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f2fs: combine nat_bits and free_nid_bitmap cache 

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

This patch also resolves performance regression reported by lkp-robot.

commit:
  4ac912427c ("f2fs: introduce free nid bitmap")
  d00030cf9cd0bb96fdccc41e33d3c91dcbb672ba ("f2fs: use __set{__clear}_bit_le")
  1382c0f3f9d3f936c8bc42ed1591cf7a593ef9f7 ("f2fs: combine nat_bits and free_nid_bitmap cache")

4ac912427c d00030cf9cd0bb96fdccc41e33 1382c0f3f9d3f936c8bc42ed15
---------------- -------------------------- --------------------------
         %stddev     %change         %stddev     %change         %stddev
             \          |                \          |                \
     77863 ±  0%      +2.1%      79485 ±  1%     +50.8%     117404 ±  0%  aim7.jobs-per-min
    231.63 ±  0%      -2.0%     227.01 ±  1%     -33.6%     153.80 ±  0%  aim7.time.elapsed_time
    231.63 ±  0%      -2.0%     227.01 ±  1%     -33.6%     153.80 ±  0%  aim7.time.elapsed_time.max
    896604 ±  0%      -0.8%     889221 ±  3%     -20.2%     715260 ±  1%  aim7.time.involuntary_context_switches
      2394 ±  1%      +4.6%       2503 ±  1%      +3.7%       2481 ±  2%  aim7.time.maximum_resident_set_size
      6240 ±  0%      -1.5%       6145 ±  1%     -14.1%       5360 ±  1%  aim7.time.system_time
   1111357 ±  3%      +1.9%    1132509 ±  2%      -6.2%    1041932 ±  2%  aim7.time.voluntary_context_switches
...

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Tested-by: Xiaolong Ye <xiaolong.ye@intel.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
hifive-unleashed-5.1
Chao Yu 2017-03-08 20:07:49 +08:00 committed by Jaegeuk Kim
parent 586d1492f3
commit 7041d5d286
1 changed files with 47 additions and 78 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

125
fs/f2fs/node.c
View File

@ -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);
@ -1824,7 +1821,7 @@ static void remove_free_nid(struct f2fs_sb_info *sbi, nid_t nid)
}
static 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);
@ -1838,12 +1835,14 @@ static 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,
@ -1872,7 +1871,7 @@ 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);
}
}
@ -1920,58 +1919,6 @@ out:
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 +1940,6 @@ 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 */
@ -2094,7 +2026,7 @@ retry:
__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;
@ -2150,7 +2082,7 @@ 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);
@ -2480,11 +2412,11 @@ 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);
}
}
@ -2590,6 +2522,40 @@ 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;
spin_lock(&nm_i->free_nid_lock);
for (; nid < last_nid; nid++)
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++) {
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 +2657,9 @@ 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;
}