diff mbox

[3/3] f2fs: provide more chance for node and data to get ssr segment

Message ID 20170223011754.GH4003@jaegeuk.local (mailing list archive)
State New, archived
Headers show

Commit Message

Jaegeuk Kim Feb. 23, 2017, 1:17 a.m. UTC 
Hi Yunlong,

I've been testing the similar patches as I attached.

Thanks,

On 02/22, Yunlong Song wrote:
> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
> ---
>  fs/f2fs/segment.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 9d13743..5fe71b9 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1540,12 +1540,17 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>  {
>  	struct curseg_info *curseg = CURSEG_I(sbi, type);
>  	const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
> +	int old_type = type;
>  
>  	if (IS_NODESEG(type)) {
>  		for (; type >= CURSEG_HOT_NODE; type--)
>  			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>  							BG_GC, type, SSR))
>  				return 1;
> +		for (type = old_type + 1; type <= CURSEG_COLD_NODE; type++)
> +			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
> +							BG_GC, type, SSR))
> +				return 1;
>  		return 0;
>  	}
>  
> @@ -1554,6 +1559,10 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>  		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>  						BG_GC, type, SSR))
>  			return 1;
> +	for (type = old_type + 1; type <= CURSEG_COLD_DATA; type++)
> +		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
> +						BG_GC, type, SSR))
> +			return 1;
>  	return 0;
>  }
>  
> -- 
> 1.8.5.2
From 92b42757ca01d6c03c4af7bb6e169855605c59ae Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Wed, 22 Feb 2017 17:10:18 -0800
Subject: [PATCH 1/2] f2fs: find data segments across all the types

Previously, if type is CURSEG_HOT_DATA, we only check CURSEG_HOT_DATA only.
This patch fixes to search all the different types for SSR.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/segment.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

Comments

Yunlong Song Feb. 23, 2017, 2:13 a.m. UTC | #1 
Hi Jay,
    But there are some differences:
1 Why not take "neighboring temperature" for ssr? For example, if type == CURSEG_COLD_DATA,
    your new patch selects CURSEG_HOT_DATA first, how about select CURSEG_WARM_DATA first?
    The patch I sent ensure this "neighboring temperature" for ssr.
2 Your new patch returns 0 for node ssr, does get_ssr_segment work only for data?
3 I see your new patch just "continue" when i == type, why not consider the current type?

On 2017/2/23 9:17, Jaegeuk Kim wrote:
> Hi Yunlong,
>
> I've been testing the similar patches as I attached.
>
> Thanks,
>
> On 02/22, Yunlong Song wrote:
>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
>> ---
>>  fs/f2fs/segment.c | 9 +++++++++
>>  1 file changed, 9 insertions(+)
>>
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index 9d13743..5fe71b9 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -1540,12 +1540,17 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>  {
>>  	struct curseg_info *curseg = CURSEG_I(sbi, type);
>>  	const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
>> +	int old_type = type;
>>  
>>  	if (IS_NODESEG(type)) {
>>  		for (; type >= CURSEG_HOT_NODE; type--)
>>  			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>  							BG_GC, type, SSR))
>>  				return 1;
>> +		for (type = old_type + 1; type <= CURSEG_COLD_NODE; type++)
>> +			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>> +							BG_GC, type, SSR))
>> +				return 1;
>>  		return 0;
>>  	}
>>  
>> @@ -1554,6 +1559,10 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>  		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>  						BG_GC, type, SSR))
>>  			return 1;
>> +	for (type = old_type + 1; type <= CURSEG_COLD_DATA; type++)
>> +		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>> +						BG_GC, type, SSR))
>> +			return 1;
>>  	return 0;
>>  }
>>  
>> -- 
>> 1.8.5.2
Yunlong Song Feb. 23, 2017, 2:41 a.m. UTC | #2 
Hi Jay,
    I miss some codes from your mail, now I check all your patch codes and make clear with question 2 and 3, it's fine.

    But still, how about question 1?

On 2017/2/23 10:13, Yunlong Song wrote:
> Hi Jay,
>     But there are some differences:
> 1 Why not take "neighboring temperature" for ssr? For example, if type == CURSEG_COLD_DATA,
>     your new patch selects CURSEG_HOT_DATA first, how about select CURSEG_WARM_DATA first?
>     The patch I sent ensure this "neighboring temperature" for ssr.
> 2 Your new patch returns 0 for node ssr, does get_ssr_segment work only for data?
> 3 I see your new patch just "continue" when i == type, why not consider the current type?
>
> On 2017/2/23 9:17, Jaegeuk Kim wrote:
>> Hi Yunlong,
>>
>> I've been testing the similar patches as I attached.
>>
>> Thanks,
>>
>> On 02/22, Yunlong Song wrote:
>>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
>>> ---
>>>  fs/f2fs/segment.c | 9 +++++++++
>>>  1 file changed, 9 insertions(+)
>>>
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 9d13743..5fe71b9 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -1540,12 +1540,17 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>>  {
>>>  	struct curseg_info *curseg = CURSEG_I(sbi, type);
>>>  	const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
>>> +	int old_type = type;
>>>  
>>>  	if (IS_NODESEG(type)) {
>>>  		for (; type >= CURSEG_HOT_NODE; type--)
>>>  			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>  							BG_GC, type, SSR))
>>>  				return 1;
>>> +		for (type = old_type + 1; type <= CURSEG_COLD_NODE; type++)
>>> +			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>> +							BG_GC, type, SSR))
>>> +				return 1;
>>>  		return 0;
>>>  	}
>>>  
>>> @@ -1554,6 +1559,10 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>>  		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>  						BG_GC, type, SSR))
>>>  			return 1;
>>> +	for (type = old_type + 1; type <= CURSEG_COLD_DATA; type++)
>>> +		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>> +						BG_GC, type, SSR))
>>> +			return 1;
>>>  	return 0;
>>>  }
>>>  
>>> -- 
>>> 1.8.5.2
>
Chao Yu Feb. 24, 2017, 9:05 a.m. UTC | #3 
Hi Jaegeuk,

Reviewed-by: Chao Yu <yuchao0@huawei.com>

For your attached two patches.

Thanks,

On 2017/2/23 9:17, Jaegeuk Kim wrote:
> Hi Yunlong,
> 
> I've been testing the similar patches as I attached.
> 
> Thanks,
> 
> On 02/22, Yunlong Song wrote:
>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
>> ---
>>  fs/f2fs/segment.c | 9 +++++++++
>>  1 file changed, 9 insertions(+)
>>
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index 9d13743..5fe71b9 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -1540,12 +1540,17 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>  {
>>  	struct curseg_info *curseg = CURSEG_I(sbi, type);
>>  	const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
>> +	int old_type = type;
>>  
>>  	if (IS_NODESEG(type)) {
>>  		for (; type >= CURSEG_HOT_NODE; type--)
>>  			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>  							BG_GC, type, SSR))
>>  				return 1;
>> +		for (type = old_type + 1; type <= CURSEG_COLD_NODE; type++)
>> +			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>> +							BG_GC, type, SSR))
>> +				return 1;
>>  		return 0;
>>  	}
>>  
>> @@ -1554,6 +1559,10 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>  		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>  						BG_GC, type, SSR))
>>  			return 1;
>> +	for (type = old_type + 1; type <= CURSEG_COLD_DATA; type++)
>> +		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>> +						BG_GC, type, SSR))
>> +			return 1;
>>  	return 0;
>>  }
>>  
>> -- 
>> 1.8.5.2
Yunlong Song Feb. 24, 2017, 9:19 a.m. UTC | #4 
Hi Jaegeuk and Chao,

    How about the question I pointed out in last mail:
    Why not take "neighboring temperature" for ssr? For example, if type == CURSEG_COLD_DATA,
    the new patch selects CURSEG_HOT_DATA first, why not select CURSEG_WARM_DATA first?
    The patch I sent ensure this "neighboring temperature" for ssr. This is to reduce the influence of
    mixing different levels of hot/code node types.

On 2017/2/24 17:05, Chao Yu wrote:
> Hi Jaegeuk,
>
> Reviewed-by: Chao Yu <yuchao0@huawei.com>
>
> For your attached two patches.
>
> Thanks,
>
> On 2017/2/23 9:17, Jaegeuk Kim wrote:
>> Hi Yunlong,
>>
>> I've been testing the similar patches as I attached.
>>
>> Thanks,
>>
>> On 02/22, Yunlong Song wrote:
>>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
>>> ---
>>>  fs/f2fs/segment.c | 9 +++++++++
>>>  1 file changed, 9 insertions(+)
>>>
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 9d13743..5fe71b9 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -1540,12 +1540,17 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>>  {
>>>  	struct curseg_info *curseg = CURSEG_I(sbi, type);
>>>  	const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
>>> +	int old_type = type;
>>>  
>>>  	if (IS_NODESEG(type)) {
>>>  		for (; type >= CURSEG_HOT_NODE; type--)
>>>  			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>  							BG_GC, type, SSR))
>>>  				return 1;
>>> +		for (type = old_type + 1; type <= CURSEG_COLD_NODE; type++)
>>> +			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>> +							BG_GC, type, SSR))
>>> +				return 1;
>>>  		return 0;
>>>  	}
>>>  
>>> @@ -1554,6 +1559,10 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>>  		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>  						BG_GC, type, SSR))
>>>  			return 1;
>>> +	for (type = old_type + 1; type <= CURSEG_COLD_DATA; type++)
>>> +		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>> +						BG_GC, type, SSR))
>>> +			return 1;
>>>  	return 0;
>>>  }
>>>  
>>> -- 
>>> 1.8.5.2
>
> .
>
Chao Yu Feb. 24, 2017, 10:47 a.m. UTC | #5 
On 2017/2/24 17:19, Yunlong Song wrote:
> Hi Jaegeuk and Chao,
> 
>     How about the question I pointed out in last mail:
>     Why not take "neighboring temperature" for ssr? For example, if type == CURSEG_COLD_DATA,
>     the new patch selects CURSEG_HOT_DATA first, why not select CURSEG_WARM_DATA first?
>     The patch I sent ensure this "neighboring temperature" for ssr. This is to reduce the influence of
>     mixing different levels of hot/code node types.

Agreed, I sent one patch for changing the policy of SSR, how do you think of it?

Thanks,

> 
> On 2017/2/24 17:05, Chao Yu wrote:
>> Hi Jaegeuk,
>>
>> Reviewed-by: Chao Yu <yuchao0@huawei.com>
>>
>> For your attached two patches.
>>
>> Thanks,
>>
>> On 2017/2/23 9:17, Jaegeuk Kim wrote:
>>> Hi Yunlong,
>>>
>>> I've been testing the similar patches as I attached.
>>>
>>> Thanks,
>>>
>>> On 02/22, Yunlong Song wrote:
>>>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
>>>> ---
>>>>  fs/f2fs/segment.c | 9 +++++++++
>>>>  1 file changed, 9 insertions(+)
>>>>
>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>>> index 9d13743..5fe71b9 100644
>>>> --- a/fs/f2fs/segment.c
>>>> +++ b/fs/f2fs/segment.c
>>>> @@ -1540,12 +1540,17 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>>>  {
>>>>  	struct curseg_info *curseg = CURSEG_I(sbi, type);
>>>>  	const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
>>>> +	int old_type = type;
>>>>  
>>>>  	if (IS_NODESEG(type)) {
>>>>  		for (; type >= CURSEG_HOT_NODE; type--)
>>>>  			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>>  							BG_GC, type, SSR))
>>>>  				return 1;
>>>> +		for (type = old_type + 1; type <= CURSEG_COLD_NODE; type++)
>>>> +			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>> +							BG_GC, type, SSR))
>>>> +				return 1;
>>>>  		return 0;
>>>>  	}
>>>>  
>>>> @@ -1554,6 +1559,10 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>>>  		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>>  						BG_GC, type, SSR))
>>>>  			return 1;
>>>> +	for (type = old_type + 1; type <= CURSEG_COLD_DATA; type++)
>>>> +		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>> +						BG_GC, type, SSR))
>>>> +			return 1;
>>>>  	return 0;
>>>>  }
>>>>  
>>>> -- 
>>>> 1.8.5.2
>>
>> .
>>
> 
>
Yunlong Song Feb. 24, 2017, 11:41 a.m. UTC | #6 
Hi, Chao,

Not looks good to me, since there is some case your code does not include:
if type is CURSEG_HOT_DATA, and if get_victim also returns 0 for both CURSEG_HOT_DATA and
CURSEG_WARM_DATA, then i will be -1 and pass to get_victim in your code.  So I still suggest
my original patch attached below.

On 2017/2/24 18:47, Chao Yu wrote:
> On 2017/2/24 17:19, Yunlong Song wrote:
>> Hi Jaegeuk and Chao,
>>
>>     How about the question I pointed out in last mail:
>>     Why not take "neighboring temperature" for ssr? For example, if type == CURSEG_COLD_DATA,
>>     the new patch selects CURSEG_HOT_DATA first, why not select CURSEG_WARM_DATA first?
>>     The patch I sent ensure this "neighboring temperature" for ssr. This is to reduce the influence of
>>     mixing different levels of hot/code node types.
> Agreed, I sent one patch for changing the policy of SSR, how do you think of it?
>
> Thanks,
>
>> On 2017/2/24 17:05, Chao Yu wrote:
>>> Hi Jaegeuk,
>>>
>>> Reviewed-by: Chao Yu <yuchao0@huawei.com>
>>>
>>> For your attached two patches.
>>>
>>> Thanks,
>>>
>>> On 2017/2/23 9:17, Jaegeuk Kim wrote:
>>>> Hi Yunlong,
>>>>
>>>> I've been testing the similar patches as I attached.
>>>>
>>>> Thanks,
>>>>
>>>> On 02/22, Yunlong Song wrote:
>>>>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
>>>>> ---
>>>>>  fs/f2fs/segment.c | 9 +++++++++
>>>>>  1 file changed, 9 insertions(+)
>>>>>
>>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>>>> index 9d13743..5fe71b9 100644
>>>>> --- a/fs/f2fs/segment.c
>>>>> +++ b/fs/f2fs/segment.c
>>>>> @@ -1540,12 +1540,17 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>>>>  {
>>>>>  	struct curseg_info *curseg = CURSEG_I(sbi, type);
>>>>>  	const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
>>>>> +	int old_type = type;
>>>>>  
>>>>>  	if (IS_NODESEG(type)) {
>>>>>  		for (; type >= CURSEG_HOT_NODE; type--)
>>>>>  			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>>>  							BG_GC, type, SSR))
>>>>>  				return 1;
>>>>> +		for (type = old_type + 1; type <= CURSEG_COLD_NODE; type++)
>>>>> +			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>>> +							BG_GC, type, SSR))
>>>>> +				return 1;
>>>>>  		return 0;
>>>>>  	}
>>>>>  
>>>>> @@ -1554,6 +1559,10 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>>>>  		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>>>  						BG_GC, type, SSR))
>>>>>  			return 1;
>>>>> +	for (type = old_type + 1; type <= CURSEG_COLD_DATA; type++)
>>>>> +		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>>> +						BG_GC, type, SSR))
>>>>> +			return 1;
>>>>>  	return 0;
>>>>>  }
>>>>>  
>>>>> -- 
>>>>> 1.8.5.2
>>> .
>>>
>>
>
> .
>
Jaegeuk Kim Feb. 24, 2017, 5:58 p.m. UTC | #7 
On 02/24, Yunlong Song wrote:
> Hi, Chao,
> 
> Not looks good to me, since there is some case your code does not include:
> if type is CURSEG_HOT_DATA, and if get_victim also returns 0 for both CURSEG_HOT_DATA and
> CURSEG_WARM_DATA, then i will be -1 and pass to get_victim in your code.  So I still suggest
> my original patch attached below.

Why does i become -1?

> 
> On 2017/2/24 18:47, Chao Yu wrote:
> > On 2017/2/24 17:19, Yunlong Song wrote:
> >> Hi Jaegeuk and Chao,
> >>
> >>     How about the question I pointed out in last mail:
> >>     Why not take "neighboring temperature" for ssr? For example, if type == CURSEG_COLD_DATA,
> >>     the new patch selects CURSEG_HOT_DATA first, why not select CURSEG_WARM_DATA first?
> >>     The patch I sent ensure this "neighboring temperature" for ssr. This is to reduce the influence of
> >>     mixing different levels of hot/code node types.
> > Agreed, I sent one patch for changing the policy of SSR, how do you think of it?
> >
> > Thanks,
> >
> >> On 2017/2/24 17:05, Chao Yu wrote:
> >>> Hi Jaegeuk,
> >>>
> >>> Reviewed-by: Chao Yu <yuchao0@huawei.com>
> >>>
> >>> For your attached two patches.
> >>>
> >>> Thanks,
> >>>
> >>> On 2017/2/23 9:17, Jaegeuk Kim wrote:
> >>>> Hi Yunlong,
> >>>>
> >>>> I've been testing the similar patches as I attached.
> >>>>
> >>>> Thanks,
> >>>>
> >>>> On 02/22, Yunlong Song wrote:
> >>>>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
> >>>>> ---
> >>>>>  fs/f2fs/segment.c | 9 +++++++++
> >>>>>  1 file changed, 9 insertions(+)
> >>>>>
> >>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> >>>>> index 9d13743..5fe71b9 100644
> >>>>> --- a/fs/f2fs/segment.c
> >>>>> +++ b/fs/f2fs/segment.c
> >>>>> @@ -1540,12 +1540,17 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
> >>>>>  {
> >>>>>  	struct curseg_info *curseg = CURSEG_I(sbi, type);
> >>>>>  	const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
> >>>>> +	int old_type = type;
> >>>>>  
> >>>>>  	if (IS_NODESEG(type)) {
> >>>>>  		for (; type >= CURSEG_HOT_NODE; type--)
> >>>>>  			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
> >>>>>  							BG_GC, type, SSR))
> >>>>>  				return 1;
> >>>>> +		for (type = old_type + 1; type <= CURSEG_COLD_NODE; type++)
> >>>>> +			if (v_ops->get_victim(sbi, &(curseg)->next_segno,
> >>>>> +							BG_GC, type, SSR))
> >>>>> +				return 1;
> >>>>>  		return 0;
> >>>>>  	}
> >>>>>  
> >>>>> @@ -1554,6 +1559,10 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
> >>>>>  		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
> >>>>>  						BG_GC, type, SSR))
> >>>>>  			return 1;
> >>>>> +	for (type = old_type + 1; type <= CURSEG_COLD_DATA; type++)
> >>>>> +		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
> >>>>> +						BG_GC, type, SSR))
> >>>>> +			return 1;
> >>>>>  	return 0;
> >>>>>  }
> >>>>>  
> >>>>> -- 
> >>>>> 1.8.5.2
> >>> .
> >>>
> >>
> >
> > .
> >
> 
> 
> -- 
> Thanks,
> Yunlong Song
>
Jaegeuk Kim Feb. 24, 2017, 8:05 p.m. UTC | #8 
On 02/25, Yunlong Song wrote:
> Hi，Jaegeuk and Chao,
>     Sorry，I misunderstood CURSEG_HOT_DATA is greater than CURSEG_WARM_DATA and use "i--" in the codes, so just forget that.
>     But there is still a issue, when type is CURSEG_WARM_DATA, chao's patch will select cold SSR segment first, but my patch will select hot SSR segment first, since I think the probability of having hot SSR segment is bigger than having cold SSR segment due to the temperature itself.

One thing that I'm seeing is, theoretically hot segments will get dirty more
frequently. So if we select dirty cold segments for warm data, we can gain
fully valid cold segments more, which can mitigate log thrashing problem.

Thanks,

> 
> 
> On 02/25/2017 01:58, Jaegeuk Kim wrote:
> On 02/24, Yunlong Song wrote:
> > Hi, Chao,
> >
> > Not looks good to me, since there is some case your code does not include:
> > if type is CURSEG_HOT_DATA, and if get_victim also returns 0 for both CURSEG_HOT_DATA and
> > CURSEG_WARM_DATA, then i will be -1 and pass to get_victim in your code.  So I still suggest
> > my original patch attached below.
> 
> Why does i become -1?
> 
> >
> > On 2017/2/24 18:47, Chao Yu wrote:
> > > On 2017/2/24 17:19, Yunlong Song wrote:
> > >> Hi Jaegeuk and Chao,
> > >>
> > >>     How about the question I pointed out in last mail:
> > >>     Why not take "neighboring temperature" for ssr? For example, if type == CURSEG_COLD_DATA,
> > >>     the new patch selects CURSEG_HOT_DATA first, why not select CURSEG_WARM_DATA first?
> > >>     The patch I sent ensure this "neighboring temperature" for ssr. This is to reduce the influence of
> > >>     mixing different levels of hot/code node types.
> > > Agreed, I sent one patch for changing the policy of SSR, how do you think of it?
> > >
> > > Thanks,
> > >
> > >> On 2017/2/24 17:05, Chao Yu wrote:
> > >>> Hi Jaegeuk,
> > >>>
> > >>> Reviewed-by: Chao Yu <yuchao0@huawei.com>
> > >>>
> > >>> For your attached two patches.
> > >>>
> > >>> Thanks,
> > >>>
> > >>> On 2017/2/23 9:17, Jaegeuk Kim wrote:
> > >>>> Hi Yunlong,
> > >>>>
> > >>>> I've been testing the similar patches as I attached.
> > >>>>
> > >>>> Thanks,
> > >>>>
> > >>>> On 02/22, Yunlong Song wrote:
> > >>>>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
> > >>>>> ---
> > >>>>>  fs/f2fs/segment.c | 9 +++++++++
> > >>>>>  1 file changed, 9 insertions(+)
> > >>>>>
> > >>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > >>>>> index 9d13743..5fe71b9 100644
> > >>>>> --- a/fs/f2fs/segment.c
> > >>>>> +++ b/fs/f2fs/segment.c
> > >>>>> @@ -1540,12 +1540,17 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
> > >>>>>  {
> > >>>>>      struct curseg_info *curseg = CURSEG_I(sbi, type);
> > >>>>>      const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
> > >>>>> +    int old_type = type;
> > >>>>>  
> > >>>>>      if (IS_NODESEG(type)) {
> > >>>>>          for (; type >= CURSEG_HOT_NODE; type--)
> > >>>>>              if (v_ops->get_victim(sbi, &(curseg)->next_segno,
> > >>>>>                              BG_GC, type, SSR))
> > >>>>>                  return 1;
> > >>>>> +        for (type = old_type + 1; type <= CURSEG_COLD_NODE; type++)
> > >>>>> +            if (v_ops->get_victim(sbi, &(curseg)->next_segno,
> > >>>>> +                            BG_GC, type, SSR))
> > >>>>> +                return 1;
> > >>>>>          return 0;
> > >>>>>      }
> > >>>>>  
> > >>>>> @@ -1554,6 +1559,10 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
> > >>>>>          if (v_ops->get_victim(sbi, &(curseg)->next_segno,
> > >>>>>                          BG_GC, type, SSR))
> > >>>>>              return 1;
> > >>>>> +    for (type = old_type + 1; type <= CURSEG_COLD_DATA; type++)
> > >>>>> +        if (v_ops->get_victim(sbi, &(curseg)->next_segno,
> > >>>>> +                        BG_GC, type, SSR))
> > >>>>> +            return 1;
> > >>>>>      return 0;
> > >>>>>  }
> > >>>>>  
> > >>>>> --
> > >>>>> 1.8.5.2
> > >>> .
> > >>>
> > >>
> > >
> > > .
> > >
> >
> >
> > --
> > Thanks,
> > Yunlong Song
> >
Yunlong Song Feb. 25, 2017, 2:16 a.m. UTC | #9 
The get_ssr_segment happens when need_SSR is true, that is to say we must make sure we can
achieve a right available SSR segment at least, so why not select the type with larger probability?
And I think warm and hot are more similar with each other, maybe the update frequency is difference,
but if time goes by, warm segments will finally update their blocks like hot segments, but cold segments
are something like which should and will never update, so I prefer to put hot and warm to one side,
and put cold to the other side.

On 2017/2/25 4:05, Jaegeuk Kim wrote:
> On 02/25, Yunlong Song wrote:
>> Hi，Jaegeuk and Chao,
>>     Sorry，I misunderstood CURSEG_HOT_DATA is greater than CURSEG_WARM_DATA and use "i--" in the codes, so just forget that.
>>     But there is still a issue, when type is CURSEG_WARM_DATA, chao's patch will select cold SSR segment first, but my patch will select hot SSR segment first, since I think the probability of having hot SSR segment is bigger than having cold SSR segment due to the temperature itself.
> One thing that I'm seeing is, theoretically hot segments will get dirty more
> frequently. So if we select dirty cold segments for warm data, we can gain
> fully valid cold segments more, which can mitigate log thrashing problem.
>
> Thanks,
>
>>
>> On 02/25/2017 01:58, Jaegeuk Kim wrote:
>> On 02/24, Yunlong Song wrote:
>>> Hi, Chao,
>>>
>>> Not looks good to me, since there is some case your code does not include:
>>> if type is CURSEG_HOT_DATA, and if get_victim also returns 0 for both CURSEG_HOT_DATA and
>>> CURSEG_WARM_DATA, then i will be -1 and pass to get_victim in your code.  So I still suggest
>>> my original patch attached below.
>> Why does i become -1?
>>
>>> On 2017/2/24 18:47, Chao Yu wrote:
>>>> On 2017/2/24 17:19, Yunlong Song wrote:
>>>>> Hi Jaegeuk and Chao,
>>>>>
>>>>>     How about the question I pointed out in last mail:
>>>>>     Why not take "neighboring temperature" for ssr? For example, if type == CURSEG_COLD_DATA,
>>>>>     the new patch selects CURSEG_HOT_DATA first, why not select CURSEG_WARM_DATA first?
>>>>>     The patch I sent ensure this "neighboring temperature" for ssr. This is to reduce the influence of
>>>>>     mixing different levels of hot/code node types.
>>>> Agreed, I sent one patch for changing the policy of SSR, how do you think of it?
>>>>
>>>> Thanks,
>>>>
>>>>> On 2017/2/24 17:05, Chao Yu wrote:
>>>>>> Hi Jaegeuk,
>>>>>>
>>>>>> Reviewed-by: Chao Yu <yuchao0@huawei.com>
>>>>>>
>>>>>> For your attached two patches.
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> On 2017/2/23 9:17, Jaegeuk Kim wrote:
>>>>>>> Hi Yunlong,
>>>>>>>
>>>>>>> I've been testing the similar patches as I attached.
>>>>>>>
>>>>>>> Thanks,
>>>>>>>
>>>>>>> On 02/22, Yunlong Song wrote:
>>>>>>>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
>>>>>>>> ---
>>>>>>>>  fs/f2fs/segment.c | 9 +++++++++
>>>>>>>>  1 file changed, 9 insertions(+)
>>>>>>>>
>>>>>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>>>>>>> index 9d13743..5fe71b9 100644
>>>>>>>> --- a/fs/f2fs/segment.c
>>>>>>>> +++ b/fs/f2fs/segment.c
>>>>>>>> @@ -1540,12 +1540,17 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>>>>>>>  {
>>>>>>>>      struct curseg_info *curseg = CURSEG_I(sbi, type);
>>>>>>>>      const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
>>>>>>>> +    int old_type = type;
>>>>>>>>  
>>>>>>>>      if (IS_NODESEG(type)) {
>>>>>>>>          for (; type >= CURSEG_HOT_NODE; type--)
>>>>>>>>              if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>>>>>>                              BG_GC, type, SSR))
>>>>>>>>                  return 1;
>>>>>>>> +        for (type = old_type + 1; type <= CURSEG_COLD_NODE; type++)
>>>>>>>> +            if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>>>>>> +                            BG_GC, type, SSR))
>>>>>>>> +                return 1;
>>>>>>>>          return 0;
>>>>>>>>      }
>>>>>>>>  
>>>>>>>> @@ -1554,6 +1559,10 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
>>>>>>>>          if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>>>>>>                          BG_GC, type, SSR))
>>>>>>>>              return 1;
>>>>>>>> +    for (type = old_type + 1; type <= CURSEG_COLD_DATA; type++)
>>>>>>>> +        if (v_ops->get_victim(sbi, &(curseg)->next_segno,
>>>>>>>> +                        BG_GC, type, SSR))
>>>>>>>> +            return 1;
>>>>>>>>      return 0;
>>>>>>>>  }
>>>>>>>>  
>>>>>>>> --
>>>>>>>> 1.8.5.2
>>>>>> .
>>>>>>
>>>> .
>>>>
>>>
>>> --
>>> Thanks,
>>> Yunlong Song
>>>
> .
>
diff mbox

Patch

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index f3d80ccd556f..605cda3e17e3 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1529,16 +1529,23 @@  static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
 {
 	struct curseg_info *curseg = CURSEG_I(sbi, type);
 	const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
+	int i;
+
+	/* need_SSR() already forces to do this */
+	if (v_ops->get_victim(sbi, &(curseg)->next_segno, BG_GC, type, SSR))
+		return 1;
 
 	if (IS_NODESEG(type))
-		return v_ops->get_victim(sbi,
-				&(curseg)->next_segno, BG_GC, type, SSR);
+		return 0;
 
 	/* For data segments, let's do SSR more intensively */
-	for (; type >= CURSEG_HOT_DATA; type--)
+	for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++) {
+		if (i == type)
+			continue;
 		if (v_ops->get_victim(sbi, &(curseg)->next_segno,
-						BG_GC, type, SSR))
+						BG_GC, i, SSR))
 			return 1;
+	}
 	return 0;
 }