Messages in this thread | | | Date | Wed, 1 Mar 2017 11:35:45 -0800 | From | Jaegeuk Kim <> | Subject | Re: [PATCH V2] f2fs: introduce free nid bitmap |
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Hi Chao,
BTW, we need to add a shrinker for this as well, right?
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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