[PATCH RFC 2/2] mm/cma: Consolidate accounting in dedicated functions

From: Jean Delvare
Date: Mon Nov 17 2025 - 06:25:38 EST


Move all accounting to dedicated functions and rename them
accordingly.

Signed-off-by: Jean Delvare <jdelvare@xxxxxxx>
---
This is based on a suggestion by SeongJae Park. Comments welcome.

mm/cma.c | 43 ++++++++++++++++++-------------------------
1 file changed, 18 insertions(+), 25 deletions(-)

--- linux-6.17.orig/mm/cma.c
+++ linux-6.17/mm/cma.c
@@ -37,31 +37,27 @@ struct cma cma_areas[MAX_CMA_AREAS];
unsigned int cma_area_count;

#ifdef CONFIG_SYSFS
-static void cma_sysfs_account_success_pages(struct cma *cma,
- unsigned long nr_pages)
+#define cma_inc_page_counter(n, a) atomic64_add((n), (a))
+#else
+#define cma_inc_page_counter(n, a) do {} while (0)
+#endif
+
+static void cma_account_success(struct cma *cma, unsigned long nr_pages)
{
- atomic64_add(nr_pages, &cma->nr_pages_succeeded);
+ count_vm_event(CMA_ALLOC_SUCCESS);
+ cma_inc_page_counter(nr_pages, &cma->nr_pages_succeeded);
}

-static void cma_sysfs_account_fail_pages(struct cma *cma,
- unsigned long nr_pages)
+static void cma_account_fail(struct cma *cma, unsigned long nr_pages)
{
- atomic64_add(nr_pages, &cma->nr_pages_failed);
+ count_vm_event(CMA_ALLOC_FAIL);
+ cma_inc_page_counter(nr_pages, &cma->nr_pages_failed);
}

-static void cma_sysfs_account_release_pages(struct cma *cma,
- unsigned long nr_pages)
+static void cma_account_release(struct cma *cma, unsigned long nr_pages)
{
- atomic64_add(nr_pages, &cma->nr_pages_released);
+ cma_inc_page_counter(nr_pages, &cma->nr_pages_released);
}
-#else
-static void cma_sysfs_account_success_pages(struct cma *cma,
- unsigned long nr_pages) {};
-static void cma_sysfs_account_fail_pages(struct cma *cma,
- unsigned long nr_pages) {};
-static void cma_sysfs_account_release_pages(struct cma *cma,
- unsigned long nr_pages) {};
-#endif

phys_addr_t cma_get_base(const struct cma *cma)
{
@@ -921,13 +917,10 @@ static struct page *__cma_alloc(struct c
pr_debug("%s(): returned %p\n", __func__, page);
trace_cma_alloc_finish(name, page ? page_to_pfn(page) : 0,
page, count, align, ret);
- if (page) {
- count_vm_event(CMA_ALLOC_SUCCESS);
- cma_sysfs_account_success_pages(cma, count);
- } else {
- count_vm_event(CMA_ALLOC_FAIL);
- cma_sysfs_account_fail_pages(cma, count);
- }
+ if (page)
+ cma_account_success(cma, count);
+ else
+ cma_account_fail(cma, count);

return page;
}
@@ -1029,7 +1022,7 @@ bool cma_release(struct cma *cma, const

free_contig_range(pfn, count);
cma_clear_bitmap(cma, cmr, pfn, count);
- cma_sysfs_account_release_pages(cma, count);
+ cma_account_release(cma, count);
trace_cma_release(cma->name, pfn, pages, count);

return true;

--
Jean Delvare
SUSE L3 Support