2010-03-24 13:32:41

by jing zhang

Subject: [PATCH] ext4: try fast merge operation in ext4_mb_free_metadata()

From: Jing Zhang <[email protected]>

Date: Wed Mar 24 21:30:22 2010

There may exist fast path for merge if merge-able.

Cc: Theodore Ts'o <[email protected]>
Cc: Andreas Dilger <[email protected]>
Cc: Dave Kleikamp <[email protected]>
Signed-off-by: Jing Zhang <[email protected]>

---

--- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800
+++ ext4_mm_leak/mballoc7.c 2010-03-24 21:27:24.000000000 +0800
@@ -4385,6 +4385,24 @@ ext4_mb_free_metadata(handle_t *handle,
}
}

+ if (parent) {
+ /* let's try fast path */
+ entry = rb_entry(parent, struct ext4_free_data, node);
+ if (n == &parent->rb_left) {
+ if (can_merge(new_entry, entry)) {
+ entry->start_blk = new_entry->start_blk;
+ entry->count += new_entry->count;
+ /* and info the caller that new_entry is
+ * not used yet.
+ */
+ return 0;
+ }
+ }
+ else if (can_merge(entry, new_entry)) {
+ entry->count += new_entry->count;
+ return 0;
+ }
+ }
rb_link_node(new_node, parent, n);
rb_insert_color(new_node, &db->bb_free_root);

2010-03-24 17:04:47

by Aneesh Kumar K.V

Subject: Re: [PATCH] ext4: try fast merge operation in ext4_mb_free_metadata()

On Wed, 24 Mar 2010 21:32:39 +0800, jing zhang <[email protected]> wrote:
> From: Jing Zhang <[email protected]>
>
> Date: Wed Mar 24 21:30:22 2010
>
> There may exist fast path for merge if merge-able.
>
> Cc: Theodore Ts'o <[email protected]>
> Cc: Andreas Dilger <[email protected]>
> Cc: Dave Kleikamp <[email protected]>
> Signed-off-by: Jing Zhang <[email protected]>
>
> ---
>
> --- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800
> +++ ext4_mm_leak/mballoc7.c 2010-03-24 21:27:24.000000000 +0800
> @@ -4385,6 +4385,24 @@ ext4_mb_free_metadata(handle_t *handle,
> }
> }
>
> + if (parent) {
> + /* let's try fast path */
> + entry = rb_entry(parent, struct ext4_free_data, node);
> + if (n == &parent->rb_left) {
> + if (can_merge(new_entry, entry)) {
> + entry->start_blk = new_entry->start_blk;
> + entry->count += new_entry->count;
> + /* and info the caller that new_entry is
> + * not used yet.
> + */
> + return 0;

return 0 on success so you may want -1 here

> + }
> + }
> + else if (can_merge(entry, new_entry)) {
> + entry->count += new_entry->count;
> + return 0;
> + }
> + }
> rb_link_node(new_node, parent, n);
> rb_insert_color(new_node, &db->bb_free_root);
> --

-aneesh

2010-03-25 14:11:58

by jing zhang

Subject: Re: [PATCH] ext4: try fast merge operation in ext4_mb_free_metadata()

2010/3/25, Aneesh Kumar K. V <[email protected]>:
> On Wed, 24 Mar 2010 21:32:39 +0800, jing zhang <[email protected]> wrote:
>> From: Jing Zhang <[email protected]>
>>
>> Date: Wed Mar 24 21:30:22 2010
>>
>> There may exist fast path for merge if merge-able.
>>
>> Cc: Theodore Ts'o <[email protected]>
>> Cc: Andreas Dilger <[email protected]>
>> Cc: Dave Kleikamp <[email protected]>
>> Signed-off-by: Jing Zhang <[email protected]>
>>
>> ---
>>
>> --- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800
>> +++ ext4_mm_leak/mballoc7.c 2010-03-24 21:27:24.000000000 +0800
>> @@ -4385,6 +4385,24 @@ ext4_mb_free_metadata(handle_t *handle,
>> }
>> }
>>
>> + if (parent) {
>> + /* let's try fast path */
>> + entry = rb_entry(parent, struct ext4_free_data, node);
>> + if (n == &parent->rb_left) {
>> + if (can_merge(new_entry, entry)) {
>> + entry->start_blk = new_entry->start_blk;
>> + entry->count += new_entry->count;
>> + /* and info the caller that new_entry is
>> + * not used yet.
>> + */
>> + return 0;
>
> return 0 on success so you may want -1 here

Agree.

- zj

>
>> + }
>> + }
>> + else if (can_merge(entry, new_entry)) {
>> + entry->count += new_entry->count;
>> + return 0;
>> + }
>> + }
>> rb_link_node(new_node, parent, n);
>> rb_insert_color(new_node, &db->bb_free_root);
>> --
>
> -aneesh
>