From nobody Sat Apr 11 11:09:11 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D9D9C00140 for ; Fri, 12 Aug 2022 20:28:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236759AbiHLU2l (ORCPT ); Fri, 12 Aug 2022 16:28:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233914AbiHLU22 (ORCPT ); Fri, 12 Aug 2022 16:28:28 -0400 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E2A8A895B for ; Fri, 12 Aug 2022 13:28:14 -0700 (PDT) Received: by mail-pj1-x1049.google.com with SMTP id 92-20020a17090a09e500b001d917022847so830914pjo.1 for ; Fri, 12 Aug 2022 13:28:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:from:to:cc; bh=h0j1tmcryfszvpEO+TtDzb67ntXXnPtNryRzQx2IqTE=; b=MzUknYElmzrxfzYxkrf+jNcWgb84/EExUa+DMdz3KNODbK/pH9TGVY8ApMKHxf9PZ9 20MhbO/K2t8F04TjtAvuSrJBCDpLDyGsf0IZkf1teTHoy7Yqq1J4q+otxM5dVI/mQYXv JoFx2TknRi3drwR4tXCdIUECBOhjpo8RMHNpBYTW3H3Zayab9mYysKBDf+6mXd+OoQIL Bw+dGjgNEXrsW/L6RJZWD0Ydv7AWBEnyCDzDv+ZoUbgRdhMJFNQiBGDuoQ6Gzdx8yERI GpVvWV/LkulDwuo7/7l2KNLjoUhc3k62bFO8L+a/b1sz4xQjEZ7jFgvXnRR2xxjTV3ik SUhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:x-gm-message-state:from:to:cc; bh=h0j1tmcryfszvpEO+TtDzb67ntXXnPtNryRzQx2IqTE=; b=bgfmIJ800DOb06WGHLuQSkmkryazBOt5LyTZMN3N/4OeZKrbiw6R5f0nj/REAQ9O9M ILWxfMgHpnYxCTJomPi+M+bI829Dno47YN6HQ4qY7qDpXVOv2INfunq1QGF04NCH+6yF 2QnUgIsgNteSihdeqRPgH4EQwZb6gM1dpfGJrp40L79/EZdw3bGr/PUMmTEF44Xe3M6o BiPK701nMkwbSa7N2v658EkLN/u+VOhOeWmIU5vWe565Em2JN9ayKtGiMWOUflK8izyK sjCKDqK7vAmxKwCCe6J0CB+Bzm38/Mj+89T5hBowSqN5HvAy5uqqW0iH9UU8mDGeIqhT jH/w== X-Gm-Message-State: ACgBeo0ZsPfxzTmaXIClzLyhEEJRLIh3Md0h5A0n/nsxsG38zlAQ0ePx 0blwv1BiU2bjrJzjYKWfufNguG7PlGuy/1ssGv2uHaD23+tEY9olALmUY3cSIpL1uAsIaUiaAbB qbjIuhoKiSYhYla1REoaMss/NLNC7T/XJpHG9rUwEYhuFIm7KCbPA0tuXPkeawVlGCD02+g== X-Google-Smtp-Source: AA6agR5fnr/CfyN8/juwe1x/CjcF4OI5zx4bcOpqulQbYRS/GyJFG7vZVJ0r20SSXvNBuA8ORSEFTbI9BlY= X-Received: from haoluo.svl.corp.google.com ([2620:15c:2d4:203:da3d:b609:da67:694a]) (user=haoluo job=sendgmr) by 2002:a05:6a00:999:b0:52e:cd5e:3453 with SMTP id u25-20020a056a00099900b0052ecd5e3453mr5138255pfg.76.1660336093994; Fri, 12 Aug 2022 13:28:13 -0700 (PDT) Date: Fri, 12 Aug 2022 13:28:00 -0700 In-Reply-To: <20220812202802.3774257-1-haoluo@google.com> Message-Id: <20220812202802.3774257-4-haoluo@google.com> Mime-Version: 1.0 References: <20220812202802.3774257-1-haoluo@google.com> X-Mailer: git-send-email 2.37.1.595.g718a3a8f04-goog Subject: [PATCH bpf-next v8 3/5] cgroup: bpf: enable bpf programs to integrate with rstat From: Hao Luo To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, netdev@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , Tejun Heo , Zefan Li , KP Singh , Johannes Weiner , Michal Hocko , John Fastabend , Michal Koutny , Roman Gushchin , David Rientjes , Stanislav Fomichev , Shakeel Butt , Yosry Ahmed , Hao Luo Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Yosry Ahmed Enable bpf programs to make use of rstat to collect cgroup hierarchical stats efficiently: - Add cgroup_rstat_updated() kfunc, for bpf progs that collect stats. - Add cgroup_rstat_flush() sleepable kfunc, for bpf progs that read stats. - Add an empty bpf_rstat_flush() hook that is called during rstat flushing, for bpf progs that flush stats to attach to. Attaching a bpf prog to this hook effectively registers it as a flush callback. Signed-off-by: Yosry Ahmed Acked-by: Tejun Heo Signed-off-by: Hao Luo --- kernel/cgroup/rstat.c | 48 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c index feb59380c896..793ecff29038 100644 --- a/kernel/cgroup/rstat.c +++ b/kernel/cgroup/rstat.c @@ -3,6 +3,10 @@ =20 #include =20 +#include +#include +#include + static DEFINE_SPINLOCK(cgroup_rstat_lock); static DEFINE_PER_CPU(raw_spinlock_t, cgroup_rstat_cpu_lock); =20 @@ -141,6 +145,31 @@ static struct cgroup *cgroup_rstat_cpu_pop_updated(str= uct cgroup *pos, return pos; } =20 +/* + * A hook for bpf stat collectors to attach to and flush their stats. + * Together with providing bpf kfuncs for cgroup_rstat_updated() and + * cgroup_rstat_flush(), this enables a complete workflow where bpf progs = that + * collect cgroup stats can integrate with rstat for efficient flushing. + * + * A static noinline declaration here could cause the compiler to optimize= away + * the function. A global noinline declaration will keep the definition, b= ut may + * optimize away the callsite. Therefore, __weak is needed to ensure that = the + * call is still emitted, by telling the compiler that we don't know what = the + * function might eventually be. + * + * __diag_* below are needed to dismiss the missing prototype warning. + */ +__diag_push(); +__diag_ignore_all("-Wmissing-prototypes", + "kfuncs which will be used in BPF programs"); + +__weak noinline void bpf_rstat_flush(struct cgroup *cgrp, + struct cgroup *parent, int cpu) +{ +} + +__diag_pop(); + /* see cgroup_rstat_flush() */ static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep) __releases(&cgroup_rstat_lock) __acquires(&cgroup_rstat_lock) @@ -168,6 +197,7 @@ static void cgroup_rstat_flush_locked(struct cgroup *cg= rp, bool may_sleep) struct cgroup_subsys_state *css; =20 cgroup_base_stat_flush(pos, cpu); + bpf_rstat_flush(pos, cgroup_parent(pos), cpu); =20 rcu_read_lock(); list_for_each_entry_rcu(css, &pos->rstat_css_list, @@ -501,3 +531,21 @@ void cgroup_base_stat_cputime_show(struct seq_file *se= q) seq_printf(seq, "core_sched.force_idle_usec %llu\n", forceidle_time); #endif } + +/* Add bpf kfuncs for cgroup_rstat_updated() and cgroup_rstat_flush() */ +BTF_SET8_START(bpf_rstat_kfunc_ids) +BTF_ID_FLAGS(func, cgroup_rstat_updated) +BTF_ID_FLAGS(func, cgroup_rstat_flush, KF_SLEEPABLE) +BTF_SET8_END(bpf_rstat_kfunc_ids) + +static const struct btf_kfunc_id_set bpf_rstat_kfunc_set =3D { + .owner =3D THIS_MODULE, + .set =3D &bpf_rstat_kfunc_ids, +}; + +static int __init bpf_rstat_kfunc_init(void) +{ + return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, + &bpf_rstat_kfunc_set); +} +late_initcall(bpf_rstat_kfunc_init); --=20 2.37.1.595.g718a3a8f04-goog