Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1175947 > unrolled thread
| Started by | Chao Yu <yuchaochina@hotmail.com> |
|---|---|
| First post | 2015-07-02 14:50 +0200 |
| Last post | 2015-07-05 11:00 +0200 |
| Articles | 2 — 2 participants |
Back to article view | Back to linux.kernel
[PATCH] f2fs: reduce lock overhead of extent node releasing Chao Yu <yuchaochina@hotmail.com> - 2015-07-02 14:50 +0200
Re: [PATCH] f2fs: reduce lock overhead of extent node releasing Jaegeuk Kim <jaegeuk@kernel.org> - 2015-07-05 11:00 +0200
| From | Chao Yu <yuchaochina@hotmail.com> |
|---|---|
| Date | 2015-07-02 14:50 +0200 |
| Subject | [PATCH] f2fs: reduce lock overhead of extent node releasing |
| Message-ID | <pHM6d-2Kb-17@gated-at.bofh.it> |
From e5c6600d01c4462c4e1ee0c70ec1d9319862077d Mon Sep 17 00:00:00 2001
From: Chao Yu <chao2.yu@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.yu@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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[toc] | [next] | [standalone]
| From | Jaegeuk Kim <jaegeuk@kernel.org> |
|---|---|
| Date | 2015-07-05 11:00 +0200 |
| Message-ID | <pINWi-Dz-3@gated-at.bofh.it> |
| In reply to | #1175947 |
On Thu, Jul 02, 2015 at 08:40:12PM +0800, Chao Yu wrote:
> >From e5c6600d01c4462c4e1ee0c70ec1d9319862077d Mon Sep 17 00:00:00 2001
> From: Chao Yu <chao2.yu@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.yu@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 */
Hmm,
Is there any overhead to traverse the rb_tree twice and any spin_lock delay
caused by contention?
Thanks,
> + 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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[toc] | [prev] | [standalone]
Back to top | Article view | linux.kernel
csiph-web