From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-170.mta0.migadu.com (out-170.mta0.migadu.com [91.218.175.170]) (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 9ED0D330B03 for ; Mon, 27 Oct 2025 23:22:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.170 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761607356; cv=none; b=aGUSGhZeP2CjyoGU494AvM368q6G81gl+DXccxtG54TDAyuGOuCo3nY6yrh9CLpCOHqnnFBb/47jrXhkLXHQt+vm2kkODKA3yA9PJAVmUqhQTD0pdwH157fB6ANADUN0mB4FD/jhr/SnV+DSP1a1c3bpAqUax6tgHAx50++rbn8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761607356; c=relaxed/simple; bh=A0TLGiVoTwt77LLaYVfxN0ZLKs9sSqDifUWYWgg8vvk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Um2tZjc5u1Z0t4h8Uiyx00EUKk0ExBLH8zcWOypbtiRbdYrYqItuAmUUv6ljVjBsLKyk+FA7Z7KAbTMri4Ym/jI08k6cL4N1Z4ObF0LvMoW+T4DB/M5dWZ71Oi+Gjc4smZwaWskT94zHwNSh0B7kH60U5n8sni8SloKa/4lE0ho= 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=LauNHSgU; arc=none smtp.client-ip=91.218.175.170 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="LauNHSgU" 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=1761607351; 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=cZ5tLITVqa9KDyo9t477rOVIrm5gFKPHpPau7ALAhGY=; b=LauNHSgUGUpJIP0Wk4mTGW3O8EQdK3D++1OLIJUOcHYVAIVVjetLzzHiNbZg/z+LihJNYb XuqL/31o/ekZjCeriN0LLSFKm9P7EhF0Kpc7iOAJL+oPn3up8+Y5zaE7XeDZvL/ixPvHyQ RCpDIP7U/kxHgVe5BsgQ3b3EH9+Ba2U= From: Roman Gushchin To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Alexei Starovoitov , Suren Baghdasaryan , Michal Hocko , Shakeel Butt , Johannes Weiner , Andrii Nakryiko , JP Kobryn , linux-mm@kvack.org, cgroups@vger.kernel.org, bpf@vger.kernel.org, Martin KaFai Lau , Song Liu , Kumar Kartikeya Dwivedi , Tejun Heo , Roman Gushchin Subject: [PATCH v2 14/23] mm: allow specifying custom oom constraint for BPF triggers Date: Mon, 27 Oct 2025 16:21:57 -0700 Message-ID: <20251027232206.473085-4-roman.gushchin@linux.dev> In-Reply-To: <20251027232206.473085-1-roman.gushchin@linux.dev> References: <20251027232206.473085-1-roman.gushchin@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 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=0x0(), order=0, oom_score_adj=0 oom_policy=default [ 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/cg2: [ 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 rss_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=CONSTRAINT_BPF_PSI_MEM,nodemask=(null),cpuset=/,mems_allowed=0,oom_memcg=/cgroup-test-work-dir673/oom_test/cg2,task_memcg=/cgroup-test-work-dir673/oom_test/cg2,task=test_progs,pid=675,uid=0 [ 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 3cbdcd013274..704fc0e786c6 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, }; enum bpf_oom_flags { @@ -63,6 +64,9 @@ struct oom_control { /* Policy name */ const char *bpf_policy_name; + + /* BPF-specific constraint name */ + const char *bpf_constraint; #endif }; diff --git a/mm/oom_kill.c b/mm/oom_kill.c index d7fca4bf575b..72a346261c79 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; } -static const char * const oom_constraint_text[] = { - [CONSTRAINT_NONE] = "CONSTRAINT_NONE", - [CONSTRAINT_CPUSET] = "CONSTRAINT_CPUSET", - [CONSTRAINT_MEMORY_POLICY] = "CONSTRAINT_MEMORY_POLICY", - [CONSTRAINT_MEMCG] = "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"; } +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 = false; int nid; + if (oc->constraint == CONSTRAINT_BPF) + return CONSTRAINT_BPF; + if (is_memcg_oom(oc)) { oc->totalpages = mem_cgroup_get_max(oc->memcg) ?: 1; return CONSTRAINT_MEMCG; @@ -458,7 +475,7 @@ static void dump_oom_victim(struct oom_control *oc, struct task_struct *victim) { /* one line summary of the oom killer context. */ pr_info("oom-kill:constraint=%s,nodemask=%*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); @@ -1350,11 +1367,14 @@ __bpf_kfunc int bpf_oom_kill_process(struct oom_control *oc, * Returns a negative value if an error occurred. */ __bpf_kfunc int bpf_out_of_memory(struct mem_cgroup *memcg__nullable, - int order, u64 flags) + int order, u64 flags, + const char *constraint_text__nullable) { struct oom_control oc = { .memcg = memcg__nullable, .order = order, + .constraint = CONSTRAINT_BPF, + .bpf_constraint = constraint_text__nullable, }; int ret; -- 2.51.0