From nobody Sat Oct 4 11:13:50 2025 Received: from out-187.mta1.migadu.com (out-187.mta1.migadu.com [95.215.58.187]) (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 5360334AB17 for ; Mon, 18 Aug 2025 17:02:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.187 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755536537; cv=none; b=clqAAAhvOQrl2q7oZKc9pVCTCuOcHkXhpqaBKUKPY3kbkU4M2WH5gbQUKy1CTg6zHnjU78VtQhlIfycWisYC/5/sQkoTmINYY0RkXybIaTaDyOOuMLt982J+9bEizeOjOeLfB4sVGfeSGQEg2BSBqJmWBE+oIJSoX0rEzvfZVdI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755536537; c=relaxed/simple; bh=iEwPyLarkYZ1SYl78PTz6f3Tq7siad3IfaAtYtYAiwk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=U9T+G4C121ZKS83ww+VW74rI7qVtNp2v330GkCCK47fRrG1i/hqagJHwiMZbQZ72ksoh4q5858YxHYfF/w1QNlw09kFIJOcHoaZrwM0V+RseciAY3gOgBMBTV+1c4EC8aD2f0ZNBjNveStWmodU2PvC/a4PBHeasmr6fYeHBuWg= 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=fGk1dplm; arc=none smtp.client-ip=95.215.58.187 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="fGk1dplm" 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=1755536533; 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=+PLsLBHEH7fH2DeVbRY37aGg0nfytx5nHxzamt/J4w8=; b=fGk1dplmhX8TBaKAV1v7A3rxD9Ol2v1dVG0iJpNbN08nSv/gNpwrxCdezuKtXAgWuH7pnH 0ubEOf+1Y1+QbRYQuqvw96/rOTlUWv2I2DKvu9jhtXsjugbpPT3L17R5EjGmPe28KovF8S xmIqxrmPCQw+j3alA32yMAWl/zfhADM= From: Roman Gushchin To: linux-mm@kvack.org, bpf@vger.kernel.org Cc: Suren Baghdasaryan , Johannes Weiner , Michal Hocko , David Rientjes , Matt Bobrowski , Song Liu , Kumar Kartikeya Dwivedi , Alexei Starovoitov , Andrew Morton , linux-kernel@vger.kernel.org, Roman Gushchin Subject: [PATCH v1 07/14] mm: allow specifying custom oom constraint for bpf triggers Date: Mon, 18 Aug 2025 10:01:29 -0700 Message-ID: <20250818170136.209169-8-roman.gushchin@linux.dev> In-Reply-To: <20250818170136.209169-1-roman.gushchin@linux.dev> References: <20250818170136.209169-1-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" Currently there is a hard-coded list of possible oom constraints: NONE, CPUSET, MEMORY_POLICY & MEMCG. Add a new one: CONSTRAINT_BPF. Also, add an ability to specify a custom constraint name when calling bpf_out_of_memory(). If an empty string is passed as an argument, CONSTRAINT_BPF is displayed. The resulting output in dmesg will look like this: [ 315.224875] kworker/u17:0 invoked oom-killer: gfp_mask=3D0x0(), order=3D= 0, oom_score_adj=3D0 oom_policy=3Ddefault [ 315.226532] CPU: 1 UID: 0 PID: 74 Comm: kworker/u17:0 Not tainted 6.16.0= -00015-gf09eb0d6badc #102 PREEMPT(full) [ 315.226534] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS = 1.17.0-5.fc42 04/01/2014 [ 315.226536] Workqueue: bpf_psi_wq bpf_psi_handle_event_fn [ 315.226542] Call Trace: [ 315.226545] [ 315.226548] dump_stack_lvl+0x4d/0x70 [ 315.226555] dump_header+0x59/0x1c6 [ 315.226561] oom_kill_process.cold+0x8/0xef [ 315.226565] out_of_memory+0x111/0x5c0 [ 315.226577] bpf_out_of_memory+0x6f/0xd0 [ 315.226580] ? srso_alias_return_thunk+0x5/0xfbef5 [ 315.226589] bpf_prog_3018b0cf55d2c6bb_handle_psi_event+0x5d/0x76 [ 315.226594] bpf__bpf_psi_ops_handle_psi_event+0x47/0xa7 [ 315.226599] bpf_psi_handle_event_fn+0x63/0xb0 [ 315.226604] process_one_work+0x1fc/0x580 [ 315.226616] ? srso_alias_return_thunk+0x5/0xfbef5 [ 315.226624] worker_thread+0x1d9/0x3b0 [ 315.226629] ? __pfx_worker_thread+0x10/0x10 [ 315.226632] kthread+0x128/0x270 [ 315.226637] ? lock_release+0xd4/0x2d0 [ 315.226645] ? __pfx_kthread+0x10/0x10 [ 315.226649] ret_from_fork+0x81/0xd0 [ 315.226652] ? __pfx_kthread+0x10/0x10 [ 315.226655] ret_from_fork_asm+0x1a/0x30 [ 315.226667] [ 315.239745] memory: usage 42240kB, limit 9007199254740988kB, failcnt 0 [ 315.240231] swap: usage 0kB, limit 0kB, failcnt 0 [ 315.240585] Memory cgroup stats for /cgroup-test-work-dir673/oom_test/cg= 2: [ 315.240603] anon 42897408 [ 315.241317] file 0 [ 315.241493] kernel 98304 ... [ 315.255946] Tasks state (memory values in pages): [ 315.256292] [ pid ] uid tgid total_vm rss rss_anon rss_file rs= s_shmem pgtables_bytes swapents oom_score_adj name [ 315.257107] [ 675] 0 675 162013 10969 10712 257 = 0 155648 0 0 test_progs [ 315.257927] oom-kill:constraint=3DCONSTRAINT_BPF_PSI_MEM,nodemask=3D(nul= l),cpuset=3D/,mems_allowed=3D0,oom_memcg=3D/cgroup-test-work-dir673/oom_tes= t/cg2,task_memcg=3D/cgroup-test-work-dir673/oom_test/cg2,task=3Dtest_progs,= pid=3D675,uid=3D0 [ 315.259371] Memory cgroup out of memory: Killed process 675 (test_progs)= total-vm:648052kB, anon-rss:42848kB, file-rss:1028kB, shmem-rss:0kB, UID:0= pgtables:152kB oom_score_adj:0 Signed-off-by: Roman Gushchin --- include/linux/oom.h | 4 ++++ mm/oom_kill.c | 38 +++++++++++++++++++++++++++++--------- 2 files changed, 33 insertions(+), 9 deletions(-) diff --git a/include/linux/oom.h b/include/linux/oom.h index ef453309b7ea..4b04944b42de 100644 --- a/include/linux/oom.h +++ b/include/linux/oom.h @@ -19,6 +19,7 @@ enum oom_constraint { CONSTRAINT_CPUSET, CONSTRAINT_MEMORY_POLICY, CONSTRAINT_MEMCG, + CONSTRAINT_BPF, }; =20 /* @@ -58,6 +59,9 @@ struct oom_control { =20 /* Policy name */ const char *bpf_policy_name; + + /* BPF-specific constraint name */ + const char *bpf_constraint; #endif }; =20 diff --git a/mm/oom_kill.c b/mm/oom_kill.c index df409f0fac45..67afcd43a5f7 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -240,13 +240,6 @@ long oom_badness(struct task_struct *p, unsigned long = totalpages) return points; } =20 -static const char * const oom_constraint_text[] =3D { - [CONSTRAINT_NONE] =3D "CONSTRAINT_NONE", - [CONSTRAINT_CPUSET] =3D "CONSTRAINT_CPUSET", - [CONSTRAINT_MEMORY_POLICY] =3D "CONSTRAINT_MEMORY_POLICY", - [CONSTRAINT_MEMCG] =3D "CONSTRAINT_MEMCG", -}; - static const char *oom_policy_name(struct oom_control *oc) { #ifdef CONFIG_BPF_SYSCALL @@ -256,6 +249,27 @@ static const char *oom_policy_name(struct oom_control = *oc) return "default"; } =20 +static const char *oom_constraint_text(struct oom_control *oc) +{ + switch (oc->constraint) { + case CONSTRAINT_NONE: + return "CONSTRAINT_NONE"; + case CONSTRAINT_CPUSET: + return "CONSTRAINT_CPUSET"; + case CONSTRAINT_MEMORY_POLICY: + return "CONSTRAINT_MEMORY_POLICY"; + case CONSTRAINT_MEMCG: + return "CONSTRAINT_MEMCG"; +#ifdef CONFIG_BPF_SYSCALL + case CONSTRAINT_BPF: + return oc->bpf_constraint ? : "CONSTRAINT_BPF"; +#endif + default: + WARN_ON_ONCE(1); + return ""; + } +} + /* * Determine the type of allocation constraint. */ @@ -267,6 +281,9 @@ static enum oom_constraint constrained_alloc(struct oom= _control *oc) bool cpuset_limited =3D false; int nid; =20 + if (oc->constraint =3D=3D CONSTRAINT_BPF) + return CONSTRAINT_BPF; + if (is_memcg_oom(oc)) { oc->totalpages =3D mem_cgroup_get_max(oc->memcg) ?: 1; return CONSTRAINT_MEMCG; @@ -458,7 +475,7 @@ static void dump_oom_victim(struct oom_control *oc, str= uct task_struct *victim) { /* one line summary of the oom killer context. */ pr_info("oom-kill:constraint=3D%s,nodemask=3D%*pbl", - oom_constraint_text[oc->constraint], + oom_constraint_text(oc), nodemask_pr_args(oc->nodemask)); cpuset_print_current_mems_allowed(); mem_cgroup_print_oom_context(oc->memcg, victim); @@ -1344,11 +1361,14 @@ __bpf_kfunc int bpf_oom_kill_process(struct oom_con= trol *oc, * Returns a negative value if an error has been occurred. */ __bpf_kfunc int bpf_out_of_memory(struct mem_cgroup *memcg__nullable, - int order, bool wait_on_oom_lock) + int order, bool wait_on_oom_lock, + const char *constraint_text__nullable) { struct oom_control oc =3D { .memcg =3D memcg__nullable, .order =3D order, + .constraint =3D CONSTRAINT_BPF, + .bpf_constraint =3D constraint_text__nullable, }; int ret; =20 --=20 2.50.1