diff options
| author | Baokun Li <libaokun1@huawei.com> | 2023-10-23 09:30:57 +0800 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2023-12-14 10:54:47 -0500 |
| commit | 665d3e0af4d35acf9a5f58dfd471bc27dbf55880 (patch) | |
| tree | 15dafab5d2e7a4307b1d5c489c9dd04945c250a9 /fs/ext4 | |
| parent | 5d1935ac02ca5aee364a449a35e2977ea84509b0 (diff) | |
ext4: reduce unnecessary memory allocation in alloc_flex_gd()
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>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20231023013057.2117948-5-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/resize.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index e168a9f59600..4d4a5a32e310 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -235,8 +235,10 @@ struct ext4_new_flex_group_data { * * Returns NULL on failure otherwise address of the allocated structure. */ -static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned int flexbg_size) +static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned int flexbg_size, + ext4_group_t o_group, ext4_group_t n_group) { + ext4_group_t last_group; struct ext4_new_flex_group_data *flex_gd; flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS); @@ -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 large 'groups' array if not needed */ + last_group = o_group | (flex_gd->resize_bg - 1); + if (n_group <= last_group) + flex_gd->resize_bg = 1 << fls(n_group - o_group + 1); + else if (n_group - last_group < flex_gd->resize_bg) + flex_gd->resize_bg = 1 << max(fls(last_group - o_group + 1), + fls(n_group - last_group)); + flex_gd->groups = kmalloc_array(flex_gd->resize_bg, sizeof(struct ext4_new_group_data), GFP_NOFS); @@ -2131,7 +2141,7 @@ retry: if (err) goto out; - flex_gd = alloc_flex_gd(flexbg_size); + flex_gd = alloc_flex_gd(flexbg_size, o_group, n_group); if (flex_gd == NULL) { err = -ENOMEM; goto out; |