Messages in this thread | | | Subject | Re: [PATCH V2] f2fs: introduce free nid bitmap | From | Chao Yu <> | Date | Thu, 2 Mar 2017 09:30:50 +0800 |
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Hi Jaegeuk,
On 2017/3/2 3:35, Jaegeuk Kim wrote: > Hi Chao, > > BTW, we need to add a shrinker for this as well, right?
Hmm...do we really have to?
As at most we will have 3900 NAT blocks, so a. free_nid_bitmap: 3900 * 57 = ~217 KB b. nat_block_bitmap: 3900 / 8 = ~487 BYTE c. free_nid_count: 3900 * 2 = ~7 KB
Thanks,
> > Thanks, > > On 02/23, Chao Yu wrote: >> In scenario of intensively node allocation, free nids will be ran out >> soon, then it needs to stop to load free nids by traversing NAT blocks, >> in worse case, if NAT blocks does not be cached in memory, it generates >> IOs which slows down our foreground operations. >> >> In order to speed up node allocation, in this patch we introduce a new >> free_nid_bitmap array, so there is an bitmap table for each NAT block, >> Once the NAT block is loaded, related bitmap cache will be switched on, >> and bitmap will be set during traversing nat entries in NAT block, later >> we can query and update nid usage status in memory completely. >> >> With such implementation, I expect performance of node allocation can be >> improved in the long-term after filesystem image is mounted. >> >> Signed-off-by: Chao Yu <yuchao0@huawei.com> >> --- >> fs/f2fs/debug.c | 2 + >> fs/f2fs/f2fs.h | 2 + >> fs/f2fs/node.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++-- >> include/linux/f2fs_fs.h | 1 + >> 4 files changed, 111 insertions(+), 3 deletions(-) >> >> diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c >> index 015ad2b73a92..a77df377e2e8 100644 >> --- a/fs/f2fs/debug.c >> +++ b/fs/f2fs/debug.c >> @@ -194,6 +194,8 @@ static void update_mem_info(struct f2fs_sb_info *sbi) >> si->base_mem += sizeof(struct f2fs_nm_info); >> si->base_mem += __bitmap_size(sbi, NAT_BITMAP); >> si->base_mem += (NM_I(sbi)->nat_bits_blocks << F2FS_BLKSIZE_BITS); >> + si->base_mem += NM_I(sbi)->nat_blocks * NAT_ENTRY_BITMAP_SIZE; >> + si->base_mem += NM_I(sbi)->nat_blocks / 8; >> >> get_cache: >> si->cache_mem = 0; >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >> index 1c9f0cc8f027..6a48e649bfef 100644 >> --- a/fs/f2fs/f2fs.h >> +++ b/fs/f2fs/f2fs.h >> @@ -556,6 +556,8 @@ struct f2fs_nm_info { >> unsigned int nid_cnt[MAX_NID_LIST]; /* the number of free node id */ >> spinlock_t nid_list_lock; /* protect nid lists ops */ >> struct mutex build_lock; /* lock for build free nids */ >> + unsigned char (*free_nid_bitmap)[NAT_ENTRY_BITMAP_SIZE]; >> + unsigned char *nat_block_bitmap; >> >> /* for checkpoint */ >> char *nat_bitmap; /* NAT bitmap pointer */ >> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c >> index b63bdb85ad66..f0f036c2d2fc 100644 >> --- a/fs/f2fs/node.c >> +++ b/fs/f2fs/node.c >> @@ -1821,14 +1821,32 @@ static void remove_free_nid(struct f2fs_sb_info *sbi, nid_t nid) >> kmem_cache_free(free_nid_slab, i); >> } >> >> +void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid, bool set) >> +{ >> + struct f2fs_nm_info *nm_i = NM_I(sbi); >> + unsigned int nat_ofs = NAT_BLOCK_OFFSET(nid); >> + unsigned int nid_ofs = nid - START_NID(nid); >> + >> + if (!test_bit_le(nat_ofs, nm_i->nat_block_bitmap)) >> + return; >> + >> + if (set) >> + set_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]); >> + else >> + clear_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]); >> +} >> + >> static void scan_nat_page(struct f2fs_sb_info *sbi, >> struct page *nat_page, nid_t start_nid) >> { >> struct f2fs_nm_info *nm_i = NM_I(sbi); >> struct f2fs_nat_block *nat_blk = page_address(nat_page); >> block_t blk_addr; >> + unsigned int nat_ofs = NAT_BLOCK_OFFSET(start_nid); >> int i; >> >> + set_bit_le(nat_ofs, nm_i->nat_block_bitmap); >> + >> i = start_nid % NAT_ENTRY_PER_BLOCK; >> >> for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) { >> @@ -1840,7 +1858,51 @@ static void scan_nat_page(struct f2fs_sb_info *sbi, >> f2fs_bug_on(sbi, blk_addr == NEW_ADDR); >> if (blk_addr == NULL_ADDR) >> add_free_nid(sbi, start_nid, true); >> + update_free_nid_bitmap(sbi, start_nid, blk_addr == NULL_ADDR); >> + } >> +} >> + >> +static void scan_free_nid_bits(struct f2fs_sb_info *sbi) >> +{ >> + struct f2fs_nm_info *nm_i = NM_I(sbi); >> + struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA); >> + struct f2fs_journal *journal = curseg->journal; >> + unsigned int i, idx; >> + unsigned int target = FREE_NID_PAGES * NAT_ENTRY_PER_BLOCK; >> + >> + down_read(&nm_i->nat_tree_lock); >> + >> + for (i = 0; i < nm_i->nat_blocks; i++) { >> + if (!test_bit_le(i, nm_i->nat_block_bitmap)) >> + continue; >> + for (idx = 0; idx < NAT_ENTRY_PER_BLOCK; idx++) { >> + nid_t nid; >> + >> + if (!test_bit_le(idx, nm_i->free_nid_bitmap[i])) >> + continue; >> + >> + nid = i * NAT_ENTRY_PER_BLOCK + idx; >> + add_free_nid(sbi, nid, true); >> + >> + if (nm_i->nid_cnt[FREE_NID_LIST] >= target) >> + goto out; >> + } >> + } >> +out: >> + down_read(&curseg->journal_rwsem); >> + for (i = 0; i < nats_in_cursum(journal); i++) { >> + block_t addr; >> + nid_t nid; >> + >> + addr = le32_to_cpu(nat_in_journal(journal, i).block_addr); >> + nid = le32_to_cpu(nid_in_journal(journal, i)); >> + if (addr == NULL_ADDR) >> + add_free_nid(sbi, nid, true); >> + else >> + remove_free_nid(sbi, nid); >> } >> + up_read(&curseg->journal_rwsem); >> + up_read(&nm_i->nat_tree_lock); >> } >> >> static int scan_nat_bits(struct f2fs_sb_info *sbi) >> @@ -1910,9 +1972,17 @@ static void __build_free_nids(struct f2fs_sb_info *sbi, bool sync, bool mount) >> if (!sync && !available_free_memory(sbi, FREE_NIDS)) >> return; >> >> - /* try to find free nids with nat_bits */ >> - if (!mount && !scan_nat_bits(sbi) && nm_i->nid_cnt[FREE_NID_LIST]) >> - return; >> + if (!mount) { >> + /* try to find free nids in free_nid_bitmap */ >> + scan_free_nid_bits(sbi); >> + >> + 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 (is_set_ckpt_flags(sbi, CP_NAT_BITS_FLAG)) { >> @@ -2005,6 +2075,9 @@ bool alloc_nid(struct f2fs_sb_info *sbi, nid_t *nid) >> i->state = NID_ALLOC; >> __insert_nid_to_list(sbi, i, ALLOC_NID_LIST, false); >> nm_i->available_nids--; >> + >> + update_free_nid_bitmap(sbi, *nid, false); >> + >> spin_unlock(&nm_i->nid_list_lock); >> return true; >> } >> @@ -2059,6 +2132,8 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid) >> >> nm_i->available_nids++; >> >> + update_free_nid_bitmap(sbi, nid, true); >> + >> spin_unlock(&nm_i->nid_list_lock); >> >> if (need_free) >> @@ -2387,6 +2462,11 @@ 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); >> + spin_unlock(&NM_I(sbi)->nid_list_lock); >> + } else { >> + spin_lock(&NM_I(sbi)->nid_list_lock); >> + update_free_nid_bitmap(sbi, nid, false); >> spin_unlock(&NM_I(sbi)->nid_list_lock); >> } >> } >> @@ -2556,6 +2636,22 @@ static int init_node_manager(struct f2fs_sb_info *sbi) >> return 0; >> } >> >> +int init_free_nid_cache(struct f2fs_sb_info *sbi) >> +{ >> + struct f2fs_nm_info *nm_i = NM_I(sbi); >> + >> + nm_i->free_nid_bitmap = f2fs_kvzalloc(nm_i->nat_blocks * >> + NAT_ENTRY_BITMAP_SIZE, GFP_KERNEL); >> + if (!nm_i->free_nid_bitmap) >> + return -ENOMEM; >> + >> + nm_i->nat_block_bitmap = f2fs_kvzalloc(nm_i->nat_blocks / 8, >> + GFP_KERNEL); >> + if (!nm_i->nat_block_bitmap) >> + return -ENOMEM; >> + return 0; >> +} >> + >> int build_node_manager(struct f2fs_sb_info *sbi) >> { >> int err; >> @@ -2568,6 +2664,10 @@ int build_node_manager(struct f2fs_sb_info *sbi) >> if (err) >> return err; >> >> + err = init_free_nid_cache(sbi); >> + if (err) >> + return err; >> + >> build_free_nids(sbi, true, true); >> return 0; >> } >> @@ -2626,6 +2726,9 @@ void destroy_node_manager(struct f2fs_sb_info *sbi) >> } >> up_write(&nm_i->nat_tree_lock); >> >> + kvfree(nm_i->nat_block_bitmap); >> + kvfree(nm_i->free_nid_bitmap); >> + >> kfree(nm_i->nat_bitmap); >> kfree(nm_i->nat_bits); >> #ifdef CONFIG_F2FS_CHECK_FS >> diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h >> index 1c92ace2e8f8..e2d239ed4c60 100644 >> --- a/include/linux/f2fs_fs.h >> +++ b/include/linux/f2fs_fs.h >> @@ -279,6 +279,7 @@ struct f2fs_node { >> * For NAT entries >> */ >> #define NAT_ENTRY_PER_BLOCK (PAGE_SIZE / sizeof(struct f2fs_nat_entry)) >> +#define NAT_ENTRY_BITMAP_SIZE ((NAT_ENTRY_PER_BLOCK + 7) / 8) >> >> struct f2fs_nat_entry { >> __u8 version; /* latest version of cached nat entry */ >> -- >> 2.8.2.295.g3f1c1d0 > > . >
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