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 C4100CD343F for ; Wed, 13 May 2026 02:11:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DB4666B0005; Tue, 12 May 2026 22:11:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D3E6B6B008A; Tue, 12 May 2026 22:11:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C05466B008C; Tue, 12 May 2026 22:11:18 -0400 (EDT) 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 ABAEF6B0005 for ; Tue, 12 May 2026 22:11:18 -0400 (EDT) Received: from smtpin01.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 3A4E04069F for ; Wed, 13 May 2026 02:11:18 +0000 (UTC) X-FDA: 84760769436.01.BE45DB2 Received: from out-180.mta1.migadu.com (out-180.mta1.migadu.com [95.215.58.180]) by imf17.hostedemail.com (Postfix) with ESMTP id 53F9F4000C for ; Wed, 13 May 2026 02:11:16 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=wqU8qVBO; spf=pass (imf17.hostedemail.com: domain of qi.zheng@linux.dev designates 95.215.58.180 as permitted sender) smtp.mailfrom=qi.zheng@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=1778638276; 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=Iq7jnY+N0UwU1xXxCmM5jCZ1Y+zQ9eUrIz+WkKBogEQ=; b=MhHnbT9EpL26MQ/QX8a2TeU35ycH+/EqHomEhUZ/UQH7Jy2mYNAR5hGDDmERVn7aV09/rZ MNZivGx8NwQxmduqEN4VzKX1ph/FC0e0O5EVSxanUEOB0H4tFeAlwYv1bHrFjA7qK/6T0c 2pECHx0poo3tiSoLvxvvpnJkSoeE7nk= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=wqU8qVBO; spf=pass (imf17.hostedemail.com: domain of qi.zheng@linux.dev designates 95.215.58.180 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1778638276; a=rsa-sha256; cv=none; b=U2wlkHNpuf+uWXjNXGfbV/OXrHNxtYZPO78zj3zn2kGVT7BblA4yi6GzsLKt7nGmAuoU6j vXaG7e9r0bHZkEMPrJy52D5uvjHlbLCYXr2oYOg6NOUxiuCLCmQi0cqCy1ljr5QcBhoeBN mL/ENM8yuif/GDxvN+xyF0/g7r1fdAM= Message-ID: <0e1b8994-944d-4dda-8966-3cd43661796d@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1778638273; 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=Iq7jnY+N0UwU1xXxCmM5jCZ1Y+zQ9eUrIz+WkKBogEQ=; b=wqU8qVBOB6nPI8tTv2ruSJGtw0S5kRmu9mGb+a0X62ASIwBhuC7sNYjp1hEHRGS3fv0Jke /+WG6c1jYbL7dgRhevSmu4bdBQDFFOeMTTgqN5ZN6GRhpq6xKym1chF7TeMNfq3QClKzpJ vwBwUHJpWeAQoQn7wwGJ/t8kSeSRdOE= Date: Wed, 13 May 2026 10:10:34 +0800 MIME-Version: 1.0 Subject: Re: [linus:master] [mm] 01b9da291c: stress-ng.switch.ops_per_sec 67.7% regression To: Shakeel Butt , kernel test robot Cc: oe-lkp@lists.linux.dev, lkp@intel.com, linux-kernel@vger.kernel.org, Andrew Morton , David Carlier , Allen Pais , Axel Rasmussen , Baoquan He , Chengming Zhou , Chen Ridong , David Hildenbrand , Hamza Mahfooz , Harry Yoo , Hugh Dickins , Imran Khan , Johannes Weiner , Kamalesh Babulal , Lance Yang , Liam Howlett , Lorenzo Stoakes , Michal Hocko , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Mike Rapoport , Muchun Song , Muchun Song , Nhat Pham , Roman Gushchin , Suren Baghdasaryan , Usama Arif , Vlastimil Babka , Wei Xu , Yosry Ahmed , Yuanchu Xie , Zi Yan , Usama Arif , cgroups@vger.kernel.org, linux-mm@kvack.org References: <202605121641.b6a60cb0-lkp@intel.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Qi Zheng In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: a5qd3cth5r6gaaqh8jrcnwgmxpg8wk1a X-Rspamd-Queue-Id: 53F9F4000C X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1778638276-797663 X-HE-Meta: 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 mkPOIB9l XqpwzRe7vapTfKDpG4RutDI0orj7Cwq0b1wb2QVShE7k1t6TnMdPkDEwhAyOAm+VUXbJwdwKu/ZK1joPJEZvgziodeUuAzhQN3GN0sD7aMVK4G9MzuMrLDcDHM06+w5Ta2PhAumDkn9oc7aY/MM+hsVoX3ZfaZof42J9PJthWS+sNL+3Qyqy//24XPZoMcpHsHL5mvlMvi66g1KXpxPHZTO4wqtfwC1m+kuOjE1aG3D99VzL9a7RnwdZ4SDCLu+Tv8G5RNhszl02gUbtYHvNo2Tt1bA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 5/13/26 12:03 AM, Shakeel Butt wrote: > On Tue, May 12, 2026 at 08:56:52PM +0800, kernel test robot wrote: >> >> >> Hello, >> >> kernel test robot noticed a 67.7% regression of stress-ng.switch.ops_per_sec on: >> >> >> commit: 01b9da291c4969354807b52956f4aae1f41b4924 ("mm: memcontrol: convert objcg to be per-memcg per-node type") >> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master > > This is most probably due to shuffling of struct mem_cgroup and struct > mem_cgroup_per_node members. Another possibility is that after objcg was split into per-node, the slab accounting fast path is still designed assuming only one current objcg per CPU: struct obj_stock_pcp { struct obj_cgroup *cached_objcg; }; So it's may cause the following thrashing: CPU stock cached = memcg/node0 objcg free object tagged = memcg/node1 objcg => __refill_obj_stock --> objcg mismatch => drain_obj_stock() => cache switches to node1 objcg next local allocation tagged = node0 objcg => mismatch again => drain_obj_stock() > > I will try to reproduce and will followup on this. Thanks! I'll also try to reproduce it locally and work on a fix.