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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1C839CCF9EB for ; Thu, 30 Oct 2025 00:43:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 78A278E01A6; Wed, 29 Oct 2025 20:43:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7629E8E0106; Wed, 29 Oct 2025 20:43:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 69EAB8E01A6; Wed, 29 Oct 2025 20:43:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 59F898E0106 for ; Wed, 29 Oct 2025 20:43:17 -0400 (EDT) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 04BB91A09CC for ; Thu, 30 Oct 2025 00:43:16 +0000 (UTC) X-FDA: 84052931634.27.2DE3AD6 Received: from out-170.mta0.migadu.com (out-170.mta0.migadu.com [91.218.175.170]) by imf28.hostedemail.com (Postfix) with ESMTP id 3FFBCC0005 for ; Thu, 30 Oct 2025 00:43:15 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ULiUj4m2; spf=pass (imf28.hostedemail.com: domain of martin.lau@linux.dev designates 91.218.175.170 as permitted sender) smtp.mailfrom=martin.lau@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761784995; 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-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=prXThHTV0GDAwL3oDEaWG8s/Dj6lCyEPeFRl/UXwls4=; b=UzSlOfx5d1rWuJt67EJQMlHMfa9i9a+7JLc1OGKPcyN2iGPC0cwpLMcTPZQHcD8AXnA96p OpmJ30vnQKcD4WHFAH05AJBzY7bXho3y3djtDzAGazey74s5DU1KeSNjwDiAtvawRih0Sc nSKfMVjE4vSiqopenIQdKwYGeVOWx0w= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ULiUj4m2; spf=pass (imf28.hostedemail.com: domain of martin.lau@linux.dev designates 91.218.175.170 as permitted sender) smtp.mailfrom=martin.lau@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1761784995; a=rsa-sha256; cv=none; b=UKmMUPUJg/HDR8EnBzx4y+eqw09cOWwHlLkQkKQ19XPNcbJnc2Dcbn6cPd5TloQIEOrP01 3nCuDlGxI0qb8v1naz9lbCcB5XMIAZ3ldytcZ3JyZCOgr8ZBxrpyfmQz1PcqN6FwVy4M0E XlnwmFpbNglWmYBInwf6+75M7w00wwE= Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1761784989; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=prXThHTV0GDAwL3oDEaWG8s/Dj6lCyEPeFRl/UXwls4=; b=ULiUj4m2ZADrpZISUHsciB+yZ7PKa6iclQpmxGVtWMVHGj6KYXWwkoKCZXXY9Uits03dv4 vupgCZLkEk8MYN4sAipt4OJzgrznJx+C4i2+XdgM1k/plomzacRE4NBqO+zq8iMFDoad9k yH8o9Eo8jbJOdnnYDOj5Jw2VA3b/1RY= Date: Wed, 29 Oct 2025 17:43:02 -0700 MIME-Version: 1.0 Subject: Re: [PATCH v2 02/23] bpf: initial support for attaching struct ops to cgroups To: Roman Gushchin 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 , Andrew Morton References: <20251027231727.472628-1-roman.gushchin@linux.dev> <20251027231727.472628-3-roman.gushchin@linux.dev> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau In-Reply-To: <20251027231727.472628-3-roman.gushchin@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 3FFBCC0005 X-Stat-Signature: uutrathi8f77sx83eojwiquq4du9a6nf X-Rspam-User: X-HE-Tag: 1761784995-979478 X-HE-Meta: U2FsdGVkX19lfk1F7wIYcFJI0lj8mS5a9nzsSM40XvYRreEVdH8Q8ogM5atpQEDsBKL63sqNBCnKAjRV3mOde0r8C5HSessseFmET320rB9Bgo6PFZ6UtAXLXEXhpLP4BzYTpHbIPK53MeJx1b2TsHBjcGuXdYiBQGOym4iJN8bPKpCA3d4eh5Y+98wJwqhmA2OdA/v1Tn+qllhY26ga5jAqj8HbTvsnctoHtXti62SXHEvkXaNydZ1tLDcSSXXGt2sRMnlYqHFCSaRUA4IrwQ4Ou+PA7v/tCZa8rKIayNCepHeLdTHxyPZBs07vJ5hmVAh7kTvYkxjqbpwmCbabFpSDAQj9zvaO5V1NdHk+wEZ+qwGq+5YQLNUHZbUwV3qwQc72NBAj3Fqc/tQjHfxE30K2SlASDsUj4Ddpc7zLNZuEC5lT7tbnuXyER3wxiDropr4Oqo03T48po3xuVbrtnWF+wVqrEbxgbfO/tBzZ6eYs3kMGxtmp787Bg5712J8cZFHXmsg1uS27sltOnMEFPvff8NH0gDYaX8V4/AF0FQyw+QtelV0Y9Xv7RuVW/lF854mHepq33XZjZ1O0RvVMSN9n7/iaPq9DP5esYRXv9v+8qtiz302erUOFCel6Me+zW0jCkwpQ199zbjMThV2M1XJNi9YFFY9r2hTxAZJsQIODLRn97l3FLGEzqjbfXBQFl2TB/THWt7I70wVvIekPqnzjKT89pL6L/SUs3cUxziSFhRQePMDHxfdHG+Hd1kd23nMVH8Ze/MFhTJU2C/+fQsDRTS737Dw9qvFccJ3J8PqM8UFyMR2REk9t6fHmQ5vtCHi1DN/krj5uiizNx8ROcT2uQUBs+Kc5/W6UA4s0EJxtgkofR2lCsgNxlT+nSp5OEIcVa3fN3YoZffIu/+k7mBwxnldBn7Ygw7Af/lf3NnpX74LQxAv/0lct1hfL/pGNcG0k89Pxe6CkWmI3BjS RiKvrMXj 2rDvnx5Hq+A2XdXylQpqdrV7iQ6VZoEs+PtvqS9/Ukd0tUIIX7z3ZO/2VgltN603ewF3IYitJWckK/FgX78bsLfZKz2lcC1nnOxflaeCYNj3DsBnB+XuqPhlAA6FkVJ6nzPV1hZ5TZclPPCZfdulnsdt8bDfLJ82w6Y9CLdAx8VNU/CduamLiJuo58Sh3EiQ/uthqlcInbL7H+lbpLk5RZ91MOui6XhqDx0IyS3RvLwKMjEmKfF4xcx9PLg== 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: On 10/27/25 4:17 PM, Roman Gushchin wrote: > When a struct ops is being attached and a bpf link is created, > allow to pass a cgroup fd using bpf attr, so that struct ops > can be attached to a cgroup instead of globally. > > Attached struct ops doesn't hold a reference to the cgroup, > only preserves cgroup id. > > Signed-off-by: Roman Gushchin > --- > include/linux/bpf.h | 1 + > kernel/bpf/bpf_struct_ops.c | 13 +++++++++++++ > 2 files changed, 14 insertions(+) > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > index eae907218188..7205b813e25f 100644 > --- a/include/linux/bpf.h > +++ b/include/linux/bpf.h > @@ -1849,6 +1849,7 @@ struct bpf_struct_ops_link { > struct bpf_link link; > struct bpf_map __rcu *map; > wait_queue_head_t wait_hup; > + u64 cgroup_id; > }; > > struct bpf_link_primer { > diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c > index 45cc5ee19dc2..58664779a2b6 100644 > --- a/kernel/bpf/bpf_struct_ops.c > +++ b/kernel/bpf/bpf_struct_ops.c > @@ -13,6 +13,7 @@ > #include > #include > #include > +#include > > struct bpf_struct_ops_value { > struct bpf_struct_ops_common_value common; > @@ -1359,6 +1360,18 @@ int bpf_struct_ops_link_create(union bpf_attr *attr) > } > bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS, &bpf_struct_ops_map_lops, NULL, > attr->link_create.attach_type); > +#ifdef CONFIG_CGROUPS > + if (attr->link_create.cgroup.relative_fd) { > + struct cgroup *cgrp; > + > + cgrp = cgroup_get_from_fd(attr->link_create.cgroup.relative_fd); > + if (IS_ERR(cgrp)) > + return PTR_ERR(cgrp); > + > + link->cgroup_id = cgroup_id(cgrp); Not sure storing the cgroup_id or storing the memcg/cgroup pointer is better here. Regardless, link->cgroup_id should be cleared in bpf_struct_ops_map_link_detach(). The cgroup_id probably is useful to bpf_struct_ops_map_link_show_fdinfo(). > + cgroup_put(cgrp); > + } > +#endif /* CONFIG_CGROUPS */ > > err = bpf_link_prime(&link->link, &link_primer); > if (err)