Re: [PATCH v2] f2fs: combine nat_bits and free_nid_bitmap cache
From: Jaegeuk Kim
Date: Tue Mar 07 2017 - 19:21:39 EST
Hi Chao,
There were two reasons for slow down; one is set_bit_le and the other was
spin_lock calls.
I think it would'b good to merge this patch in yours as well.
Let me know. I'm ready to integrate together and test them.
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/node.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 3377a512e299..0a1ea59c9d31 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1815,7 +1815,7 @@ static void remove_free_nid(struct f2fs_sb_info *sbi, nid_t nid)
}
void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid,
- bool set, bool build)
+ bool set, bool build, bool locked)
{
struct f2fs_nm_info *nm_i = NM_I(sbi);
unsigned int nat_ofs = NAT_BLOCK_OFFSET(nid);
@@ -1829,12 +1829,14 @@ void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid,
else
__clear_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
- spin_lock(&nm_i->free_nid_lock);
+ if (!locked)
+ spin_lock(&nm_i->free_nid_lock);
if (set)
nm_i->free_nid_count[nat_ofs]++;
else if (!build)
nm_i->free_nid_count[nat_ofs]--;
- spin_unlock(&nm_i->free_nid_lock);
+ if (!locked)
+ spin_unlock(&nm_i->free_nid_lock);
}
static void scan_nat_page(struct f2fs_sb_info *sbi,
@@ -1863,7 +1865,7 @@ static void scan_nat_page(struct f2fs_sb_info *sbi,
f2fs_bug_on(sbi, blk_addr == NEW_ADDR);
if (blk_addr == NULL_ADDR)
freed = add_free_nid(sbi, start_nid, true);
- update_free_nid_bitmap(sbi, start_nid, freed, true);
+ update_free_nid_bitmap(sbi, start_nid, freed, true, false);
}
}
@@ -2018,7 +2020,7 @@ bool alloc_nid(struct f2fs_sb_info *sbi, nid_t *nid)
__insert_nid_to_list(sbi, i, ALLOC_NID_LIST, false);
nm_i->available_nids--;
- update_free_nid_bitmap(sbi, *nid, false, false);
+ update_free_nid_bitmap(sbi, *nid, false, false, false);
spin_unlock(&nm_i->nid_list_lock);
return true;
@@ -2074,7 +2076,7 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
nm_i->available_nids++;
- update_free_nid_bitmap(sbi, nid, true, false);
+ update_free_nid_bitmap(sbi, nid, true, false, false);
spin_unlock(&nm_i->nid_list_lock);
@@ -2404,11 +2406,11 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
add_free_nid(sbi, nid, false);
spin_lock(&NM_I(sbi)->nid_list_lock);
NM_I(sbi)->available_nids++;
- update_free_nid_bitmap(sbi, nid, true, false);
+ update_free_nid_bitmap(sbi, nid, true, false, false);
spin_unlock(&NM_I(sbi)->nid_list_lock);
} else {
spin_lock(&NM_I(sbi)->nid_list_lock);
- update_free_nid_bitmap(sbi, nid, false, false);
+ update_free_nid_bitmap(sbi, nid, false, false, false);
spin_unlock(&NM_I(sbi)->nid_list_lock);
}
}
@@ -2533,8 +2535,10 @@ inline void load_free_nid_bitmap(struct f2fs_sb_info *sbi)
nid = i * NAT_ENTRY_PER_BLOCK;
last_nid = (i + 1) * NAT_ENTRY_PER_BLOCK;
+ spin_lock(&nm_i->free_nid_lock);
for (; nid < last_nid; nid++)
- update_free_nid_bitmap(sbi, nid, true, true);
+ update_free_nid_bitmap(sbi, nid, true, true, true);
+ spin_unlock(&nm_i->free_nid_lock);
}
for (i = 0; i < nm_i->nat_blocks; i++) {
--
2.11.0
On 03/06, Chao Yu wrote:
> Both nat_bits cache and free_nid_bitmap cache provide same functionality
> as a intermediate cache between free nid cache and disk, but with
> different granularity of indicating free nid range, and different
> persistence policy. nat_bits cache provides better persistence ability,
> and free_nid_bitmap provides better granularity.
>
> In this patch we combine advantage of both caches, so finally policy of
> the intermediate cache would be:
> - init: load free nid status from nat_bits into free_nid_bitmap
> - lookup: scan free_nid_bitmap before load NAT blocks
> - update: update free_nid_bitmap in real-time
> - persistence: udpate and persist nat_bits in checkpoint
>
> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
> ---
> fs/f2fs/node.c | 105 +++++++++++++++++++--------------------------------------
> 1 file changed, 35 insertions(+), 70 deletions(-)
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 1a759d45b7e4..625b46bc55ad 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -338,9 +338,6 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
> set_nat_flag(e, IS_CHECKPOINTED, false);
> __set_nat_cache_dirty(nm_i, e);
>
> - if (enabled_nat_bits(sbi, NULL) && new_blkaddr == NEW_ADDR)
> - clear_bit_le(NAT_BLOCK_OFFSET(ni->nid), nm_i->empty_nat_bits);
> -
> /* update fsync_mark if its inode nat entry is still alive */
> if (ni->nid != ni->ino)
> e = __lookup_nat_cache(nm_i, ni->ino);
> @@ -1920,58 +1917,6 @@ static void scan_free_nid_bits(struct f2fs_sb_info *sbi)
> up_read(&nm_i->nat_tree_lock);
> }
>
> -static int scan_nat_bits(struct f2fs_sb_info *sbi)
> -{
> - struct f2fs_nm_info *nm_i = NM_I(sbi);
> - struct page *page;
> - unsigned int i = 0;
> - nid_t nid;
> -
> - if (!enabled_nat_bits(sbi, NULL))
> - return -EAGAIN;
> -
> - down_read(&nm_i->nat_tree_lock);
> -check_empty:
> - i = find_next_bit_le(nm_i->empty_nat_bits, nm_i->nat_blocks, i);
> - if (i >= nm_i->nat_blocks) {
> - i = 0;
> - goto check_partial;
> - }
> -
> - for (nid = i * NAT_ENTRY_PER_BLOCK; nid < (i + 1) * NAT_ENTRY_PER_BLOCK;
> - nid++) {
> - if (unlikely(nid >= nm_i->max_nid))
> - break;
> - add_free_nid(sbi, nid, true);
> - }
> -
> - if (nm_i->nid_cnt[FREE_NID_LIST] >= MAX_FREE_NIDS)
> - goto out;
> - i++;
> - goto check_empty;
> -
> -check_partial:
> - i = find_next_zero_bit_le(nm_i->full_nat_bits, nm_i->nat_blocks, i);
> - if (i >= nm_i->nat_blocks) {
> - disable_nat_bits(sbi, true);
> - up_read(&nm_i->nat_tree_lock);
> - return -EINVAL;
> - }
> -
> - nid = i * NAT_ENTRY_PER_BLOCK;
> - page = get_current_nat_page(sbi, nid);
> - scan_nat_page(sbi, page, nid);
> - f2fs_put_page(page, 1);
> -
> - if (nm_i->nid_cnt[FREE_NID_LIST] < MAX_FREE_NIDS) {
> - i++;
> - goto check_partial;
> - }
> -out:
> - up_read(&nm_i->nat_tree_lock);
> - return 0;
> -}
> -
> static void __build_free_nids(struct f2fs_sb_info *sbi, bool sync, bool mount)
> {
> struct f2fs_nm_info *nm_i = NM_I(sbi);
> @@ -1993,21 +1938,6 @@ static void __build_free_nids(struct f2fs_sb_info *sbi, bool sync, bool mount)
>
> if (nm_i->nid_cnt[FREE_NID_LIST])
> return;
> -
> - /* try to find free nids with nat_bits */
> - if (!scan_nat_bits(sbi) && nm_i->nid_cnt[FREE_NID_LIST])
> - return;
> - }
> -
> - /* find next valid candidate */
> - if (enabled_nat_bits(sbi, NULL)) {
> - int idx = find_next_zero_bit_le(nm_i->full_nat_bits,
> - nm_i->nat_blocks, 0);
> -
> - if (idx >= nm_i->nat_blocks)
> - set_sbi_flag(sbi, SBI_NEED_FSCK);
> - else
> - nid = idx * NAT_ENTRY_PER_BLOCK;
> }
>
> /* readahead nat pages to be scanned */
> @@ -2590,6 +2520,38 @@ static int __get_nat_bitmaps(struct f2fs_sb_info *sbi)
> return 0;
> }
>
> +inline void load_free_nid_bitmap(struct f2fs_sb_info *sbi)
> +{
> + struct f2fs_nm_info *nm_i = NM_I(sbi);
> + unsigned int i = 0;
> + nid_t nid, last_nid;
> +
> + if (!enabled_nat_bits(sbi, NULL))
> + return;
> +
> + for (i = 0; i < nm_i->nat_blocks; i++) {
> + i = find_next_bit_le(nm_i->empty_nat_bits, nm_i->nat_blocks, i);
> + if (i >= nm_i->nat_blocks)
> + break;
> +
> + __set_bit_le(i, nm_i->nat_block_bitmap);
> +
> + nid = i * NAT_ENTRY_PER_BLOCK;
> + last_nid = (i + 1) * NAT_ENTRY_PER_BLOCK;
> +
> + for (; nid < last_nid; nid++)
> + update_free_nid_bitmap(sbi, nid, true, true);
> + }
> +
> + for (i = 0; i < nm_i->nat_blocks; i++) {
> + i = find_next_bit_le(nm_i->full_nat_bits, nm_i->nat_blocks, i);
> + if (i >= nm_i->nat_blocks)
> + break;
> +
> + __set_bit_le(i, nm_i->nat_block_bitmap);
> + }
> +}
> +
> static int init_node_manager(struct f2fs_sb_info *sbi)
> {
> struct f2fs_super_block *sb_raw = F2FS_RAW_SUPER(sbi);
> @@ -2691,6 +2653,9 @@ int build_node_manager(struct f2fs_sb_info *sbi)
> if (err)
> return err;
>
> + /* load free nid status from nat_bits table */
> + load_free_nid_bitmap(sbi);
> +
> build_free_nids(sbi, true, true);
> return 0;
> }
> --
> 2.8.2.295.g3f1c1d0