>From e5c6600d01c4462c4e1ee0c70ec1d9319862077d Mon Sep 17 00:00:00 2001
From: Chao Yu <chao2...@samsung.com>
Date: Thu, 2 Jul 2015 18:52:46 +0800
Subject: [PATCH] f2fs: reduce lock overhead of extent node releasing
Open and close critical section for each extent node when traversing rb-tree
results in high overhead of cpu, slows thing down.
This patch alternates to batch mode for removing extent nodes under spin lock.
Signed-off-by: Chao Yu <chao2...@samsung.com>
---
fs/f2fs/data.c | 28 ++++++++++++++++++++--------
1 file changed, 20 insertions(+), 8 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 6a706dd..7fb56a0 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -441,19 +441,31 @@ static unsigned int __free_extent_tree(struct
f2fs_sb_info *sbi,
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 (!et->count)
+ return 0;
+
+ /* 1. remove all extent nodes in global lru list */
+ if (free_all) {
+ spin_lock(&sbi->extent_lock);
+ 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);
+ node = next;
}
+ spin_unlock(&sbi->extent_lock);
+ }
+
+ /* 2. release all extent nodes which are not in global lru list */
+ node = rb_first(&et->root);
+ while (node) {
+ next = rb_next(node);
+ en = rb_entry(node, struct extent_node, rb_node);
- if (free_all || list_empty(&en->list)) {
+ if (list_empty(&en->list)) {
__detach_extent_node(sbi, et, en);
kmem_cache_free(extent_node_slab, en);
}
--
2.4.2
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