>>>     void f2fs_restore_inmem_curseg(struct f2fs_sb_info *sbi);
> >>>>> +int f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi);
> >>>>>     int f2fs_allocate_segment_for_resize(struct f2fs_sb_info *sbi, =
int type,
> >>>>>                                         unsigned int start, unsigne=
d int end);
> >>>>>     int f2fs_allocate_new_section(struct f2fs_sb_info *sbi, int typ=
e, bool force);
> >>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> >>>>> index 71dc8042..44923d4 100644
> >>>>> --- a/fs/f2fs/segment.c
> >>>>> +++ b/fs/f2fs/segment.c
> >>>>> @@ -2931,14 +2931,11 @@ static int get_atssr_segment(struct f2fs_sb=
_info *sbi, int type,
> >>>>>         return ret;
> >>>>>     }
> >>>>>
> >>>>> -static int __f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi)
> >>>>> +int f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi)
> >>>>>     {
> >>>>>         struct curseg_info *curseg =3D CURSEG_I(sbi, CURSEG_ALL_DAT=
A_ATGC);
> >>>>>         int ret =3D 0;
> >>>>>
> >>>>> -     if (!sbi->am.atgc_enabled)
> >>>>> -             return 0;
> >>>>> -
> >>>>>         f2fs_down_read(&SM_I(sbi)->curseg_lock);
> >>>>>
> >>>>>         mutex_lock(&curseg->curseg_mutex);
> >>>>> @@ -2955,7 +2952,9 @@ static int __f2fs_init_atgc_curseg(struct f2f=
s_sb_info *sbi)
> >>>>>     }
> >>>>>     int f2fs_init_inmem_curseg(struct f2fs_sb_info *sbi)
> >>>>>     {
> >>>>> -     return __f2fs_init_atgc_curseg(sbi);
> >>>>> +     if (!sbi->am.atgc_enabled)
> >>>>> +             return 0;
> >>>>> +     return f2fs_init_atgc_curseg(sbi);
> >>>>>     }
> >>>>>
> >>>>>     static void __f2fs_save_inmem_curseg(struct f2fs_sb_info *sbi, =
int type)
> >>>>> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> >>>>> index 09d3ecf..72676c5 100644
> >>>>> --- a/fs/f2fs/sysfs.c
> >>>>> +++ b/fs/f2fs/sysfs.c
> >>>>> @@ -673,6 +673,22 @@ static ssize_t __sbi_store(struct f2fs_attr *a=
,
> >>>>>                 return count;
> >>>>>         }
> >>>>>
> >>>>> +     if (!strcmp(a->attr.name, "atgc_age_threshold")) {
> >>>>> +             if (t < 0)
> >>>>> +                     return -EINVAL;
> >>>>> +             sbi->am.age_threshold =3D t;
> >>>>> +             if (sbi->am.atgc_enabled)
> >>>>> +                     return count;
> >>>>> +
> >>>>> +             if (test_opt(sbi, ATGC) &&
> >>>>> +                     le64_to_cpu(sbi->ckpt->elapsed_time) >=3D t) =
{
> >>>>
> >>> Hi Chao,
> >>>> Oh, I guess you want to fix this:
> >>> Yes,  Sorry for not making it clear before.
> >>>>
> >>>> static void init_atgc_management(struct f2fs_sb_info *sbi)
> >>>> {
> >>>> ...
> >>>>           if (test_opt(sbi, ATGC) &&
> >>>>                   SIT_I(sbi)->elapsed_time >=3D DEF_GC_THREAD_AGE_TH=
RESHOLD)
> >>>>                   am->atgc_enabled =3D true;
> >>>>
> >>>> What about enabling atgc_enabled during checkpoint once elapsed time=
 is
> >>>> satisfed w/ the condition? I guess this can give another chance when=
ever
> >>>> CP is been triggered, and it can avoid the racing condition as well.
> >>> 1. I'm not sure if this will increase checkpoint time consumption?
> >>
> >> Since it won't increase any IO time, I guess it's fine tolerate time c=
onsumed
> >> by initialization of atgc curseg.
> >>
> >>> 2. dynamically enabling atgc may have other problems. Is this confirm=
ed?
> >>
> >> I think so, checkpoint has avoided most race cases.
> >>
> >> So, how do you think of below diff:
> > Hi Chao,
> >   I think flow is ok,  some details need to be discussed.
> >>
> >> ---
> >>    fs/f2fs/checkpoint.c |  2 ++
> >>    fs/f2fs/f2fs.h       |  1 +
> >>    fs/f2fs/segment.c    | 26 +++++++++++++++++++++++---
> >>    3 files changed, 26 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> >> index 55d444bec5c0..4a73bd481a25 100644
> >> --- a/fs/f2fs/checkpoint.c
> >> +++ b/fs/f2fs/checkpoint.c
> >> @@ -1718,6 +1718,8 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *s=
bi, struct cp_control *cpc)
> >>          }
> >>
> >>          f2fs_restore_inmem_curseg(sbi);
> >> +       f2fs_reinit_atgc_curseg(sbi);
> >> +
> >>          stat_inc_cp_count(sbi);
> >>    stop:
> >>          unblock_operations(sbi);
> >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> >> index 9688df332147..8d385a1c75ad 100644
> >> --- a/fs/f2fs/f2fs.h
> >> +++ b/fs/f2fs/f2fs.h
> >> @@ -3693,6 +3693,7 @@ void f2fs_release_discard_addrs(struct f2fs_sb_i=
nfo *sbi);
> >>    int f2fs_npages_for_summary_flush(struct f2fs_sb_info *sbi, bool fo=
r_ra);
> >>    bool f2fs_segment_has_free_slot(struct f2fs_sb_info *sbi, int segno=
);
> >>    int f2fs_init_inmem_curseg(struct f2fs_sb_info *sbi);
> >> +int f2fs_reinit_atgc_curseg(struct f2fs_sb_info *sbi);
> >>    void f2fs_save_inmem_curseg(struct f2fs_sb_info *sbi);
> >>    void f2fs_restore_inmem_curseg(struct f2fs_sb_info *sbi);
> >>    int f2fs_allocate_segment_for_resize(struct f2fs_sb_info *sbi, int =
type,
> >> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> >> index bdc2247387e8..6d4273faf061 100644
> >> --- a/fs/f2fs/segment.c
> >> +++ b/fs/f2fs/segment.c
> >> @@ -2949,12 +2949,12 @@ static int get_atssr_segment(struct f2fs_sb_in=
fo *sbi, int type,
> >>          return ret;
> >>    }
> >>
> >> -static int __f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi)
> >> +static int __f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi, bool for=
ce)
> >>    {
> >>          struct curseg_info *curseg =3D CURSEG_I(sbi, CURSEG_ALL_DATA_=
ATGC);
> >>          int ret =3D 0;
> >>
> >> -       if (!sbi->am.atgc_enabled)
> >> +       if (!sbi->am.atgc_enabled && !force)
> > Is this parameter  "force" unnecessary?
> > in mount flow, even atgc enable conditions are all met, it is not
> > enabled because of force=3Dfalse.
> > Or am I missing something?
> >>                  return 0;
> >>
> >>          f2fs_down_read(&SM_I(sbi)->curseg_lock);
> >> @@ -2971,9 +2971,29 @@ static int __f2fs_init_atgc_curseg(struct f2fs_=
sb_info *sbi)
> >>          f2fs_up_read(&SM_I(sbi)->curseg_lock);
> >>          return ret;
> >>    }
> >> +
> >>    int f2fs_init_inmem_curseg(struct f2fs_sb_info *sbi)
> >>    {
> >> -       return __f2fs_init_atgc_curseg(sbi);
> >> +       return __f2fs_init_atgc_curseg(sbi, false);
> >> +}
> >> +
> >> +int f2fs_reinit_atgc_curseg(struct f2fs_sb_info *sbi)
> >> +{
> >> +       int ret;
> >> +
> >> +       if (!test_opt(sbi, ATGC))
> >> +               return 0;
> >> +       if (sbi->am.atgc_enabled)
> >> +               return 0;
> >> +       if (SIT_I(sbi)->elapsed_time < sbi->am.age_threshold)
> > SIT(sbi)->elapsed_time is just updated in mount flow, so
> > ckpt->elapsed_time is  more suitable here?
>
> Agreed, it needs to be fixed.
>
> Can you please update those changes into v2?
Hi Chao,
OK, and I will also verify the basic function.
thanks=EF=BC=81
>
> Thanks,
>
> > thanks!
> >> +               return 0;
> >> +
> >> +       ret =3D __f2fs_init_atgc_curseg(sbi, true);
> >> +       if (!ret) {
> >> +               sbi->am.atgc_enabled =3D true;
> >> +               f2fs_info(sbi, "reenabled age threshold GC");
> >> +       }
> >> +       return ret;
> >>    }
> >>
> >>    static void __f2fs_save_inmem_curseg(struct f2fs_sb_info *sbi, int =
type)
> >> --
> >> 2.40.1
> >>
> >>> thanks=EF=BC=81
> >>>>
> >>>> Thanks,
> >>>>
> >>>>> +                     if (f2fs_init_atgc_curseg(sbi))
> >>>>> +                             return -EINVAL;
> >>>>> +                     sbi->am.atgc_enabled =3D true;
> >>>>> +             }
> >>>>> +             return count;
> >>>>> +     }
> >>>>> +
> >>>>>         if (!strcmp(a->attr.name, "gc_segment_mode")) {
> >>>>>                 if (t < MAX_GC_MODE)
> >>>>>                         sbi->gc_segment_mode =3D t;