x86, bts: memory accounting

Impact: move the BTS buffer accounting to the mlock bucket

Add alloc_locked_buffer() and free_locked_buffer() functions to mm/mlock.c
to kalloc a buffer and account the locked memory to current.

Account the memory for the BTS buffer to the tracer.

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index ffee2f7..9979d3f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1286,5 +1286,7 @@
 int vmemmap_populate(struct page *start_page, unsigned long pages, int node);
 void vmemmap_populate_print_last(void);
 
+extern void *alloc_locked_buffer(size_t size);
+extern void free_locked_buffer(void *buffer, size_t size);
 #endif /* __KERNEL__ */
 #endif /* _LINUX_MM_H */