| Message ID | 20231116022411.2250072-4-yosryahmed@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: memcg: subtree stats flushing and thresholds | expand |
Hello,
kernel test robot noticed a -30.2% regression of will-it-scale.per_thread_ops on:
commit: c7fbfc7b4e089c4a9b292b1973a42a5761c1342f ("[PATCH v3 3/5] mm: memcg: make stats flushing threshold per-memcg")
url: https://github.com/intel-lab-lkp/linux/commits/Yosry-Ahmed/mm-memcg-change-flush_next_time-to-flush_last_time/20231116-103300
base: https://git.kernel.org/cgit/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/all/20231116022411.2250072-4-yosryahmed@google.com/
patch subject: [PATCH v3 3/5] mm: memcg: make stats flushing threshold per-memcg
testcase: will-it-scale
test machine: 104 threads 2 sockets (Skylake) with 192G memory
parameters:
nr_task: 50%
mode: thread
test: fallocate2
cpufreq_governor: performance
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 <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202311221542.973f16ad-oliver.sang@intel.com
Details are as below:
-------------------------------------------------------------------------------------------------->
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20231122/202311221542.973f16ad-oliver.sang@intel.com
=========================================================================================
compiler/cpufreq_governor/kconfig/mode/nr_task/rootfs/tbox_group/test/testcase:
gcc-12/performance/x86_64-rhel-8.3/thread/50%/debian-11.1-x86_64-20220510.cgz/lkp-skl-fpga01/fallocate2/will-it-scale
commit:
c5caa5bb03 ("mm: memcg: move vmstats structs definition above flushing code")
c7fbfc7b4e ("mm: memcg: make stats flushing threshold per-memcg")
c5caa5bb0376e3e5 c7fbfc7b4e089c4a9b292b1973a
---------------- ---------------------------
%stddev %change %stddev
\ | \
1.84 -0.5 1.37 ± 9% mpstat.cpu.all.usr%
0.08 -25.0% 0.06 turbostat.IPC
3121 -9.2% 2835 ± 5% vmstat.system.cs
78.17 ± 12% +96.6% 153.67 ± 18% perf-c2c.DRAM.local
504.17 ± 6% +34.4% 677.50 ± 4% perf-c2c.DRAM.remote
3980762 -30.2% 2777359 will-it-scale.52.threads
76552 -30.2% 53410 will-it-scale.per_thread_ops
3980762 -30.2% 2777359 will-it-scale.workload
1.192e+09 ± 2% -30.2% 8.324e+08 ± 3% numa-numastat.node0.local_node
1.192e+09 ± 2% -30.2% 8.324e+08 ± 3% numa-numastat.node0.numa_hit
1.215e+09 ± 2% -30.3% 8.471e+08 ± 3% numa-numastat.node1.local_node
1.215e+09 ± 2% -30.3% 8.474e+08 ± 3% numa-numastat.node1.numa_hit
1.192e+09 ± 2% -30.2% 8.324e+08 ± 3% numa-vmstat.node0.numa_hit
1.192e+09 ± 2% -30.2% 8.324e+08 ± 3% numa-vmstat.node0.numa_local
1.215e+09 ± 2% -30.3% 8.474e+08 ± 3% numa-vmstat.node1.numa_hit
1.215e+09 ± 2% -30.3% 8.471e+08 ± 3% numa-vmstat.node1.numa_local
31404 -1.6% 30913 proc-vmstat.nr_slab_reclaimable
2.408e+09 -30.2% 1.68e+09 proc-vmstat.numa_hit
2.407e+09 -30.2% 1.68e+09 proc-vmstat.numa_local
2.404e+09 -30.2% 1.678e+09 proc-vmstat.pgalloc_normal
2.403e+09 -30.2% 1.678e+09 proc-vmstat.pgfree
0.05 ± 8% -27.3% 0.04 ± 4% perf-sched.wait_and_delay.avg.ms.__cond_resched.shmem_fallocate.vfs_fallocate.__x64_sys_fallocate.do_syscall_64
0.05 ± 10% -24.9% 0.04 ± 8% perf-sched.wait_and_delay.avg.ms.__cond_resched.shmem_inode_acct_blocks.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate
0.05 ± 8% -27.2% 0.04 ± 5% perf-sched.wait_and_delay.avg.ms.__cond_resched.shmem_undo_range.shmem_setattr.notify_change.do_truncate
1.14 +14.1% 1.30 perf-sched.wait_and_delay.avg.ms.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
198.38 ± 3% +16.5% 231.12 ± 3% perf-sched.wait_and_delay.avg.ms.smpboot_thread_fn.kthread.ret_from_fork.ret_from_fork_asm
1563 ± 5% -11.4% 1384 ± 5% perf-sched.wait_and_delay.count.__cond_resched.shmem_fallocate.vfs_fallocate.__x64_sys_fallocate.do_syscall_64
1677 ± 5% -18.7% 1364 ± 4% perf-sched.wait_and_delay.count.__cond_resched.shmem_undo_range.shmem_setattr.notify_change.do_truncate
3815 ± 2% -14.5% 3260 ± 2% perf-sched.wait_and_delay.count.smpboot_thread_fn.kthread.ret_from_fork.ret_from_fork_asm
0.51 ± 5% -32.3% 0.35 ± 16% perf-sched.wait_and_delay.max.ms.__cond_resched.shmem_fallocate.vfs_fallocate.__x64_sys_fallocate.do_syscall_64
0.47 ± 11% -33.3% 0.31 ± 20% perf-sched.wait_and_delay.max.ms.__cond_resched.shmem_inode_acct_blocks.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate
2.37 +13.0% 2.68 ± 2% perf-sched.wait_and_delay.max.ms.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
0.05 ± 8% -27.3% 0.04 ± 4% perf-sched.wait_time.avg.ms.__cond_resched.shmem_fallocate.vfs_fallocate.__x64_sys_fallocate.do_syscall_64
0.05 ± 10% -24.9% 0.04 ± 8% perf-sched.wait_time.avg.ms.__cond_resched.shmem_inode_acct_blocks.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate
0.05 ± 8% -27.2% 0.04 ± 5% perf-sched.wait_time.avg.ms.__cond_resched.shmem_undo_range.shmem_setattr.notify_change.do_truncate
1.14 +14.1% 1.30 perf-sched.wait_time.avg.ms.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
198.37 ± 3% +16.5% 231.11 ± 3% perf-sched.wait_time.avg.ms.smpboot_thread_fn.kthread.ret_from_fork.ret_from_fork_asm
0.39 ± 31% -72.9% 0.11 ± 28% perf-sched.wait_time.max.ms.__cond_resched.__alloc_pages.alloc_pages_mpol.shmem_alloc_folio.shmem_alloc_and_add_folio
0.51 ± 5% -32.3% 0.35 ± 16% perf-sched.wait_time.max.ms.__cond_resched.shmem_fallocate.vfs_fallocate.__x64_sys_fallocate.do_syscall_64
0.47 ± 11% -33.3% 0.31 ± 20% perf-sched.wait_time.max.ms.__cond_resched.shmem_inode_acct_blocks.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate
2.37 +13.1% 2.68 ± 2% perf-sched.wait_time.max.ms.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
0.82 ± 14% +174.7% 2.24 ± 30% perf-stat.i.MPKI
8.476e+09 -27.7% 6.127e+09 ± 10% perf-stat.i.branch-instructions
55486131 -28.1% 39884260 ± 6% perf-stat.i.branch-misses
14.80 ± 2% +6.2 20.96 ± 7% perf-stat.i.cache-miss-rate%
30690945 ± 3% +79.9% 55207216 ± 10% perf-stat.i.cache-misses
2.066e+08 +24.2% 2.567e+08 ± 7% perf-stat.i.cache-references
3070 -9.7% 2772 ± 5% perf-stat.i.context-switches
3.58 ± 2% +39.7% 5.00 ± 11% perf-stat.i.cpi
4688 ± 3% -47.9% 2442 ± 4% perf-stat.i.cycles-between-cache-misses
4098916 -29.7% 2879809 perf-stat.i.dTLB-load-misses
1.052e+10 -27.5% 7.63e+09 ± 10% perf-stat.i.dTLB-loads
5.845e+09 -30.7% 4.051e+09 ± 10% perf-stat.i.dTLB-stores
77.61 -6.0 71.56 perf-stat.i.iTLB-load-miss-rate%
4058819 -32.5% 2739054 ± 8% perf-stat.i.iTLB-load-misses
4.089e+10 -28.3% 2.932e+10 ± 10% perf-stat.i.instructions
0.28 -26.8% 0.21 ± 5% perf-stat.i.ipc
240.84 -27.9% 173.57 ± 10% perf-stat.i.metric.M/sec
3814721 ± 3% +72.2% 6569712 ± 10% perf-stat.i.node-load-misses
407308 ± 7% +72.0% 700502 ± 18% perf-stat.i.node-loads
1323090 ± 2% -28.1% 951590 ± 12% perf-stat.i.node-store-misses
36568 ± 2% -20.7% 29014 ± 12% perf-stat.i.node-stores
0.75 ± 3% +151.0% 1.88 perf-stat.overall.MPKI
14.85 ± 2% +6.6 21.47 ± 3% perf-stat.overall.cache-miss-rate%
3.53 +33.8% 4.72 perf-stat.overall.cpi
4704 ± 3% -46.8% 2505 perf-stat.overall.cycles-between-cache-misses
77.62 -6.2 71.39 perf-stat.overall.iTLB-load-miss-rate%
0.28 -25.3% 0.21 perf-stat.overall.ipc
3121462 +7.4% 3353425 perf-stat.overall.path-length
8.451e+09 -27.6% 6.119e+09 ± 10% perf-stat.ps.branch-instructions
55320195 -28.0% 39804925 ± 6% perf-stat.ps.branch-misses
30594557 ± 3% +80.2% 55116821 ± 9% perf-stat.ps.cache-misses
2.059e+08 +24.4% 2.561e+08 ± 6% perf-stat.ps.cache-references
3059 -9.6% 2765 ± 5% perf-stat.ps.context-switches
4085949 -29.7% 2871251 perf-stat.ps.dTLB-load-misses
1.049e+10 -27.4% 7.62e+09 ± 10% perf-stat.ps.dTLB-loads
5.828e+09 -30.6% 4.046e+09 ± 10% perf-stat.ps.dTLB-stores
4046367 -32.4% 2734227 ± 7% perf-stat.ps.iTLB-load-misses
4.077e+10 -28.2% 2.928e+10 ± 10% perf-stat.ps.instructions
3802900 ± 3% +72.5% 6559980 ± 10% perf-stat.ps.node-load-misses
406123 ± 7% +72.2% 699397 ± 17% perf-stat.ps.node-loads
1319155 ± 2% -28.0% 950261 ± 12% perf-stat.ps.node-store-misses
36542 ± 2% -20.6% 29007 ± 11% perf-stat.ps.node-stores
1.243e+13 -25.0% 9.313e+12 perf-stat.total.instructions
1.26 ± 2% -0.4 0.91 perf-profile.calltrace.cycles-pp.syscall_return_via_sysret.fallocate64
1.22 -0.3 0.88 ± 2% perf-profile.calltrace.cycles-pp.shmem_alloc_folio.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate.vfs_fallocate
0.92 ± 2% -0.3 0.62 ± 3% perf-profile.calltrace.cycles-pp.shmem_inode_acct_blocks.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate.vfs_fallocate
1.04 -0.3 0.76 ± 2% perf-profile.calltrace.cycles-pp.alloc_pages_mpol.shmem_alloc_folio.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate
0.80 -0.2 0.58 ± 3% perf-profile.calltrace.cycles-pp.__alloc_pages.alloc_pages_mpol.shmem_alloc_folio.shmem_alloc_and_add_folio.shmem_get_folio_gfp
1.25 ± 2% -0.2 1.07 perf-profile.calltrace.cycles-pp.folio_batch_move_lru.lru_add_drain_cpu.__folio_batch_release.shmem_undo_range.shmem_setattr
1.25 ± 2% -0.2 1.07 perf-profile.calltrace.cycles-pp.lru_add_drain_cpu.__folio_batch_release.shmem_undo_range.shmem_setattr.notify_change
1.23 ± 2% -0.2 1.06 perf-profile.calltrace.cycles-pp.folio_lruvec_lock_irqsave.folio_batch_move_lru.lru_add_drain_cpu.__folio_batch_release.shmem_undo_range
1.23 ± 2% -0.2 1.06 perf-profile.calltrace.cycles-pp._raw_spin_lock_irqsave.folio_lruvec_lock_irqsave.folio_batch_move_lru.lru_add_drain_cpu.__folio_batch_release
1.23 ± 2% -0.2 1.05 perf-profile.calltrace.cycles-pp.native_queued_spin_lock_slowpath._raw_spin_lock_irqsave.folio_lruvec_lock_irqsave.folio_batch_move_lru.lru_add_drain_cpu
1.16 ± 2% -0.1 1.02 ± 2% perf-profile.calltrace.cycles-pp.syscall_exit_to_user_mode.do_syscall_64.entry_SYSCALL_64_after_hwframe.fallocate64
0.68 +0.1 0.75 ± 2% perf-profile.calltrace.cycles-pp.__mem_cgroup_uncharge_list.release_pages.__folio_batch_release.shmem_undo_range.shmem_setattr
1.07 +0.1 1.18 ± 2% perf-profile.calltrace.cycles-pp.lru_add_fn.folio_batch_move_lru.folio_add_lru.shmem_alloc_and_add_folio.shmem_get_folio_gfp
2.95 +0.3 3.21 ± 2% perf-profile.calltrace.cycles-pp.truncate_inode_folio.shmem_undo_range.shmem_setattr.notify_change.do_truncate
2.60 +0.4 2.95 perf-profile.calltrace.cycles-pp.filemap_remove_folio.truncate_inode_folio.shmem_undo_range.shmem_setattr.notify_change
2.27 +0.4 2.71 ± 2% perf-profile.calltrace.cycles-pp.__filemap_remove_folio.filemap_remove_folio.truncate_inode_folio.shmem_undo_range.shmem_setattr
1.38 ± 3% +0.5 1.85 ± 5% perf-profile.calltrace.cycles-pp.get_mem_cgroup_from_mm.__mem_cgroup_charge.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate
2.29 ± 2% +0.6 2.90 ± 2% perf-profile.calltrace.cycles-pp.shmem_add_to_page_cache.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate.vfs_fallocate
0.00 +0.6 0.63 ± 2% perf-profile.calltrace.cycles-pp.__mod_memcg_lruvec_state.release_pages.__folio_batch_release.shmem_undo_range.shmem_setattr
0.00 +0.7 0.74 ± 3% perf-profile.calltrace.cycles-pp.__mod_memcg_lruvec_state.lru_add_fn.folio_batch_move_lru.folio_add_lru.shmem_alloc_and_add_folio
1.30 +0.8 2.07 ± 3% perf-profile.calltrace.cycles-pp.filemap_unaccount_folio.__filemap_remove_folio.filemap_remove_folio.truncate_inode_folio.shmem_undo_range
0.73 ± 2% +0.8 1.53 ± 2% perf-profile.calltrace.cycles-pp.__mod_memcg_lruvec_state.__mod_lruvec_page_state.filemap_unaccount_folio.__filemap_remove_folio.filemap_remove_folio
1.23 +0.8 2.04 ± 3% perf-profile.calltrace.cycles-pp.__mod_lruvec_page_state.filemap_unaccount_folio.__filemap_remove_folio.filemap_remove_folio.truncate_inode_folio
0.00 +0.8 0.82 ± 2% perf-profile.calltrace.cycles-pp.__count_memcg_events.mem_cgroup_commit_charge.__mem_cgroup_charge.shmem_alloc_and_add_folio.shmem_get_folio_gfp
1.39 ± 2% +0.9 2.32 ± 2% perf-profile.calltrace.cycles-pp.__mod_lruvec_page_state.shmem_add_to_page_cache.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate
0.59 ± 2% +0.9 1.53 ± 2% perf-profile.calltrace.cycles-pp.__mod_memcg_lruvec_state.__mod_lruvec_page_state.shmem_add_to_page_cache.shmem_alloc_and_add_folio.shmem_get_folio_gfp
38.12 +1.0 39.16 perf-profile.calltrace.cycles-pp.vfs_fallocate.__x64_sys_fallocate.do_syscall_64.entry_SYSCALL_64_after_hwframe.fallocate64
0.62 ± 4% +1.1 1.71 ± 3% perf-profile.calltrace.cycles-pp.mem_cgroup_commit_charge.__mem_cgroup_charge.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate
37.61 +1.2 38.80 perf-profile.calltrace.cycles-pp.shmem_fallocate.vfs_fallocate.__x64_sys_fallocate.do_syscall_64.entry_SYSCALL_64_after_hwframe
36.54 +1.5 38.02 perf-profile.calltrace.cycles-pp.shmem_get_folio_gfp.shmem_fallocate.vfs_fallocate.__x64_sys_fallocate.do_syscall_64
35.97 +1.6 37.60 perf-profile.calltrace.cycles-pp.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate.vfs_fallocate.__x64_sys_fallocate
2.48 ± 3% +2.3 4.80 ± 4% perf-profile.calltrace.cycles-pp.__mem_cgroup_charge.shmem_alloc_and_add_folio.shmem_get_folio_gfp.shmem_fallocate.vfs_fallocate
1.28 ± 2% -0.4 0.92 perf-profile.children.cycles-pp.syscall_return_via_sysret
1.23 -0.3 0.88 ± 2% perf-profile.children.cycles-pp.shmem_alloc_folio
0.95 ± 2% -0.3 0.64 ± 3% perf-profile.children.cycles-pp.shmem_inode_acct_blocks
1.07 -0.3 0.77 ± 3% perf-profile.children.cycles-pp.alloc_pages_mpol
0.86 ± 2% -0.3 0.58 ± 2% perf-profile.children.cycles-pp.xas_store
0.84 -0.2 0.61 ± 3% perf-profile.children.cycles-pp.__alloc_pages
1.26 ± 2% -0.2 1.08 perf-profile.children.cycles-pp.lru_add_drain_cpu
0.61 ± 3% -0.2 0.43 perf-profile.children.cycles-pp.__entry_text_start
0.56 ± 2% -0.2 0.40 ± 3% perf-profile.children.cycles-pp.free_unref_page_list
0.26 ± 7% -0.2 0.11 ± 5% perf-profile.children.cycles-pp.__list_add_valid_or_report
1.19 ± 2% -0.1 1.04 ± 2% perf-profile.children.cycles-pp.syscall_exit_to_user_mode
0.45 ± 4% -0.1 0.31 perf-profile.children.cycles-pp.__mod_lruvec_state
0.48 ± 2% -0.1 0.35 ± 2% perf-profile.children.cycles-pp.get_page_from_freelist
0.38 ± 5% -0.1 0.27 ± 2% perf-profile.children.cycles-pp.xas_load
0.38 ± 2% -0.1 0.27 ± 2% perf-profile.children.cycles-pp._raw_spin_lock
0.33 ± 4% -0.1 0.23 ± 2% perf-profile.children.cycles-pp.__mod_node_page_state
0.42 ± 2% -0.1 0.32 ± 5% perf-profile.children.cycles-pp.find_lock_entries
0.32 ± 2% -0.1 0.23 ± 2% perf-profile.children.cycles-pp.__dquot_alloc_space
0.33 ± 2% -0.1 0.24 ± 3% perf-profile.children.cycles-pp.rmqueue
0.24 ± 3% -0.1 0.17 ± 4% perf-profile.children.cycles-pp.xas_descend
0.23 ± 3% -0.1 0.16 ± 4% perf-profile.children.cycles-pp.xas_init_marks
0.25 ± 3% -0.1 0.17 ± 2% perf-profile.children.cycles-pp.xas_clear_mark
0.23 ± 2% -0.1 0.16 ± 5% perf-profile.children.cycles-pp.__cond_resched
0.28 ± 5% -0.1 0.22 ± 2% perf-profile.children.cycles-pp.filemap_get_entry
0.24 ± 3% -0.1 0.18 ± 4% perf-profile.children.cycles-pp.truncate_cleanup_folio
0.16 ± 4% -0.1 0.10 ± 4% perf-profile.children.cycles-pp.xas_find_conflict
0.09 ± 7% -0.1 0.03 ± 70% perf-profile.children.cycles-pp.mem_cgroup_update_lru_size
0.18 -0.1 0.12 ± 6% perf-profile.children.cycles-pp.shmem_recalc_inode
0.18 ± 2% -0.1 0.12 ± 3% perf-profile.children.cycles-pp.folio_unlock
0.17 ± 4% -0.1 0.12 ± 3% perf-profile.children.cycles-pp.free_unref_page_prepare
0.16 ± 6% -0.1 0.11 ± 4% perf-profile.children.cycles-pp.security_file_permission
0.13 ± 7% -0.0 0.08 ± 13% perf-profile.children.cycles-pp.security_vm_enough_memory_mm
0.20 ± 4% -0.0 0.15 ± 2% perf-profile.children.cycles-pp.free_unref_page_commit
0.16 ± 5% -0.0 0.11 ± 3% perf-profile.children.cycles-pp.noop_dirty_folio
0.15 ± 5% -0.0 0.11 ± 4% perf-profile.children.cycles-pp.file_modified
0.12 ± 10% -0.0 0.08 perf-profile.children.cycles-pp.__percpu_counter_limited_add
0.19 ± 5% -0.0 0.14 ± 5% perf-profile.children.cycles-pp._raw_spin_lock_irq
0.11 ± 12% -0.0 0.06 ± 17% perf-profile.children.cycles-pp.cap_vm_enough_memory
0.14 ± 5% -0.0 0.10 ± 6% perf-profile.children.cycles-pp.__fget_light
0.14 ± 7% -0.0 0.10 ± 4% perf-profile.children.cycles-pp.apparmor_file_permission
0.14 ± 2% -0.0 0.10 ± 4% perf-profile.children.cycles-pp.__folio_cancel_dirty
0.12 ± 3% -0.0 0.08 ± 4% perf-profile.children.cycles-pp.entry_SYSCALL_64_safe_stack
0.11 ± 10% -0.0 0.08 ± 16% perf-profile.children.cycles-pp.__vm_enough_memory
0.11 ± 8% -0.0 0.08 ± 4% perf-profile.children.cycles-pp.xas_start
0.11 ± 3% -0.0 0.08 ± 4% perf-profile.children.cycles-pp.__fsnotify_parent
0.18 ± 2% -0.0 0.14 ± 6% perf-profile.children.cycles-pp.__list_del_entry_valid_or_report
0.08 ± 6% -0.0 0.04 ± 45% perf-profile.children.cycles-pp.__get_file_rcu
0.12 ± 7% -0.0 0.09 ± 5% perf-profile.children.cycles-pp.inode_add_bytes
0.11 ± 4% -0.0 0.08 ± 8% perf-profile.children.cycles-pp._raw_spin_trylock
0.08 ± 6% -0.0 0.05 ± 45% perf-profile.children.cycles-pp.percpu_counter_add_batch
0.10 -0.0 0.07 ± 9% perf-profile.children.cycles-pp.inode_needs_update_time
0.09 ± 7% -0.0 0.06 ± 6% perf-profile.children.cycles-pp.get_pfnblock_flags_mask
0.07 ± 6% -0.0 0.05 ± 45% perf-profile.children.cycles-pp.shmem_is_huge
0.09 ± 7% -0.0 0.07 ± 7% perf-profile.children.cycles-pp.entry_SYSRETQ_unsafe_stack
0.08 ± 4% -0.0 0.06 ± 8% perf-profile.children.cycles-pp.policy_nodemask
0.19 ± 3% -0.0 0.17 ± 4% perf-profile.children.cycles-pp.try_charge_memcg
0.08 ± 8% -0.0 0.06 ± 8% perf-profile.children.cycles-pp.down_write
0.09 ± 7% -0.0 0.07 ± 5% perf-profile.children.cycles-pp.xas_create
0.09 ± 7% -0.0 0.07 ± 7% perf-profile.children.cycles-pp.filemap_free_folio
0.08 ± 4% -0.0 0.06 ± 6% perf-profile.children.cycles-pp.xas_find
0.07 ± 5% +0.0 0.09 ± 5% perf-profile.children.cycles-pp.propagate_protected_usage
0.25 +0.0 0.28 ± 2% perf-profile.children.cycles-pp.uncharge_folio
0.43 ± 2% +0.0 0.47 ± 2% perf-profile.children.cycles-pp.uncharge_batch
0.69 +0.1 0.75 ± 2% perf-profile.children.cycles-pp.__mem_cgroup_uncharge_list
1.10 +0.1 1.20 ± 2% perf-profile.children.cycles-pp.lru_add_fn
2.96 +0.3 3.21 perf-profile.children.cycles-pp.truncate_inode_folio
2.60 +0.4 2.96 perf-profile.children.cycles-pp.filemap_remove_folio
2.29 +0.4 2.73 ± 2% perf-profile.children.cycles-pp.__filemap_remove_folio
1.39 ± 3% +0.5 1.85 ± 5% perf-profile.children.cycles-pp.get_mem_cgroup_from_mm
2.34 ± 2% +0.6 2.93 ± 2% perf-profile.children.cycles-pp.shmem_add_to_page_cache
0.18 ± 5% +0.7 0.92 ± 2% perf-profile.children.cycles-pp.__count_memcg_events
1.32 +0.8 2.07 ± 3% perf-profile.children.cycles-pp.filemap_unaccount_folio
38.14 +1.0 39.17 perf-profile.children.cycles-pp.vfs_fallocate
0.64 ± 4% +1.1 1.72 ± 3% perf-profile.children.cycles-pp.mem_cgroup_commit_charge
37.63 +1.2 38.81 perf-profile.children.cycles-pp.shmem_fallocate
36.57 +1.5 38.05 perf-profile.children.cycles-pp.shmem_get_folio_gfp
36.04 +1.6 37.65 perf-profile.children.cycles-pp.shmem_alloc_and_add_folio
2.66 +1.7 4.38 ± 3% perf-profile.children.cycles-pp.__mod_lruvec_page_state
2.49 ± 2% +2.3 4.80 ± 4% perf-profile.children.cycles-pp.__mem_cgroup_charge
1.99 ± 2% +2.5 4.46 perf-profile.children.cycles-pp.__mod_memcg_lruvec_state
1.28 ± 2% -0.4 0.92 perf-profile.self.cycles-pp.syscall_return_via_sysret
0.69 ± 2% -0.2 0.50 ± 2% perf-profile.self.cycles-pp.entry_SYSCALL_64_after_hwframe
0.54 ± 2% -0.2 0.36 ± 2% perf-profile.self.cycles-pp.release_pages
0.47 ± 2% -0.2 0.31 ± 2% perf-profile.self.cycles-pp.xas_store
0.53 ± 3% -0.2 0.37 ± 2% perf-profile.self.cycles-pp.__entry_text_start
0.36 ± 3% -0.2 0.21 ± 2% perf-profile.self.cycles-pp.shmem_add_to_page_cache
0.26 ± 8% -0.2 0.11 ± 5% perf-profile.self.cycles-pp.__list_add_valid_or_report
1.14 ± 2% -0.1 1.01 ± 2% perf-profile.self.cycles-pp.syscall_exit_to_user_mode
0.40 ± 4% -0.1 0.28 ± 4% perf-profile.self.cycles-pp.lru_add_fn
0.37 ± 2% -0.1 0.26 perf-profile.self.cycles-pp._raw_spin_lock
0.32 ± 3% -0.1 0.22 ± 2% perf-profile.self.cycles-pp.__mod_node_page_state
0.35 ± 3% -0.1 0.25 ± 2% perf-profile.self.cycles-pp.shmem_fallocate
0.50 ± 2% -0.1 0.40 ± 3% perf-profile.self.cycles-pp.folio_batch_move_lru
0.34 ± 3% -0.1 0.26 ± 5% perf-profile.self.cycles-pp.find_lock_entries
0.28 ± 2% -0.1 0.20 ± 5% perf-profile.self.cycles-pp.__alloc_pages
0.22 ± 2% -0.1 0.16 ± 3% perf-profile.self.cycles-pp.xas_clear_mark
0.21 ± 3% -0.1 0.15 ± 4% perf-profile.self.cycles-pp.shmem_alloc_and_add_folio
0.18 ± 3% -0.1 0.12 ± 5% perf-profile.self.cycles-pp.free_unref_page_list
0.22 ± 3% -0.1 0.16 ± 3% perf-profile.self.cycles-pp.xas_descend
0.20 ± 6% -0.1 0.14 ± 2% perf-profile.self.cycles-pp.__dquot_alloc_space
0.18 ± 4% -0.1 0.12 ± 6% perf-profile.self.cycles-pp.shmem_inode_acct_blocks
0.21 ± 5% -0.1 0.15 ± 5% perf-profile.self.cycles-pp.vfs_fallocate
0.18 ± 2% -0.1 0.12 ± 3% perf-profile.self.cycles-pp.__filemap_remove_folio
0.17 ± 4% -0.1 0.12 ± 3% perf-profile.self.cycles-pp.folio_unlock
0.20 ± 3% -0.0 0.14 ± 5% perf-profile.self.cycles-pp.shmem_get_folio_gfp
0.16 ± 5% -0.0 0.12 ± 6% perf-profile.self.cycles-pp.__cond_resched
0.17 ± 5% -0.0 0.12 ± 3% perf-profile.self.cycles-pp._raw_spin_lock_irq
0.14 ± 4% -0.0 0.10 ± 5% perf-profile.self.cycles-pp.xas_load
0.15 ± 2% -0.0 0.10 ± 4% perf-profile.self.cycles-pp.get_page_from_freelist
0.16 ± 4% -0.0 0.12 ± 4% perf-profile.self.cycles-pp.alloc_pages_mpol
0.12 ± 6% -0.0 0.08 ± 6% perf-profile.self.cycles-pp.rmqueue
0.13 ± 6% -0.0 0.09 ± 4% perf-profile.self.cycles-pp._raw_spin_lock_irqsave
0.13 ± 8% -0.0 0.09 ± 4% perf-profile.self.cycles-pp.apparmor_file_permission
0.15 ± 3% -0.0 0.11 ± 3% perf-profile.self.cycles-pp.noop_dirty_folio
0.10 ± 10% -0.0 0.06 ± 17% perf-profile.self.cycles-pp.cap_vm_enough_memory
0.07 ± 8% -0.0 0.03 ± 70% perf-profile.self.cycles-pp.percpu_counter_add_batch
0.12 ± 10% -0.0 0.08 ± 4% perf-profile.self.cycles-pp.__percpu_counter_limited_add
0.12 ± 4% -0.0 0.08 ± 8% perf-profile.self.cycles-pp.folio_add_lru
0.10 ± 3% -0.0 0.06 ± 7% perf-profile.self.cycles-pp.xas_init_marks
0.10 ± 9% -0.0 0.07 perf-profile.self.cycles-pp.xas_start
0.13 ± 3% -0.0 0.10 ± 5% perf-profile.self.cycles-pp.filemap_remove_folio
0.11 ± 6% -0.0 0.08 ± 6% perf-profile.self.cycles-pp.__fsnotify_parent
0.16 ± 4% -0.0 0.12 ± 4% perf-profile.self.cycles-pp.free_unref_page_commit
0.12 ± 4% -0.0 0.08 ± 4% perf-profile.self.cycles-pp.__mod_lruvec_state
0.11 ± 3% -0.0 0.08 ± 7% perf-profile.self.cycles-pp.fallocate64
0.08 ± 6% -0.0 0.04 ± 45% perf-profile.self.cycles-pp.__get_file_rcu
0.11 ± 4% -0.0 0.08 ± 8% perf-profile.self.cycles-pp.__folio_cancel_dirty
0.11 ± 3% -0.0 0.08 ± 6% perf-profile.self.cycles-pp._raw_spin_trylock
0.11 ± 6% -0.0 0.08 ± 6% perf-profile.self.cycles-pp.truncate_cleanup_folio
0.06 ± 7% -0.0 0.03 ± 70% perf-profile.self.cycles-pp.__fget_light
0.17 ± 3% -0.0 0.14 ± 5% perf-profile.self.cycles-pp.__list_del_entry_valid_or_report
0.09 ± 5% -0.0 0.06 ± 7% perf-profile.self.cycles-pp.filemap_get_entry
0.22 ± 6% -0.0 0.19 ± 3% perf-profile.self.cycles-pp.page_counter_uncharge
0.09 ± 7% -0.0 0.06 ± 6% perf-profile.self.cycles-pp.get_pfnblock_flags_mask
0.08 ± 5% -0.0 0.06 ± 8% perf-profile.self.cycles-pp.free_unref_page_prepare
0.07 ± 11% -0.0 0.04 ± 44% perf-profile.self.cycles-pp.shmem_is_huge
0.08 ± 6% -0.0 0.05 ± 7% perf-profile.self.cycles-pp.__x64_sys_fallocate
0.08 ± 7% -0.0 0.06 ± 6% perf-profile.self.cycles-pp.entry_SYSRETQ_unsafe_stack
0.09 ± 7% -0.0 0.07 ± 7% perf-profile.self.cycles-pp.filemap_free_folio
0.08 ± 8% -0.0 0.06 perf-profile.self.cycles-pp.shmem_alloc_folio
0.12 ± 6% -0.0 0.10 ± 6% perf-profile.self.cycles-pp.try_charge_memcg
0.07 ± 5% +0.0 0.09 ± 5% perf-profile.self.cycles-pp.propagate_protected_usage
0.24 +0.0 0.27 ± 3% perf-profile.self.cycles-pp.uncharge_folio
0.46 ± 4% +0.4 0.86 ± 5% perf-profile.self.cycles-pp.mem_cgroup_commit_charge
1.38 ± 3% +0.5 1.84 ± 5% perf-profile.self.cycles-pp.get_mem_cgroup_from_mm
0.16 ± 3% +0.7 0.90 ± 2% perf-profile.self.cycles-pp.__count_memcg_events
0.28 ± 3% +0.8 1.06 ± 5% perf-profile.self.cycles-pp.__mem_cgroup_charge
1.86 ± 2% +2.5 4.36 perf-profile.self.cycles-pp.__mod_memcg_lruvec_state
Disclaimer:
Results have been estimated based on internal Intel analysis and are provided
for informational purposes only. Any difference in system hardware or software
design or configuration may affect actual performance.
On Wed, Nov 22, 2023 at 5:54 AM kernel test robot <oliver.sang@intel.com> wrote: > > > > Hello, > > kernel test robot noticed a -30.2% regression of will-it-scale.per_thread_ops on: > > > commit: c7fbfc7b4e089c4a9b292b1973a42a5761c1342f ("[PATCH v3 3/5] mm: memcg: make stats flushing threshold per-memcg") > url: https://github.com/intel-lab-lkp/linux/commits/Yosry-Ahmed/mm-memcg-change-flush_next_time-to-flush_last_time/20231116-103300 > base: https://git.kernel.org/cgit/linux/kernel/git/akpm/mm.git mm-everything > patch link: https://lore.kernel.org/all/20231116022411.2250072-4-yosryahmed@google.com/ > patch subject: [PATCH v3 3/5] mm: memcg: make stats flushing threshold per-memcg > > testcase: will-it-scale > test machine: 104 threads 2 sockets (Skylake) with 192G memory > parameters: > > nr_task: 50% > mode: thread > test: fallocate2 > cpufreq_governor: performance > > This regression was also reported in v2, and I explicitly mention it in the cover letter here: https://lore.kernel.org/lkml/20231116022411.2250072-1-yosryahmed@google.com/ In a nutshell, I think this microbenchmark regression does not represent real workloads. On the other hand, there are demonstrated benefits on real workloads from this series in terms of stats reading time.
hi, Yosry Ahmed, On Mon, Nov 27, 2023 at 01:13:44PM -0800, Yosry Ahmed wrote: > On Wed, Nov 22, 2023 at 5:54 AM kernel test robot <oliver.sang@intel.com> wrote: > > > > > > > > Hello, > > > > kernel test robot noticed a -30.2% regression of will-it-scale.per_thread_ops on: > > > > > > commit: c7fbfc7b4e089c4a9b292b1973a42a5761c1342f ("[PATCH v3 3/5] mm: memcg: make stats flushing threshold per-memcg") > > url: https://github.com/intel-lab-lkp/linux/commits/Yosry-Ahmed/mm-memcg-change-flush_next_time-to-flush_last_time/20231116-103300 > > base: https://git.kernel.org/cgit/linux/kernel/git/akpm/mm.git mm-everything > > patch link: https://lore.kernel.org/all/20231116022411.2250072-4-yosryahmed@google.com/ > > patch subject: [PATCH v3 3/5] mm: memcg: make stats flushing threshold per-memcg > > > > testcase: will-it-scale > > test machine: 104 threads 2 sockets (Skylake) with 192G memory > > parameters: > > > > nr_task: 50% > > mode: thread > > test: fallocate2 > > cpufreq_governor: performance > > > > > > This regression was also reported in v2, and I explicitly mention it > in the cover letter here: > https://lore.kernel.org/lkml/20231116022411.2250072-1-yosryahmed@google.com/ got it. this also reminds us to read cover letter for a patch set in the future. Thanks! > > In a nutshell, I think this microbenchmark regression does not > represent real workloads. On the other hand, there are demonstrated > benefits on real workloads from this series in terms of stats reading > time. > ok, if there are future versions of this patch, or when it is merged, we will ignore similar results. just a small question, since we focus on microbenchmark, if we found other regression (or improvement) on tests other than will-it-scale::fallocate, do you want us to send report or just ignore them, either?
On Mon, Nov 27, 2023 at 5:46 PM Oliver Sang <oliver.sang@intel.com> wrote: > > hi, Yosry Ahmed, > > On Mon, Nov 27, 2023 at 01:13:44PM -0800, Yosry Ahmed wrote: > > On Wed, Nov 22, 2023 at 5:54 AM kernel test robot <oliver.sang@intel.com> wrote: > > > > > > > > > > > > Hello, > > > > > > kernel test robot noticed a -30.2% regression of will-it-scale.per_thread_ops on: > > > > > > > > > commit: c7fbfc7b4e089c4a9b292b1973a42a5761c1342f ("[PATCH v3 3/5] mm: memcg: make stats flushing threshold per-memcg") > > > url: https://github.com/intel-lab-lkp/linux/commits/Yosry-Ahmed/mm-memcg-change-flush_next_time-to-flush_last_time/20231116-103300 > > > base: https://git.kernel.org/cgit/linux/kernel/git/akpm/mm.git mm-everything > > > patch link: https://lore.kernel.org/all/20231116022411.2250072-4-yosryahmed@google.com/ > > > patch subject: [PATCH v3 3/5] mm: memcg: make stats flushing threshold per-memcg > > > > > > testcase: will-it-scale > > > test machine: 104 threads 2 sockets (Skylake) with 192G memory > > > parameters: > > > > > > nr_task: 50% > > > mode: thread > > > test: fallocate2 > > > cpufreq_governor: performance > > > > > > > > > > This regression was also reported in v2, and I explicitly mention it > > in the cover letter here: > > https://lore.kernel.org/lkml/20231116022411.2250072-1-yosryahmed@google.com/ > > got it. this also reminds us to read cover letter for a patch set in the > future. Thanks! > > > > > In a nutshell, I think this microbenchmark regression does not > > represent real workloads. On the other hand, there are demonstrated > > benefits on real workloads from this series in terms of stats reading > > time. > > > > ok, if there are future versions of this patch, or when it is merged, we will > ignore similar results. > > just a small question, since we focus on microbenchmark, if we found other > regression (or improvement) on tests other than will-it-scale::fallocate, > do you want us to send report or just ignore them, either? I think it would be useful to know if there are regressions/improvements in other microbenchmarks, at least to investigate whether they represent real regressions.
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 5ae2a8f04be45..74db05237775d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -630,6 +630,9 @@ struct memcg_vmstats_percpu { /* Cgroup1: threshold notifications & softlimit tree updates */ unsigned long nr_page_events; unsigned long targets[MEM_CGROUP_NTARGETS]; + + /* Stats updates since the last flush */ + unsigned int stats_updates; }; struct memcg_vmstats { @@ -644,6 +647,9 @@ struct memcg_vmstats { /* Pending child counts during tree propagation */ long state_pending[MEMCG_NR_STAT]; unsigned long events_pending[NR_MEMCG_EVENTS]; + + /* Stats updates since the last flush */ + atomic64_t stats_updates; }; /* @@ -663,9 +669,7 @@ struct memcg_vmstats { */ static void flush_memcg_stats_dwork(struct work_struct *w); static DECLARE_DEFERRABLE_WORK(stats_flush_dwork, flush_memcg_stats_dwork); -static DEFINE_PER_CPU(unsigned int, stats_updates); static atomic_t stats_flush_ongoing = ATOMIC_INIT(0); -static atomic_t stats_flush_threshold = ATOMIC_INIT(0); static u64 flush_last_time; #define FLUSH_TIME (2UL*HZ) @@ -692,26 +696,37 @@ static void memcg_stats_unlock(void) preempt_enable_nested(); } + +static bool memcg_should_flush_stats(struct mem_cgroup *memcg) +{ + return atomic64_read(&memcg->vmstats->stats_updates) > + MEMCG_CHARGE_BATCH * num_online_cpus(); +} + static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val) { + int cpu = smp_processor_id(); unsigned int x; if (!val) return; - cgroup_rstat_updated(memcg->css.cgroup, smp_processor_id()); + cgroup_rstat_updated(memcg->css.cgroup, cpu); + + for (; memcg; memcg = parent_mem_cgroup(memcg)) { + x = __this_cpu_add_return(memcg->vmstats_percpu->stats_updates, + abs(val)); + + if (x < MEMCG_CHARGE_BATCH) + continue; - x = __this_cpu_add_return(stats_updates, abs(val)); - if (x > MEMCG_CHARGE_BATCH) { /* - * If stats_flush_threshold exceeds the threshold - * (>num_online_cpus()), cgroup stats update will be triggered - * in __mem_cgroup_flush_stats(). Increasing this var further - * is redundant and simply adds overhead in atomic update. + * If @memcg is already flush-able, increasing stats_updates is + * redundant. Avoid the overhead of the atomic update. */ - if (atomic_read(&stats_flush_threshold) <= num_online_cpus()) - atomic_add(x / MEMCG_CHARGE_BATCH, &stats_flush_threshold); - __this_cpu_write(stats_updates, 0); + if (!memcg_should_flush_stats(memcg)) + atomic64_add(x, &memcg->vmstats->stats_updates); + __this_cpu_write(memcg->vmstats_percpu->stats_updates, 0); } } @@ -730,13 +745,12 @@ static void do_flush_stats(void) cgroup_rstat_flush(root_mem_cgroup->css.cgroup); - atomic_set(&stats_flush_threshold, 0); atomic_set(&stats_flush_ongoing, 0); } void mem_cgroup_flush_stats(void) { - if (atomic_read(&stats_flush_threshold) > num_online_cpus()) + if (memcg_should_flush_stats(root_mem_cgroup)) do_flush_stats(); } @@ -750,8 +764,8 @@ void mem_cgroup_flush_stats_ratelimited(void) static void flush_memcg_stats_dwork(struct work_struct *w) { /* - * Always flush here so that flushing in latency-sensitive paths is - * as cheap as possible. + * Deliberately ignore memcg_should_flush_stats() here so that flushing + * in latency-sensitive paths is as cheap as possible. */ do_flush_stats(); queue_delayed_work(system_unbound_wq, &stats_flush_dwork, FLUSH_TIME); @@ -5784,6 +5798,10 @@ static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) } } } + statc->stats_updates = 0; + /* We are in a per-cpu loop here, only do the atomic write once */ + if (atomic64_read(&memcg->vmstats->stats_updates)) + atomic64_set(&memcg->vmstats->stats_updates, 0); } #ifdef CONFIG_MMU
A global counter for the magnitude of memcg stats update is maintained on the memcg side to avoid invoking rstat flushes when the pending updates are not significant. This avoids unnecessary flushes, which are not very cheap even if there isn't a lot of stats to flush. It also avoids unnecessary lock contention on the underlying global rstat lock. Make this threshold per-memcg. The scheme is followed where percpu (now also per-memcg) counters are incremented in the update path, and only propagated to per-memcg atomics when they exceed a certain threshold. This provides two benefits: (a) On large machines with a lot of memcgs, the global threshold can be reached relatively fast, so guarding the underlying lock becomes less effective. Making the threshold per-memcg avoids this. (b) Having a global threshold makes it hard to do subtree flushes, as we cannot reset the global counter except for a full flush. Per-memcg counters removes this as a blocker from doing subtree flushes, which helps avoid unnecessary work when the stats of a small subtree are needed. Nothing is free, of course. This comes at a cost: (a) A new per-cpu counter per memcg, consuming NR_CPUS * NR_MEMCGS * 4 bytes. The extra memory usage is insigificant. (b) More work on the update side, although in the common case it will only be percpu counter updates. The amount of work scales with the number of ancestors (i.e. tree depth). This is not a new concept, adding a cgroup to the rstat tree involves a parent loop, so is charging. Testing results below show no significant regressions. (c) The error margin in the stats for the system as a whole increases from NR_CPUS * MEMCG_CHARGE_BATCH to NR_CPUS * MEMCG_CHARGE_BATCH * NR_MEMCGS. This is probably fine because we have a similar per-memcg error in charges coming from percpu stocks, and we have a periodic flusher that makes sure we always flush all the stats every 2s anyway. This patch was tested to make sure no significant regressions are introduced on the update path as follows. The following benchmarks were ran in a cgroup that is 2 levels deep (/sys/fs/cgroup/a/b/): (1) Running 22 instances of netperf on a 44 cpu machine with hyperthreading disabled. All instances are run in a level 2 cgroup, as well as netserver: # netserver -6 # netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K Averaging 20 runs, the numbers are as follows: Base: 40198.0 mbps Patched: 38629.7 mbps (-3.9%) The regression is minimal, especially for 22 instances in the same cgroup sharing all ancestors (so updating the same atomics). (2) will-it-scale page_fault tests. These tests (specifically per_process_ops in page_fault3 test) detected a 25.9% regression before for a change in the stats update path [1]. These are the numbers from 10 runs (+ is good) on a machine with 256 cpus: LABEL | MEAN | MEDIAN | STDDEV | ------------------------------+-------------+-------------+------------- page_fault1_per_process_ops | | | | (A) base | 270249.164 | 265437.000 | 13451.836 | (B) patched | 261368.709 | 255725.000 | 13394.767 | | -3.29% | -3.66% | | page_fault1_per_thread_ops | | | | (A) base | 242111.345 | 239737.000 | 10026.031 | (B) patched | 237057.109 | 235305.000 | 9769.687 | | -2.09% | -1.85% | | page_fault1_scalability | | | (A) base | 0.034387 | 0.035168 | 0.0018283 | (B) patched | 0.033988 | 0.034573 | 0.0018056 | | -1.16% | -1.69% | | page_fault2_per_process_ops | | | (A) base | 203561.836 | 203301.000 | 2550.764 | (B) patched | 197195.945 | 197746.000 | 2264.263 | | -3.13% | -2.73% | | page_fault2_per_thread_ops | | | (A) base | 171046.473 | 170776.000 | 1509.679 | (B) patched | 166626.327 | 166406.000 | 768.753 | | -2.58% | -2.56% | | page_fault2_scalability | | | (A) base | 0.054026 | 0.053821 | 0.00062121 | (B) patched | 0.053329 | 0.05306 | 0.00048394 | | -1.29% | -1.41% | | page_fault3_per_process_ops | | | (A) base | 1295807.782 | 1297550.000 | 5907.585 | (B) patched | 1275579.873 | 1273359.000 | 8759.160 | | -1.56% | -1.86% | | page_fault3_per_thread_ops | | | (A) base | 391234.164 | 390860.000 | 1760.720 | (B) patched | 377231.273 | 376369.000 | 1874.971 | | -3.58% | -3.71% | | page_fault3_scalability | | | (A) base | 0.60369 | 0.60072 | 0.0083029 | (B) patched | 0.61733 | 0.61544 | 0.009855 | | +2.26% | +2.45% | | All regressions seem to be minimal, and within the normal variance for the benchmark. The fix for [1] assumes that 3% is noise -- and there were no further practical complaints), so hopefully this means that such variations in these microbenchmarks do not reflect on practical workloads. (3) I also ran stress-ng in a nested cgroup and did not observe any obvious regressions. [1]https://lore.kernel.org/all/20190520063534.GB19312@shao2-debian/ Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com> --- mm/memcontrol.c | 50 +++++++++++++++++++++++++++++++++---------------- 1 file changed, 34 insertions(+), 16 deletions(-)