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 97019C5B572 for ; Thu, 13 Aug 2026 17:15:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 66D836B055A; Thu, 13 Aug 2026 13:15:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 61EB06B055B; Thu, 13 Aug 2026 13:15:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 533FF6B055C; Thu, 13 Aug 2026 13:15:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 30DCC6B055A for ; Thu, 13 Aug 2026 13:15:11 -0400 (EDT) Received: from smtpin02.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id BC9D280216 for ; Thu, 13 Aug 2026 17:15:10 +0000 (UTC) X-FDA: 85096896780.02.4A0B063 Received: from mta0.migadu.com (out-151.mta0.migadu.com [91.218.175.151]) by imf28.hostedemail.com (Postfix) with ESMTP id 7D220C000A for ; Thu, 13 Aug 2026 17:15:08 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=YA7ZfcUJ; spf=pass (imf28.hostedemail.com: domain of usama.arif@linux.dev designates 91.218.175.151 as permitted sender) smtp.mailfrom=usama.arif@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=1786641308; 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=pTLxQstLkB4+RKAm8Qn/u/Sbo0fsNC8qLPC1ltU8D4k=; b=aiTJweem1JQ3e1u5TDMoDq6PVJLKG6wo9hoG5KXRTPaJrKdcDeE5z7tmwyBGy794HXynhc MEpvpW7AuOOCkVoDnCFjTCpwB8a0GiF7MIZNi+4v+peaZQnvDS0mYooHkcRLY+bcygYdJ4 S/okqfaEfujzYDyxQ8owlk2Mnr+y0lU= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=YA7ZfcUJ; spf=pass (imf28.hostedemail.com: domain of usama.arif@linux.dev designates 91.218.175.151 as permitted sender) smtp.mailfrom=usama.arif@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1786641308; b=jwcFVxke2/7TSGaV3fAX4xQFdvf/uptyFmD/c9BbTp08i65/xzk3wQBggJLYiXZtkMhCFf k6W11V2c1pgG+MuwIAZ+He+NZlUr42N25kMmfy5fmp89qtcuTI6PgBRFTKYwQghs1eJsY3 Fz4yMnu9nJy3UGIQsJS4tG9SBbsO8k8= X-Envelope-To: linux-mm@kvack.org DKIM-Signature: a=rsa-sha256; bh=Yec5Wj8ZUY9zXGuHPs7l8wD80d+XYwicM6WJm2aA3IY=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1786641307; v=1; x=1787246107; b=YA7ZfcUJa2liuDoGBWGG+/y0Iv+PY4Q13Hgtd/L0Hl6Phnrqy6mjVyTCAnNtxVhfAWXwmqNU lKrIBlDTJq9K2icM7myrhlDxbmYs0Vy7wtFHm/nd04iIR08a2KnOja5fT1xl7pq1bPJPhuNM4l0 f5U922JvjCfjbskRa2bRhaYA= X-Envelope-To: linux-mm@kvack.org Received: from [IPV6:2a03:83e0:1126:4:9d:a05e:5bd8:c200] (2620:10d:c092:500::6:def8) by smtp.migadu.com with ESMTPS id de41cf8ec9c54807; Thu, 13 Aug 2026 17:14:57 +0000 X-Migadu-Flow: FLOW_OUT Message-ID: <017721a3-5eae-449e-8b86-75cffb503dd3@linux.dev> Date: Thu, 13 Aug 2026 18:14:50 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [linux-next:master] [mm/vmpressure] ea928e9e18: stress-ng.mremap.ops_per_sec 36.2% regression To: Shakeel Butt , kernel test robot Cc: oe-lkp@lists.linux.dev, lkp@intel.com, Andrew Morton , David Hildenbrand , Johannes Weiner , "Liam R. Howlett" , Lorenzo Stoakes , Michal Hocko , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Mike Rapoport , Roman Gushchin , Suren Baghdasaryan , Tejun Heo , Vlastimil Babka , linux-mm@kvack.org, cgroups@vger.kernel.org References: <202608131743.c6a7dda4-lkp@intel.com> Content-Language: en-US From: Usama Arif In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 7frzd8oo4qprc6qow78t369ruyke7zcj X-Rspamd-Queue-Id: 7D220C000A X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1786641308-103054 X-HE-Meta: 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 Qrug1wVn ZJeiBG+iWOxycXDLBydBG0FZcHuRonLp3rI5qXVolGAf9LEeBZj/+xe0ztsDCun+BAaZG6YjzdFZuimyoZa/GHhcSD7Pvyz+dC/gsHw4NSzgiYNeSximvjMZ3wSJDun7q+GZtRkHnDjx5a6Kp8RG0j2pbhNXifGIYQzHANDworJErTCSasPGyeQehfWBnffq8sPJIU6EQ6pvbK/ArRPzom+rzN6GTLJ/KQ1Xj1/kveu4laiWfaCo4pc6W3hayqx7IWBbopI9zhp19MDVAeaqWnntJ+FBpPoxwuoLnYazX4IXZqazXy7KWZ4HP3+GFVXRHmc6EpwYJJEw/GmMX3KXxmROB6hq4yDzyfIVRzNH/g0Fd2fByp2ZZjjGPrQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 13/08/2026 18:01, Shakeel Butt wrote: > On Thu, Aug 13, 2026 at 09:16:22PM +0800, kernel test robot wrote: >> >> >> Hello, >> >> kernel test robot noticed a 36.2% regression of stress-ng.mremap.ops_per_sec on: >> >> commit: ea928e9e18da682e9a5bc40aa862bff7ce5ae42e ("mm/vmpressure: move v1 userspace eventfd code into memcontrol-v1.c") https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master >> >> in testcase: stress-ng >> version: stress-ng-x86_64-29ce10a2c-1_20260712 >> with following parameters: >> >> nr_threads: 100% >> testtime: 60s >> test: mremap >> cpufreq_governor: performance >> >> >> >> config: x86_64-rhel-9.4 (CONFIG_MEMCG=y and CONFIG_MEMCG_V1 is not set) >> compiler: gcc-14 >> test machine: 256 threads 4 sockets INTEL(R) XEON(R) PLATINUM 8592+ (Emerald Rapids) with 256G memory >> >> (please refer to attached dmesg/kmsg for entire log/backtrace) >> > > Hi there, > > Can you please test the following patch and see if it fixes the regression? > > > From 84c0b05b3bc5cf73ee66ead75aafb1ad684462c3 Mon Sep 17 00:00:00 2001 > From: Shakeel Butt > Date: Thu, 13 Aug 2026 09:38:28 -0700 > Subject: [PATCH] memcg: keep vmstats_percpu off the memory_events[] cacheline > > Signed-off-by: Shakeel Butt > --- > include/linux/memcontrol.h | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index e78bc98ab229..e25d5b9a1db8 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -246,8 +246,13 @@ struct mem_cgroup { > /* handle for "memory.swap.events" */ > struct cgroup_file swap_events_file; > > - /* memory.stat */ > + /* Read-mostly. */ > struct memcg_vmstats *vmstats; > + struct memcg_vmstats_percpu __percpu *vmstats_percpu; > + int kmemcg_id; > + > + /* Write-hot from here on; do not let it share with the above. */ > + CACHELINE_PADDING(_pad_); > > /* memory.events */ > atomic_long_t memory_events[MEMCG_NR_MEMORY_EVENTS]; > @@ -266,9 +271,6 @@ struct mem_cgroup { > #if BITS_PER_LONG < 64 > seqlock_t socket_pressure_seqlock; > #endif > - int kmemcg_id; > - > - struct memcg_vmstats_percpu __percpu *vmstats_percpu; > > #ifdef CONFIG_CGROUP_WRITEBACK > struct list_head cgwb_list; I was currently testing this diff, not sure which one would be better. diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index e78bc98ab229b..215e2e87f42b2 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -268,10 +268,15 @@ struct mem_cgroup { #endif int kmemcg_id; - struct memcg_vmstats_percpu __percpu *vmstats_percpu; - #ifdef CONFIG_CGROUP_WRITEBACK struct list_head cgwb_list; +#endif + + /* Keep the hot per-CPU stats pointer away from memory event counters. */ + struct memcg_vmstats_percpu __percpu *vmstats_percpu + ____cacheline_aligned_in_smp; + +#ifdef CONFIG_CGROUP_WRITEBACK struct wb_domain cgwb_domain; struct memcg_cgwb_frn cgwb_frn[MEMCG_CGWB_FRN_CNT]; #endif