diff options
| author | Hao Ge <hao.ge@linux.dev> | 2026-06-04 10:40:08 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-06-21 11:31:28 -0700 |
| commit | 0c3a350d13ce8bb7c3427597819b0dfbc19ba242 (patch) | |
| tree | 3c4d58f9e7c1180ddf3e57ad99461846ca7de7a0 /include/linux | |
| parent | e3d8707358ea76b78bdec9928937bb9a797f2c8f (diff) | |
mm/alloc_tag: replace fixed-size early PFN array with dynamic linked list
Pages allocated before page_ext is available have their codetag left
uninitialized. Track these early PFNs and clear their codetag in
clear_early_alloc_pfn_tag_refs() to avoid "alloc_tag was not set" warnings
when they are freed later.
Currently a fixed-size array of 8192 entries is used, with a warning if
the limit is exceeded. However, the number of early allocations depends
on the number of CPUs and can be larger than 8192.
Replace the fixed-size array with a dynamically allocated linked list of
pfn_pool structs. Each node is allocated via alloc_page() and mapped to a
pfn_pool containing a next pointer, an atomic slot counter, and a PFN
array that fills the remainder of the page.
The tracking pages themselves are allocated via alloc_page(), which would
trigger __pgalloc_tag_add() -> alloc_tag_add_early_pfn() and recurse
indefinitely. Introduce __GFP_NO_CODETAG (reuses the %__GFP_NO_OBJ_EXT
bit) and pass gfp_flags through pgalloc_tag_add() so that the early path
can skip recording allocations that carry this flag.
Link: https://lore.kernel.org/20260604024008.46592-1-hao.ge@linux.dev
Signed-off-by: Hao Ge <hao.ge@linux.dev>
Suggested-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/alloc_tag.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h index 02de2ede560f..068ba2e77c5d 100644 --- a/include/linux/alloc_tag.h +++ b/include/linux/alloc_tag.h @@ -163,11 +163,11 @@ static inline void alloc_tag_sub_check(union codetag_ref *ref) { WARN_ONCE(ref && !ref->ct, "alloc_tag was not set\n"); } -void alloc_tag_add_early_pfn(unsigned long pfn); +void alloc_tag_add_early_pfn(unsigned long pfn, gfp_t gfp_flags); #else static inline void alloc_tag_add_check(union codetag_ref *ref, struct alloc_tag *tag) {} static inline void alloc_tag_sub_check(union codetag_ref *ref) {} -static inline void alloc_tag_add_early_pfn(unsigned long pfn) {} +static inline void alloc_tag_add_early_pfn(unsigned long pfn, gfp_t gfp_flags) {} #endif /* Caller should verify both ref and tag to be valid */ |