| Message ID | 1500033432-57620-1-git-send-email-yunlong.song@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Yunlong, On 07/14, Yunlong Song wrote: > Suppose that the valid blocks of each section are all over sbi->fggc_threshold, How about adding a kernel message first to detect your *supposed* sceanrio? If that happens, it'll be a sort of bug which we haven't assumed. Thanks, > and even has_not_enough_free_secs is true, f2fs_gc cannot do its job since the > no_fggc_candidate always returns true. As a result, the reserved segments can be > used up, and finally there is no free segment at all, and get_new_segment cannot > get a free segment, filesystem will trap into a wrong status. > > To fix this, we record the segno which has a rough minimum cost and return it to > __get_victim to continue f2fs_gc's job. > > Signed-off-by: Yunlong Song <yunlong.song@huawei.com> > --- > fs/f2fs/gc.c | 19 ++++++++++++++----- > fs/f2fs/segment.h | 17 ++++++++++++++--- > 2 files changed, 28 insertions(+), 8 deletions(-) > > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > index fa3d2e2..965e783 100644 > --- a/fs/f2fs/gc.c > +++ b/fs/f2fs/gc.c > @@ -178,6 +178,8 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type, > p->offset = 0; > else > p->offset = SIT_I(sbi)->last_victim[p->gc_mode]; > + > + p->min_cost_r = UINT_MAX; > } > > static unsigned int get_max_cost(struct f2fs_sb_info *sbi, > @@ -194,7 +196,7 @@ static unsigned int get_max_cost(struct f2fs_sb_info *sbi, > return 0; > } > > -static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) > +static unsigned int check_bg_victims(struct f2fs_sb_info *sbi, struct victim_sel_policy *p) > { > struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); > unsigned int secno; > @@ -208,11 +210,12 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) > if (sec_usage_check(sbi, secno)) > continue; > > - if (no_fggc_candidate(sbi, secno)) > + p->cur_segno_r = GET_SEG_FROM_SEC(sbi, secno); > + if (no_fggc_candidate(sbi, secno, p)) > continue; > > clear_bit(secno, dirty_i->victim_secmap); > - return GET_SEG_FROM_SEC(sbi, secno); > + return p->cur_segno_r; > } > return NULL_SEGNO; > } > @@ -332,7 +335,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, > > last_victim = sm->last_victim[p.gc_mode]; > if (p.alloc_mode == LFS && gc_type == FG_GC) { > - p.min_segno = check_bg_victims(sbi); > + p.min_segno = check_bg_victims(sbi, &p); > if (p.min_segno != NULL_SEGNO) > goto got_it; > } > @@ -369,8 +372,9 @@ 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; > + p.cur_segno_r = segno; > if (gc_type == FG_GC && p.alloc_mode == LFS && > - no_fggc_candidate(sbi, secno)) > + no_fggc_candidate(sbi, secno, &p)) > goto next; > > cost = get_gc_cost(sbi, segno, &p); > @@ -403,6 +407,11 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, > trace_f2fs_get_victim(sbi->sb, type, gc_type, &p, > sbi->cur_victim_sec, > prefree_segments(sbi), free_segments(sbi)); > + } else if (has_not_enough_free_secs(sbi, 0, 0)) { > + p.min_segno = p.min_segno_r; > + if (p.alloc_mode == LFS && gc_type == FG_GC) > + clear_bit(GET_SEC_FROM_SEG(sbi, p.min_segno), dirty_i->victim_secmap); > + goto got_it; > } > out: > mutex_unlock(&dirty_i->seglist_lock); > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > index 6b871b4..7d2d0f3 100644 > --- a/fs/f2fs/segment.h > +++ b/fs/f2fs/segment.h > @@ -169,6 +169,9 @@ struct victim_sel_policy { > unsigned int ofs_unit; /* bitmap search unit */ > unsigned int min_cost; /* minimum cost */ > unsigned int min_segno; /* segment # having min. cost */ > + unsigned int min_cost_r; /* rough minimum cost */ > + unsigned int min_segno_r; /* segment # having rough min. cost */ > + unsigned int cur_segno_r; /* segment # rough process is handling */ > }; > > struct seg_entry { > @@ -743,11 +746,19 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type) > } > > static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi, > - unsigned int secno) > + unsigned int secno, struct victim_sel_policy *p) > { > - if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >= > - sbi->fggc_threshold) > + unsigned int cur_cost; > + > + cur_cost = get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true); > + if (cur_cost >= sbi->fggc_threshold) { > + if (p->min_cost_r > cur_cost) { > + p->min_cost_r = cur_cost; > + p->min_segno_r = p->cur_segno_r; > + } > return true; > + } > + > return false; > } > > -- > 1.8.5.2
Hi Jay,
In fact，this is not "suppose" case yet, we have already met this problem several times in some test suits for corner case, or I cannot notice that this could happen.
On 2017/7/16 9:09, Jaegeuk Kim wrote:
> Hi Yunlong,
>
> On 07/14, Yunlong Song wrote:
>> Suppose that the valid blocks of each section are all over sbi->fggc_threshold,
> How about adding a kernel message first to detect your *supposed* sceanrio?
> If that happens, it'll be a sort of bug which we haven't assumed.
>
> Thanks,
>
>> and even has_not_enough_free_secs is true, f2fs_gc cannot do its job since the
>> no_fggc_candidate always returns true. As a result, the reserved segments can be
>> used up, and finally there is no free segment at all, and get_new_segment cannot
>> get a free segment, filesystem will trap into a wrong status.
>>
>> To fix this, we record the segno which has a rough minimum cost and return it to
>> __get_victim to continue f2fs_gc's job.
>>
>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
>> ---
>> fs/f2fs/gc.c | 19 ++++++++++++++-----
>> fs/f2fs/segment.h | 17 ++++++++++++++---
>> 2 files changed, 28 insertions(+), 8 deletions(-)
>>
>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>> index fa3d2e2..965e783 100644
>> --- a/fs/f2fs/gc.c
>> +++ b/fs/f2fs/gc.c
>> @@ -178,6 +178,8 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
>> p->offset = 0;
>> else
>> p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
>> +
>> + p->min_cost_r = UINT_MAX;
>> }
>>
>> static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
>> @@ -194,7 +196,7 @@ static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
>> return 0;
>> }
>>
>> -static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
>> +static unsigned int check_bg_victims(struct f2fs_sb_info *sbi, struct victim_sel_policy *p)
>> {
>> struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
>> unsigned int secno;
>> @@ -208,11 +210,12 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
>> if (sec_usage_check(sbi, secno))
>> continue;
>>
>> - if (no_fggc_candidate(sbi, secno))
>> + p->cur_segno_r = GET_SEG_FROM_SEC(sbi, secno);
>> + if (no_fggc_candidate(sbi, secno, p))
>> continue;
>>
>> clear_bit(secno, dirty_i->victim_secmap);
>> - return GET_SEG_FROM_SEC(sbi, secno);
>> + return p->cur_segno_r;
>> }
>> return NULL_SEGNO;
>> }
>> @@ -332,7 +335,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
>>
>> last_victim = sm->last_victim[p.gc_mode];
>> if (p.alloc_mode == LFS && gc_type == FG_GC) {
>> - p.min_segno = check_bg_victims(sbi);
>> + p.min_segno = check_bg_victims(sbi, &p);
>> if (p.min_segno != NULL_SEGNO)
>> goto got_it;
>> }
>> @@ -369,8 +372,9 @@ 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;
>> + p.cur_segno_r = segno;
>> if (gc_type == FG_GC && p.alloc_mode == LFS &&
>> - no_fggc_candidate(sbi, secno))
>> + no_fggc_candidate(sbi, secno, &p))
>> goto next;
>>
>> cost = get_gc_cost(sbi, segno, &p);
>> @@ -403,6 +407,11 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
>> trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
>> sbi->cur_victim_sec,
>> prefree_segments(sbi), free_segments(sbi));
>> + } else if (has_not_enough_free_secs(sbi, 0, 0)) {
>> + p.min_segno = p.min_segno_r;
>> + if (p.alloc_mode == LFS && gc_type == FG_GC)
>> + clear_bit(GET_SEC_FROM_SEG(sbi, p.min_segno), dirty_i->victim_secmap);
>> + goto got_it;
>> }
>> out:
>> mutex_unlock(&dirty_i->seglist_lock);
>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
>> index 6b871b4..7d2d0f3 100644
>> --- a/fs/f2fs/segment.h
>> +++ b/fs/f2fs/segment.h
>> @@ -169,6 +169,9 @@ struct victim_sel_policy {
>> unsigned int ofs_unit; /* bitmap search unit */
>> unsigned int min_cost; /* minimum cost */
>> unsigned int min_segno; /* segment # having min. cost */
>> + unsigned int min_cost_r; /* rough minimum cost */
>> + unsigned int min_segno_r; /* segment # having rough min. cost */
>> + unsigned int cur_segno_r; /* segment # rough process is handling */
>> };
>>
>> struct seg_entry {
>> @@ -743,11 +746,19 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type)
>> }
>>
>> static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi,
>> - unsigned int secno)
>> + unsigned int secno, struct victim_sel_policy *p)
>> {
>> - if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >=
>> - sbi->fggc_threshold)
>> + unsigned int cur_cost;
>> +
>> + cur_cost = get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true);
>> + if (cur_cost >= sbi->fggc_threshold) {
>> + if (p->min_cost_r > cur_cost) {
>> + p->min_cost_r = cur_cost;
>> + p->min_segno_r = p->cur_segno_r;
>> + }
>> return true;
>> + }
>> +
>> return false;
>> }
>>
>> --
>> 1.8.5.2
> .
>
On 07/16, sylinux wrote: > In fact，this is not "suppose" case yet, we have already met this problem several times in some test suits for corner case, or I cannot notice that this could happen. So, have you taken a look at distribution of valid blocks in that case? I'm wondering what distribution can cause this. Thanks, > > > > > 发自网易邮箱大师 > On 07/16/2017 09:09, Jaegeuk Kim wrote: > Hi Yunlong, > > On 07/14, Yunlong Song wrote: > > Suppose that the valid blocks of each section are all over sbi->fggc_threshold, > > How about adding a kernel message first to detect your *supposed* sceanrio? > If that happens, it'll be a sort of bug which we haven't assumed. > > Thanks, > > > and even has_not_enough_free_secs is true, f2fs_gc cannot do its job since the > > no_fggc_candidate always returns true. As a result, the reserved segments can be > > used up, and finally there is no free segment at all, and get_new_segment cannot > > get a free segment, filesystem will trap into a wrong status. > > > > To fix this, we record the segno which has a rough minimum cost and return it to > > __get_victim to continue f2fs_gc's job. > > > > Signed-off-by: Yunlong Song <yunlong.song@huawei.com> > > --- > > fs/f2fs/gc.c | 19 ++++++++++++++----- > > fs/f2fs/segment.h | 17 ++++++++++++++--- > > 2 files changed, 28 insertions(+), 8 deletions(-) > > > > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > > index fa3d2e2..965e783 100644 > > --- a/fs/f2fs/gc.c > > +++ b/fs/f2fs/gc.c > > @@ -178,6 +178,8 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type, > > p->offset = 0; > > else > > p->offset = SIT_I(sbi)->last_victim[p->gc_mode]; > > + > > + p->min_cost_r = UINT_MAX; > > } > > > > static unsigned int get_max_cost(struct f2fs_sb_info *sbi, > > @@ -194,7 +196,7 @@ static unsigned int get_max_cost(struct f2fs_sb_info *sbi, > > return 0; > > } > > > > -static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) > > +static unsigned int check_bg_victims(struct f2fs_sb_info *sbi, struct victim_sel_policy *p) > > { > > struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); > > unsigned int secno; > > @@ -208,11 +210,12 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) > > if (sec_usage_check(sbi, secno)) > > continue; > > > > - if (no_fggc_candidate(sbi, secno)) > > + p->cur_segno_r = GET_SEG_FROM_SEC(sbi, secno); > > + if (no_fggc_candidate(sbi, secno, p)) > > continue; > > > > clear_bit(secno, dirty_i->victim_secmap); > > - return GET_SEG_FROM_SEC(sbi, secno); > > + return p->cur_segno_r; > > } > > return NULL_SEGNO; > > } > > @@ -332,7 +335,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, > > > > last_victim = sm->last_victim[p.gc_mode]; > > if (p.alloc_mode == LFS && gc_type == FG_GC) { > > - p.min_segno = check_bg_victims(sbi); > > + p.min_segno = check_bg_victims(sbi, &p); > > if (p.min_segno != NULL_SEGNO) > > goto got_it; > > } > > @@ -369,8 +372,9 @@ 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; > > + p.cur_segno_r = segno; > > if (gc_type == FG_GC && p.alloc_mode == LFS && > > - no_fggc_candidate(sbi, secno)) > > + no_fggc_candidate(sbi, secno, &p)) > > goto next; > > > > cost = get_gc_cost(sbi, segno, &p); > > @@ -403,6 +407,11 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, > > trace_f2fs_get_victim(sbi->sb, type, gc_type, &p, > > sbi->cur_victim_sec, > > prefree_segments(sbi), free_segments(sbi)); > > + } else if (has_not_enough_free_secs(sbi, 0, 0)) { > > + p.min_segno = p.min_segno_r; > > + if (p.alloc_mode == LFS && gc_type == FG_GC) > > + clear_bit(GET_SEC_FROM_SEG(sbi, p.min_segno), dirty_i->victim_secmap); > > + goto got_it; > > } > > out: > > mutex_unlock(&dirty_i->seglist_lock); > > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > > index 6b871b4..7d2d0f3 100644 > > --- a/fs/f2fs/segment.h > > +++ b/fs/f2fs/segment.h > > @@ -169,6 +169,9 @@ struct victim_sel_policy { > > unsigned int ofs_unit; /* bitmap search unit */ > > unsigned int min_cost; /* minimum cost */ > > unsigned int min_segno; /* segment # having min. cost */ > > + unsigned int min_cost_r; /* rough minimum cost */ > > + unsigned int min_segno_r; /* segment # having rough min. cost */ > > + unsigned int cur_segno_r; /* segment # rough process is handling */ > > }; > > > > struct seg_entry { > > @@ -743,11 +746,19 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type) > > } > > > > static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi, > > - unsigned int secno) > > + unsigned int secno, struct victim_sel_policy *p) > > { > > - if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >= > > - sbi->fggc_threshold) > > + unsigned int cur_cost; > > + > > + cur_cost = get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true); > > + if (cur_cost >= sbi->fggc_threshold) { > > + if (p->min_cost_r > cur_cost) { > > + p->min_cost_r = cur_cost; > > + p->min_segno_r = p->cur_segno_r; > > + } > > return true; > > + } > > + > > return false; > > } > > > > -- > > 1.8.5.2
Hi, Jay,
The distribution is like this, unit is segment counts:
cnt_free: 0 (free blocks)
cnt_full: 25182 (segment which has 512 blocks)
cnt_over: 25192 (segment which valid blocks over fggc_threshold)
cnt_below: 870 (segment which valid blocks below fggc_threshold)
The test is fragment test, add and delete small files over and over.
On 2017/7/18 0:56, Jaegeuk Kim wrote:
> On 07/16, sylinux wrote:
>> In fact，this is not "suppose" case yet, we have already met this problem several times in some test suits for corner case, or I cannot notice that this could happen.
> So, have you taken a look at distribution of valid blocks in that case?
> I'm wondering what distribution can cause this.
>
> Thanks,
>
>>
>>
>>
>> 发自网易邮箱大师
>> On 07/16/2017 09:09, Jaegeuk Kim wrote:
>> Hi Yunlong,
>>
>> On 07/14, Yunlong Song wrote:
>>> Suppose that the valid blocks of each section are all over sbi->fggc_threshold,
>> How about adding a kernel message first to detect your *supposed* sceanrio?
>> If that happens, it'll be a sort of bug which we haven't assumed.
>>
>> Thanks,
>>
>>> and even has_not_enough_free_secs is true, f2fs_gc cannot do its job since the
>>> no_fggc_candidate always returns true. As a result, the reserved segments can be
>>> used up, and finally there is no free segment at all, and get_new_segment cannot
>>> get a free segment, filesystem will trap into a wrong status.
>>>
>>> To fix this, we record the segno which has a rough minimum cost and return it to
>>> __get_victim to continue f2fs_gc's job.
>>>
>>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
>>> ---
>>> fs/f2fs/gc.c | 19 ++++++++++++++-----
>>> fs/f2fs/segment.h | 17 ++++++++++++++---
>>> 2 files changed, 28 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>>> index fa3d2e2..965e783 100644
>>> --- a/fs/f2fs/gc.c
>>> +++ b/fs/f2fs/gc.c
>>> @@ -178,6 +178,8 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
>>> p->offset = 0;
>>> else
>>> p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
>>> +
>>> + p->min_cost_r = UINT_MAX;
>>> }
>>>
>>> static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
>>> @@ -194,7 +196,7 @@ static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
>>> return 0;
>>> }
>>>
>>> -static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
>>> +static unsigned int check_bg_victims(struct f2fs_sb_info *sbi, struct victim_sel_policy *p)
>>> {
>>> struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
>>> unsigned int secno;
>>> @@ -208,11 +210,12 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
>>> if (sec_usage_check(sbi, secno))
>>> continue;
>>>
>>> - if (no_fggc_candidate(sbi, secno))
>>> + p->cur_segno_r = GET_SEG_FROM_SEC(sbi, secno);
>>> + if (no_fggc_candidate(sbi, secno, p))
>>> continue;
>>>
>>> clear_bit(secno, dirty_i->victim_secmap);
>>> - return GET_SEG_FROM_SEC(sbi, secno);
>>> + return p->cur_segno_r;
>>> }
>>> return NULL_SEGNO;
>>> }
>>> @@ -332,7 +335,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
>>>
>>> last_victim = sm->last_victim[p.gc_mode];
>>> if (p.alloc_mode == LFS && gc_type == FG_GC) {
>>> - p.min_segno = check_bg_victims(sbi);
>>> + p.min_segno = check_bg_victims(sbi, &p);
>>> if (p.min_segno != NULL_SEGNO)
>>> goto got_it;
>>> }
>>> @@ -369,8 +372,9 @@ 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;
>>> + p.cur_segno_r = segno;
>>> if (gc_type == FG_GC && p.alloc_mode == LFS &&
>>> - no_fggc_candidate(sbi, secno))
>>> + no_fggc_candidate(sbi, secno, &p))
>>> goto next;
>>>
>>> cost = get_gc_cost(sbi, segno, &p);
>>> @@ -403,6 +407,11 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
>>> trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
>>> sbi->cur_victim_sec,
>>> prefree_segments(sbi), free_segments(sbi));
>>> + } else if (has_not_enough_free_secs(sbi, 0, 0)) {
>>> + p.min_segno = p.min_segno_r;
>>> + if (p.alloc_mode == LFS && gc_type == FG_GC)
>>> + clear_bit(GET_SEC_FROM_SEG(sbi, p.min_segno), dirty_i->victim_secmap);
>>> + goto got_it;
>>> }
>>> out:
>>> mutex_unlock(&dirty_i->seglist_lock);
>>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
>>> index 6b871b4..7d2d0f3 100644
>>> --- a/fs/f2fs/segment.h
>>> +++ b/fs/f2fs/segment.h
>>> @@ -169,6 +169,9 @@ struct victim_sel_policy {
>>> unsigned int ofs_unit; /* bitmap search unit */
>>> unsigned int min_cost; /* minimum cost */
>>> unsigned int min_segno; /* segment # having min. cost */
>>> + unsigned int min_cost_r; /* rough minimum cost */
>>> + unsigned int min_segno_r; /* segment # having rough min. cost */
>>> + unsigned int cur_segno_r; /* segment # rough process is handling */
>>> };
>>>
>>> struct seg_entry {
>>> @@ -743,11 +746,19 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type)
>>> }
>>>
>>> static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi,
>>> - unsigned int secno)
>>> + unsigned int secno, struct victim_sel_policy *p)
>>> {
>>> - if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >=
>>> - sbi->fggc_threshold)
>>> + unsigned int cur_cost;
>>> +
>>> + cur_cost = get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true);
>>> + if (cur_cost >= sbi->fggc_threshold) {
>>> + if (p->min_cost_r > cur_cost) {
>>> + p->min_cost_r = cur_cost;
>>> + p->min_segno_r = p->cur_segno_r;
>>> + }
>>> return true;
>>> + }
>>> +
>>> return false;
>>> }
>>>
>>> --
>>> 1.8.5.2
> .
>
Hi Yunlong, On 07/20, Yunlong Song wrote: > Hi, Jay, > The distribution is like this, unit is segment counts: > cnt_free: 0 (free blocks) > cnt_full: 25182 (segment which has 512 blocks) > cnt_over: 25192 (segment which valid blocks over fggc_threshold) > cnt_below: 870 (segment which valid blocks below fggc_threshold) What are the values of fggc_threshold and ovp ratio or reserved_segments? How was the proc/segment_info? Thanks, > > The test is fragment test, add and delete small files over and over. > > On 2017/7/18 0:56, Jaegeuk Kim wrote: > > On 07/16, sylinux wrote: > >> In fact，this is not "suppose" case yet, we have already met this problem several times in some test suits for corner case, or I cannot notice that this could happen. > > So, have you taken a look at distribution of valid blocks in that case? > > I'm wondering what distribution can cause this. > > > > Thanks, > > > >> > >> > >> > >> 发自网易邮箱大师 > >> On 07/16/2017 09:09, Jaegeuk Kim wrote: > >> Hi Yunlong, > >> > >> On 07/14, Yunlong Song wrote: > >>> Suppose that the valid blocks of each section are all over sbi->fggc_threshold, > >> How about adding a kernel message first to detect your *supposed* sceanrio? > >> If that happens, it'll be a sort of bug which we haven't assumed. > >> > >> Thanks, > >> > >>> and even has_not_enough_free_secs is true, f2fs_gc cannot do its job since the > >>> no_fggc_candidate always returns true. As a result, the reserved segments can be > >>> used up, and finally there is no free segment at all, and get_new_segment cannot > >>> get a free segment, filesystem will trap into a wrong status. > >>> > >>> To fix this, we record the segno which has a rough minimum cost and return it to > >>> __get_victim to continue f2fs_gc's job. > >>> > >>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com> > >>> --- > >>> fs/f2fs/gc.c | 19 ++++++++++++++----- > >>> fs/f2fs/segment.h | 17 ++++++++++++++--- > >>> 2 files changed, 28 insertions(+), 8 deletions(-) > >>> > >>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > >>> index fa3d2e2..965e783 100644 > >>> --- a/fs/f2fs/gc.c > >>> +++ b/fs/f2fs/gc.c > >>> @@ -178,6 +178,8 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type, > >>> p->offset = 0; > >>> else > >>> p->offset = SIT_I(sbi)->last_victim[p->gc_mode]; > >>> + > >>> + p->min_cost_r = UINT_MAX; > >>> } > >>> > >>> static unsigned int get_max_cost(struct f2fs_sb_info *sbi, > >>> @@ -194,7 +196,7 @@ static unsigned int get_max_cost(struct f2fs_sb_info *sbi, > >>> return 0; > >>> } > >>> > >>> -static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) > >>> +static unsigned int check_bg_victims(struct f2fs_sb_info *sbi, struct victim_sel_policy *p) > >>> { > >>> struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); > >>> unsigned int secno; > >>> @@ -208,11 +210,12 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) > >>> if (sec_usage_check(sbi, secno)) > >>> continue; > >>> > >>> - if (no_fggc_candidate(sbi, secno)) > >>> + p->cur_segno_r = GET_SEG_FROM_SEC(sbi, secno); > >>> + if (no_fggc_candidate(sbi, secno, p)) > >>> continue; > >>> > >>> clear_bit(secno, dirty_i->victim_secmap); > >>> - return GET_SEG_FROM_SEC(sbi, secno); > >>> + return p->cur_segno_r; > >>> } > >>> return NULL_SEGNO; > >>> } > >>> @@ -332,7 +335,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, > >>> > >>> last_victim = sm->last_victim[p.gc_mode]; > >>> if (p.alloc_mode == LFS && gc_type == FG_GC) { > >>> - p.min_segno = check_bg_victims(sbi); > >>> + p.min_segno = check_bg_victims(sbi, &p); > >>> if (p.min_segno != NULL_SEGNO) > >>> goto got_it; > >>> } > >>> @@ -369,8 +372,9 @@ 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; > >>> + p.cur_segno_r = segno; > >>> if (gc_type == FG_GC && p.alloc_mode == LFS && > >>> - no_fggc_candidate(sbi, secno)) > >>> + no_fggc_candidate(sbi, secno, &p)) > >>> goto next; > >>> > >>> cost = get_gc_cost(sbi, segno, &p); > >>> @@ -403,6 +407,11 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, > >>> trace_f2fs_get_victim(sbi->sb, type, gc_type, &p, > >>> sbi->cur_victim_sec, > >>> prefree_segments(sbi), free_segments(sbi)); > >>> + } else if (has_not_enough_free_secs(sbi, 0, 0)) { > >>> + p.min_segno = p.min_segno_r; > >>> + if (p.alloc_mode == LFS && gc_type == FG_GC) > >>> + clear_bit(GET_SEC_FROM_SEG(sbi, p.min_segno), dirty_i->victim_secmap); > >>> + goto got_it; > >>> } > >>> out: > >>> mutex_unlock(&dirty_i->seglist_lock); > >>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > >>> index 6b871b4..7d2d0f3 100644 > >>> --- a/fs/f2fs/segment.h > >>> +++ b/fs/f2fs/segment.h > >>> @@ -169,6 +169,9 @@ struct victim_sel_policy { > >>> unsigned int ofs_unit; /* bitmap search unit */ > >>> unsigned int min_cost; /* minimum cost */ > >>> unsigned int min_segno; /* segment # having min. cost */ > >>> + unsigned int min_cost_r; /* rough minimum cost */ > >>> + unsigned int min_segno_r; /* segment # having rough min. cost */ > >>> + unsigned int cur_segno_r; /* segment # rough process is handling */ > >>> }; > >>> > >>> struct seg_entry { > >>> @@ -743,11 +746,19 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type) > >>> } > >>> > >>> static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi, > >>> - unsigned int secno) > >>> + unsigned int secno, struct victim_sel_policy *p) > >>> { > >>> - if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >= > >>> - sbi->fggc_threshold) > >>> + unsigned int cur_cost; > >>> + > >>> + cur_cost = get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true); > >>> + if (cur_cost >= sbi->fggc_threshold) { > >>> + if (p->min_cost_r > cur_cost) { > >>> + p->min_cost_r = cur_cost; > >>> + p->min_segno_r = p->cur_segno_r; > >>> + } > >>> return true; > >>> + } > >>> + > >>> return false; > >>> } > >>> > >>> -- > >>> 1.8.5.2 > > . > > > > > -- > Thanks, > Yunlong Song >
Hi Jay,
fggc_threshold is 507, reserved_segment is 462.
On 2017/7/22 5:07, Jaegeuk Kim wrote:
> Hi Yunlong,
>
> On 07/20, Yunlong Song wrote:
>> Hi, Jay,
>> The distribution is like this, unit is segment counts:
>> cnt_free: 0 (free blocks)
>> cnt_full: 25182 (segment which has 512 blocks)
>> cnt_over: 25192 (segment which valid blocks over fggc_threshold)
>> cnt_below: 870 (segment which valid blocks below fggc_threshold)
> What are the values of fggc_threshold and ovp ratio or reserved_segments?
> How was the proc/segment_info?
>
> Thanks,
>
>> The test is fragment test, add and delete small files over and over.
>>
>> On 2017/7/18 0:56, Jaegeuk Kim wrote:
>>> On 07/16, sylinux wrote:
>>>> In fact，this is not "suppose" case yet, we have already met this problem several times in some test suits for corner case, or I cannot notice that this could happen.
>>> So, have you taken a look at distribution of valid blocks in that case?
>>> I'm wondering what distribution can cause this.
>>>
>>> Thanks,
>>>
>>>>
>>>>
>>>> 发自网易邮箱大师
>>>> On 07/16/2017 09:09, Jaegeuk Kim wrote:
>>>> Hi Yunlong,
>>>>
>>>> On 07/14, Yunlong Song wrote:
>>>>> Suppose that the valid blocks of each section are all over sbi->fggc_threshold,
>>>> How about adding a kernel message first to detect your *supposed* sceanrio?
>>>> If that happens, it'll be a sort of bug which we haven't assumed.
>>>>
>>>> Thanks,
>>>>
>>>>> and even has_not_enough_free_secs is true, f2fs_gc cannot do its job since the
>>>>> no_fggc_candidate always returns true. As a result, the reserved segments can be
>>>>> used up, and finally there is no free segment at all, and get_new_segment cannot
>>>>> get a free segment, filesystem will trap into a wrong status.
>>>>>
>>>>> To fix this, we record the segno which has a rough minimum cost and return it to
>>>>> __get_victim to continue f2fs_gc's job.
>>>>>
>>>>> Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
>>>>> ---
>>>>> fs/f2fs/gc.c | 19 ++++++++++++++-----
>>>>> fs/f2fs/segment.h | 17 ++++++++++++++---
>>>>> 2 files changed, 28 insertions(+), 8 deletions(-)
>>>>>
>>>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>>>>> index fa3d2e2..965e783 100644
>>>>> --- a/fs/f2fs/gc.c
>>>>> +++ b/fs/f2fs/gc.c
>>>>> @@ -178,6 +178,8 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
>>>>> p->offset = 0;
>>>>> else
>>>>> p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
>>>>> +
>>>>> + p->min_cost_r = UINT_MAX;
>>>>> }
>>>>>
>>>>> static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
>>>>> @@ -194,7 +196,7 @@ static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
>>>>> return 0;
>>>>> }
>>>>>
>>>>> -static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
>>>>> +static unsigned int check_bg_victims(struct f2fs_sb_info *sbi, struct victim_sel_policy *p)
>>>>> {
>>>>> struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
>>>>> unsigned int secno;
>>>>> @@ -208,11 +210,12 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
>>>>> if (sec_usage_check(sbi, secno))
>>>>> continue;
>>>>>
>>>>> - if (no_fggc_candidate(sbi, secno))
>>>>> + p->cur_segno_r = GET_SEG_FROM_SEC(sbi, secno);
>>>>> + if (no_fggc_candidate(sbi, secno, p))
>>>>> continue;
>>>>>
>>>>> clear_bit(secno, dirty_i->victim_secmap);
>>>>> - return GET_SEG_FROM_SEC(sbi, secno);
>>>>> + return p->cur_segno_r;
>>>>> }
>>>>> return NULL_SEGNO;
>>>>> }
>>>>> @@ -332,7 +335,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
>>>>>
>>>>> last_victim = sm->last_victim[p.gc_mode];
>>>>> if (p.alloc_mode == LFS && gc_type == FG_GC) {
>>>>> - p.min_segno = check_bg_victims(sbi);
>>>>> + p.min_segno = check_bg_victims(sbi, &p);
>>>>> if (p.min_segno != NULL_SEGNO)
>>>>> goto got_it;
>>>>> }
>>>>> @@ -369,8 +372,9 @@ 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;
>>>>> + p.cur_segno_r = segno;
>>>>> if (gc_type == FG_GC && p.alloc_mode == LFS &&
>>>>> - no_fggc_candidate(sbi, secno))
>>>>> + no_fggc_candidate(sbi, secno, &p))
>>>>> goto next;
>>>>>
>>>>> cost = get_gc_cost(sbi, segno, &p);
>>>>> @@ -403,6 +407,11 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
>>>>> trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
>>>>> sbi->cur_victim_sec,
>>>>> prefree_segments(sbi), free_segments(sbi));
>>>>> + } else if (has_not_enough_free_secs(sbi, 0, 0)) {
>>>>> + p.min_segno = p.min_segno_r;
>>>>> + if (p.alloc_mode == LFS && gc_type == FG_GC)
>>>>> + clear_bit(GET_SEC_FROM_SEG(sbi, p.min_segno), dirty_i->victim_secmap);
>>>>> + goto got_it;
>>>>> }
>>>>> out:
>>>>> mutex_unlock(&dirty_i->seglist_lock);
>>>>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
>>>>> index 6b871b4..7d2d0f3 100644
>>>>> --- a/fs/f2fs/segment.h
>>>>> +++ b/fs/f2fs/segment.h
>>>>> @@ -169,6 +169,9 @@ struct victim_sel_policy {
>>>>> unsigned int ofs_unit; /* bitmap search unit */
>>>>> unsigned int min_cost; /* minimum cost */
>>>>> unsigned int min_segno; /* segment # having min. cost */
>>>>> + unsigned int min_cost_r; /* rough minimum cost */
>>>>> + unsigned int min_segno_r; /* segment # having rough min. cost */
>>>>> + unsigned int cur_segno_r; /* segment # rough process is handling */
>>>>> };
>>>>>
>>>>> struct seg_entry {
>>>>> @@ -743,11 +746,19 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type)
>>>>> }
>>>>>
>>>>> static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi,
>>>>> - unsigned int secno)
>>>>> + unsigned int secno, struct victim_sel_policy *p)
>>>>> {
>>>>> - if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >=
>>>>> - sbi->fggc_threshold)
>>>>> + unsigned int cur_cost;
>>>>> +
>>>>> + cur_cost = get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true);
>>>>> + if (cur_cost >= sbi->fggc_threshold) {
>>>>> + if (p->min_cost_r > cur_cost) {
>>>>> + p->min_cost_r = cur_cost;
>>>>> + p->min_segno_r = p->cur_segno_r;
>>>>> + }
>>>>> return true;
>>>>> + }
>>>>> +
>>>>> return false;
>>>>> }
>>>>>
>>>>> --
>>>>> 1.8.5.2
>>> .
>>>
>>
>> --
>> Thanks,
>> Yunlong Song
>>
> .
>
On 07/14, Yunlong Song wrote: > Suppose that the valid blocks of each section are all over sbi->fggc_threshold, > and even has_not_enough_free_secs is true, f2fs_gc cannot do its job since the > no_fggc_candidate always returns true. As a result, the reserved segments can be > used up, and finally there is no free segment at all, and get_new_segment cannot > get a free segment, filesystem will trap into a wrong status. > > To fix this, we record the segno which has a rough minimum cost and return it to > __get_victim to continue f2fs_gc's job. > > Signed-off-by: Yunlong Song <yunlong.song@huawei.com> > --- > fs/f2fs/gc.c | 19 ++++++++++++++----- > fs/f2fs/segment.h | 17 ++++++++++++++--- > 2 files changed, 28 insertions(+), 8 deletions(-) > > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > index fa3d2e2..965e783 100644 > --- a/fs/f2fs/gc.c > +++ b/fs/f2fs/gc.c > @@ -178,6 +178,8 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type, > p->offset = 0; > else > p->offset = SIT_I(sbi)->last_victim[p->gc_mode]; > + > + p->min_cost_r = UINT_MAX; > } > > static unsigned int get_max_cost(struct f2fs_sb_info *sbi, > @@ -194,7 +196,7 @@ static unsigned int get_max_cost(struct f2fs_sb_info *sbi, > return 0; > } > > -static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) > +static unsigned int check_bg_victims(struct f2fs_sb_info *sbi, struct victim_sel_policy *p) > { > struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); > unsigned int secno; > @@ -208,11 +210,12 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) > if (sec_usage_check(sbi, secno)) > continue; > > - if (no_fggc_candidate(sbi, secno)) > + p->cur_segno_r = GET_SEG_FROM_SEC(sbi, secno); > + if (no_fggc_candidate(sbi, secno, p)) > continue; > > clear_bit(secno, dirty_i->victim_secmap); > - return GET_SEG_FROM_SEC(sbi, secno); > + return p->cur_segno_r; > } > return NULL_SEGNO; > } > @@ -332,7 +335,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, > > last_victim = sm->last_victim[p.gc_mode]; > if (p.alloc_mode == LFS && gc_type == FG_GC) { > - p.min_segno = check_bg_victims(sbi); > + p.min_segno = check_bg_victims(sbi, &p); > if (p.min_segno != NULL_SEGNO) > goto got_it; > } > @@ -369,8 +372,9 @@ 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; > + p.cur_segno_r = segno; > if (gc_type == FG_GC && p.alloc_mode == LFS && > - no_fggc_candidate(sbi, secno)) > + no_fggc_candidate(sbi, secno, &p)) > goto next; > > cost = get_gc_cost(sbi, segno, &p); > @@ -403,6 +407,11 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, > trace_f2fs_get_victim(sbi->sb, type, gc_type, &p, > sbi->cur_victim_sec, > prefree_segments(sbi), free_segments(sbi)); > + } else if (has_not_enough_free_secs(sbi, 0, 0)) { > + p.min_segno = p.min_segno_r; > + if (p.alloc_mode == LFS && gc_type == FG_GC) > + clear_bit(GET_SEC_FROM_SEG(sbi, p.min_segno), dirty_i->victim_secmap); It seems you want to give a victim segment which has valid blocks larger than fggc_threshold. fggc: 507 reserve: 462 cnt_full: 25182 over: 25912 (>= fggc) less: 870 (< fggc) What is ovp segments? It looks like there are 870 candidates for FG_GC, and GC with 103 segments must give 104 free segments in the worst case. Is there a problem on p.max_search? Thanks, > + goto got_it; > } > out: > mutex_unlock(&dirty_i->seglist_lock); > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > index 6b871b4..7d2d0f3 100644 > --- a/fs/f2fs/segment.h > +++ b/fs/f2fs/segment.h > @@ -169,6 +169,9 @@ struct victim_sel_policy { > unsigned int ofs_unit; /* bitmap search unit */ > unsigned int min_cost; /* minimum cost */ > unsigned int min_segno; /* segment # having min. cost */ > + unsigned int min_cost_r; /* rough minimum cost */ > + unsigned int min_segno_r; /* segment # having rough min. cost */ > + unsigned int cur_segno_r; /* segment # rough process is handling */ > }; > > struct seg_entry { > @@ -743,11 +746,19 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type) > } > > static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi, > - unsigned int secno) > + unsigned int secno, struct victim_sel_policy *p) > { > - if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >= > - sbi->fggc_threshold) > + unsigned int cur_cost; > + > + cur_cost = get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true); > + if (cur_cost >= sbi->fggc_threshold) { > + if (p->min_cost_r > cur_cost) { > + p->min_cost_r = cur_cost; > + p->min_segno_r = p->cur_segno_r; > + } > return true; > + } > + > return false; > } > > -- > 1.8.5.2
Hi, Jay, Sorry for the mistake in last mail, the ovp is 462, and the reserved is 235. I check the code and have not found problems with p.max_search yet. Just forget the this patch, since there is still 870 segments below, so it should not be the assumed case of this patch. By the way, I have sent another patch to provide f2fs_balance_fs to __write_node_page, similar as that in __write_data_page, to avoid missing f2fs_balance_fs in node page writeback. Please check that. On 2017/7/26 2:55, Jaegeuk Kim wrote: > On 07/14, Yunlong Song wrote: >> Suppose that the valid blocks of each section are all over sbi->fggc_threshold, >> and even has_not_enough_free_secs is true, f2fs_gc cannot do its job since the >> no_fggc_candidate always returns true. As a result, the reserved segments can be >> used up, and finally there is no free segment at all, and get_new_segment cannot >> get a free segment, filesystem will trap into a wrong status. >> >> To fix this, we record the segno which has a rough minimum cost and return it to >> __get_victim to continue f2fs_gc's job. >> >> Signed-off-by: Yunlong Song <yunlong.song@huawei.com> >> --- >> fs/f2fs/gc.c | 19 ++++++++++++++----- >> fs/f2fs/segment.h | 17 ++++++++++++++--- >> 2 files changed, 28 insertions(+), 8 deletions(-) >> >> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c >> index fa3d2e2..965e783 100644 >> --- a/fs/f2fs/gc.c >> +++ b/fs/f2fs/gc.c >> @@ -178,6 +178,8 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type, >> p->offset = 0; >> else >> p->offset = SIT_I(sbi)->last_victim[p->gc_mode]; >> + >> + p->min_cost_r = UINT_MAX; >> } >> >> static unsigned int get_max_cost(struct f2fs_sb_info *sbi, >> @@ -194,7 +196,7 @@ static unsigned int get_max_cost(struct f2fs_sb_info *sbi, >> return 0; >> } >> >> -static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) >> +static unsigned int check_bg_victims(struct f2fs_sb_info *sbi, struct victim_sel_policy *p) >> { >> struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); >> unsigned int secno; >> @@ -208,11 +210,12 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) >> if (sec_usage_check(sbi, secno)) >> continue; >> >> - if (no_fggc_candidate(sbi, secno)) >> + p->cur_segno_r = GET_SEG_FROM_SEC(sbi, secno); >> + if (no_fggc_candidate(sbi, secno, p)) >> continue; >> >> clear_bit(secno, dirty_i->victim_secmap); >> - return GET_SEG_FROM_SEC(sbi, secno); >> + return p->cur_segno_r; >> } >> return NULL_SEGNO; >> } >> @@ -332,7 +335,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, >> >> last_victim = sm->last_victim[p.gc_mode]; >> if (p.alloc_mode == LFS && gc_type == FG_GC) { >> - p.min_segno = check_bg_victims(sbi); >> + p.min_segno = check_bg_victims(sbi, &p); >> if (p.min_segno != NULL_SEGNO) >> goto got_it; >> } >> @@ -369,8 +372,9 @@ 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; >> + p.cur_segno_r = segno; >> if (gc_type == FG_GC && p.alloc_mode == LFS && >> - no_fggc_candidate(sbi, secno)) >> + no_fggc_candidate(sbi, secno, &p)) >> goto next; >> >> cost = get_gc_cost(sbi, segno, &p); >> @@ -403,6 +407,11 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, >> trace_f2fs_get_victim(sbi->sb, type, gc_type, &p, >> sbi->cur_victim_sec, >> prefree_segments(sbi), free_segments(sbi)); >> + } else if (has_not_enough_free_secs(sbi, 0, 0)) { >> + p.min_segno = p.min_segno_r; >> + if (p.alloc_mode == LFS && gc_type == FG_GC) >> + clear_bit(GET_SEC_FROM_SEG(sbi, p.min_segno), dirty_i->victim_secmap); > It seems you want to give a victim segment which has valid blocks larger than > fggc_threshold. > > fggc: 507 > reserve: 462 > cnt_full: 25182 > over: 25912 (>= fggc) > less: 870 (< fggc) > > What is ovp segments? > It looks like there are 870 candidates for FG_GC, and GC with 103 segments must > give 104 free segments in the worst case. Is there a problem on p.max_search? > > Thanks, > >> + goto got_it; >> } >> out: >> mutex_unlock(&dirty_i->seglist_lock); >> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h >> index 6b871b4..7d2d0f3 100644 >> --- a/fs/f2fs/segment.h >> +++ b/fs/f2fs/segment.h >> @@ -169,6 +169,9 @@ struct victim_sel_policy { >> unsigned int ofs_unit; /* bitmap search unit */ >> unsigned int min_cost; /* minimum cost */ >> unsigned int min_segno; /* segment # having min. cost */ >> + unsigned int min_cost_r; /* rough minimum cost */ >> + unsigned int min_segno_r; /* segment # having rough min. cost */ >> + unsigned int cur_segno_r; /* segment # rough process is handling */ >> }; >> >> struct seg_entry { >> @@ -743,11 +746,19 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type) >> } >> >> static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi, >> - unsigned int secno) >> + unsigned int secno, struct victim_sel_policy *p) >> { >> - if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >= >> - sbi->fggc_threshold) >> + unsigned int cur_cost; >> + >> + cur_cost = get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true); >> + if (cur_cost >= sbi->fggc_threshold) { >> + if (p->min_cost_r > cur_cost) { >> + p->min_cost_r = cur_cost; >> + p->min_segno_r = p->cur_segno_r; >> + } >> return true; >> + } >> + >> return false; >> } >> >> -- >> 1.8.5.2 > . >
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index fa3d2e2..965e783 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -178,6 +178,8 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type, p->offset = 0; else p->offset = SIT_I(sbi)->last_victim[p->gc_mode]; + + p->min_cost_r = UINT_MAX; } static unsigned int get_max_cost(struct f2fs_sb_info *sbi, @@ -194,7 +196,7 @@ static unsigned int get_max_cost(struct f2fs_sb_info *sbi, return 0; } -static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) +static unsigned int check_bg_victims(struct f2fs_sb_info *sbi, struct victim_sel_policy *p) { struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); unsigned int secno; @@ -208,11 +210,12 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) if (sec_usage_check(sbi, secno)) continue; - if (no_fggc_candidate(sbi, secno)) + p->cur_segno_r = GET_SEG_FROM_SEC(sbi, secno); + if (no_fggc_candidate(sbi, secno, p)) continue; clear_bit(secno, dirty_i->victim_secmap); - return GET_SEG_FROM_SEC(sbi, secno); + return p->cur_segno_r; } return NULL_SEGNO; } @@ -332,7 +335,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, last_victim = sm->last_victim[p.gc_mode]; if (p.alloc_mode == LFS && gc_type == FG_GC) { - p.min_segno = check_bg_victims(sbi); + p.min_segno = check_bg_victims(sbi, &p); if (p.min_segno != NULL_SEGNO) goto got_it; } @@ -369,8 +372,9 @@ 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; + p.cur_segno_r = segno; if (gc_type == FG_GC && p.alloc_mode == LFS && - no_fggc_candidate(sbi, secno)) + no_fggc_candidate(sbi, secno, &p)) goto next; cost = get_gc_cost(sbi, segno, &p); @@ -403,6 +407,11 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, trace_f2fs_get_victim(sbi->sb, type, gc_type, &p, sbi->cur_victim_sec, prefree_segments(sbi), free_segments(sbi)); + } else if (has_not_enough_free_secs(sbi, 0, 0)) { + p.min_segno = p.min_segno_r; + if (p.alloc_mode == LFS && gc_type == FG_GC) + clear_bit(GET_SEC_FROM_SEG(sbi, p.min_segno), dirty_i->victim_secmap); + goto got_it; } out: mutex_unlock(&dirty_i->seglist_lock); diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index 6b871b4..7d2d0f3 100644 --- a/fs/f2fs/segment.h +++ b/fs/f2fs/segment.h @@ -169,6 +169,9 @@ struct victim_sel_policy { unsigned int ofs_unit; /* bitmap search unit */ unsigned int min_cost; /* minimum cost */ unsigned int min_segno; /* segment # having min. cost */ + unsigned int min_cost_r; /* rough minimum cost */ + unsigned int min_segno_r; /* segment # having rough min. cost */ + unsigned int cur_segno_r; /* segment # rough process is handling */ }; struct seg_entry { @@ -743,11 +746,19 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type) } static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi, - unsigned int secno) + unsigned int secno, struct victim_sel_policy *p) { - if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >= - sbi->fggc_threshold) + unsigned int cur_cost; + + cur_cost = get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true); + if (cur_cost >= sbi->fggc_threshold) { + if (p->min_cost_r > cur_cost) { + p->min_cost_r = cur_cost; + p->min_segno_r = p->cur_segno_r; + } return true; + } + return false; }
Suppose that the valid blocks of each section are all over sbi->fggc_threshold, and even has_not_enough_free_secs is true, f2fs_gc cannot do its job since the no_fggc_candidate always returns true. As a result, the reserved segments can be used up, and finally there is no free segment at all, and get_new_segment cannot get a free segment, filesystem will trap into a wrong status. To fix this, we record the segno which has a rough minimum cost and return it to __get_victim to continue f2fs_gc's job. Signed-off-by: Yunlong Song <yunlong.song@huawei.com> --- fs/f2fs/gc.c | 19 ++++++++++++++----- fs/f2fs/segment.h | 17 ++++++++++++++--- 2 files changed, 28 insertions(+), 8 deletions(-)