On Mon, May 20, 2019 at 05:37:41AM +0530, Amit Kumar wrote:
HI,
mm/slub.c: line 3973 int __kmem_cache_shrink(struct kmem_cache *s) { int node; int i; struct kmem_cache_node *n; struct page *page; struct page *t; struct list_head discard; struct list_head promote[SHRINK_PROMOTE_MAX]; unsigned long flags; int ret = 0;
flush_all(s); for_each_kmem_cache_node(s, node, n) {
How uninitialized variable node is being used in macro for_each_kmem_cache_node?
node is a local variable with no extern and not initialized.
mm/slab.h: line 490 #define for_each_kmem_cache_node(__s, __node, __n) \ for (__node = 0; __node < nr_node_ids; __node++) \
This _is_ the initialization of node. Macros are kinda funky, there isn't much more to say about that other than perhaps read up some more about how macros work in C and read a bunch more macros in the kernel e.g. include/linux/list.h Good luck, Tobin.