Re: [f2fs-dev] [PATCH] mkfs.f2fs: update allocation policy for ro feature

[Chao Yu <chao@kernel.org>]

On 2022/10/1 6:33, Jaegeuk Kim wrote:
> On 09/30, Chao Yu wrote:
>> On 2022/9/30 2:27, Jaegeuk Kim wrote:
>>> On 09/28, Chao Yu wrote:
>>>> On 2022/9/28 11:15, Jaegeuk Kim wrote:
>>>>> On 09/28, Chao Yu wrote:
>>>>>> On 2022/9/28 0:40, Jaegeuk Kim wrote:
>>>>>>> On 09/25, Chao Yu wrote:
>>>>>>>> Update allocation policy for ro feature:
>>>>>>>> - hot_data: allocating blocks by LBA ascending order
>>>>>>>> - hot_node: allocating blocks by LBA descending order
>>>>>>>
>>>>>>> This will increase the RO image size.
>>>>>>
>>>>>> Shouldn't RO image has fixed-size during mkfs?
>>>>>
>>>>> First run gives the reduced size information, and second round makes the image
>>>>> with the required size.
>>>>
>>>> I didn't get it, in which step it may increase the RO image size?
>>>>
>>>> IIUC, after we apply this patch, reduced size information won't change due
>>>> to that after sload in first run, total used block count should be fixed?
>>>
>>> First run fills the data and leaves the maximum LBA touched in the image. Then,
>>
>> How about caclulating required size w/ total used blocks rather than maximum LBA?
> 
> Do you think that can give the smallest size for the image?

I guess so, but let me do some tests to check that.

Segments for data block and node block should be calculated separately:
required_blks = roundup(data_blks, blks_per_seg) + roundup(node_blks, blks_per_seg)

Am I missing something?

Thanks,

> 
>>
>> Thanks,
>>
>>> it'll resize the image file and run again with the smallest image.
>>>
>>>>
>>>> Thanks,
>>>>
>>>>>
>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> Signed-off-by: Chao Yu <chao@kernel.org>
>>>>>>>> ---
>>>>>>>>      mkfs/f2fs_format.c | 4 ++--
>>>>>>>>      1 file changed, 2 insertions(+), 2 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c
>>>>>>>> index 40ac589..8d0f410 100644
>>>>>>>> --- a/mkfs/f2fs_format.c
>>>>>>>> +++ b/mkfs/f2fs_format.c
>>>>>>>> @@ -544,10 +544,10 @@ static int f2fs_prepare_super_block(void)
>>>>>>>>      	}
>>>>>>>>      	if (c.feature & cpu_to_le32(F2FS_FEATURE_RO)) {
>>>>>>>> -		c.cur_seg[CURSEG_HOT_NODE] = 0;
>>>>>>>> +		c.cur_seg[CURSEG_HOT_NODE] = last_section(last_zone(total_zones));
>>>>>>>>      		c.cur_seg[CURSEG_WARM_NODE] = 0;
>>>>>>>>      		c.cur_seg[CURSEG_COLD_NODE] = 0;
>>>>>>>> -		c.cur_seg[CURSEG_HOT_DATA] = 1;
>>>>>>>> +		c.cur_seg[CURSEG_HOT_DATA] = 0;
>>>>>>>>      		c.cur_seg[CURSEG_COLD_DATA] = 0;
>>>>>>>>      		c.cur_seg[CURSEG_WARM_DATA] = 0;
>>>>>>>>      	} else if (c.heap) {
>>>>>>>> -- 
>>>>>>>> 2.36.1


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