[linux-next:master] [mm/vmpressure] ea928e9e18: stress-ng.mremap.ops_per_sec 36.2% regression

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)




If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-lkp/[email protected]


2026-08-11 09:13:23 sysctl -w kernel.sched_autogroup_enabled=0 kernel.sched_autogroup_enabled = 0
2026-08-11 09:13:23 stress-ng --timeout 60 --times --verify --metrics --no-rand-seed --mremap 256
stress-ng: info:  [10886] setting to a 1 min run per stressor
stress-ng: info:  [10886] dispatching hogs: 256 mremap
stress-ng: info:  [11033] mremap: using 1MB per stressor instance (total 256MB of 243.06GB available memory)
stress-ng: metrc: [10886] stressor       bogo ops real time  usr time  sys time   bogo ops/s     bogo ops/s CPU used per       RSS Max
stress-ng: metrc: [10886]                           (secs)    (secs)    (secs)   (real time) (usr+sys time) instance (%)          (KB)
stress-ng: metrc: [10886] mremap          2212529     59.96    209.34  15014.92     36901.22         145.33        99.19          6684
stress-ng: metrc: [10886] miscellaneous metrics:
stress-ng: metrc: [10886] mremap            151372.07 nanosecs per mremap call (harmonic mean of 256 instances)
stress-ng: info:  [10886] for a 60.01s run time:
stress-ng: info:  [10886]   15363.58s available CPU time
stress-ng: info:  [10886]     209.34s user time   (  1.36%)
stress-ng: info:  [10886]   15015.19s system time ( 97.73%)
stress-ng: info:  [10886]   15224.53s total time  ( 99.09%)
stress-ng: info:  [10886] load average: 163.54 47.28 16.30
stress-ng: info:  [10886] skipped: 0
stress-ng: info:  [10886] passed: 256: mremap (256)
stress-ng: info:  [10886] failed: 0
stress-ng: info:  [10886] metrics untrustworthy: 0
stress-ng: info:  [10886] successful run completed in 1 min



The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20260813/[email protected]



--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki