path: root/fs/proc/internal.h
diff options
authorAlexey Dobriyan <>2018-04-10 16:31:52 -0700
committerLinus Torvalds <>2018-04-11 10:28:34 -0700
commitb4884f23331ae31e9ecb617956986c3b76ab9a91 (patch)
tree2f25f7337f1aedbfed4fa18b1b26ffa208136544 /fs/proc/internal.h
parentc4219edf1de2af44fd98903f72f6e1ceb7f3c701 (diff)
proc: move "struct proc_dir_entry" into kmem cache
"struct proc_dir_entry" is variable sized because of 0-length trailing array for name, however, because of SLAB padding allocations it is possible to make "struct proc_dir_entry" fixed sized and allocate same amount of memory. It buys fine-grained debugging with poisoning and usercopy protection which is not possible with kmalloc-* caches. Currently, on 32-bit 91+ byte allocations go into kmalloc-128 and on 64-bit 147+ byte allocations go to kmalloc-192 anyway. Additional memory is allocated only for 38/46+ byte long names which are rare or may not even exist in the wild. Link: Signed-off-by: Alexey Dobriyan <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'fs/proc/internal.h')
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index dc00ef8538cb..0ead00771384 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -52,11 +52,20 @@ struct proc_dir_entry {
struct proc_dir_entry *parent;
struct rb_root_cached subdir;
struct rb_node subdir_node;
+ char *name;
umode_t mode;
u8 namelen;
- char name[];
+#ifdef CONFIG_64BIT
+#define SIZEOF_PDE_INLINE_NAME (192-147)
+#define SIZEOF_PDE_INLINE_NAME (128-91)
+ char inline_name[SIZEOF_PDE_INLINE_NAME];
} __randomize_layout;
+extern struct kmem_cache *proc_dir_entry_cache;
+void pde_free(struct proc_dir_entry *pde);
union proc_op {
int (*proc_get_link)(struct dentry *, struct path *);
int (*proc_show)(struct seq_file *m,