[PATCH v3 33/35] codetag: debug: mark codetags for reserved pages as empty

Suren Baghdasaryan
2024-02-12T21:40:45Z

To avoid debug warnings while freeing reserved pages which were not
allocated with usual allocators, mark their codetags as empty before
freeing.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
include/linux/alloc_tag.h | 2 ++
include/linux/mm.h | 8 ++++++++
include/linux/pgalloc_tag.h | 2 ++
mm/mm_init.c | 9 +++++++++
4 files changed, 21 insertions(+)

diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h
index 1f3207097b03..102caf62c2a9 100644
--- a/include/linux/alloc_tag.h
+++ b/include/linux/alloc_tag.h
@@ -95,6 +95,7 @@ static inline void set_codetag_empty(union codetag_ref *ref)
#else /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */

static inline bool is_codetag_empty(union codetag_ref *ref) { return false; }
+static inline void set_codetag_empty(union codetag_ref *ref) {}

#endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */

@@ -155,6 +156,7 @@ static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes) {}
static inline void alloc_tag_sub_noalloc(union codetag_ref *ref, size_t bytes) {}
static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag,
size_t bytes) {}
+static inline void set_codetag_empty(union codetag_ref *ref) {}

#endif

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f5a97dec5169..ac1b661987ed 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -5,6 +5,7 @@
#include <linux/errno.h>
#include <linux/mmdebug.h>
#include <linux/gfp.h>
+#include <linux/pgalloc_tag.h>
#include <linux/bug.h>
#include <linux/list.h>
#include <linux/mmzone.h>
@@ -3112,6 +3113,13 @@ extern void reserve_bootmem_region(phys_addr_t start,
/* Free the reserved page into the buddy system, so it gets managed. */
static inline void free_reserved_page(struct page *page)
{
+ union codetag_ref *ref;
+
+ ref = get_page_tag_ref(page);
+ if (ref) {
+ set_codetag_empty(ref);
+ put_page_tag_ref(ref);
+ }
ClearPageReserved(page);
init_page_count(page);
__free_page(page);
diff --git a/include/linux/pgalloc_tag.h b/include/linux/pgalloc_tag.h
index 0174aff5e871..ae9b0f359264 100644
--- a/include/linux/pgalloc_tag.h
+++ b/include/linux/pgalloc_tag.h
@@ -93,6 +93,8 @@ static inline void pgalloc_tag_split(struct page *page, unsigned int nr)

#else /* CONFIG_MEM_ALLOC_PROFILING */

+static inline union codetag_ref *get_page_tag_ref(struct page *page) { return NULL; }
+static inline void put_page_tag_ref(union codetag_ref *ref) {}
static inline void pgalloc_tag_add(struct page *page, struct task_struct *task,
unsigned int order) {}
static inline void pgalloc_tag_sub(struct page *page, unsigned int order) {}
diff --git a/mm/mm_init.c b/mm/mm_init.c
index e9ea2919d02d..f5386632fe86 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -2566,6 +2566,7 @@ void __init set_dma_reserve(unsigned long new_dma_reserve)
void __init memblock_free_pages(struct page *page, unsigned long pfn,
unsigned int order)
{
+ union codetag_ref *ref;

if (IS_ENABLED(CONFIG_DEFERRED_STRUCT_PAGE_INIT)) {
int nid = early_pfn_to_nid(pfn);
@@ -2578,6 +2579,14 @@ void __init memblock_free_pages(struct page *page, unsigned long pfn,
/* KMSAN will take care of these pages. */
return;
}
+
+ /* pages were reserved and not allocated */
+ ref = get_page_tag_ref(page);
+ if (ref) {
+ set_codetag_empty(ref);
+ put_page_tag_ref(ref);
+ }
+
__free_pages_core(page, order);
}

--
2.43.0.687.g38aa6559b0-goog