From 6eca32567455db2db38b1126e0d6ad8f0e5c3ed9 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Tue, 9 Apr 2024 21:22:58 +0200 Subject: [PATCH] trace/events/page_ref: trace the raw page mapcount value We want to limit the use of page_mapcount() to the places where it is absolutely necessary. We already trace raw page->refcount, raw page->flags and raw page->mapping, and don't involve any folios. Let's also trace the raw mapcount value that does not consider the entire mapcount of large folios, and we don't add "1" to it. When dealing with typed folios, this makes a lot more sense. ... and it's for debugging purposes only either way. Link: https://lkml.kernel.org/r/20240409192301.907377-16-david@redhat.com Signed-off-by: David Hildenbrand Cc: Chris Zankel Cc: Hugh Dickins Cc: John Paul Adrian Glaubitz Cc: Jonathan Corbet Cc: Matthew Wilcox (Oracle) Cc: Max Filippov Cc: Miaohe Lin Cc: Muchun Song Cc: Naoya Horiguchi Cc: Peter Xu Cc: Richard Chang Cc: Rich Felker Cc: Ryan Roberts Cc: Yang Shi Cc: Yin Fengwei Cc: Yoshinori Sato Cc: Zi Yan Signed-off-by: Andrew Morton --- include/trace/events/page_ref.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/trace/events/page_ref.h b/include/trace/events/page_ref.h index 8a99c1cd417b..fe33a255b7d0 100644 --- a/include/trace/events/page_ref.h +++ b/include/trace/events/page_ref.h @@ -30,7 +30,7 @@ DECLARE_EVENT_CLASS(page_ref_mod_template, __entry->pfn = page_to_pfn(page); __entry->flags = page->flags; __entry->count = page_ref_count(page); - __entry->mapcount = page_mapcount(page); + __entry->mapcount = atomic_read(&page->_mapcount); __entry->mapping = page->mapping; __entry->mt = get_pageblock_migratetype(page); __entry->val = v; @@ -79,7 +79,7 @@ DECLARE_EVENT_CLASS(page_ref_mod_and_test_template, __entry->pfn = page_to_pfn(page); __entry->flags = page->flags; __entry->count = page_ref_count(page); - __entry->mapcount = page_mapcount(page); + __entry->mapcount = atomic_read(&page->_mapcount); __entry->mapping = page->mapping; __entry->mt = get_pageblock_migratetype(page); __entry->val = v; -- 2.25.1