On Mon, Jun 09, 2025 at 03:56:08PM -0700, Shakeel Butt <shakeel.butt@xxxxxxxxx> wrote: > BPF programs can run in nmi context and may trigger memcg charged memory > allocation in such context. Recently linux added support to nmi safe > page allocation along with memcg charging of such allocations. However > the kmalloc/slab support and corresponding memcg charging is still > lacking, > > To provide nmi safe support for memcg charging for kmalloc/slab > allocations, we need nmi safe memcg stats and for that we need nmi safe > css_rstat_updated() which adds the given cgroup state whose stats are > updated into the per-cpu per-ss update tree. This series took the aim to > make css_rstat_updated() nmi safe. memcg charging relies on page counters and per-cpu stocks. css_rstat_updated() is "only" for statistics (which has admiteddly some in-kernel consumers but those are already affected by batching and flushing errors). Have I missed some updates that make css_rstat_updated() calls critical for memcg charging? I'd find it useful to explain this aspect more in the cover letter. Thanks, Michal
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