From 43d9bb4236fd1dd2e4646bee7f556542eefa422a Mon Sep 17 00:00:00 2001 From: Harry Yoo Date: Tue, 13 Jan 2026 15:18:39 +0900 Subject: [PATCH] ext4: specify the free pointer offset for ext4_inode_cache Convert ext4_inode_cache to use the kmem_cache_args interface and specify a free pointer offset. Since ext4_inode_cache uses a constructor, the free pointer would be placed after the object to prevent overwriting fields used by the constructor. However, some fields such as ->i_flags are not used by the constructor and can safely be repurposed for the free pointer. Specify the free pointer offset at i_flags to reduce the object size. Signed-off-by: Harry Yoo Link: https://patch.msgid.link/20260113061845.159790-4-harry.yoo@oracle.com Signed-off-by: Vlastimil Babka --- fs/ext4/super.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 87205660c5d02..6f1c2c4978716 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1491,12 +1491,19 @@ static void init_once(void *foo) static int __init init_inodecache(void) { - ext4_inode_cachep = kmem_cache_create_usercopy("ext4_inode_cache", - sizeof(struct ext4_inode_info), 0, - SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT, - offsetof(struct ext4_inode_info, i_data), - sizeof_field(struct ext4_inode_info, i_data), - init_once); + struct kmem_cache_args args = { + .useroffset = offsetof(struct ext4_inode_info, i_data), + .usersize = sizeof_field(struct ext4_inode_info, i_data), + .use_freeptr_offset = true, + .freeptr_offset = offsetof(struct ext4_inode_info, i_flags), + .ctor = init_once, + }; + + ext4_inode_cachep = kmem_cache_create("ext4_inode_cache", + sizeof(struct ext4_inode_info), + &args, + SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT); + if (ext4_inode_cachep == NULL) return -ENOMEM; return 0; -- 2.47.3