On 2018/2/12 14:55, Yunlei He wrote:
> This patch introduce a method to make nat journal more fresh:
> i. sort set list using entry # plus cp version difference (last modify
> set cp # and current cp #)
> ii. if meet with cache hit, update last modify cp # to current cp #
As we discuss off-line, I think we can record weighted average of cpver for all
dirty nat entries into nat set.
Thanks,
>
> Signed-off-by: Yunlei He <heyun...@huawei.com>
> ---
> fs/f2fs/f2fs.h | 2 ++
> fs/f2fs/node.c | 57 +++++++++++++++++++++++++++++++++++++++++----------------
> fs/f2fs/node.h | 2 ++
> 3 files changed, 45 insertions(+), 16 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index b7ba496..bd1e775 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -297,6 +297,8 @@ struct fsync_inode_entry {
> block_t last_dentry; /* block address locating the last dentry */
> };
>
> +#define DEF_NAT_FACTOR 10
> +
> #define nats_in_cursum(jnl) (le16_to_cpu((jnl)->n_nats))
> #define sits_in_cursum(jnl) (le16_to_cpu((jnl)->n_sits))
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index ced986d..f3f89e3 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -195,8 +195,8 @@ 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
> from_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;
> @@ -209,9 +209,15 @@ 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->to_journal = false;
> + head->cp_ver = cur_cp_version(F2FS_CKPT(sbi));
> f2fs_radix_tree_insert(&nm_i->nat_set_root, set, head);
> }
>
> + /* journal hit case, try to locate set in journal */
> + if (head->to_journal && !from_journal)
> + head->cp_ver = cur_cp_version(F2FS_CKPT(sbi));
> +
> if (get_nat_flag(ne, IS_DIRTY))
> goto refresh_list;
>
> @@ -359,7 +365,7 @@ 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);
> + __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)
> @@ -2397,14 +2403,30 @@ 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 bool cost_compare(struct f2fs_sb_info *sbi,
> + struct nat_entry_set *nes, struct nat_entry_set * cur)
> +{
> + struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
> + __u64 cost1 = nes->entry_cnt * DEF_NAT_FACTOR +
> + (nes->cp_ver <= cur_cp_version(ckpt)) ?
> + cur_cp_version(ckpt) - nes->cp_ver :
> + ULONG_MAX - nes->cp_ver + cur_cp_version(ckpt);
> + __u64 cost2 = cur->entry_cnt * DEF_NAT_FACTOR +
> + (cur->cp_ver <= cur_cp_version(ckpt)) ?
> + cur_cp_version(ckpt) - cur->cp_ver :
> + ULONG_MAX - cur->cp_ver + cur_cp_version(ckpt);
> +
> + return cost1 <= cost2;
> +}
> +
> +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;
>
> @@ -2412,7 +2434,7 @@ 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 (cost_compare(sbi, nes, cur)) {
> list_add(&nes->set_list, cur->set_list.prev);
> return;
> }
> @@ -2460,7 +2482,6 @@ 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;
> @@ -2470,11 +2491,13 @@ 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);
> @@ -2490,7 +2513,7 @@ 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);
> @@ -2511,17 +2534,19 @@ 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);
> f2fs_put_page(page, 1);
> }
>
> - /* Allow dirty nats by node block allocation in write_begin */
> + if (!set->to_journal || cpc->reason & CP_UMOUNT) {
> + radix_tree_delete(&NM_I(sbi)->nat_set_root, set->set);
> + kmem_cache_free(nat_entry_set_slab, set);
> + }
> +
> f2fs_bug_on(sbi, set->entry_cnt);
> - radix_tree_delete(&NM_I(sbi)->nat_set_root, set->set);
> - kmem_cache_free(nat_entry_set_slab, set);
> }
>
> /*
> @@ -2557,7 +2582,7 @@ 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));
> }
>
> diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
> index 081ef0d..aba5ada 100644
> --- a/fs/f2fs/node.h
> +++ b/fs/f2fs/node.h
> @@ -149,6 +149,8 @@ struct nat_entry_set {
> 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 */
> + __u64 cp_ver; /* cp version of this set modify */
> + bool to_journal; /* set flush to journal */
> };
>
> struct free_nid {
>
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