From: Roman Gushchin <guro@fb.com>
To: Song Liu <songliubraving@fb.com>
Cc: bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Shakeel Butt <shakeelb@google.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Kernel Team <Kernel-team@fb.com>
Subject: Re: [PATCH bpf-next v5 06/34] bpf: prepare for memcg-based memory accounting for bpf maps
Date: Fri, 13 Nov 2020 11:40:23 -0800 [thread overview]
Message-ID: <20201113194023.GD2955309@carbon.dhcp.thefacebook.com> (raw)
In-Reply-To: <3645417A-F356-4422-B336-874DFEB74014@fb.com>
On Fri, Nov 13, 2020 at 09:46:49AM -0800, Song Liu wrote:
>
>
> > On Nov 12, 2020, at 2:15 PM, Roman Gushchin <guro@fb.com> wrote:
>
> [...]
>
> >
> > +#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;
> }
Yeah, it's a good idea!
in_interrupt() check is very cheap (like checking some bits in a per-cpu variable),
so I don't think there will be any measurable difference. So I suggest to implement
it later as an enhancement on top (maybe in the next merge window), to avoid an another
delay. Otherwise I'll need to send a patch to mm@, wait for reviews and an inclusion
into the mm tree, etc). Does it work for you?
Thanks!
next prev parent reply other threads:[~2020-11-13 19:40 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 22:15 [PATCH bpf-next v5 00/34] bpf: switch to memcg-based memory accounting Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 05/34] bpf: memcg-based memory accounting for bpf progs Roman Gushchin
2020-11-13 17:31 ` Song Liu
2020-11-12 22:15 ` [PATCH bpf-next v5 06/34] bpf: prepare for memcg-based memory accounting for bpf maps Roman Gushchin
2020-11-13 17:46 ` Song Liu
2020-11-13 19:40 ` Roman Gushchin [this message]
2020-11-13 20:48 ` Song Liu
2020-11-12 22:15 ` [PATCH bpf-next v5 07/34] bpf: " Roman Gushchin
2020-11-13 18:04 ` Song Liu
2020-11-12 22:15 ` [PATCH bpf-next v5 08/34] bpf: refine memcg-based memory accounting for arraymap maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 09/34] bpf: refine memcg-based memory accounting for cpumap maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 10/34] bpf: memcg-based memory accounting for cgroup storage maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 11/34] bpf: refine memcg-based memory accounting for devmap maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 12/34] bpf: refine memcg-based memory accounting for hashtab maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 13/34] bpf: memcg-based memory accounting for lpm_trie maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 14/34] bpf: memcg-based memory accounting for bpf ringbuffer Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 15/34] bpf: memcg-based memory accounting for bpf local storage maps Roman Gushchin
2020-11-13 18:07 ` Song Liu
2020-11-12 22:15 ` [PATCH bpf-next v5 16/34] bpf: refine memcg-based memory accounting for sockmap and sockhash maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 17/34] bpf: refine memcg-based memory accounting for xskmap maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 18/34] bpf: eliminate rlimit-based memory accounting for arraymap maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 19/34] bpf: eliminate rlimit-based memory accounting for bpf_struct_ops maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 20/34] bpf: eliminate rlimit-based memory accounting for cpumap maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 21/34] bpf: eliminate rlimit-based memory accounting for cgroup storage maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 22/34] bpf: eliminate rlimit-based memory accounting for devmap maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 23/34] bpf: eliminate rlimit-based memory accounting for hashtab maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 24/34] bpf: eliminate rlimit-based memory accounting for lpm_trie maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 25/34] bpf: eliminate rlimit-based memory accounting for queue_stack_maps maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 26/34] bpf: eliminate rlimit-based memory accounting for reuseport_array maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 27/34] bpf: eliminate rlimit-based memory accounting for bpf ringbuffer Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 28/34] bpf: eliminate rlimit-based memory accounting for sockmap and sockhash maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 29/34] bpf: eliminate rlimit-based memory accounting for stackmap maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 30/34] bpf: eliminate rlimit-based memory accounting for xskmap maps Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 31/34] bpf: eliminate rlimit-based memory accounting for bpf local storage maps Roman Gushchin
2020-11-13 18:14 ` Song Liu
2020-11-13 19:33 ` Roman Gushchin
2020-11-13 20:53 ` Song Liu
2020-11-12 22:15 ` [PATCH bpf-next v5 32/34] bpf: eliminate rlimit-based memory accounting infra for bpf maps Roman Gushchin
2020-11-13 18:17 ` Song Liu
2020-11-12 22:15 ` [PATCH bpf-next v5 33/34] bpf: eliminate rlimit-based memory accounting for bpf progs Roman Gushchin
2020-11-12 22:15 ` [PATCH bpf-next v5 34/34] bpf: samples: do not touch RLIMIT_MEMLOCK Roman Gushchin
[not found] ` <20201112221543.3621014-2-guro@fb.com>
2020-11-12 22:56 ` [PATCH bpf-next v5 01/34] mm: memcontrol: use helpers to read page's memcg data Stephen Rothwell
2020-11-13 0:26 ` Roman Gushchin
2020-11-13 3:04 ` Alexei Starovoitov
2020-11-13 3:18 ` Andrew Morton
2020-11-13 3:25 ` Alexei Starovoitov
2020-11-13 3:40 ` Andrew Morton
2020-11-13 4:08 ` Alexei Starovoitov
2020-11-13 4:01 ` Roman Gushchin
2020-11-13 14:25 ` Shakeel Butt
2020-11-13 17:18 ` Roman Gushchin
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