linux-kernel - Re: [PATCH] f2fs: enable atgc if atgc_age_threshold from user is less than elapsed

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Date: Thu, 30 May 2024 17:49:30 +0800
From: Zhiguo Niu <niuzhiguo84@...il.com>
To: Chao Yu <chao@...nel.org>
Cc: Zhiguo Niu <zhiguo.niu@...soc.com>, jaegeuk@...nel.org, 
	linux-f2fs-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org, 
	ke.wang@...soc.com
Subject: Re: [PATCH] f2fs: enable atgc if atgc_age_threshold from user is less
 than elapsed_time

On Mon, May 27, 2024 at 12:07 PM Zhiguo Niu <niuzhiguo84@...il.com> wrote:
>
> On Mon, May 27, 2024 at 11:49 AM Chao Yu <chao@...nel.org> wrote:
> >
> > 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 can
> > > not work even the above conditions met.
> >
> > Zhiguo, I didn't get it, can you please explain more about this issue?
> >
> > Thanks,
> Hi Chao,
>
> At present, the point of atgc enale is checked during the mount
> process. What I mean is that if a device has not been rebooted
> (re-mounted) for a long time, even if the above two conditions are
> met(ATGC mount option is set, and the device has been powered on long
> enough， more than atgc default threshold ), atgc cannot be dynamically
> enabled.
>
> If the user is used to not restarting the phone after turning it on,
> it will be difficult to use atgc.
> thanks!
Hi Chao,
Do you have any suggestions or comments on this?
thanks！

> >
> > >
> > > It is better to enable atgc dynamiclly when user change atgc_age_threshold
> > > meanwhile this vale is less than elapsed_time and ATGC mount option is on.
> > >
> > > Signed-off-by: Zhiguo Niu <zhiguo.niu@...soc.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, unsigned int end);
> > >   int f2fs_allocate_new_section(struct f2fs_sb_info *sbi, int type, 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 = CURSEG_I(sbi, CURSEG_ALL_DATA_ATGC);
> > >       int ret = 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 f2fs_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 = t;
> > > +             if (sbi->am.atgc_enabled)
> > > +                     return count;
> > > +
> > > +             if (test_opt(sbi, ATGC) &&
> > > +                     le64_to_cpu(sbi->ckpt->elapsed_time) >= t) {
> > > +                     if (f2fs_init_atgc_curseg(sbi))
> > > +                             return -EINVAL;
> > > +                     sbi->am.atgc_enabled = true;
> > > +             }
> > > +             return count;
> > > +     }
> > > +
> > >       if (!strcmp(a->attr.name, "gc_segment_mode")) {
> > >               if (t < MAX_GC_MODE)
> > >                       sbi->gc_segment_mode = t;