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

From: Chao Yu
Date: Tue Jan 23 2018 - 20:26:29 EST

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On 2018/1/24 6:19, Jaegeuk Kim wrote:
> On 01/23, Jaegeuk Kim wrote:
>> On 01/23, Chao Yu wrote:
>>> 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?
>>
>> Yes, thanks for checking the codes. Let me play with this for some time.
>
> It simply triggers a panic, if kernel does not have the patch to detect the
> feature. Hmm...

Yes, because we have changed disk layout of nat/sit_version_bitmap in
mkfs.f2fs, if kernel can not detect that, we will encounter panic simply.

Thanks,

>
> Thanks,
>
>>
>> Thanks,
>>
>>>
>>> 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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