From: Andrew Morton <akpm@linux-foundation.org>
To: "Hui Zhu" <hui.zhu@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>,
JP Kobryn <inwardvessel@gmail.com>,
Shakeel Butt <shakeel.butt@linux.dev>,
Andrii Nakryiko <andrii@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>,
Ihor Solodrai <ihor.solodrai@linux.dev>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
Jiri Olsa <jolsa@kernel.org>,
Emil Tsalapatis <emil@etsalapatis.com>,
Shuah Khan <shuah@kernel.org>, Barry Song <baohua@kernel.org>,
Geliang Tang <geliang@kernel.org>,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
Hui Zhu <zhuhui@kylinos.cn>
Subject: Re: [PATCH bpf-next v7 1/2] mm/bpf: Add bpf_proactive_reclaim kfunc
Date: Fri, 4 Sep 2026 11:03:08 -0700 [thread overview]
Message-ID: <20260904110308.4473cde499e91aab14dbd5fc@linux-foundation.org> (raw)
In-Reply-To: <7d8b77dc99ffe99a7bef874a257472fdaaf07e1c.1788516769.git.zhuhui@kylinos.cn>
On Fri, 4 Sep 2026 18:20:19 +0800 "Hui Zhu" <hui.zhu@linux.dev> wrote:
> @@ -159,6 +160,74 @@ __bpf_kfunc void bpf_mem_cgroup_flush_stats(struct mem_cgroup *memcg)
> mem_cgroup_flush_stats(memcg);
> }
>
> +/*
> + * Reclaim must not recurse: try_to_free_mem_cgroup_pages() overwrites
> + * current->reclaim_state, so a nested call would corrupt the outer
> + * reclaim state. Reclaim windows are marked with PF_MEMALLOC;
> + * reclaim_state is also checked because it is installed slightly
> + * before PF_MEMALLOC.
> + */
> +static bool bpf_in_reclaim_context(void)
> +{
> + return (current->flags & PF_MEMALLOC) || current->reclaim_state;
> +}
> +
Would life improve if try_to_free_mem_cgroup_pages() didn't do that?
If try_to_free_mem_cgroup_pages() (or some variant of it) were to
permit nesting?
rs = new_thing(current, &sc.reclaim_state);
...
set_task_reclaim_state(current, rs);
?
next prev parent reply other threads:[~2026-09-04 18:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-04 10:20 [PATCH bpf-next v7 0/2] bpf: BPF-driven proactive memcg reclaim Hui Zhu
2026-09-04 10:20 ` [PATCH bpf-next v7 1/2] mm/bpf: Add bpf_proactive_reclaim kfunc Hui Zhu
2026-09-04 11:25 ` bot+bpf-ci
2026-09-04 18:03 ` Andrew Morton [this message]
2026-09-04 10:20 ` [PATCH bpf-next v7 2/2] selftests/bpf: Add memcg async reclaim test Hui Zhu
2026-09-04 11:25 ` bot+bpf-ci
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