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 F1CE2E95A8C for ; Tue, 30 Dec 2025 13:25:11 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F41836B0005; Tue, 30 Dec 2025 08:25:10 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EEFB86B0089; Tue, 30 Dec 2025 08:25:10 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DEDB16B008A; Tue, 30 Dec 2025 08:25:10 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id CD70F6B0005 for ; Tue, 30 Dec 2025 08:25:10 -0500 (EST) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 76021953CC for ; Tue, 30 Dec 2025 13:25:10 +0000 (UTC) X-FDA: 84276208380.11.B375A21 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by imf15.hostedemail.com (Postfix) with ESMTP id 40C35A0007 for ; Tue, 30 Dec 2025 13:25:04 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; spf=pass (imf15.hostedemail.com: domain of chenridong@huaweicloud.com designates 45.249.212.51 as permitted sender) smtp.mailfrom=chenridong@huaweicloud.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1767101108; a=rsa-sha256; cv=none; b=iDJPNJLc3f5msMcuvP60Ezds5Xi507txl6IdqfRtNHBByzOzUNjvYFBw9X+JdNRhZaoZiV EYERCifJq5FgzwApM0MMv/sSXirsEoHjPIHxGWh5gxIkrfjdGfa/QJrclHeuA7PyFw64r7 4XjMZ0SiSYmj1Mnmd+q/0b3j2KkPRTY= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf15.hostedemail.com: domain of chenridong@huaweicloud.com designates 45.249.212.51 as permitted sender) smtp.mailfrom=chenridong@huaweicloud.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1767101108; 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; bh=PXJDmpjXWca0v7gUPR7ngrX+Kf+HJ+gV7pJXFGSYVvo=; b=uMTk1Er9uPQo6eqPjjfLcdO7FxbQEbRxOkK0XiMVO9BjnEl9HzEGkviwaGaN9wLs33ytP+ +imKHRCiepwxUigNEJmswtRkVTUCDdpc5lCLwNPVTwtt8z9wZMihyF/ThPLuvlxqWaEHXq kXGVqh/UXos2VuOyEoqqSSuLJ9lh6to= Received: from mail.maildlp.com (unknown [172.19.163.198]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4dgYhT5MqKzYQtjp for ; Tue, 30 Dec 2025 21:24:09 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 869AC4056B for ; Tue, 30 Dec 2025 21:24:58 +0800 (CST) Received: from [10.67.111.176] (unknown [10.67.111.176]) by APP4 (Coremail) with SMTP id gCh0CgAniPim0lNpM+wYCA--.38240S2; Tue, 30 Dec 2025 21:24:56 +0800 (CST) Message-ID: <31d3fdfa-799e-426b-bb64-42e06392f0b4@huaweicloud.com> Date: Tue, 30 Dec 2025 21:24:53 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 0/3] Memory Controller eBPF support To: =?UTF-8?Q?Michal_Koutn=C3=BD?= , Hui Zhu , jiayuan.chen@linux.dev Cc: Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan , Peter Zijlstra , Miguel Ojeda , Nathan Chancellor , Kees Cook , Tejun Heo , Jeff Xu , Jan Hendrik Farr , Christian Brauner , Randy Dunlap , Brian Gerst , Masahiro Yamada , davem@davemloft.net, Jakub Kicinski , Jesper Dangaard Brouer , linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, Hui Zhu References: Content-Language: en-US From: Chen Ridong In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CM-TRANSID:gCh0CgAniPim0lNpM+wYCA--.38240S2 X-Coremail-Antispam: 1UD129KBjvJXoWxJr4kAFW7Zw4xJr18tryxXwb_yoW8tw17pF WkKFy8WFWkXw17tw4kZ39F9a1Iv395Gr43KFn3Jry7K3ZFqr12vr4Iyr4UuFZrZFnxtr10 vryY9w4ku3Z0v3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvYb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x 0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG 6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFV Cjc4AY6r1j6r4UM4x0Y48IcVAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxkF7I0En4kS 14v26rWY6Fy7MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I 8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWrXVW8 Jr1lIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7 CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v2 6r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07 j6a0PUUUUU= X-CM-SenderInfo: hfkh02xlgr0w46kxt4xhlfz01xgou0bp/ X-Rspamd-Queue-Id: 40C35A0007 X-Stat-Signature: nto713y1795ndkq3kq83ke7hjfyfnmmi X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1767101104-489344 X-HE-Meta: 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 RzBCGXl4 Dyr+kBvAiXu+cbD3WHgbGUH05+frTnDDw9c06M4n7Z5Gm/9h+YMCAOz5o3lW1f+RwrDX4ICpPPEblH2XUK6Wt1rNv4y+IQ9AW0CKZpqbW9s08q082QyO0xGLOsYviw/NKKwuAjIgPLOo2bXL464R3j9qlsSiC8xfDaJsF2NS8yZpwU011UDCI/haK6h+Z7qXvyfPwaPwhzZHgFllbyp7ledbOkKUY7H/PzisRO3L6mcvUkNY= 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 2025/12/30 17:49, Michal Koutný wrote: > Hi Hui. > > On Tue, Dec 30, 2025 at 11:01:58AM +0800, Hui Zhu wrote: >> This allows administrators to suppress low-priority cgroups' memory >> usage based on custom policies implemented in BPF programs. > > BTW memory.low was conceived as a work-conserving mechanism for > prioritization of different workloads. Have you tried that? No need to > go directly to (high) limits. (<- Main question, below are some > secondary implementation questions/remarks.) > > ... >> This series introduces a BPF hook that allows reporting >> additional "pages over high" for specific cgroups, effectively >> increasing memory pressure and throttling for lower-priority >> workloads when higher-priority cgroups need resources. > > Have you considered hooking into calculate_high_delay() instead? (That > function has undergone some evolution so it'd seem like the candidate > for BPFication.) > +1 This issue[1] might be resolved by hooking into calculate_high_delay(). [1] https://lore.kernel.org/cgroups/4txrfjc5lqkmydmsesfq3l5drmzdio6pkmtfb64sk3ld6bwkhs@w4dkn76s4dbo/T/#t > ... >> 3. Cgroup hierarchy management (inheritance during online/offline) > > I see you're copying the program upon memcg creation. > Configuration copies aren't such a good way to properly handle > hierarchical behavior. > I wonder if this could follow the more generic pattern of how BPF progs > are evaluated in hierarchies, see BPF_F_ALLOW_OVERRIDE and > BPF_F_ALLOW_MULTI. > > >> Example Results > ... >> Results show the low-priority cgroup (/sys/fs/cgroup/low) was >> significantly throttled: >> - High-priority cgroup: 21,033,377 bogo ops at 347,825 ops/s >> - Low-priority cgroup: 11,568 bogo ops at 177 ops/s >> >> The stress-ng process in the low-priority cgroup experienced a >> ~99.9% slowdown in memory operations compared to the >> high-priority cgroup, demonstrating effective priority >> enforcement through BPF-controlled memory pressure. > > As a demonstrator, it'd be good to compare this with a baseline without > any extra progs, e.g. show that high-prio performed better and low-prio > wasn't throttled for nothing. > > Thanks, > Michal -- Best regards, Ridong