2024-01-17 11:56:23

by yangerkun

Subject: [PATCH 1/2] ext4: remove unused buddy_loaded in ext4_mb_seq_groups_show

We can just first call ext4_mb_unload_buddy, then copy information from
ext4_group_info. So remove this unused value.

Signed-off-by: yangerkun <[email protected]>
---
fs/ext4/mballoc.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index f44f668e407f..139f232bdbb5 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2990,8 +2990,7 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
{
struct super_block *sb = pde_data(file_inode(seq->file));
ext4_group_t group = (ext4_group_t) ((unsigned long) v);
- int i;
- int err, buddy_loaded = 0;
+ int i, err;
struct ext4_buddy e4b;
struct ext4_group_info *grinfo;
unsigned char blocksize_bits = min_t(unsigned char,
@@ -3021,14 +3020,10 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
seq_printf(seq, "#%-5u: I/O error\n", group);
return 0;
}
- buddy_loaded = 1;
+ ext4_mb_unload_buddy(&e4b);
}

memcpy(&sg, grinfo, i);
-
- if (buddy_loaded)
- ext4_mb_unload_buddy(&e4b);
-
seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
sg.info.bb_fragments, sg.info.bb_first_free);
for (i = 0; i <= 13; i++)
--
2.39.2

2024-01-17 12:56:55

by Jan Kara

Subject: Re: [PATCH 1/2] ext4: remove unused buddy_loaded in ext4_mb_seq_groups_show

On Wed 17-01-24 19:52:22, yangerkun wrote:
> We can just first call ext4_mb_unload_buddy, then copy information from
> ext4_group_info. So remove this unused value.
>
> Signed-off-by: yangerkun <[email protected]>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <[email protected]>

Although I'd prefer if you add a comment before memcpy() like:

/*
* We care only about free space counters in the group info and
* these are safe to access even after the buddy has been unloaded
*/

Honza

> ---
> fs/ext4/mballoc.c | 9 ++-------
> 1 file changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index f44f668e407f..139f232bdbb5 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2990,8 +2990,7 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
> {
> struct super_block *sb = pde_data(file_inode(seq->file));
> ext4_group_t group = (ext4_group_t) ((unsigned long) v);
> - int i;
> - int err, buddy_loaded = 0;
> + int i, err;
> struct ext4_buddy e4b;
> struct ext4_group_info *grinfo;
> unsigned char blocksize_bits = min_t(unsigned char,
> @@ -3021,14 +3020,10 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
> seq_printf(seq, "#%-5u: I/O error\n", group);
> return 0;
> }
> - buddy_loaded = 1;
> + ext4_mb_unload_buddy(&e4b);
> }
>
> memcpy(&sg, grinfo, i);
> -
> - if (buddy_loaded)
> - ext4_mb_unload_buddy(&e4b);
> -
> seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
> sg.info.bb_fragments, sg.info.bb_first_free);
> for (i = 0; i <= 13; i++)
> --
> 2.39.2
>
--
Jan Kara <[email protected]>
SUSE Labs, CR

2024-01-18 04:22:55

by yangerkun

Subject: Re: [PATCH 1/2] ext4: remove unused buddy_loaded in ext4_mb_seq_groups_show

在 2024/1/17 20:56, Jan Kara 写道:
> On Wed 17-01-24 19:52:22, yangerkun wrote:
>> We can just first call ext4_mb_unload_buddy, then copy information from
>> ext4_group_info. So remove this unused value.
>>
>> Signed-off-by: yangerkun <[email protected]>
>
> Looks good. Feel free to add:
>
> Reviewed-by: Jan Kara <[email protected]>
>
> Although I'd prefer if you add a comment before memcpy() like:
>
> /*
> * We care only about free space counters in the group info and
> * these are safe to access even after the buddy has been unloaded
> */
>
> Honza
>

Thanks a lot for your review! I will do it next version!

>> ---
>> fs/ext4/mballoc.c | 9 ++-------
>> 1 file changed, 2 insertions(+), 7 deletions(-)
>>
>> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
>> index f44f668e407f..139f232bdbb5 100644
>> --- a/fs/ext4/mballoc.c
>> +++ b/fs/ext4/mballoc.c
>> @@ -2990,8 +2990,7 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
>> {
>> struct super_block *sb = pde_data(file_inode(seq->file));
>> ext4_group_t group = (ext4_group_t) ((unsigned long) v);
>> - int i;
>> - int err, buddy_loaded = 0;
>> + int i, err;
>> struct ext4_buddy e4b;
>> struct ext4_group_info *grinfo;
>> unsigned char blocksize_bits = min_t(unsigned char,
>> @@ -3021,14 +3020,10 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
>> seq_printf(seq, "#%-5u: I/O error\n", group);
>> return 0;
>> }
>> - buddy_loaded = 1;
>> + ext4_mb_unload_buddy(&e4b);
>> }
>>
>> memcpy(&sg, grinfo, i);
>> -
>> - if (buddy_loaded)
>> - ext4_mb_unload_buddy(&e4b);
>> -
>> seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
>> sg.info.bb_fragments, sg.info.bb_first_free);
>> for (i = 0; i <= 13; i++)
>> --
>> 2.39.2
>>