From mboxrd@z Thu Jan 1 00:00:00 1970 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C02BC369C2 for ; Mon, 28 Apr 2025 03:37:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8AB9A6B002B; Sun, 27 Apr 2025 23:37:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 859626B002C; Sun, 27 Apr 2025 23:37:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 686D66B002D; Sun, 27 Apr 2025 23:37:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 41D9C6B002B for ; Sun, 27 Apr 2025 23:37:06 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 4A7DBBC0FF for ; Mon, 28 Apr 2025 03:37:06 +0000 (UTC) X-FDA: 83382041652.12.1BB9EEE Received: from out-180.mta1.migadu.com (out-180.mta1.migadu.com [95.215.58.180]) by imf07.hostedemail.com (Postfix) with ESMTP id A45FF40009 for ; Mon, 28 Apr 2025 03:37:04 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="c/+BhYCM"; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf07.hostedemail.com: domain of roman.gushchin@linux.dev designates 95.215.58.180 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1745811424; a=rsa-sha256; cv=none; b=UoNT9AscZczATOLlEt0Td5VtgSQyYAAkMTSxna/q0Ldl4r65x8nvbBvMc8XPcx3gX9gt1L zzeJPzzI/HEzvfeuQPXRqvxfwWVceJtf9vHxQXo2f5m8VvInh0Ipi1e0vMtHWUvNX2LYKH U0KH4bE6zanEZtWQgP0TrUww2rbjyqg= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="c/+BhYCM"; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf07.hostedemail.com: domain of roman.gushchin@linux.dev designates 95.215.58.180 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1745811424; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=8WtdDCF/fOjk7l1oSxAg6r0dFrFtCENHh8DzkFeOJww=; b=08501a/rhYza5YaJp5VhSn53oMEudOJVBDtwqnGfODcZ/wMBc3iF8zLJRr43mTrKiObfEA Bl1kywUgnnmocWYqn3mFJQtWlzHCktbfwmcaHLlPEGrRSOk6dTm4m/Cta4FT5Ga/qAYduN Lb9AJ1vRWe3z6geqpMsm+SAwf16VaxI= 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=1745811423; 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=8WtdDCF/fOjk7l1oSxAg6r0dFrFtCENHh8DzkFeOJww=; b=c/+BhYCMrRSBr4yTd5mv7I5T0rvQOkVKbFl9XgTAeowasGX83nsPkgUVRynyVYaolN9nj8 Wc3beDU42dsEqeUnOao909cO5CNBY1mhRNOzYIyFs52IGCEiGXH2XiE+X/xtR9CO4B/eMp PeX97/KKF4tPd4+/I2wRyhQiGvbphn8= 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 10/12] mm: introduce bpf_out_of_memory() bpf kfunc Date: Mon, 28 Apr 2025 03:36:15 +0000 Message-ID: <20250428033617.3797686-11-roman.gushchin@linux.dev> In-Reply-To: <20250428033617.3797686-1-roman.gushchin@linux.dev> References: <20250428033617.3797686-1-roman.gushchin@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: A45FF40009 X-Stat-Signature: xf7yp76pchdi7xxe6w1ehhgynu63c3xh X-HE-Tag: 1745811424-337158 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Introduce bpf_out_of_memory() bpf kfunc, which allows to declare an out of memory events and trigger the corresponding kernel OOM handling mechanism. It takes a trusted memcg pointer (or NULL for system-wide OOMs) as an argument, as well as the page order. Only one OOM can be declared and handled in the system at once, so if the function is called in parallel to another OOM handling, it bails out with -EBUSY. The function is declared as sleepable. It guarantees that it won't be called from an atomic context. It's required by the OOM handling code, which is not guaranteed to work in a non-blocking context. Handling of a memcg OOM almost always requires taking of the css_set_lock spinlock. The fact that bpf_out_of_memory() is sleepable also guarantees that it can't be called with acquired css_set_lock, so the kernel can't deadlock on it. Signed-off-by: Roman Gushchin --- mm/oom_kill.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 2e922e75a9df..246510572e34 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -1333,6 +1333,27 @@ __bpf_kfunc int bpf_oom_kill_process(struct oom_control *oc, return 0; } +__bpf_kfunc int bpf_out_of_memory(struct mem_cgroup *memcg__nullable, int order) +{ + struct oom_control oc = { + .memcg = memcg__nullable, + .order = order, + }; + int ret = -EINVAL; + + if (oc.order < 0 || oc.order > MAX_PAGE_ORDER) + goto out; + + ret = -EBUSY; + if (mutex_trylock(&oom_lock)) { + ret = out_of_memory(&oc); + mutex_unlock(&oom_lock); + } + +out: + return ret; +} + __bpf_kfunc_end_defs(); __bpf_hook_start(); @@ -1358,6 +1379,7 @@ static const struct btf_kfunc_id_set bpf_oom_hook_set = { BTF_KFUNCS_START(bpf_oom_kfuncs) BTF_ID_FLAGS(func, bpf_oom_kill_process, KF_SLEEPABLE | KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_out_of_memory, KF_SLEEPABLE | KF_TRUSTED_ARGS) BTF_KFUNCS_END(bpf_oom_kfuncs) static const struct btf_kfunc_id_set bpf_oom_kfunc_set = { -- 2.49.0.901.g37484f566f-goog