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btrfs: use kvzalloc to allocate btrfs_fs_info

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The srcu_struct in btrfs_fs_info scales in size with NR_CPUS.  On
kernels built with NR_CPUS=8192, this can result in kmalloc failures
that prevent mounting.

There is work in progress to try to resolve this for every user of
srcu_struct but using kvzalloc will work around the failures until
that is complete.

As an example with NR_CPUS=512 on x86_64: the overall size of
subvol_srcu is 3460 bytes, fs_info is 6496.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Jeff Mahoney 2018-02-15 22:59:47 -05:00 committed by David Sterba
parent fd649f10c3
commit a8fd1f7174
2 changed files with 2 additions and 2 deletions
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2
fs/btrfs/ctree.h
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@ -2974,7 +2974,7 @@ static inline void free_fs_info(struct btrfs_fs_info *fs_info)
kfree(fs_info->super_copy);
kfree(fs_info->super_for_commit);
security_free_mnt_opts(&fs_info->security_opts);
kfree(fs_info);
kvfree(fs_info);
}
/* tree mod log functions from ctree.c */

2
fs/btrfs/super.c
View file

@ -1545,7 +1545,7 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
* it for searching for existing supers, so this lets us do that and
* then open_ctree will properly initialize everything later.
*/
fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
if (!fs_info) {
error = -ENOMEM;
goto error_sec_opts;