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From: Jan Kara <jack@suse.cz>
To: Baokun Li <libaokun1@huawei.com>
Cc: linux-ext4@vger.kernel.org, tytso@mit.edu,
	adilger.kernel@dilger.ca, jack@suse.cz, ritesh.list@gmail.com,
	linux-kernel@vger.kernel.org, yi.zhang@huawei.com,
	yangerkun@huawei.com, yukuai3@huawei.com
Subject: Re: [PATCH 4/4] ext4: reduce unnecessary memory allocation in alloc_flex_gd()
Date: Thu, 19 Oct 2023 13:57:19 +0200	[thread overview]
Message-ID: <20231019115719.54wd6q6dxanaodid@quack3> (raw)
In-Reply-To: <20231018114221.441526-5-libaokun1@huawei.com>

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@huawei.com>

Looks good, just one small comment below. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>


> @@ -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
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

  reply	other threads:[~2023-10-19 11:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-18 11:42 [PATCH 0/4] ext4: fix WARN_ON in alloc_flex_gd() Baokun Li
2023-10-18 11:42 ` [PATCH 1/4] ext4: unify the type of flexbg_size to unsigned int Baokun Li
2023-10-19 11:21   ` Jan Kara
2023-10-18 11:42 ` [PATCH 2/4] ext4: remove unnecessary check from alloc_flex_gd() Baokun Li
2023-10-19 11:24   ` Jan Kara
2023-10-18 11:42 ` [PATCH 3/4] ext4: avoid online resizing failures due to oversized flex bg Baokun Li
2023-10-19 11:44   ` Jan Kara
2023-10-18 11:42 ` [PATCH 4/4] ext4: reduce unnecessary memory allocation in alloc_flex_gd() Baokun Li
2023-10-19 11:57   ` Jan Kara [this message]
2023-10-19 12:03     ` Baokun Li

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