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Howlett" , Lorenzo Stoakes , Michal Hocko , Michal =?utf-8?Q?Koutn=C3=BD?= , Mike Rapoport , Roman Gushchin , Suren Baghdasaryan , Tejun Heo , Vlastimil Babka , linux-mm@kvack.org, cgroups@vger.kernel.org Subject: Re: [linux-next:master] [mm/vmpressure] ea928e9e18: stress-ng.mremap.ops_per_sec 36.2% regression Message-ID: References: <202608131743.c6a7dda4-lkp@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202608131743.c6a7dda4-lkp@intel.com> X-Rspam-User: X-Stat-Signature: 1pgk446xzetde5zkc1qjke4abnswta1s X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 31547C001A X-HE-Tag: 1786640484-985920 X-HE-Meta: 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 VZMwYQTu mAVC9KWKYoo7vDyHz0VKjn+DxJ1sYuybR2D+s770iDt+Z00QKGUZfY39b7YU9VZmki23GYFt6sYl4w9M5Z8yepOgv4y5Hw96GtLVRxA4HFeBSGcCpHN/r6PZppqIzQloBfjlblNjs6ViPWB5FuOK8+40q4S8tZK8J6TObNoZXa8UMsTpArfvsGwgcvI4/rnI/bR6SFzbBDEOUq92b+c8cDOp+JQkJOWXk7OoOpGHYv6/zXN/LNpUnklUbuIz5EKWAC/2c5VAis4+qx7vxQXdWsSIVaFQc53JOM14znuRhPyQLUEviUoEmW7Y7g6VLGFhjz4j/HSrViclJWJuasG4nSBubrS1A7JacdIx8E03o5N2Ltmso2PhdSwaFxhI1TdQXEHWFnBbmlYw06v8= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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; -- 2.53.0-Meta