Hi,

On Mon, Jan 29, 2024 at 03:01:24PM +0530, Anshuman Khandual wrote:

On 1/25/24 22:12, Alexandru Elisei wrote:

quoted

Similar to the two events that relate to CMA allocations, add the
CMA_RELEASE_SUCCESS and CMA_RELEASE_FAIL events that count when CMA pages
are freed.

How is this is going to be beneficial towards analyzing CMA alloc/release
behaviour - particularly with respect to this series. OR just adding this
from parity perspective with CMA alloc side counters ? Regardless this
CMA change too could be discussed separately.

Added for parity and because it's useful for this series (see my reply to
the previous patch where I discuss how I've used the counters).

Thanks,
Alex

quoted

Signed-off-by: Alexandru Elisei <redacted>
---

Changes since rfc v2:

* New patch.

 include/linux/vm_event_item.h | 2 ++
 mm/cma.c                      | 6 +++++-
 mm/vmstat.c                   | 2 ++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 747943bc8cc2..aba5c5bf8127 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h

@@ -83,6 +83,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 #ifdef CONFIG_CMA
 		CMA_ALLOC_SUCCESS,
 		CMA_ALLOC_FAIL,
+		CMA_RELEASE_SUCCESS,
+		CMA_RELEASE_FAIL,
 #endif
 		UNEVICTABLE_PGCULLED,	/* culled to noreclaim list */
 		UNEVICTABLE_PGSCANNED,	/* scanned for reclaimability */

diff --git a/mm/cma.c b/mm/cma.c
index dbf7fe8cb1bd..543bb6b3be8e 100644
--- a/mm/cma.c
+++ b/mm/cma.c

@@ -562,8 +562,10 @@ bool cma_release(struct cma *cma, const struct page *pages,
 {
 	unsigned long pfn;
 
-	if (!cma_pages_valid(cma, pages, count))
+	if (!cma_pages_valid(cma, pages, count)) {
+		count_vm_events(CMA_RELEASE_FAIL, count);
 		return false;
+	}
 
 	pr_debug("%s(page %p, count %lu)\n", __func__, (void *)pages, count);
 

@@ -575,6 +577,8 @@ bool cma_release(struct cma *cma, const struct page *pages,
 	cma_clear_bitmap(cma, pfn, count);
 	trace_cma_release(cma->name, pfn, pages, count);
 
+	count_vm_events(CMA_RELEASE_SUCCESS, count);
+
 	return true;
 }
 

diff --git a/mm/vmstat.c b/mm/vmstat.c
index db79935e4a54..eebfd5c6c723 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c

@@ -1340,6 +1340,8 @@ const char * const vmstat_text[] = {
 #ifdef CONFIG_CMA
 	"cma_alloc_success",
 	"cma_alloc_fail",
+	"cma_release_success",
+	"cma_release_fail",
 #endif
 	"unevictable_pgs_culled",
 	"unevictable_pgs_scanned",