Re: [PATCH 2/2] Revert "f2fs: add ovp valid_blocks check for bg gc victim to fg_gc"

From: Chao Yu
Date: Sat May 05 2018 - 01:37:33 EST


Ping,

On 2018/4/27 10:55, Chao Yu wrote:
> Hi Jaegeuk,
>
> Missed this patch, or any problem in it?
>
> Thanks,
>
> On 2018/4/26 17:05, Chao Yu wrote:
>> For extreme case:
>> 10 section, op = 10%, no_fggc_threshold = 90%
>> All section usage: 85% 85% 85% 85% 90% 90% 95% 95% 95% 95%
>>
>> During foreground GC, if we skip select dirty section whose usage
>> is larger than no_fggc_threshold, we can only recycle 80% invalid
>> space from four 85% usage sections and two 90% usage sections,
>> result in encountering out-of-space issue.
>>
>> This reverts commit e93b9865251a0503d83fd570e7d5a7c8bc351715 to
>> fix this issue, besides, we keep the logic that we scan all dirty
>> section when searching a victim, so that GC can select victim with
>> least valid blocks.
>>
>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>> ---
>> fs/f2fs/f2fs.h | 3 ---
>> fs/f2fs/gc.c | 16 ----------------
>> fs/f2fs/segment.h | 9 ---------
>> 3 files changed, 28 deletions(-)
>>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 64e3677998d8..9f8b327272df 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -1192,9 +1192,6 @@ struct f2fs_sb_info {
>> struct f2fs_gc_kthread *gc_thread; /* GC thread */
>> unsigned int cur_victim_sec; /* current victim section num */
>>
>> - /* threshold for converting bg victims for fg */
>> - u64 fggc_threshold;
>> -
>> /* threshold for gc trials on pinned files */
>> u64 gc_pin_file_threshold;
>>
>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>> index 3134dd781252..62eba4a71123 100644
>> --- a/fs/f2fs/gc.c
>> +++ b/fs/f2fs/gc.c
>> @@ -263,10 +263,6 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
>> for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
>> if (sec_usage_check(sbi, secno))
>> continue;
>> -
>> - if (no_fggc_candidate(sbi, secno))
>> - continue;
>> -
>> clear_bit(secno, dirty_i->victim_secmap);
>> return GET_SEG_FROM_SEC(sbi, secno);
>> }
>> @@ -406,9 +402,6 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
>> goto next;
>> if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
>> goto next;
>> - if (gc_type == FG_GC && p.alloc_mode == LFS &&
>> - no_fggc_candidate(sbi, secno))
>> - goto next;
>>
>> cost = get_gc_cost(sbi, segno, &p);
>>
>> @@ -1152,17 +1145,8 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
>>
>> void build_gc_manager(struct f2fs_sb_info *sbi)
>> {
>> - u64 main_count, resv_count, ovp_count;
>> -
>> DIRTY_I(sbi)->v_ops = &default_v_ops;
>>
>> - /* threshold of # of valid blocks in a section for victims of FG_GC */
>> - main_count = SM_I(sbi)->main_segments << sbi->log_blocks_per_seg;
>> - resv_count = SM_I(sbi)->reserved_segments << sbi->log_blocks_per_seg;
>> - ovp_count = SM_I(sbi)->ovp_segments << sbi->log_blocks_per_seg;
>> -
>> - sbi->fggc_threshold = div64_u64((main_count - ovp_count) *
>> - BLKS_PER_SEC(sbi), (main_count - resv_count));
>> sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
>>
>> /* give warm/cold data area from slower device */
>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
>> index 7702b054689c..c385daabcb67 100644
>> --- a/fs/f2fs/segment.h
>> +++ b/fs/f2fs/segment.h
>> @@ -774,15 +774,6 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type)
>> - (base + 1) + type;
>> }
>>
>> -static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi,
>> - unsigned int secno)
>> -{
>> - if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >
>> - sbi->fggc_threshold)
>> - return true;
>> - return false;
>> -}
>> -
>> static inline bool sec_usage_check(struct f2fs_sb_info *sbi, unsigned int secno)
>> {
>> if (IS_CURSEC(sbi, secno) || (sbi->cur_victim_sec == secno))
>>
>
>
> .
>