Re: [PATCH 2/2] f2fs:use fggc_set_cold_data instead of set_cold_data in fggc

[Hou Pengyang <houpengyang@huawei.com>]

On 2017/2/23 8:39, Jaegeuk Kim wrote:
> Hi Pengyang,
>
> On 02/22, Hou Pengyang wrote:
>> When no dirty colde segment for fggc ssr, we do NOT set_cold_data.
>
> The get_ssr_segment() finds a victim segment across all the hot/warm/cold data
> logs. When does this happen?
>
Oh, I miss the travel across hot/warm/cold, sorry.
how about the following filter in get_victim_segment, which can avoid
unnecessary afterwards bitmap scanning.

Thanks,

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index a0eed23..00791d2 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -290,9 +290,16 @@ static int get_victim_by_default(struct 
f2fs_sb_info *sbi,
         unsigned int secno, last_victim;
         unsigned int last_segment = MAIN_SEGS(sbi);
         unsigned int nsearched = 0;
+       int nr_dirty;

         mutex_lock(&dirty_i->seglist_lock);

+       if (alloc_mode == SSR) {
+               nr_dirty = dirty_i->nr_dirty[type];
+               if (!nr_dirty)
+                       goto out;
+       }
+
         p.alloc_mode = alloc_mode;
         select_policy(sbi, gc_type, type, &p);


> Thanks,
>
>>
>> Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
>> ---
>>   fs/f2fs/gc.c | 21 ++++++++++++++++++++-
>>   1 file changed, 20 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>> index 4ee749f..a0eed23 100644
>> --- a/fs/f2fs/gc.c
>> +++ b/fs/f2fs/gc.c
>> @@ -666,6 +666,25 @@ static void move_encrypted_block(struct inode *inode, block_t bidx,
>>   	f2fs_put_page(page, 1);
>>   }
>>
>> +/*
>> + * If NOT enough dirty cold data segments for fggc, fggc would consume
>> + * a valuable free segment, which would slow down the fggc procedure,
>> + * If there are NO COLD dirty segment, we do not set_cold_page.
>> + */
>> +static void fggc_set_cold_data(struct page *page)
>> +{
>> +	struct f2fs_sb_info *sbi = F2FS_P_SB(page);
>> +	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
>> +	int nr_cold_dirties;
>> +
>> +	mutex_lock(&dirty_i->seglist_lock);
>> +	nr_cold_dirties = dirty_i->nr_dirty[DIRTY_COLD_DATA];
>> +	mutex_unlock(&dirty_i->seglist_lock);
>> +
>> +	if (nr_cold_dirties)
>> +		set_cold_data(page);
>> +
>> +}
>>   static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
>>   							unsigned int segno, int off)
>>   {
>> @@ -706,7 +725,7 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
>>   			remove_dirty_inode(inode);
>>   		}
>>
>> -		set_cold_data(page);
>> +		fggc_set_cold_data(page);
>>
>>   		err = do_write_data_page(&fio);
>>   		if (err == -ENOMEM && is_dirty) {
>> --
>> 2.10.1
>>
>>
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>
> .
>



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