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Commit36df6e3dbd("cgroup: make css_rstat_updated nmi safe") used this_cpu_cmpxchg() for the lockless insertion, and therefore required both ARCH_HAVE_NMI_SAFE_CMPXCHG and ARCH_HAS_NMI_SAFE_THIS_CPU_OPS in the NMI guard: on archs without the latter, this_cpu_cmpxchg() falls back to "local_irq_save() + plain cmpxchg", and local_irq_save() cannot mask NMIs. Commit3309b63a22("cgroup: rstat: use LOCK CMPXCHG in css_rstat_updated") later replaced this_cpu_cmpxchg() with plain try_cmpxchg() to fix cross-CPU lockless-list corruption, but left the NMI guard untouched. After that switch, css_rstat_updated() no longer performs any this_cpu_*() RMW operations and only relies on the arch having NMI-safe cmpxchg, so ARCH_HAS_NMI_SAFE_THIS_CPU_OPS is no longer required in the guard. Relax the guard accordingly so that archs which have HAVE_NMI and ARCH_HAVE_NMI_SAFE_CMPXCHG but not ARCH_HAS_NMI_SAFE_THIS_CPU_OPS (e.g. sparc, powerpc on PPC64/BOOK3S) can benefit from the existing CONFIG_MEMCG_NMI_SAFETY_REQUIRES_ATOMIC path. Without this, the css is never queued in NMI on those archs, and the atomics staged by account_{slab,kmem}_nmi_safe() are not drained by flush_nmi_stats(). Fixes:3309b63a22("cgroup: rstat: use LOCK CMPXCHG in css_rstat_updated") Signed-off-by: Cunlong Li <shenxiaogll@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>