The patch titled
Subject: mm: fix non-compound multi-order memory accounting in __free_pages
has been added to the -mm mm-unstable branch. Its filename is
mm-fix-non-compound-multi-order-memory-accounting-in-__free_pages.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-fix-non-compound-multi-order-memory-accounting-in-__free_pages.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: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Subject: mm: fix non-compound multi-order memory accounting in __free_pages
Date: Thu, 21 Mar 2024 09:36:42 -0700
When a non-compound multi-order page is freed, it is possible that a
speculative reference keeps the page pinned. In this case we free all
pages except for the first page, which will be freed later by the last
put_page(). However the page passed to put_page() is indistinguishable
from an order-0 page, so it cannot do the accounting, just as it cannot
free the subsequent pages. Do the accounting here, where we free the
pages.
Link: https://lkml.kernel.org/r/20240321163705.3067592-21-surenb@xxxxxxxxxx
Reported-by: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Alex Gaynor <alex.gaynor@xxxxxxxxx>
Cc: Alice Ryhl <aliceryhl@xxxxxxxxxx>
Cc: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
Cc: Benno Lossin <benno.lossin@xxxxxxxxx>
Cc: "Björn Roy Baron" <bjorn3_gh@xxxxxxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Gary Guo <gary@xxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Miguel Ojeda <ojeda@xxxxxxxxxx>
Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Wedson Almeida Filho <wedsonaf@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/pgalloc_tag.h | 24 ++++++++++++++++++++++++
mm/page_alloc.c | 5 ++++-
2 files changed, 28 insertions(+), 1 deletion(-)
--- a/include/linux/pgalloc_tag.h~mm-fix-non-compound-multi-order-memory-accounting-in-__free_pages
+++ a/include/linux/pgalloc_tag.h
@@ -96,12 +96,36 @@ out:
page_ext_put(page_ext);
}
+static inline struct alloc_tag *pgalloc_tag_get(struct page *page)
+{
+ struct alloc_tag *tag = NULL;
+
+ if (mem_alloc_profiling_enabled()) {
+ union codetag_ref *ref = get_page_tag_ref(page);
+
+ alloc_tag_sub_check(ref);
+ if (ref && ref->ct)
+ tag = ct_to_alloc_tag(ref->ct);
+ put_page_tag_ref(ref);
+ }
+
+ return tag;
+}
+
+static inline void pgalloc_tag_sub_pages(struct alloc_tag *tag, unsigned int nr)
+{
+ if (mem_alloc_profiling_enabled() && tag)
+ this_cpu_sub(tag->counters->bytes, PAGE_SIZE * nr);
+}
+
#else /* CONFIG_MEM_ALLOC_PROFILING */
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) {}
static inline void pgalloc_tag_split(struct page *page, unsigned int nr) {}
+static inline struct alloc_tag *pgalloc_tag_get(struct page *page) { return NULL; }
+static inline void pgalloc_tag_sub_pages(struct alloc_tag *tag, unsigned int nr) {}
#endif /* CONFIG_MEM_ALLOC_PROFILING */
--- a/mm/page_alloc.c~mm-fix-non-compound-multi-order-memory-accounting-in-__free_pages
+++ a/mm/page_alloc.c
@@ -4664,12 +4664,15 @@ void __free_pages(struct page *page, uns
{
/* get PageHead before we drop reference */
int head = PageHead(page);
+ struct alloc_tag *tag = pgalloc_tag_get(page);
if (put_page_testzero(page))
free_the_page(page, order);
- else if (!head)
+ else if (!head) {
+ pgalloc_tag_sub_pages(tag, (1 << order) - 1);
while (order-- > 0)
free_the_page(page + (1 << order), order);
+ }
}
EXPORT_SYMBOL(__free_pages);
_
Patches currently in -mm which might be from surenb@xxxxxxxxxx are
mm-introduce-slabobj_ext-to-support-slab-object-extensions.patch
mm-introduce-__gfp_no_obj_ext-flag-to-selectively-prevent-slabobj_ext-creation.patch
mm-slab-introduce-slab_no_obj_ext-to-avoid-obj_ext-creation.patch
slab-objext-introduce-objext_flags-as-extension-to-page_memcg_data_flags.patch
lib-code-tagging-framework.patch
lib-code-tagging-module-support.patch
lib-prevent-module-unloading-if-memory-is-not-freed.patch
lib-add-allocation-tagging-support-for-memory-allocation-profiling.patch
lib-introduce-support-for-page-allocation-tagging.patch
lib-introduce-early-boot-parameter-to-avoid-page_ext-memory-overhead.patch
mm-percpu-increase-percpu_module_reserve-to-accommodate-allocation-tags.patch
change-alloc_pages-name-in-dma_map_ops-to-avoid-name-conflicts.patch
mm-enable-page-allocation-tagging.patch
mm-create-new-codetag-references-during-page-splitting.patch
mm-fix-non-compound-multi-order-memory-accounting-in-__free_pages.patch
mm-page_ext-enable-early_page_ext-when-config_mem_alloc_profiling_debug=y.patch
lib-add-codetag-reference-into-slabobj_ext.patch
mm-slab-add-allocation-accounting-into-slab-allocation-and-free-paths.patch
mm-slab-enable-slab-allocation-tagging-for-kmalloc-and-friends.patch
mm-percpu-enable-per-cpu-allocation-tagging.patch
lib-add-memory-allocations-report-in-show_mem.patch
codetag-debug-skip-objext-checking-when-its-for-objext-itself.patch
codetag-debug-mark-codetags-for-reserved-pages-as-empty.patch
codetag-debug-introduce-objexts_alloc_fail-to-mark-failed-slab_ext-allocations.patch
