From nobody Mon Feb 9 00:31:19 2026 Received: from out-188.mta1.migadu.com (out-188.mta1.migadu.com [95.215.58.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 44ECC1E98F3 for ; Mon, 28 Apr 2025 03:37:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.188 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745811425; cv=none; b=SaVZ1ht7vehIRv4mkxrRgfkS3L4StUQ86e/aIxPV5qfVCmW1CL+GA6ySNuXa37GMGkeycTN0usJw05iv+3RpSB/rdZDEryb/2sAGZddBbnPZkgsGtmPCV8oXJAG5ZphbCMc4a33ctw7WRDCFubvx9ixOpO4Rt0ZMaVsL3YzQQ6E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745811425; c=relaxed/simple; bh=MSuCn/IFWqQlylKlbdwaS8cTvPrEiuR18JIMnVpqPEA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZPar1TZptCbtJclPWJXLNpizxGpMVzNHjGvTZNHArNt2E/OkdK+EuQdsWQX9lUakMZTsm1r6J25iA2MPoh2KvYFozSFdo2lGWinXldzYfvsn1QxEiufqNyP16vsDDua2auknV14MwkaE3N7EOuYw/A2/cgDQrTxFvNALTOJ2aU0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Gf5dRr3T; arc=none smtp.client-ip=95.215.58.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Gf5dRr3T" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1745811420; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5mgjhUpiTMjjN/y1DN45zRe/y1CtVNZ7gASyknJ+oe4=; b=Gf5dRr3TIZDIRx58GflQe6YhjrDUw+0tzYVZbiKzXUNkPSh7HUd7ek/cBcTFcLuHz3q+G4 96GXvmnprLNKAGeRu8Zk/E1HlHIvJXfcWn8DjkRrxGuKHhy7GYP+ik89uT0QxKhw9T72Vp oJoSXAS2Ltc8+hfooGk4XMHgY8G/unk= From: Roman Gushchin To: linux-kernel@vger.kernel.org Cc: Andrew Morton , Alexei Starovoitov , Johannes Weiner , Michal Hocko , Shakeel Butt , Suren Baghdasaryan , David Rientjes , Josh Don , Chuyi Zhou , cgroups@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org, Roman Gushchin Subject: [PATCH rfc 09/12] sched: psi: bpf hook to handle psi events Date: Mon, 28 Apr 2025 03:36:14 +0000 Message-ID: <20250428033617.3797686-10-roman.gushchin@linux.dev> In-Reply-To: <20250428033617.3797686-1-roman.gushchin@linux.dev> References: <20250428033617.3797686-1-roman.gushchin@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" Introduce a bpf hook to handle psi events. The primary intended purpose of this hook is to declare OOM events based on the reaching a certain memory pressure level, similar to what systemd-oomd and oomd are doing in userspace. Signed-off-by: Roman Gushchin --- kernel/sched/psi.c | 36 +++++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 1396674fa722..4c4eb4ead8f6 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -176,6 +176,32 @@ static void psi_avgs_work(struct work_struct *work); =20 static void poll_timer_fn(struct timer_list *t); =20 +#ifdef CONFIG_BPF_SYSCALL +__bpf_hook_start(); + +__weak noinline int bpf_handle_psi_event(struct psi_trigger *t) +{ + return 0; +} + +__bpf_hook_end(); + +BTF_KFUNCS_START(bpf_psi_hooks) +BTF_ID_FLAGS(func, bpf_handle_psi_event, KF_SLEEPABLE) +BTF_KFUNCS_END(bpf_psi_hooks) + +static const struct btf_kfunc_id_set bpf_psi_hook_set =3D { + .owner =3D THIS_MODULE, + .set =3D &bpf_psi_hooks, +}; + +#else +static inline int bpf_handle_psi_event(struct psi_trigger *t) +{ + return 0; +} +#endif + static void group_init(struct psi_group *group) { int cpu; @@ -489,6 +515,7 @@ static void update_triggers(struct psi_group *group, u6= 4 now, =20 /* Generate an event */ if (cmpxchg(&t->event, 0, 1) =3D=3D 0) { + bpf_handle_psi_event(t); if (t->of) kernfs_notify(t->of->kn); else @@ -1655,6 +1682,8 @@ static const struct proc_ops psi_irq_proc_ops =3D { =20 static int __init psi_proc_init(void) { + int err =3D 0; + if (psi_enable) { proc_mkdir("pressure", NULL); proc_create("pressure/io", 0666, NULL, &psi_io_proc_ops); @@ -1662,9 +1691,14 @@ static int __init psi_proc_init(void) proc_create("pressure/cpu", 0666, NULL, &psi_cpu_proc_ops); #ifdef CONFIG_IRQ_TIME_ACCOUNTING proc_create("pressure/irq", 0666, NULL, &psi_irq_proc_ops); +#endif +#ifdef CONFIG_BPF_SYSCALL + err =3D register_btf_fmodret_id_set(&bpf_psi_hook_set); + if (err) + pr_err("error while registering bpf psi hooks: %d", err); #endif } - return 0; + return err; } module_init(psi_proc_init); =20 --=20 2.49.0.901.g37484f566f-goog