Re: [PATCH 4/4] ext4: reduce unnecessary memory allocation in alloc_flex_gd()

From: Baokun Li
Date: Thu Oct 19 2023 - 08:04:54 EST


On 2023/10/19 19:57, Jan Kara wrote:
On Wed 18-10-23 19:42:21, Baokun Li wrote:
When a large flex_bg file system is resized, the number of groups to be
added may be small, and a large amount of memory that will not be used will
be allocated. Therefore, resize_bg can be set to the size after the number
of new_group_data to be used is aligned upwards to the power of 2. This
does not affect the disk layout after online resize and saves some memory.

Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
Looks good, just one small comment below. Feel free to add:

Reviewed-by: Jan Kara <jack@xxxxxxx>


@@ -248,6 +250,14 @@ static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned int flexbg_size)
else
flex_gd->resize_bg = flexbg_size;
+ /* Avoid allocating new groups that will not be used. */
Perhaps make the comment more understandable like:
/* Avoid allocating large 'groups' array if not needed */

Honza
Thank you very much for your careful review!
I'll change the comment to this more understandable one in the next version.

Cheers!
--
With Best Regards,
Baokun Li
.