The patch titled Subject: mm/codetag: add pgalloc_tag_copy() has been added to the -mm mm-unstable branch. Its filename is mm-codetag-add-pgalloc_tag_copy.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-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Yu Zhao yuzhao@google.com Subject: mm/codetag: add pgalloc_tag_copy() Date: Thu, 5 Sep 2024 22:21:08 -0600

Add pgalloc_tag_copy() to transfer the codetag from the old folio to the new one during migration. This makes original allocation sites persist cross migration rather than lump into the get_new_folio callbacks passed into migrate_pages(), e.g., compaction_alloc():

# echo 1 >/proc/sys/vm/compact_memory # grep compaction_alloc /proc/allocinfo

Before this patch: 132968448 32463 mm/compaction.c:1880 func:compaction_alloc

After this patch: 0 0 mm/compaction.c:1880 func:compaction_alloc

Link: https://lkml.kernel.org/r/20240906042108.1150526-3-yuzhao@google.com Fixes: dcfe378c81f7 ("lib: introduce support for page allocation tagging") Signed-off-by: Yu Zhao yuzhao@google.com Acked-by: Suren Baghdasaryan surenb@google.com Cc: stable@vger.kernel.org Cc: Kent Overstreet kent.overstreet@linux.dev Cc: Muchun Song muchun.song@linux.dev Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

include/linux/alloc_tag.h | 24 ++++++++++-------------- include/linux/mm.h | 27 +++++++++++++++++++++++++++ mm/migrate.c | 1 + 3 files changed, 38 insertions(+), 14 deletions(-)

--- a/include/linux/alloc_tag.h~mm-codetag-add-pgalloc_tag_copy +++ a/include/linux/alloc_tag.h @@ -137,7 +137,16 @@ static inline void alloc_tag_sub_check(u /* Caller should verify both ref and tag to be valid */ static inline void __alloc_tag_ref_set(union codetag_ref *ref, struct alloc_tag *tag) { + alloc_tag_add_check(ref, tag); + if (!ref || !tag) + return; + ref->ct = &tag->ct; +} + +static inline void alloc_tag_ref_set(union codetag_ref *ref, struct alloc_tag *tag) +{ + __alloc_tag_ref_set(ref, tag); /* * We need in increment the call counter every time we have a new * allocation or when we split a large allocation into smaller ones. @@ -147,22 +156,9 @@ static inline void __alloc_tag_ref_set(u this_cpu_inc(tag->counters->calls); }

-static inline void alloc_tag_ref_set(union codetag_ref *ref, struct alloc_tag *tag) -{ - alloc_tag_add_check(ref, tag); - if (!ref || !tag) - return; - - __alloc_tag_ref_set(ref, tag); -} - static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag, size_t bytes) { - alloc_tag_add_check(ref, tag); - if (!ref || !tag) - return; - - __alloc_tag_ref_set(ref, tag); + alloc_tag_ref_set(ref, tag); this_cpu_add(tag->counters->bytes, bytes); }

--- a/include/linux/mm.h~mm-codetag-add-pgalloc_tag_copy +++ a/include/linux/mm.h @@ -4161,10 +4161,37 @@ static inline void pgalloc_tag_split(str } } } + +static inline void pgalloc_tag_copy(struct folio *new, struct folio *old) +{ + struct alloc_tag *tag; + union codetag_ref *ref; + + tag = pgalloc_tag_get(&old->page); + if (!tag) + return; + + ref = get_page_tag_ref(&new->page); + if (!ref) + return; + + /* Clear the old ref to the original allocation tag. */ + clear_page_tag_ref(&old->page); + /* Decrement the counters of the tag on get_new_folio. */ + alloc_tag_sub(ref, folio_nr_pages(new)); + + __alloc_tag_ref_set(ref, tag); + + put_page_tag_ref(ref); +} #else /* !CONFIG_MEM_ALLOC_PROFILING */ static inline void pgalloc_tag_split(struct folio *folio, int old_order, int new_order) { } + +static inline void pgalloc_tag_copy(struct folio *new, struct folio *old) +{ +} #endif /* CONFIG_MEM_ALLOC_PROFILING */

#endif /* _LINUX_MM_H */ --- a/mm/migrate.c~mm-codetag-add-pgalloc_tag_copy +++ a/mm/migrate.c @@ -743,6 +743,7 @@ void folio_migrate_flags(struct folio *n folio_set_readahead(newfolio);

folio_copy_owner(newfolio, folio); + pgalloc_tag_copy(newfolio, folio);

mem_cgroup_migrate(folio, newfolio); } _

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

mm-remap-unused-subpages-to-shared-zeropage-when-splitting-isolated-thp.patch mm-codetag-fix-a-typo.patch mm-codetag-fix-pgalloc_tag_split.patch mm-codetag-add-pgalloc_tag_copy.patch