The patch titled Subject: alloc_tag: introduce clear_page_tag_ref() helper function has been added to the -mm mm-hotfixes-unstable branch. Its filename is alloc_tag-introduce-clear_page_tag_ref-helper-function.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days

------------------------------------------------------ From: Suren Baghdasaryan surenb@google.com Subject: alloc_tag: introduce clear_page_tag_ref() helper function Date: Tue, 13 Aug 2024 08:07:56 -0700

In several cases we are freeing pages which were not allocated using common page allocators. For such cases, in order to keep allocation accounting correct, we should clear the page tag to indicate that the page being freed is expected to not have a valid allocation tag. Introduce clear_page_tag_ref() helper function to be used for this.

Link: https://lkml.kernel.org/r/20240813150758.855881-1-surenb@google.com Fixes: d224eb0287fb ("codetag: debug: mark codetags for reserved pages as empty") Signed-off-by: Suren Baghdasaryan surenb@google.com Suggested-by: David Hildenbrand david@redhat.com Acked-by: David Hildenbrand david@redhat.com Cc: Kees Cook keescook@chromium.org Cc: Kent Overstreet kent.overstreet@linux.dev Cc: Pasha Tatashin pasha.tatashin@soleen.com Cc: Sourav Panda souravpanda@google.com Cc: Vlastimil Babka vbabka@suse.cz Cc: stable@vger.kernel.org [6.10] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

include/linux/pgalloc_tag.h | 13 +++++++++++++ mm/mm_init.c | 10 +--------- mm/page_alloc.c | 9 +-------- 3 files changed, 15 insertions(+), 17 deletions(-)

--- a/include/linux/pgalloc_tag.h~alloc_tag-introduce-clear_page_tag_ref-helper-function +++ a/include/linux/pgalloc_tag.h @@ -43,6 +43,18 @@ static inline void put_page_tag_ref(unio page_ext_put(page_ext_from_codetag_ref(ref)); }

+static inline void clear_page_tag_ref(struct page *page) +{ + if (mem_alloc_profiling_enabled()) { + union codetag_ref *ref = get_page_tag_ref(page); + + if (ref) { + set_codetag_empty(ref); + put_page_tag_ref(ref); + } + } +} + static inline void pgalloc_tag_add(struct page *page, struct task_struct *task, unsigned int nr) { @@ -126,6 +138,7 @@ static inline void pgalloc_tag_sub_pages

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 clear_page_tag_ref(struct page *page) {} static inline void pgalloc_tag_add(struct page *page, struct task_struct *task, unsigned int nr) {} static inline void pgalloc_tag_sub(struct page *page, unsigned int nr) {} --- a/mm/mm_init.c~alloc_tag-introduce-clear_page_tag_ref-helper-function +++ a/mm/mm_init.c @@ -2459,15 +2459,7 @@ void __init memblock_free_pages(struct p }

/* pages were reserved and not allocated */ - if (mem_alloc_profiling_enabled()) { - union codetag_ref *ref = get_page_tag_ref(page); - - if (ref) { - set_codetag_empty(ref); - put_page_tag_ref(ref); - } - } - + clear_page_tag_ref(page); __free_pages_core(page, order, MEMINIT_EARLY); }

--- a/mm/page_alloc.c~alloc_tag-introduce-clear_page_tag_ref-helper-function +++ a/mm/page_alloc.c @@ -5815,14 +5815,7 @@ unsigned long free_reserved_area(void *s

void free_reserved_page(struct page *page) { - if (mem_alloc_profiling_enabled()) { - union codetag_ref *ref = get_page_tag_ref(page); - - if (ref) { - set_codetag_empty(ref); - put_page_tag_ref(ref); - } - } + clear_page_tag_ref(page); ClearPageReserved(page); init_page_count(page); __free_page(page); _

Patches currently in -mm which might be from surenb@google.com are

alloc_tag-introduce-clear_page_tag_ref-helper-function.patch alloc_tag-mark-pages-reserved-during-cma-activation-as-not-tagged.patch