Re: [PATCH v2] mkfs.f2fs: expand scalability of nat bitmap

From: Chao Yu
Date: Tue Jan 23 2018 - 01:16:37 EST

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On 2018/1/23 7:00, Jaegeuk Kim wrote:
> On 01/17, Chao Yu wrote:
>> Hi Jaegeuk,
>>
>> On 2018/1/17 8:47, Jaegeuk Kim wrote:
>>> Hi Chao,
>>>
>>> On 01/15, Chao Yu wrote:
>>>> Previously, our total node number (nat_bitmap) and total nat segment count
>>>> will not monotonously increase along with image size, and max nat_bitmap size
>>>> is limited by "CHECKSUM_OFFSET - sizeof(struct f2fs_checkpoint) + 1", it is
>>>> with bad scalability when user wants to create more inode/node in larger image.
>>>>
>>>> So this patch tries to relieve the limitation, by default, limitting total nat
>>>> entry number with 20% of total block number.
>>>>
>>>> Before:
>>>> image_size(GB) nat_bitmap sit_bitmap nat_segment sit_segment
>>>> 16 3836 64 36 2
>>>> 32 3836 64 72 2
>>>> 64 3772 128 116 4
>>>> 128 3708 192 114 6
>>>> 256 3580 320 110 10
>>
>> As you see, nat_segment count will reduce when image size increases
>> starting from 64GB, that means nat segment count will not monotonously
>> increase when image size is increasing, so it would be better to active
>> this when image size is larger than 32GB?
>>
>> IMO, configuring basic nid ratio to fixed value like ext4 ("free inode" :
>> "free block" is about 1 : 4) would be better:
>> a. It will be easy for user to predict nid count or nat segment count with
>> fix-sized image;
>> b. If user wants to reserve more nid count, we can support -N option in
>> mkfs.f2fs to specify total nid count as user wish.
>
> My concern is about a CTS failure in terms of # of free inodes.

You mean testSaneInodes()?

final long maxsize = stat.f_blocks * stat.f_frsize;
final long maxInodes = maxsize / 4096;
final long minsize = stat.f_bavail * stat.f_frsize;
final long minInodes = minsize / 32768;

The range is about [1/8, 1], so our 20% threshold can just let it passed,
right?

Thanks,

>
> Thanks,
>
>>
>> How do you think?
>>
>> Thanks,
>>
>>>> 512 3260 640 100 20
>>>> 1024 2684 1216 82 38
>>>> 2048 1468 2432 44 76
>>>> 4096 3900 4800 120 150
>>>>
>>>> After:
>>>> image_size(GB) nat_bitmap sit_bitmap nat_segment sit_segment
>>>> 16 256 64 8 2
>>>> 32 512 64 16 2
>>>> 64 960 128 30 4
>>>> 128 1856 192 58 6
>>>> 256 3712 320 116 10
>>>
>>> Can we activate this, if size is larger than 256GB or something around that?
>>>
>>> Thanks,
>>>
>>>> 512 7424 640 232 20
>>>> 1024 14787 1216 462 38
>>>> 2048 29504 2432 922 76
>>>> 4096 59008 4800 1844 150
>>>>
>>>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>>>> ---
>>>> v2:
>>>> - add CP_LARGE_NAT_BITMAP_FLAG flag to indicate new layout of nat/sit bitmap.
>>>> fsck/f2fs.h | 19 +++++++++++++------
>>>> fsck/resize.c | 35 +++++++++++++++++------------------
>>>> include/f2fs_fs.h | 8 ++++++--
>>>> lib/libf2fs.c | 1 +
>>>> mkfs/f2fs_format.c | 45 +++++++++++++++++++++++----------------------
>>>> 5 files changed, 60 insertions(+), 48 deletions(-)
>>>>
>>>> diff --git a/fsck/f2fs.h b/fsck/f2fs.h
>>>> index f5970d9dafc0..8a5ce365282d 100644
>>>> --- a/fsck/f2fs.h
>>>> +++ b/fsck/f2fs.h
>>>> @@ -239,6 +239,12 @@ static inline unsigned int ofs_of_node(struct f2fs_node *node_blk)
>>>> return flag >> OFFSET_BIT_SHIFT;
>>>> }
>>>>
>>>> +static inline bool is_set_ckpt_flags(struct f2fs_checkpoint *cp, unsigned int f)
>>>> +{
>>>> + unsigned int ckpt_flags = le32_to_cpu(cp->ckpt_flags);
>>>> + return ckpt_flags & f ? 1 : 0;
>>>> +}
>>>> +
>>>> static inline unsigned long __bitmap_size(struct f2fs_sb_info *sbi, int flag)
>>>> {
>>>> struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
>>>> @@ -256,6 +262,13 @@ static inline void *__bitmap_ptr(struct f2fs_sb_info *sbi, int flag)
>>>> {
>>>> struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
>>>> int offset;
>>>> +
>>>> + if (is_set_ckpt_flags(ckpt, CP_LARGE_NAT_BITMAP_FLAG)) {
>>>> + offset = (flag == SIT_BITMAP) ?
>>>> + le32_to_cpu(ckpt->nat_ver_bitmap_bytesize) : 0;
>>>> + return &ckpt->sit_nat_version_bitmap + offset;
>>>> + }
>>>> +
>>>> if (le32_to_cpu(F2FS_RAW_SUPER(sbi)->cp_payload) > 0) {
>>>> if (flag == NAT_BITMAP)
>>>> return &ckpt->sit_nat_version_bitmap;
>>>> @@ -268,12 +281,6 @@ static inline void *__bitmap_ptr(struct f2fs_sb_info *sbi, int flag)
>>>> }
>>>> }
>>>>
>>>> -static inline bool is_set_ckpt_flags(struct f2fs_checkpoint *cp, unsigned int f)
>>>> -{
>>>> - unsigned int ckpt_flags = le32_to_cpu(cp->ckpt_flags);
>>>> - return ckpt_flags & f ? 1 : 0;
>>>> -}
>>>> -
>>>> static inline block_t __start_cp_addr(struct f2fs_sb_info *sbi)
>>>> {
>>>> block_t start_addr = le32_to_cpu(F2FS_RAW_SUPER(sbi)->cp_blkaddr);
>>>> diff --git a/fsck/resize.c b/fsck/resize.c
>>>> index 143ad5d3c0a1..f3547c86f351 100644
>>>> --- a/fsck/resize.c
>>>> +++ b/fsck/resize.c
>>>> @@ -13,10 +13,10 @@ static int get_new_sb(struct f2fs_super_block *sb)
>>>> {
>>>> u_int32_t zone_size_bytes, zone_align_start_offset;
>>>> u_int32_t blocks_for_sit, blocks_for_nat, blocks_for_ssa;
>>>> - u_int32_t sit_segments, diff, total_meta_segments;
>>>> + u_int32_t sit_segments, nat_segments, diff, total_meta_segments;
>>>> u_int32_t total_valid_blks_available;
>>>> u_int32_t sit_bitmap_size, max_sit_bitmap_size;
>>>> - u_int32_t max_nat_bitmap_size, max_nat_segments;
>>>> + u_int32_t max_nat_bitmap_size;
>>>> u_int32_t segment_size_bytes = 1 << (get_sb(log_blocksize) +
>>>> get_sb(log_blocks_per_seg));
>>>> u_int32_t blks_per_seg = 1 << get_sb(log_blocks_per_seg);
>>>> @@ -47,7 +47,15 @@ static int get_new_sb(struct f2fs_super_block *sb)
>>>> get_sb(segment_count_sit))) * blks_per_seg;
>>>> blocks_for_nat = SIZE_ALIGN(total_valid_blks_available,
>>>> NAT_ENTRY_PER_BLOCK);
>>>> - set_sb(segment_count_nat, SEG_ALIGN(blocks_for_nat));
>>>> + nat_segments = SEG_ALIGN(blocks_for_nat) *
>>>> + DEFAULT_NAT_ENTRY_RATIO / 100;
>>>> + set_sb(segment_count_nat, nat_segments ? nat_segments : 1);
>>>> +
>>>> + max_nat_bitmap_size = (get_sb(segment_count_nat) <<
>>>> + get_sb(log_blocks_per_seg)) / 8;
>>>> + set_sb(segment_count_nat, get_sb(segment_count_nat) * 2);
>>>> +
>>>> + c.large_nat_bitmap = 1;
>>>>
>>>> sit_bitmap_size = ((get_sb(segment_count_sit) / 2) <<
>>>> get_sb(log_blocks_per_seg)) / 8;
>>>> @@ -56,25 +64,16 @@ static int get_new_sb(struct f2fs_super_block *sb)
>>>> else
>>>> max_sit_bitmap_size = sit_bitmap_size;
>>>>
>>>> - /*
>>>> - * It should be reserved minimum 1 segment for nat.
>>>> - * When sit is too large, we should expand cp area. It requires more pages for cp.
>>>> - */
>>>> - if (max_sit_bitmap_size > MAX_SIT_BITMAP_SIZE_IN_CKPT) {
>>>> - max_nat_bitmap_size = CHECKSUM_OFFSET - sizeof(struct f2fs_checkpoint) + 1;
>>>> - set_sb(cp_payload, F2FS_BLK_ALIGN(max_sit_bitmap_size));
>>>> + /* use cp_payload if free space of f2fs_checkpoint is not enough */
>>>> + if (max_sit_bitmap_size + max_nat_bitmap_size >
>>>> + MAX_BITMAP_SIZE_IN_CKPT) {
>>>> + u_int32_t diff = max_sit_bitmap_size + max_nat_bitmap_size -
>>>> + MAX_BITMAP_SIZE_IN_CKPT;
>>>> + set_sb(cp_payload, F2FS_BLK_ALIGN(diff));
>>>> } else {
>>>> - max_nat_bitmap_size = CHECKSUM_OFFSET - sizeof(struct f2fs_checkpoint) + 1
>>>> - - max_sit_bitmap_size;
>>>> set_sb(cp_payload, 0);
>>>> }
>>>>
>>>> - max_nat_segments = (max_nat_bitmap_size * 8) >>
>>>> - get_sb(log_blocks_per_seg);
>>>> -
>>>> - if (get_sb(segment_count_nat) > max_nat_segments)
>>>> - set_sb(segment_count_nat, max_nat_segments);
>>>> -
>>>> set_sb(segment_count_nat, get_sb(segment_count_nat) * 2);
>>>>
>>>> set_sb(ssa_blkaddr, get_sb(nat_blkaddr) +
>>>> diff --git a/include/f2fs_fs.h b/include/f2fs_fs.h
>>>> index 4739085ed98f..edf351412702 100644
>>>> --- a/include/f2fs_fs.h
>>>> +++ b/include/f2fs_fs.h
>>>> @@ -362,6 +362,7 @@ struct f2fs_configuration {
>>>> int preen_mode;
>>>> int ro;
>>>> int preserve_limits; /* preserve quota limits */
>>>> + int large_nat_bitmap;
>>>> __le32 feature; /* defined features */
>>>>
>>>> /* defragmentation parameters */
>>>> @@ -613,6 +614,7 @@ struct f2fs_super_block {
>>>> /*
>>>> * For checkpoint
>>>> */
>>>> +#define CP_LARGE_NAT_BITMAP_FLAG 0x00000200
>>>> #define CP_TRIMMED_FLAG 0x00000100
>>>> #define CP_NAT_BITS_FLAG 0x00000080
>>>> #define CP_CRC_RECOVERY_FLAG 0x00000040
>>>> @@ -657,8 +659,8 @@ struct f2fs_checkpoint {
>>>> unsigned char sit_nat_version_bitmap[1];
>>>> } __attribute__((packed));
>>>>
>>>> -#define MAX_SIT_BITMAP_SIZE_IN_CKPT \
>>>> - (CHECKSUM_OFFSET - sizeof(struct f2fs_checkpoint) + 1 - 64)
>>>> +#define MAX_BITMAP_SIZE_IN_CKPT \
>>>> + (CHECKSUM_OFFSET - sizeof(struct f2fs_checkpoint) + 1)
>>>>
>>>> /*
>>>> * For orphan inode management
>>>> @@ -846,6 +848,8 @@ struct f2fs_node {
>>>> #define NAT_ENTRY_PER_BLOCK (PAGE_CACHE_SIZE / sizeof(struct f2fs_nat_entry))
>>>> #define NAT_BLOCK_OFFSET(start_nid) (start_nid / NAT_ENTRY_PER_BLOCK)
>>>>
>>>> +#define DEFAULT_NAT_ENTRY_RATIO 20
>>>> +
>>>> #ifdef ANDROID_WINDOWS_HOST
>>>> #pragma pack(1)
>>>> #endif
>>>> diff --git a/lib/libf2fs.c b/lib/libf2fs.c
>>>> index ffdbccb34627..e8b1842b7391 100644
>>>> --- a/lib/libf2fs.c
>>>> +++ b/lib/libf2fs.c
>>>> @@ -623,6 +623,7 @@ void f2fs_init_configuration(void)
>>>> c.ro = 0;
>>>> c.kd = -1;
>>>> c.dry_run = 0;
>>>> + c.large_nat_bitmap = 0;
>>>> c.fixed_time = -1;
>>>> }
>>>>
>>>> diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c
>>>> index a13000184300..23eaf40c5962 100644
>>>> --- a/mkfs/f2fs_format.c
>>>> +++ b/mkfs/f2fs_format.c
>>>> @@ -151,13 +151,13 @@ static int f2fs_prepare_super_block(void)
>>>> u_int32_t log_sectorsize, log_sectors_per_block;
>>>> u_int32_t log_blocksize, log_blks_per_seg;
>>>> u_int32_t segment_size_bytes, zone_size_bytes;
>>>> - u_int32_t sit_segments;
>>>> + u_int32_t sit_segments, nat_segments;
>>>> u_int32_t blocks_for_sit, blocks_for_nat, blocks_for_ssa;
>>>> u_int32_t total_valid_blks_available;
>>>> u_int64_t zone_align_start_offset, diff;
>>>> u_int64_t total_meta_zones, total_meta_segments;
>>>> u_int32_t sit_bitmap_size, max_sit_bitmap_size;
>>>> - u_int32_t max_nat_bitmap_size, max_nat_segments;
>>>> + u_int32_t max_nat_bitmap_size;
>>>> u_int32_t total_zones;
>>>> u_int32_t next_ino;
>>>> enum quota_type qtype;
>>>> @@ -272,7 +272,18 @@ static int f2fs_prepare_super_block(void)
>>>> blocks_for_nat = SIZE_ALIGN(total_valid_blks_available,
>>>> NAT_ENTRY_PER_BLOCK);
>>>>
>>>> - set_sb(segment_count_nat, SEG_ALIGN(blocks_for_nat));
>>>> + nat_segments = SEG_ALIGN(blocks_for_nat) *
>>>> + DEFAULT_NAT_ENTRY_RATIO / 100;
>>>> +
>>>> + set_sb(segment_count_nat, nat_segments ? nat_segments : 1);
>>>> +
>>>> + max_nat_bitmap_size = (get_sb(segment_count_nat) <<
>>>> + log_blks_per_seg) / 8;
>>>> +
>>>> + set_sb(segment_count_nat, get_sb(segment_count_nat) * 2);
>>>> +
>>>> + c.large_nat_bitmap = 1;
>>>> +
>>>> /*
>>>> * The number of node segments should not be exceeded a "Threshold".
>>>> * This number resizes NAT bitmap area in a CP page.
>>>> @@ -286,29 +297,16 @@ static int f2fs_prepare_super_block(void)
>>>> else
>>>> max_sit_bitmap_size = sit_bitmap_size;
>>>>
>>>> - /*
>>>> - * It should be reserved minimum 1 segment for nat.
>>>> - * When sit is too large, we should expand cp area. It requires more
>>>> - * pages for cp.
>>>> - */
>>>> - if (max_sit_bitmap_size > MAX_SIT_BITMAP_SIZE_IN_CKPT) {
>>>> - max_nat_bitmap_size = CHECKSUM_OFFSET -
>>>> - sizeof(struct f2fs_checkpoint) + 1;
>>>> - set_sb(cp_payload, F2FS_BLK_ALIGN(max_sit_bitmap_size));
>>>> + /* use cp_payload if free space of f2fs_checkpoint is not enough */
>>>> + if (max_sit_bitmap_size + max_nat_bitmap_size >
>>>> + MAX_BITMAP_SIZE_IN_CKPT) {
>>>> + u_int32_t diff = max_sit_bitmap_size + max_nat_bitmap_size -
>>>> + MAX_BITMAP_SIZE_IN_CKPT;
>>>> + set_sb(cp_payload, F2FS_BLK_ALIGN(diff));
>>>> } else {
>>>> - max_nat_bitmap_size =
>>>> - CHECKSUM_OFFSET - sizeof(struct f2fs_checkpoint) + 1
>>>> - - max_sit_bitmap_size;
>>>> set_sb(cp_payload, 0);
>>>> }
>>>>
>>>> - max_nat_segments = (max_nat_bitmap_size * 8) >> log_blks_per_seg;
>>>> -
>>>> - if (get_sb(segment_count_nat) > max_nat_segments)
>>>> - set_sb(segment_count_nat, max_nat_segments);
>>>> -
>>>> - set_sb(segment_count_nat, get_sb(segment_count_nat) * 2);
>>>> -
>>>> set_sb(ssa_blkaddr, get_sb(nat_blkaddr) + get_sb(segment_count_nat) *
>>>> c.blks_per_seg);
>>>>
>>>> @@ -622,6 +620,9 @@ static int f2fs_write_check_point_pack(void)
>>>> if (c.trimmed)
>>>> flags |= CP_TRIMMED_FLAG;
>>>>
>>>> + if (c.large_nat_bitmap)
>>>> + flags |= CP_LARGE_NAT_BITMAP_FLAG;
>>>> +
>>>> set_cp(ckpt_flags, flags);
>>>> set_cp(cp_pack_start_sum, 1 + get_sb(cp_payload));
>>>> set_cp(valid_node_count, 1 + quota_inum);
>>>> --
>>>> 2.15.0.55.gc2ece9dc4de6
>>>
>>> .
>>>
>
> .
>

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