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

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Date: Fri, 31 May 2024 10:04:39 +0800
From: Chao Yu <chao@...nel.org>
To: Zhiguo Niu <niuzhiguo84@...il.com>
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 2024/5/30 17:49, Zhiguo Niu wrote:
> 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?

Zhiguo,

I remember that atgc can not be enabled at runtime due to some reasons, but
I need some time to recall and check the details...

Thanks,

> 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;