On Wed, Feb 17, 2021 at 12:57:25PM -0800, John Hubbard wrote:

On 2/17/21 9:00 AM, Minchan Kim wrote:

quoted

Since CMA is used more widely, it's worth to have CMA
allocation statistics into vmstat. With it, we could
know how agressively system uses cma allocation and
how often it fails.

Signed-off-by: Minchan Kim <minchan@kernel.org>
---
  include/linux/vm_event_item.h |  3 +++
  mm/cma.c                      | 12 +++++++++---
  mm/vmstat.c                   |  4 ++++
  3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 18e75974d4e3..0c567014ce82 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h

@@ -70,6 +70,9 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
  #endif
  #ifdef CONFIG_HUGETLB_PAGE
  		HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,
+#endif
+#ifdef CONFIG_CMA
+		CMA_ALLOC, CMA_ALLOC_FAIL,

This seems wrong: here it's called "alloc", but in the output it's
called "alloc success", and in the implementation it's clearly
"alloc attempt" that is being counted.

Argh, I wanted to introduce CMA_ALLOC, not ALLOC_ATTEMPTS.
Let me fix.

Once these are all made consistent, then the bug should naturally
go away as part of that.

nit: I think the multiple items per line is a weak idea at best, even
though it's used here already. Each item is important and needs to be
visually compared to it's output item later. So one per line might
have helped avoid mismatches, and I think we should change to that to
encourage that trend.

No problem.
Thanks for the review, John.