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/mm-codetag-add-pgalloc_tag_copy.patch
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@xxxxxxxxxx>
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@xxxxxxxxxx
Fixes: dcfe378c81f7 ("lib: introduce support for page allocation tagging")
Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Acked-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxx 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
