diff options
| author | Hao Ge <gehao@kylinos.cn> | 2025-06-18 09:58:09 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-07-09 22:42:15 -0700 |
| commit | 59b5ed409d03bc8b7bb153d78afcd7cea9d7bbfa (patch) | |
| tree | b147fa66ee313b6ea508cd56dfc8285b1d295c1f /lib | |
| parent | cf34cfbf1784be7ce9f22789aa157535eff2195f (diff) | |
mm/percpu: conditionally define _shared_alloc_tag via CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU
Recently discovered this entry while checking kallsyms on ARM64:
ffff800083e509c0 D _shared_alloc_tag
If ARCH_NEEDS_WEAK_PER_CPU is not defined(it is only defined for s390 and
alpha architectures), there's no need to statically define the percpu
variable _shared_alloc_tag.
Therefore, we need to implement isolation for this purpose.
When building the core kernel code for s390 or alpha architectures,
ARCH_NEEDS_WEAK_PER_CPU remains undefined (as it is gated by #if
defined(MODULE)). However, when building modules for these architectures,
the macro is explicitly defined.
Therefore, we remove all instances of ARCH_NEEDS_WEAK_PER_CPU from the
code and introduced CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU to replace the
relevant logic. We can now conditionally define the perpcu variable
_shared_alloc_tag based on CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU. This
allows architectures (such as s390/alpha) that require weak definitions
for percpu variables in modules to include the definition, while others
can omit it via compile-time exclusion.
Link: https://lkml.kernel.org/r/20250618015809.1235761-1-hao.ge@linux.dev
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Suggested-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> [s390]
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Chistoph Lameter <cl@linux.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/alloc_tag.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c index 36f07dc950699..41ccfb035b7b4 100644 --- a/lib/alloc_tag.c +++ b/lib/alloc_tag.c @@ -25,8 +25,10 @@ static bool mem_profiling_support; static struct codetag_type *alloc_tag_cttype; +#ifdef CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU DEFINE_PER_CPU(struct alloc_tag_counters, _shared_alloc_tag); EXPORT_SYMBOL(_shared_alloc_tag); +#endif DEFINE_STATIC_KEY_MAYBE(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT, mem_alloc_profiling_key); |