Hi Chao, Hmm. The original patch was just going under testing, and we couldn't post them since there is a kernel panic issue. This patch seems quite better approach, so I think we can integrate both of the patches together.
So, how about this patch? Hope you don't mind this. Thanks, >From a7844e0438db9ea9d12b7c0c40b655c3371bd6c9 Mon Sep 17 00:00:00 2001 From: Hou Pengyang <[email protected]> Date: Tue, 26 Jan 2016 12:56:26 +0000 Subject: [PATCH] f2fs: improve shrink performance of extent nodes On the worst case, we need to scan the whole radix tree and every rb-tree to free the victimed extent_nodes when shrinking. Pengyang initially introduced a victim_list to record the victimed extent_nodes, and free these extent_nodes by just scanning a list. Later, Chao Yu enhances the original patch to improve memory footprint by removing victim list. The policy of lru list shrinking becomes: 1) lock lru list's lock 2) trylock extent tree's lock 3) remove extent node from lru list 4) unlock lru list's lock 5) do shrink 6) repeat 1) to 5) Signed-off-by: Hou Pengyang <[email protected]> Signed-off-by: Chao Yu <[email protected]> Signed-off-by: Jaegeuk Kim <[email protected]> --- fs/f2fs/extent_cache.c | 87 +++++++++++++++++++++----------------------------- fs/f2fs/f2fs.h | 1 + 2 files changed, 37 insertions(+), 51 deletions(-) diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c index aae99f2..759b1b1 100644 --- a/fs/f2fs/extent_cache.c +++ b/fs/f2fs/extent_cache.c @@ -33,6 +33,7 @@ static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi, en->ei = *ei; INIT_LIST_HEAD(&en->list); + en->et = et; rb_link_node(&en->rb_node, parent, p); rb_insert_color(&en->rb_node, &et->root); @@ -63,8 +64,8 @@ static void __release_extent_node(struct f2fs_sb_info *sbi, struct extent_tree *et, struct extent_node *en) { spin_lock(&sbi->extent_lock); - if (!list_empty(&en->list)) - list_del_init(&en->list); + f2fs_bug_on(sbi, list_empty(&en->list)); + list_del_init(&en->list); spin_unlock(&sbi->extent_lock); __detach_extent_node(sbi, et, en); @@ -147,7 +148,7 @@ static struct extent_node *__init_extent_tree(struct f2fs_sb_info *sbi, } static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi, - struct extent_tree *et, bool free_all) + struct extent_tree *et) { struct rb_node *node, *next; struct extent_node *en; @@ -157,11 +158,7 @@ static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi, while (node) { next = rb_next(node); en = rb_entry(node, struct extent_node, rb_node); - - if (free_all) - __release_extent_node(sbi, et, en); - else if (list_empty(&en->list)) - __detach_extent_node(sbi, et, en); + __release_extent_node(sbi, et, en); node = next; } @@ -532,7 +529,7 @@ static unsigned int f2fs_update_extent_tree_range(struct inode *inode, } if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT)) - __free_extent_tree(sbi, et, true); + __free_extent_tree(sbi, et); write_unlock(&et->lock); @@ -541,14 +538,10 @@ static unsigned int f2fs_update_extent_tree_range(struct inode *inode, unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) { - struct extent_tree *treevec[EXT_TREE_VEC_SIZE]; struct extent_tree *et, *next; - struct extent_node *en, *tmp; - unsigned long ino = F2FS_ROOT_INO(sbi); - unsigned int found; + struct extent_node *en; unsigned int node_cnt = 0, tree_cnt = 0; int remained; - bool do_free = false; if (!test_opt(sbi, EXTENT_CACHE)) return 0; @@ -561,11 +554,11 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) /* 1. remove unreferenced extent tree */ list_for_each_entry_safe(et, next, &sbi->zombie_list, list) { - if (atomic_read(&et->node_cnt)) { - write_lock(&et->lock); - node_cnt += __free_extent_tree(sbi, et, true); - write_unlock(&et->lock); - } + write_lock(&et->lock); + node_cnt += __free_extent_tree(sbi, et); + write_unlock(&et->lock); + if (atomic_read(&et->node_cnt) > 0) + goto unlock_out; list_del_init(&et->list); radix_tree_delete(&sbi->extent_tree_root, et->ino); @@ -587,42 +580,29 @@ free_node: remained = nr_shrink - (node_cnt + tree_cnt); spin_lock(&sbi->extent_lock); - list_for_each_entry_safe(en, tmp, &sbi->extent_list, list) { - if (!remained--) + for (; remained > 0; remained--) { + if (list_empty(&sbi->extent_list)) break; - list_del_init(&en->list); - do_free = true; - } - spin_unlock(&sbi->extent_lock); - - if (do_free == false) - goto unlock_out; - - /* - * reset ino for searching victims from beginning of global extent tree. - */ - ino = F2FS_ROOT_INO(sbi); - - 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]; + en = list_first_entry(&sbi->extent_list, + struct extent_node, list); + et = en->et; + if (!write_trylock(&et->lock)) { + /* refresh this extent node's position in extent list */ + list_move_tail(&en->list, &sbi->extent_list); + continue; + } - if (!atomic_read(&et->node_cnt)) - continue; + list_del_init(&en->list); + spin_unlock(&sbi->extent_lock); - if (write_trylock(&et->lock)) { - node_cnt += __free_extent_tree(sbi, et, false); - write_unlock(&et->lock); - } + __detach_extent_node(sbi, et, en); - if (node_cnt + tree_cnt >= nr_shrink) - goto unlock_out; - } + write_unlock(&et->lock); + node_cnt++; + spin_lock(&sbi->extent_lock); } + spin_unlock(&sbi->extent_lock); + unlock_out: up_write(&sbi->extent_tree_lock); out: @@ -641,7 +621,7 @@ unsigned int f2fs_destroy_extent_node(struct inode *inode) return 0; write_lock(&et->lock); - node_cnt = __free_extent_tree(sbi, et, true); + node_cnt = __free_extent_tree(sbi, et); write_unlock(&et->lock); return node_cnt; @@ -666,10 +646,15 @@ void f2fs_destroy_extent_tree(struct inode *inode) } /* free all extent info belong to this extent tree */ +free_more: node_cnt = f2fs_destroy_extent_node(inode); /* delete extent tree entry in radix tree */ down_write(&sbi->extent_tree_lock); + if (atomic_read(&et->node_cnt) > 0) { + up_write(&sbi->extent_tree_lock); + goto free_more; + } f2fs_bug_on(sbi, atomic_read(&et->node_cnt)); radix_tree_delete(&sbi->extent_tree_root, inode->i_ino); kmem_cache_free(extent_tree_slab, et); diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index c4e723b..4e7eab9 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -354,6 +354,7 @@ struct extent_node { struct rb_node rb_node; /* rb node located in rb-tree */ struct list_head list; /* node in global extent list of sbi */ struct extent_info ei; /* extent info */ + struct extent_tree *et; /* extent tree pointer */ }; struct extent_tree { -- 2.6.3
