>-----Original Message-----
>From: Yuchao (T)
>Sent: Friday, March 16, 2018 4:49 PM
>To: heyunlei; [email protected]; [email protected]
>Cc: Wangbintian; Zhangdianfang (Euler)
>Subject: Re: [f2fs-dev][PATCH v3] f2fs: introduce a method to make nat journal
>more fresh
>
>
>
>On 2018/3/14 14:33, Yunlei He wrote:
>> This patch introduce a method to make nat journal more fresh:
>> i. sort set list using dirty entry number and cp version
>> average value.
>> ii. if meet with cache hit, update average version valus with
>> current cp version.
>>
>> With this patch, newly modified nat set will flush to journal,
>> and flush old nat set with same dirty entry number to nat area.
>>
>> Signed-off-by: Yunlei He <[email protected]>
>> ---
>> fs/f2fs/node.c | 45 ++++++++++++++++++++++++++-------------------
>> fs/f2fs/node.h | 4 +++-
>> 2 files changed, 29 insertions(+), 20 deletions(-)
>>
>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>> index 177c438..74f6079 100644
>> --- a/fs/f2fs/node.c
>> +++ b/fs/f2fs/node.c
>> @@ -193,8 +193,8 @@ static void __del_from_nat_cache(struct f2fs_nm_info
>> *nm_i, struct nat_entry *e)
>> __free_nat_entry(e);
>> }
>>
>> -static void __set_nat_cache_dirty(struct f2fs_nm_info *nm_i,
>> - struct nat_entry *ne)
>> +static void __set_nat_cache_dirty(struct f2fs_sb_info *sbi, bool
>> remove_journal,
>> + struct f2fs_nm_info *nm_i, struct nat_entry *ne)
>> {
>> nid_t set = NAT_BLOCK_OFFSET(ne->ni.nid);
>> struct nat_entry_set *head;
>> @@ -207,9 +207,15 @@ static void __set_nat_cache_dirty(struct f2fs_nm_info
>> *nm_i,
>> INIT_LIST_HEAD(&head->set_list);
>> head->set = set;
>> head->entry_cnt = 0;
>> + head->cp_ver = 0;
>> f2fs_radix_tree_insert(&nm_i->nat_set_root, set, head);
>> }
>>
>> + /* journal hit case, try to locate set in journal */
>> + if (!remove_journal && head->entry_cnt <= NAT_JOURNAL_ENTRIES)
>> + head->cp_ver += div_u64(cur_cp_version(F2FS_CKPT(sbi)),
>> + NAT_JOURNAL_ENTRIES);
>> +
>> if (get_nat_flag(ne, IS_DIRTY))
>> goto refresh_list;
>
> else {
> update head version here?
> }
Okay, if one nat entry update more than once, here will be overflow.
>
>>
>> @@ -217,10 +223,7 @@ static void __set_nat_cache_dirty(struct f2fs_nm_info
>> *nm_i,
>> head->entry_cnt++;
>> set_nat_flag(ne, IS_DIRTY, true);
>> refresh_list:
>> - if (nat_get_blkaddr(ne) == NEW_ADDR)
>> - list_del_init(&ne->list);
>> - else
>> - list_move_tail(&ne->list, &head->entry_list);
>> + list_move_tail(&ne->list, &head->entry_list);
>
>For NEW_ADDR case, why we need to track this nat entry in entry_list?
If new_blkaddr == NEW_ADDR, we don't need to call __set_nat_cache_dirty:
i nat entry with NEW_ADDR will increase dirty nat entry count in nat
set，which will cause
a nat set has large nat entry count（most is NEW_ADDR）， but fewer of nat
entries should
be written back in this checkpoint
ii nat entry with NEW_ADDR will call __set_nat_cache_dirty again, when we
write back its node
page, in this time, new_blkaddr != NEW_ADDR
So, I think we'd better bypass _set_nat_cache_dirty if blkaddr == NEW_ADDR
Thanks.
>
>> }
>>
>> static void __clear_nat_cache_dirty(struct f2fs_nm_info *nm_i,
>> @@ -357,7 +360,8 @@ static void set_node_addr(struct f2fs_sb_info *sbi,
>> struct node_info *ni,
>> nat_set_blkaddr(e, new_blkaddr);
>> if (new_blkaddr == NEW_ADDR || new_blkaddr == NULL_ADDR)
>> set_nat_flag(e, IS_CHECKPOINTED, false);
>> - __set_nat_cache_dirty(nm_i, e);
>> + if (new_blkaddr != NEW_ADDR)
>> + __set_nat_cache_dirty(sbi, false, nm_i, e);
>>
>> /* update fsync_mark if its inode nat entry is still alive */
>> if (ni->nid != ni->ino)
>> @@ -2395,14 +2399,14 @@ static void remove_nats_in_journal(struct
>> f2fs_sb_info *sbi)
>> spin_unlock(&nm_i->nid_list_lock);
>> }
>>
>> - __set_nat_cache_dirty(nm_i, ne);
>> + __set_nat_cache_dirty(sbi, true, nm_i, ne);
>> }
>> update_nats_in_cursum(journal, -i);
>> up_write(&curseg->journal_rwsem);
>> }
>>
>> -static void __adjust_nat_entry_set(struct nat_entry_set *nes,
>> - struct list_head *head, int max)
>> +static void __adjust_nat_entry_set(struct f2fs_sb_info *sbi,
>> + struct nat_entry_set *nes, struct list_head *head, int max)
>> {
>> struct nat_entry_set *cur;
>>
>> @@ -2410,7 +2414,9 @@ static void __adjust_nat_entry_set(struct
>> nat_entry_set *nes,
>> goto add_out;
>>
>> list_for_each_entry(cur, head, set_list) {
>> - if (cur->entry_cnt >= nes->entry_cnt) {
>> + if (cur->entry_cnt > nes->entry_cnt ||
>> + (cur->entry_cnt == nes->entry_cnt &&
>> + cur->cp_ver < nes->cp_ver)) {
>> list_add(&nes->set_list, cur->set_list.prev);
>> return;
>> }
>> @@ -2458,7 +2464,6 @@ static void __flush_nat_entry_set(struct f2fs_sb_info
>> *sbi,
>> struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
>> struct f2fs_journal *journal = curseg->journal;
>> nid_t start_nid = set->set * NAT_ENTRY_PER_BLOCK;
>> - bool to_journal = true;
>> struct f2fs_nat_block *nat_blk;
>> struct nat_entry *ne, *cur;
>> struct page *page = NULL;
>> @@ -2468,11 +2473,14 @@ static void __flush_nat_entry_set(struct
>> f2fs_sb_info *sbi,
>> * #1, flush nat entries to journal in current hot data summary block.
>> * #2, flush nat entries to nat page.
>> */
>> +
>> + set->to_journal = true;
>> +
>> if (enabled_nat_bits(sbi, cpc) ||
>> !__has_cursum_space(journal, set->entry_cnt, NAT_JOURNAL))
>> - to_journal = false;
>> + set->to_journal = false;
>>
>> - if (to_journal) {
>> + if (set->to_journal) {
>> down_write(&curseg->journal_rwsem);
>> } else {
>> page = get_next_nat_page(sbi, start_nid);
>> @@ -2488,7 +2496,7 @@ static void __flush_nat_entry_set(struct f2fs_sb_info
>> *sbi,
>>
>> f2fs_bug_on(sbi, nat_get_blkaddr(ne) == NEW_ADDR);
>>
>> - if (to_journal) {
>> + if (set->to_journal) {
>> offset = lookup_journal_in_cursum(journal,
>> NAT_JOURNAL, nid, 1);
>> f2fs_bug_on(sbi, offset < 0);
>> @@ -2509,7 +2517,7 @@ static void __flush_nat_entry_set(struct f2fs_sb_info
>> *sbi,
>> }
>> }
>>
>> - if (to_journal) {
>> + if (set->to_journal) {
>> up_write(&curseg->journal_rwsem);
>> } else {
>> __update_nat_bits(sbi, start_nid, page);
>> @@ -2517,7 +2525,7 @@ static void __flush_nat_entry_set(struct f2fs_sb_info
>> *sbi,
>> }
>>
>> /* Allow dirty nats by node block allocation in write_begin */
>> - if (!set->entry_cnt) {
>> + if (!set->to_journal) {
>
>if (!set->to_journal && !set->entry_cnt) ?
>
>Thanks,
>
>> radix_tree_delete(&NM_I(sbi)->nat_set_root, set->set);
>> kmem_cache_free(nat_entry_set_slab, set);
>> }
>> @@ -2556,7 +2564,7 @@ void flush_nat_entries(struct f2fs_sb_info *sbi,
>> struct cp_control *cpc)
>> unsigned idx;
>> set_idx = setvec[found - 1]->set + 1;
>> for (idx = 0; idx < found; idx++)
>> - __adjust_nat_entry_set(setvec[idx], &sets,
>> + __adjust_nat_entry_set(sbi, setvec[idx], &sets,
>> MAX_NAT_JENTRIES(journal));
>> }
>>
>> @@ -2565,7 +2573,6 @@ void flush_nat_entries(struct f2fs_sb_info *sbi,
>> struct cp_control *cpc)
>> __flush_nat_entry_set(sbi, set, cpc);
>>
>> up_write(&nm_i->nat_tree_lock);
>> - /* Allow dirty nats by node block allocation in write_begin */
>> }
>>
>> static int __get_nat_bitmaps(struct f2fs_sb_info *sbi)
>> diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
>> index 081ef0d..3cf9c8b6 100644
>> --- a/fs/f2fs/node.h
>> +++ b/fs/f2fs/node.h
>> @@ -148,7 +148,9 @@ struct nat_entry_set {
>> struct list_head set_list; /* link with other nat sets */
>> struct list_head entry_list; /* link with dirty nat entries */
>> nid_t set; /* set number*/
>> - unsigned int entry_cnt; /* the # of nat entries in set */
>> + unsigned int entry_cnt:9; /* the # of nat entries in set */
>> + unsigned int to_journal:1; /* set flush to journal */
>> + __u64 cp_ver; /* cp version of this set modify */
>> };
>>
>> struct free_nid {
>>
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Linux-f2fs-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
