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Message-ID: <d00102d0-846c-ce4e-c667-496cbd52cc1f@kernel.org>
Date: Tue, 20 Jul 2021 08:39:38 +0800
From: Chao Yu <chao@...nel.org>
To: Jaegeuk Kim <jaegeuk@...nel.org>
Cc: linux-f2fs-devel@...ts.sourceforge.net,
linux-kernel@...r.kernel.org, Chao Yu <chao.yu@...ux.dev>
Subject: Re: [RFC NO MERGE] f2fs: extent cache: support unaligned extent
On 2021/7/20 2:36, Jaegeuk Kim wrote:
> On 07/07, Chao Yu wrote:
>> Compressed inode may suffer read performance issue due to it can not
>> use extent cache, so I propose to add this unaligned extent support
>> to improve it.
>>
>> Currently, it only works in readonly format f2fs image.
>>
>> Unaligned extent: in one compressed cluster, physical block number
>> will be less than logical block number, so we add an extra physical
>> block length in extent info in order to indicate such extent status.
>>
>> The idea is if one whole cluster blocks are contiguous physically,
>> once its mapping info was readed at first time, we will cache an
>> unaligned (or aligned) extent info entry in extent cache, it expects
>> that the mapping info will be hitted when rereading cluster.
>
> How about just modifying to handle COMPRESS_ADDR when modifying the extent_cache
> like RO case?
IIUC, update_largest_extent() in sload tries to find largest non-compressed cluster,
and persist its extent into inode, for a compressed file, non-compressed cluster is
not a common case, so I guess it's valuable to handle compressed cluster mapping
in extent cache to enhance read performance, especially for inode which has large
sized cluster.
Let me if I misunderstood what you mean.
Thanks,
>
>>
>> Merge policy:
>> - Aligned extents can be merged.
>> - Aligned extent and unaligned extent can not be merged.
>>
>> Signed-off-by: Chao Yu <chao@...nel.org>
>> ---
>>
>> I just post this for comments, it passes compiling, w/o any test.
>>
>> fs/f2fs/compress.c | 25 ++++++++++++
>> fs/f2fs/data.c | 38 +++++++++++++-----
>> fs/f2fs/extent_cache.c | 90 +++++++++++++++++++++++++++++++++++++-----
>> fs/f2fs/f2fs.h | 33 +++++++++++++---
>> fs/f2fs/node.c | 20 ++++++++++
>> 5 files changed, 181 insertions(+), 25 deletions(-)
>>
>> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
>> index 455561826c7d..f072ac33eba5 100644
>> --- a/fs/f2fs/compress.c
>> +++ b/fs/f2fs/compress.c
>> @@ -1666,6 +1666,31 @@ void f2fs_put_page_dic(struct page *page)
>> f2fs_put_dic(dic);
>> }
>>
>> +/*
>> + * check whether cluster blocks are contiguous, and add extent cache entry
>> + * only if cluster blocks are logically and physically contiguous.
>> + */
>> +int f2fs_cluster_blocks_are_contiguous(struct dnode_of_data *dn)
>> +{
>> + bool compressed = f2fs_data_blkaddr(dn) == COMPRESS_ADDR;
>> + int i = compressed ? 1 : 0;
>> + block_t first_blkaddr = data_blkaddr(dn->inode, dn->node_page,
>> + dn->ofs_in_node + i);
>> +
>> + for (i += 1; i < F2FS_I(dn->inode)->i_cluster_size; i++) {
>> + block_t blkaddr = data_blkaddr(dn->inode, dn->node_page,
>> + dn->ofs_in_node + i);
>> +
>> + if (!__is_valid_data_blkaddr(blkaddr))
>> + break;
>> + if (first_blkaddr + i - 1 != blkaddr)
>> + return 0;
>> + }
>> +
>> + return compressed ? i - 1 : i;
>> +}
>> +
>> +
>> const struct address_space_operations f2fs_compress_aops = {
>> .releasepage = f2fs_release_page,
>> .invalidatepage = f2fs_invalidate_page,
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index d2cf48c5a2e4..9572d78da4d7 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -2115,6 +2115,8 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
>> sector_t last_block_in_file;
>> const unsigned blocksize = blks_to_bytes(inode, 1);
>> struct decompress_io_ctx *dic = NULL;
>> + struct extent_info_unaligned eiu;
>> + bool extent_cache = false;
>> int i;
>> int ret = 0;
>>
>> @@ -2145,18 +2147,26 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
>> if (f2fs_cluster_is_empty(cc))
>> goto out;
>>
>> - set_new_dnode(&dn, inode, NULL, NULL, 0);
>> - ret = f2fs_get_dnode_of_data(&dn, start_idx, LOOKUP_NODE);
>> - if (ret)
>> - goto out;
>> + if (f2fs_lookup_extent_cache_unaligned(inode, start_idx, &eiu))
>> + extent_cache = true;
>>
>> - f2fs_bug_on(sbi, dn.data_blkaddr != COMPRESS_ADDR);
>> + if (!extent_cache) {
>> + set_new_dnode(&dn, inode, NULL, NULL, 0);
>> + ret = f2fs_get_dnode_of_data(&dn, start_idx, LOOKUP_NODE);
>> + if (ret)
>> + goto out;
>> +
>> + f2fs_bug_on(sbi, dn.data_blkaddr != COMPRESS_ADDR);
>> + }
>>
>> for (i = 1; i < cc->cluster_size; i++) {
>> block_t blkaddr;
>>
>> - blkaddr = data_blkaddr(dn.inode, dn.node_page,
>> - dn.ofs_in_node + i);
>> + if (extent_cache)
>> + blkaddr = eiu.ei.blk + i;
>> + else
>> + blkaddr = data_blkaddr(dn.inode, dn.node_page,
>> + dn.ofs_in_node + i);
>>
>> if (!__is_valid_data_blkaddr(blkaddr))
>> break;
>> @@ -2166,6 +2176,9 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
>> goto out_put_dnode;
>> }
>> cc->nr_cpages++;
>> +
>> + if (extent_cache && i >= eiu.plen)
>> + break;
>> }
>>
>> /* nothing to decompress */
>> @@ -2185,7 +2198,10 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
>> block_t blkaddr;
>> struct bio_post_read_ctx *ctx;
>>
>> - blkaddr = data_blkaddr(dn.inode, dn.node_page,
>> + if (extent_cache)
>> + blkaddr = eiu.plen + i + 1;
>> + else
>> + blkaddr = data_blkaddr(dn.inode, dn.node_page,
>> dn.ofs_in_node + i + 1);
>>
>> f2fs_wait_on_block_writeback(inode, blkaddr);
>> @@ -2231,13 +2247,15 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
>> *last_block_in_bio = blkaddr;
>> }
>>
>> - f2fs_put_dnode(&dn);
>> + if (!extent_cache)
>> + f2fs_put_dnode(&dn);
>>
>> *bio_ret = bio;
>> return 0;
>>
>> out_put_dnode:
>> - f2fs_put_dnode(&dn);
>> + if (!extent_cache)
>> + f2fs_put_dnode(&dn);
>> out:
>> for (i = 0; i < cc->cluster_size; i++) {
>> if (cc->rpages[i]) {
>> diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
>> index 3ebf976a682d..db9de95f90dc 100644
>> --- a/fs/f2fs/extent_cache.c
>> +++ b/fs/f2fs/extent_cache.c
>> @@ -235,7 +235,7 @@ static struct kmem_cache *extent_node_slab;
>> static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi,
>> struct extent_tree *et, struct extent_info *ei,
>> struct rb_node *parent, struct rb_node **p,
>> - bool leftmost)
>> + bool leftmost, bool unaligned)
>> {
>> struct extent_node *en;
>>
>> @@ -247,6 +247,11 @@ static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi,
>> INIT_LIST_HEAD(&en->list);
>> en->et = et;
>>
>> +#ifdef CONFIG_F2FS_FS_COMPRESSION
>> + if (unaligned)
>> + en->plen = ((struct extent_info_unaligned *)ei)->plen;
>> +#endif
>> +
>> rb_link_node(&en->rb_node, parent, p);
>> rb_insert_color_cached(&en->rb_node, &et->root, leftmost);
>> atomic_inc(&et->node_cnt);
>> @@ -320,7 +325,7 @@ static struct extent_node *__init_extent_tree(struct f2fs_sb_info *sbi,
>> struct rb_node **p = &et->root.rb_root.rb_node;
>> struct extent_node *en;
>>
>> - en = __attach_extent_node(sbi, et, ei, NULL, p, true);
>> + en = __attach_extent_node(sbi, et, ei, NULL, p, true, false);
>> if (!en)
>> return NULL;
>>
>> @@ -439,6 +444,17 @@ static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
>> stat_inc_rbtree_node_hit(sbi);
>>
>> *ei = en->ei;
>> +
>> +#ifdef CONFIG_F2FS_FS_COMPRESSION
>> + if (is_inode_flag_set(inode, FI_COMPRESSED_FILE) &&
>> + !f2fs_sb_has_readonly(sbi)) {
>> + struct extent_info_unaligned *eiu =
>> + (struct extent_info_unaligned *)ei;
>> +
>> + eiu->plen = en->plen;
>> + }
>> +#endif
>> +
>> spin_lock(&sbi->extent_lock);
>> if (!list_empty(&en->list)) {
>> list_move_tail(&en->list, &sbi->extent_list);
>> @@ -457,17 +473,18 @@ static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
>> static struct extent_node *__try_merge_extent_node(struct f2fs_sb_info *sbi,
>> struct extent_tree *et, struct extent_info *ei,
>> struct extent_node *prev_ex,
>> - struct extent_node *next_ex)
>> + struct extent_node *next_ex,
>> + bool unaligned)
>> {
>> struct extent_node *en = NULL;
>>
>> - if (prev_ex && __is_back_mergeable(ei, &prev_ex->ei)) {
>> + if (prev_ex && __is_back_mergeable(ei, &prev_ex->ei, unaligned)) {
>> prev_ex->ei.len += ei->len;
>> ei = &prev_ex->ei;
>> en = prev_ex;
>> }
>>
>> - if (next_ex && __is_front_mergeable(ei, &next_ex->ei)) {
>> + if (next_ex && __is_front_mergeable(ei, &next_ex->ei, unaligned)) {
>> next_ex->ei.fofs = ei->fofs;
>> next_ex->ei.blk = ei->blk;
>> next_ex->ei.len += ei->len;
>> @@ -495,7 +512,7 @@ static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
>> struct extent_tree *et, struct extent_info *ei,
>> struct rb_node **insert_p,
>> struct rb_node *insert_parent,
>> - bool leftmost)
>> + bool leftmost, bool unaligned)
>> {
>> struct rb_node **p;
>> struct rb_node *parent = NULL;
>> @@ -512,7 +529,7 @@ static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
>> p = f2fs_lookup_rb_tree_for_insert(sbi, &et->root, &parent,
>> ei->fofs, &leftmost);
>> do_insert:
>> - en = __attach_extent_node(sbi, et, ei, parent, p, leftmost);
>> + en = __attach_extent_node(sbi, et, ei, parent, p, leftmost, unaligned);
>> if (!en)
>> return NULL;
>>
>> @@ -594,7 +611,7 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
>> end - dei.fofs + dei.blk,
>> org_end - end);
>> en1 = __insert_extent_tree(sbi, et, &ei,
>> - NULL, NULL, true);
>> + NULL, NULL, true, false);
>> next_en = en1;
>> } else {
>> en->ei.fofs = end;
>> @@ -633,9 +650,10 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
>> if (blkaddr) {
>>
>> set_extent_info(&ei, fofs, blkaddr, len);
>> - if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en))
>> + if (!__try_merge_extent_node(sbi, et, &ei,
>> + prev_en, next_en, false))
>> __insert_extent_tree(sbi, et, &ei,
>> - insert_p, insert_parent, leftmost);
>> + insert_p, insert_parent, leftmost, false);
>>
>> /* give up extent_cache, if split and small updates happen */
>> if (dei.len >= 1 &&
>> @@ -661,6 +679,47 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
>> f2fs_mark_inode_dirty_sync(inode, true);
>> }
>>
>> +void f2fs_update_extent_tree_range_unaligned(struct inode *inode,
>> + pgoff_t fofs, block_t blkaddr, unsigned int llen,
>> + unsigned int plen)
>> +{
>> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>> + struct extent_tree *et = F2FS_I(inode)->extent_tree;
>> + struct extent_node *en = NULL;
>> + struct extent_node *prev_en = NULL, *next_en = NULL;
>> + struct extent_info_unaligned eiu;
>> + struct rb_node **insert_p = NULL, *insert_parent = NULL;
>> + bool leftmost = false;
>> +
>> + trace_f2fs_update_extent_tree_range(inode, fofs, blkaddr, llen);
>> +
>> + write_lock(&et->lock);
>> +
>> + if (is_inode_flag_set(inode, FI_NO_EXTENT)) {
>> + write_unlock(&et->lock);
>> + return;
>> + }
>> +
>> + en = (struct extent_node *)f2fs_lookup_rb_tree_ret(&et->root,
>> + (struct rb_entry *)et->cached_en, fofs,
>> + (struct rb_entry **)&prev_en,
>> + (struct rb_entry **)&next_en,
>> + &insert_p, &insert_parent, false,
>> + &leftmost);
>> + f2fs_bug_on(sbi, en);
>> +
>> + set_extent_info(&eiu.ei, fofs, blkaddr, llen);
>> + eiu.plen = plen;
>> +
>> + if (!__try_merge_extent_node(sbi, et, (struct extent_info *)&eiu,
>> + prev_en, next_en, true))
>> + __insert_extent_tree(sbi, et, (struct extent_info *)&eiu,
>> + insert_p, insert_parent, leftmost, true);
>> +
>> + write_unlock(&et->lock);
>> +}
>> +
>> +
>> unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
>> {
>> struct extent_tree *et, *next;
>> @@ -818,6 +877,17 @@ bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs,
>> return f2fs_lookup_extent_tree(inode, pgofs, ei);
>> }
>>
>> +#ifdef CONFIG_F2FS_FS_COMPRESSION
>> +bool f2fs_lookup_extent_cache_unaligned(struct inode *inode, pgoff_t pgofs,
>> + struct extent_info_unaligned *eiu)
>> +{
>> + if (!f2fs_may_extent_tree(inode))
>> + return false;
>> +
>> + return f2fs_lookup_extent_tree(inode, pgofs, (struct extent_info *)eiu);
>> +}
>> +#endif
>> +
>> void f2fs_update_extent_cache(struct dnode_of_data *dn)
>> {
>> pgoff_t fofs;
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 0fe239dd50f4..3a02642a26d4 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -578,11 +578,21 @@ struct extent_info {
>> u32 blk; /* start block address of the extent */
>> };
>>
>> +#ifdef CONFIG_F2FS_FS_COMPRESSION
>> +struct extent_info_unaligned {
>> + struct extent_info ei; /* extent info */
>> + unsigned int plen; /* physical extent length of compressed blocks */
>> +};
>> +#endif
>> +
>> struct extent_node {
>> struct rb_node rb_node; /* rb node located in rb-tree */
>> struct extent_info ei; /* extent info */
>> struct list_head list; /* node in global extent list of sbi */
>> struct extent_tree *et; /* extent tree pointer */
>> +#ifdef CONFIG_F2FS_FS_COMPRESSION
>> + unsigned int plen; /* physical extent length of compressed blocks */
>> +#endif
>> };
>>
>> struct extent_tree {
>> @@ -817,22 +827,29 @@ static inline bool __is_discard_front_mergeable(struct discard_info *cur,
>> }
>>
>> static inline bool __is_extent_mergeable(struct extent_info *back,
>> - struct extent_info *front)
>> + struct extent_info *front, bool unaligned)
>> {
>> +#ifdef CONFIG_F2FS_FS_COMPRESSION
>> + struct extent_info_unaligned *be = (struct extent_info_unaligned *)back;
>> + struct extent_info_unaligned *fe = (struct extent_info_unaligned *)front;
>> +
>> + if (!unaligned || be->ei.len != be->plen || fe->ei.len != fe->plen)
>> + return false;
>> +#endif
>> return (back->fofs + back->len == front->fofs &&
>> back->blk + back->len == front->blk);
>> }
>>
>> static inline bool __is_back_mergeable(struct extent_info *cur,
>> - struct extent_info *back)
>> + struct extent_info *back, bool unaligned)
>> {
>> - return __is_extent_mergeable(back, cur);
>> + return __is_extent_mergeable(back, cur, unaligned);
>> }
>>
>> static inline bool __is_front_mergeable(struct extent_info *cur,
>> - struct extent_info *front)
>> + struct extent_info *front, bool unaligned)
>> {
>> - return __is_extent_mergeable(cur, front);
>> + return __is_extent_mergeable(cur, front, unaligned);
>> }
>>
>> extern void f2fs_mark_inode_dirty_sync(struct inode *inode, bool sync);
>> @@ -3972,6 +3989,9 @@ struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root_cached *root,
>> bool force, bool *leftmost);
>> bool f2fs_check_rb_tree_consistence(struct f2fs_sb_info *sbi,
>> struct rb_root_cached *root, bool check_key);
>> +void f2fs_update_extent_tree_range_unaligned(struct inode *inode,
>> + pgoff_t fofs, block_t blkaddr, unsigned int llen,
>> + unsigned int plen);
>> unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink);
>> void f2fs_init_extent_tree(struct inode *inode, struct page *ipage);
>> void f2fs_drop_extent_tree(struct inode *inode);
>> @@ -3979,6 +3999,8 @@ unsigned int f2fs_destroy_extent_node(struct inode *inode);
>> void f2fs_destroy_extent_tree(struct inode *inode);
>> bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs,
>> struct extent_info *ei);
>> +bool f2fs_lookup_extent_cache_unaligned(struct inode *inode, pgoff_t pgofs,
>> + struct extent_info_unaligned *eiu);
>> void f2fs_update_extent_cache(struct dnode_of_data *dn);
>> void f2fs_update_extent_cache_range(struct dnode_of_data *dn,
>> pgoff_t fofs, block_t blkaddr, unsigned int len);
>> @@ -4055,6 +4077,7 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
>> struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc);
>> void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed);
>> void f2fs_put_page_dic(struct page *page);
>> +int f2fs_cluster_blocks_are_contiguous(struct dnode_of_data *dn);
>> int f2fs_init_compress_ctx(struct compress_ctx *cc);
>> void f2fs_destroy_compress_ctx(struct compress_ctx *cc, bool reuse);
>> void f2fs_init_compress_info(struct f2fs_sb_info *sbi);
>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>> index dd611efa8aa4..7be2b01caa2a 100644
>> --- a/fs/f2fs/node.c
>> +++ b/fs/f2fs/node.c
>> @@ -832,6 +832,26 @@ int f2fs_get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int mode)
>> dn->ofs_in_node = offset[level];
>> dn->node_page = npage[level];
>> dn->data_blkaddr = f2fs_data_blkaddr(dn);
>> +
>> +#ifdef CONFIG_F2FS_FS_COMPRESSION
>> + if (is_inode_flag_set(dn->inode, FI_COMPRESSED_FILE) &&
>> + !f2fs_sb_has_readonly(sbi)) {
>> + int blknum = f2fs_cluster_blocks_are_contiguous(dn);
>> +
>> + if (blknum) {
>> + block_t blkaddr = f2fs_data_blkaddr(dn);
>> +
>> + if (blkaddr == COMPRESS_ADDR)
>> + blkaddr = data_blkaddr(dn->inode, dn->node_page,
>> + dn->ofs_in_node + 1);
>> +
>> + f2fs_update_extent_tree_range_unaligned(dn->inode,
>> + index, blkaddr,
>> + F2FS_I(dn->inode)->i_cluster_size,
>> + blknum);
>> + }
>> + }
>> +#endif
>> return 0;
>>
>> release_pages:
>> --
>> 2.22.1
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