Messages in this thread | | | From | Song Liu <> | Subject | Re: [PATCH bpf-next v5 06/34] bpf: prepare for memcg-based memory accounting for bpf maps | Date | Fri, 13 Nov 2020 17:46:49 +0000 |
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> On Nov 12, 2020, at 2:15 PM, Roman Gushchin <guro@fb.com> wrote:
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> > +#ifdef CONFIG_MEMCG_KMEM > +static __always_inline int __bpf_map_update_elem(struct bpf_map *map, void *key, > + void *value, u64 flags) > +{ > + struct mem_cgroup *old_memcg; > + bool in_interrupt; > + int ret; > + > + /* > + * If update from an interrupt context results in a memory allocation, > + * the memory cgroup to charge can't be determined from the context > + * of the current task. Instead, we charge the memory cgroup, which > + * contained a process created the map. > + */ > + in_interrupt = in_interrupt(); > + if (in_interrupt) > + old_memcg = set_active_memcg(map->memcg);
set_active_memcg() checks in_interrupt() again. Maybe we can introduce another helper to avoid checking it twice? Something like
static inline struct mem_cgroup * set_active_memcg_int(struct mem_cgroup *memcg) { struct mem_cgroup *old;
old = this_cpu_read(int_active_memcg); this_cpu_write(int_active_memcg, memcg); return old; }
Thanks, Song
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