diff options
author | Chao Yu <chao2.yu@samsung.com> | 2015-02-05 17:54:31 +0800 |
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committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2015-03-03 09:58:46 -0800 |
commit | 429511cdf8b3a9b894b914f282a9293df405a449 (patch) | |
tree | dfec625ca5189c65d109b39d0423913a0d0d2418 /fs/f2fs/data.c | |
parent | 13054c548a1c9e78f8f8ba5f134909cb56152285 (diff) | |
download | linux-429511cdf8b3a9b894b914f282a9293df405a449.tar.bz2 |
f2fs: add core functions for rb-tree extent cache
This patch adds core functions including slab cache init function and
init/lookup/update/shrink/destroy function for rb-tree based extent cache.
Thank Jaegeuk Kim and Changman Lee as they gave much suggestion about detail
design and implementation of extent cache.
Todo:
* register rb-based extent cache shrink with mm shrink interface.
v2:
o move set_extent_info and __is_{extent,back,front}_mergeable into f2fs.h.
o introduce __{attach,detach}_extent_node for code readability.
o add cond_resched() when fail to invoke kmem_cache_alloc/radix_tree_insert.
o fix some coding style and typo issues.
v3:
o fix oops due to using an unassigned pointer.
o use list_del to remove extent node in shrink list.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Changman Lee <cm224.lee@samsung.com>
[Jaegeuk Kim: add static for some funcitons and declare in f2fs.h]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/data.c')
-rw-r--r-- | fs/f2fs/data.c | 411 |
1 files changed, 411 insertions, 0 deletions
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 3dbaa475fce4..f52745346205 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -25,6 +25,9 @@ #include "trace.h" #include <trace/events/f2fs.h> +static struct kmem_cache *extent_tree_slab; +static struct kmem_cache *extent_node_slab; + static void f2fs_read_end_io(struct bio *bio, int err) { struct bio_vec *bvec; @@ -366,6 +369,383 @@ end_update: return need_update; } +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) +{ + struct extent_node *en; + + en = kmem_cache_alloc(extent_node_slab, GFP_ATOMIC); + if (!en) + return NULL; + + en->ei = *ei; + INIT_LIST_HEAD(&en->list); + + rb_link_node(&en->rb_node, parent, p); + rb_insert_color(&en->rb_node, &et->root); + et->count++; + atomic_inc(&sbi->total_ext_node); + return en; +} + +static void __detach_extent_node(struct f2fs_sb_info *sbi, + struct extent_tree *et, struct extent_node *en) +{ + rb_erase(&en->rb_node, &et->root); + et->count--; + atomic_dec(&sbi->total_ext_node); +} + +static struct extent_node *__lookup_extent_tree(struct extent_tree *et, + unsigned int fofs) +{ + struct rb_node *node = et->root.rb_node; + struct extent_node *en; + + while (node) { + en = rb_entry(node, struct extent_node, rb_node); + + if (fofs < en->ei.fofs) + node = node->rb_left; + else if (fofs >= en->ei.fofs + en->ei.len) + node = node->rb_right; + else + return en; + } + return NULL; +} + +static struct extent_node *__try_back_merge(struct f2fs_sb_info *sbi, + struct extent_tree *et, struct extent_node *en) +{ + struct extent_node *prev; + struct rb_node *node; + + node = rb_prev(&en->rb_node); + if (!node) + return NULL; + + prev = rb_entry(node, struct extent_node, rb_node); + if (__is_back_mergeable(&en->ei, &prev->ei)) { + en->ei.fofs = prev->ei.fofs; + en->ei.blk = prev->ei.blk; + en->ei.len += prev->ei.len; + __detach_extent_node(sbi, et, prev); + return prev; + } + return NULL; +} + +static struct extent_node *__try_front_merge(struct f2fs_sb_info *sbi, + struct extent_tree *et, struct extent_node *en) +{ + struct extent_node *next; + struct rb_node *node; + + node = rb_next(&en->rb_node); + if (!node) + return NULL; + + next = rb_entry(node, struct extent_node, rb_node); + if (__is_front_mergeable(&en->ei, &next->ei)) { + en->ei.len += next->ei.len; + __detach_extent_node(sbi, et, next); + return next; + } + return NULL; +} + +static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi, + struct extent_tree *et, struct extent_info *ei, + struct extent_node **den) +{ + struct rb_node **p = &et->root.rb_node; + struct rb_node *parent = NULL; + struct extent_node *en; + + while (*p) { + parent = *p; + en = rb_entry(parent, struct extent_node, rb_node); + + if (ei->fofs < en->ei.fofs) { + if (__is_front_mergeable(ei, &en->ei)) { + f2fs_bug_on(sbi, !den); + en->ei.fofs = ei->fofs; + en->ei.blk = ei->blk; + en->ei.len += ei->len; + *den = __try_back_merge(sbi, et, en); + return en; + } + p = &(*p)->rb_left; + } else if (ei->fofs >= en->ei.fofs + en->ei.len) { + if (__is_back_mergeable(ei, &en->ei)) { + f2fs_bug_on(sbi, !den); + en->ei.len += ei->len; + *den = __try_front_merge(sbi, et, en); + return en; + } + p = &(*p)->rb_right; + } else { + f2fs_bug_on(sbi, 1); + } + } + + return __attach_extent_node(sbi, et, ei, parent, p); +} + +static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi, + struct extent_tree *et, bool free_all) +{ + struct rb_node *node, *next; + struct extent_node *en; + unsigned int count = et->count; + + node = rb_first(&et->root); + while (node) { + next = rb_next(node); + en = rb_entry(node, struct extent_node, rb_node); + + if (free_all) { + spin_lock(&sbi->extent_lock); + if (!list_empty(&en->list)) + list_del_init(&en->list); + spin_unlock(&sbi->extent_lock); + } + + if (free_all || list_empty(&en->list)) { + __detach_extent_node(sbi, et, en); + kmem_cache_free(extent_node_slab, en); + } + node = next; + } + + return count - et->count; +} + +static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs, + struct extent_info *ei) +{ + struct f2fs_sb_info *sbi = F2FS_I_SB(inode); + struct extent_tree *et; + struct extent_node *en; + + if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT)) + return false; + + down_read(&sbi->extent_tree_lock); + et = radix_tree_lookup(&sbi->extent_tree_root, inode->i_ino); + if (!et) { + up_read(&sbi->extent_tree_lock); + return false; + } + atomic_inc(&et->refcount); + up_read(&sbi->extent_tree_lock); + + read_lock(&et->lock); + en = __lookup_extent_tree(et, pgofs); + if (en) { + *ei = en->ei; + spin_lock(&sbi->extent_lock); + if (!list_empty(&en->list)) + list_move_tail(&en->list, &sbi->extent_list); + spin_unlock(&sbi->extent_lock); + stat_inc_read_hit(sbi->sb); + } + stat_inc_total_hit(sbi->sb); + read_unlock(&et->lock); + + atomic_dec(&et->refcount); + return en ? true : false; +} + +static void f2fs_update_extent_tree(struct inode *inode, pgoff_t fofs, + block_t blkaddr) +{ + struct f2fs_sb_info *sbi = F2FS_I_SB(inode); + nid_t ino = inode->i_ino; + struct extent_tree *et; + struct extent_node *en = NULL, *en1 = NULL, *en2 = NULL, *en3 = NULL; + struct extent_node *den = NULL; + struct extent_info ei, dei; + unsigned int endofs; + + if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT)) + return; + + down_write(&sbi->extent_tree_lock); + et = radix_tree_lookup(&sbi->extent_tree_root, ino); + if (!et) { + et = f2fs_kmem_cache_alloc(extent_tree_slab, GFP_NOFS); + f2fs_radix_tree_insert(&sbi->extent_tree_root, ino, et); + memset(et, 0, sizeof(struct extent_tree)); + et->ino = ino; + et->root = RB_ROOT; + rwlock_init(&et->lock); + atomic_set(&et->refcount, 0); + et->count = 0; + sbi->total_ext_tree++; + } + atomic_inc(&et->refcount); + up_write(&sbi->extent_tree_lock); + + write_lock(&et->lock); + + /* 1. lookup and remove existing extent info in cache */ + en = __lookup_extent_tree(et, fofs); + if (!en) + goto update_extent; + + dei = en->ei; + __detach_extent_node(sbi, et, en); + + /* 2. if extent can be split more, split and insert the left part */ + if (dei.len > 1) { + /* insert left part of split extent into cache */ + if (fofs - dei.fofs >= F2FS_MIN_EXTENT_LEN) { + set_extent_info(&ei, dei.fofs, dei.blk, + fofs - dei.fofs); + en1 = __insert_extent_tree(sbi, et, &ei, NULL); + } + + /* insert right part of split extent into cache */ + endofs = dei.fofs + dei.len - 1; + if (endofs - fofs >= F2FS_MIN_EXTENT_LEN) { + set_extent_info(&ei, fofs + 1, + fofs - dei.fofs + dei.blk, endofs - fofs); + en2 = __insert_extent_tree(sbi, et, &ei, NULL); + } + } + +update_extent: + /* 3. update extent in extent cache */ + if (blkaddr) { + set_extent_info(&ei, fofs, blkaddr, 1); + en3 = __insert_extent_tree(sbi, et, &ei, &den); + } + + /* 4. update in global extent list */ + spin_lock(&sbi->extent_lock); + if (en && !list_empty(&en->list)) + list_del(&en->list); + /* + * en1 and en2 split from en, they will become more and more smaller + * fragments after splitting several times. So if the length is smaller + * than F2FS_MIN_EXTENT_LEN, we will not add them into extent tree. + */ + if (en1) + list_add_tail(&en1->list, &sbi->extent_list); + if (en2) + list_add_tail(&en2->list, &sbi->extent_list); + if (en3) { + if (list_empty(&en3->list)) + list_add_tail(&en3->list, &sbi->extent_list); + else + list_move_tail(&en3->list, &sbi->extent_list); + } + if (den && !list_empty(&den->list)) + list_del(&den->list); + spin_unlock(&sbi->extent_lock); + + /* 5. release extent node */ + if (en) + kmem_cache_free(extent_node_slab, en); + if (den) + kmem_cache_free(extent_node_slab, den); + + write_unlock(&et->lock); + atomic_dec(&et->refcount); +} + +void f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) +{ + struct extent_tree *treevec[EXT_TREE_VEC_SIZE]; + struct extent_node *en, *tmp; + unsigned long ino = F2FS_ROOT_INO(sbi); + struct radix_tree_iter iter; + void **slot; + unsigned int found; + + if (available_free_memory(sbi, EXTENT_CACHE)) + return; + + spin_lock(&sbi->extent_lock); + list_for_each_entry_safe(en, tmp, &sbi->extent_list, list) { + if (!nr_shrink--) + break; + list_del_init(&en->list); + } + spin_unlock(&sbi->extent_lock); + + down_read(&sbi->extent_tree_lock); + while ((found = radix_tree_gang_lookup(&sbi->extent_tree_root, + (void **)treevec, ino, EXT_TREE_VEC_SIZE))) { + unsigned i; + + ino = treevec[found - 1]->ino + 1; + for (i = 0; i < found; i++) { + struct extent_tree *et = treevec[i]; + + atomic_inc(&et->refcount); + write_lock(&et->lock); + __free_extent_tree(sbi, et, false); + write_unlock(&et->lock); + atomic_dec(&et->refcount); + } + } + up_read(&sbi->extent_tree_lock); + + down_write(&sbi->extent_tree_lock); + radix_tree_for_each_slot(slot, &sbi->extent_tree_root, &iter, + F2FS_ROOT_INO(sbi)) { + struct extent_tree *et = (struct extent_tree *)*slot; + + if (!atomic_read(&et->refcount) && !et->count) { + radix_tree_delete(&sbi->extent_tree_root, et->ino); + kmem_cache_free(extent_tree_slab, et); + sbi->total_ext_tree--; + } + } + up_write(&sbi->extent_tree_lock); +} + +void f2fs_destroy_extent_tree(struct inode *inode) +{ + struct f2fs_sb_info *sbi = F2FS_I_SB(inode); + struct extent_tree *et; + + down_read(&sbi->extent_tree_lock); + et = radix_tree_lookup(&sbi->extent_tree_root, inode->i_ino); + if (!et) { + up_read(&sbi->extent_tree_lock); + goto out; + } + atomic_inc(&et->refcount); + up_read(&sbi->extent_tree_lock); + + /* free all extent info belong to this extent tree */ + write_lock(&et->lock); + __free_extent_tree(sbi, et, true); + write_unlock(&et->lock); + + atomic_dec(&et->refcount); + + /* try to find and delete extent tree entry in radix tree */ + down_write(&sbi->extent_tree_lock); + et = radix_tree_lookup(&sbi->extent_tree_root, inode->i_ino); + if (!et) { + up_write(&sbi->extent_tree_lock); + goto out; + } + f2fs_bug_on(sbi, atomic_read(&et->refcount) || et->count); + radix_tree_delete(&sbi->extent_tree_root, inode->i_ino); + kmem_cache_free(extent_tree_slab, et); + sbi->total_ext_tree--; + up_write(&sbi->extent_tree_lock); +out: + return; +} + static bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs, struct extent_info *ei) { @@ -1256,6 +1636,37 @@ static sector_t f2fs_bmap(struct address_space *mapping, sector_t block) return generic_block_bmap(mapping, block, get_data_block); } +void init_extent_cache_info(struct f2fs_sb_info *sbi) +{ + INIT_RADIX_TREE(&sbi->extent_tree_root, GFP_NOIO); + init_rwsem(&sbi->extent_tree_lock); + INIT_LIST_HEAD(&sbi->extent_list); + spin_lock_init(&sbi->extent_lock); + sbi->total_ext_tree = 0; + atomic_set(&sbi->total_ext_node, 0); +} + +int __init create_extent_cache(void) +{ + extent_tree_slab = f2fs_kmem_cache_create("f2fs_extent_tree", + sizeof(struct extent_tree)); + if (!extent_tree_slab) + return -ENOMEM; + extent_node_slab = f2fs_kmem_cache_create("f2fs_extent_node", + sizeof(struct extent_node)); + if (!extent_node_slab) { + kmem_cache_destroy(extent_tree_slab); + return -ENOMEM; + } + return 0; +} + +void destroy_extent_cache(void) +{ + kmem_cache_destroy(extent_node_slab); + kmem_cache_destroy(extent_tree_slab); +} + const struct address_space_operations f2fs_dblock_aops = { .readpage = f2fs_read_data_page, .readpages = f2fs_read_data_pages, |