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: http://lkml.kernel.org/r/20180223205504.GA17139@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 98797b76..cd45abf 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -208,7 +208,8 @@ struct proc_dir_entry proc_root = {
.proc_fops = &proc_root_operations,
.parent = &proc_root,
.subdir = RB_ROOT_CACHED,
- .name = "/proc",
+ .name = proc_root.inline_name,
+ .inline_name = "/proc",
};
int pid_ns_prepare_proc(struct pid_namespace *ns)
