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Subject: Re: [f2fs-dev] [PATCH v2] f2fs: add sysfs nodes to get GC info for
 each GC mode
To:     Daeho Jeong <daeho43@gmail.com>,
        Daeho Jeong <daehojeong@google.com>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com
References: <20210709204430.1293298-1-daeho43@gmail.com>
From:   Chao Yu <chao@kernel.org>
Message-ID: <4f88fac8-2838-45ac-8f87-789b8b7c2d09@kernel.org>
Date:   Sat, 10 Jul 2021 08:17:02 +0800
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On 2021/7/10 4:44, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@google.com>
> 
> Added gc_dirty_segs and gc_dirty_segs_mode sysfs nodes.
> 1) "gc_dirty_segs" shows how many dirty segments have been
> reclaimed by GC during a specific GC mode.
> 2) "gc_dirty_segs_mode" is used to control for which gc mode
> the "gc_dirty_segs" node shows.
> 
> Signed-off-by: Daeho Jeong <daehojeong@google.com>
> ---
>   Documentation/ABI/testing/sysfs-fs-f2fs | 14 +++++++++++++
>   fs/f2fs/debug.c                         |  9 ++++++++
>   fs/f2fs/f2fs.h                          |  5 +++++
>   fs/f2fs/gc.c                            |  1 +
>   fs/f2fs/sysfs.c                         | 28 +++++++++++++++++++++++++
>   5 files changed, 57 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
> index 95155e4ec7fe..0d863eb185f6 100644
> --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> @@ -493,3 +493,17 @@ Contact:	"Chao Yu" <yuchao0@huawei.com>
>   Description:	When ATGC is on, it controls age threshold to bypass GCing young
>   		candidates whose age is not beyond the threshold, by default it was
>   		initialized as 604800 seconds (equals to 7 days).
> +
> +What:		/sys/fs/f2fs/<disk>/gc_dirty_segs

How about renaming gc_dirty_segs to gc_reclaimed_segments?

> +Date:		July 2021
> +Contact:	"Daeho Jeong" <daehojeong@google.com>
> +Description:	Show how many dirty segments have been reclaimed by GC during
> +		a specific GC mode (0: GC normal, 1: GC idle CB, 2: GC idle greedy,
> +		3: gc idle AT, 4: GC urgent high, 5: GC urgent low)

3. GC idle AT

> +		You can re-initialize this value to "0".
> +
> +What:		/sys/fs/f2fs/<disk>/gc_dirty_segs_mode

You know, F2FS_IOC_FLUSH_DEVICE/F2FS_IOC_RESIZE_FS needs to migrate all
blocks of target segment to other place, no matter the segment has partially
or fully valid blocks, so it looks 'gc_segment_mode' will be more appropriate?

Thanks,