On 09/02/2014 03:18 PM, Johannes Weiner wrote: > Accounting new pages is buffered through per-cpu caches, but taking > them off the counters on free is not, so I'm guessing that above a > certain allocation rate the cost of locking and changing the counters > takes over. Is there a chance you could profile this to see if locks > and res_counter-related operations show up? It looks pretty much the same, although it might have equalized the charge and uncharge sides a bit. Full 'perf top' output attached.
PerfTop: 275580 irqs/sec kernel:98.0% exact: 0.0% [4000Hz cycles], (all, 160 CPUs)
-------------------------------------------------------------------------------
68.10% 68.10% [kernel] [k] _raw_spin_lock
|
--- _raw_spin_lock
|
|--57.35%-- __res_counter_charge
| res_counter_charge
| try_charge
| mem_cgroup_try_charge
| |
| |--99.93%-- do_cow_fault
| | handle_mm_fault
| | __do_page_fault
| | do_page_fault
| | page_fault
| | testcase
| --0.07%-- [...]
|
|--53.93%-- res_counter_uncharge_until
| res_counter_uncharge
| refill_stock
| uncharge_batch
| uncharge_list
| mem_cgroup_uncharge_list
| release_pages
| free_pages_and_swap_cache
| tlb_flush_mmu_free
| |
| |--98.62%-- unmap_single_vma
| | unmap_vmas
| | unmap_region
| | do_munmap
| | vm_munmap
| | sys_munmap
| | system_call_fastpath
| | __GI___munmap
| |
| --1.38%-- tlb_flush_mmu
| tlb_finish_mmu
| unmap_region
| do_munmap
| vm_munmap
| sys_munmap
| system_call_fastpath
| __GI___munmap
|
|--2.18%-- do_cow_fault
| handle_mm_fault
| __do_page_fault
| do_page_fault
| page_fault
| testcase
--9307219025.55%-- [...]
64.00% 1.34% page_fault2_processes [.] testcase
|
--- testcase
62.64% 0.37% [kernel] [k] page_fault
|
--- page_fault
|
|--114.21%-- testcase
--10118485450.89%-- [...]
62.27% 0.01% [kernel] [k] do_page_fault
|
--- do_page_fault
|
|--114.28%-- page_fault
| |
| |--99.93%-- testcase
| --0.07%-- [...]
--10178525138.33%-- [...]
62.25% 0.07% [kernel] [k] __do_page_fault
|
--- __do_page_fault
|
|--114.27%-- do_page_fault
| page_fault
| |
| |--99.93%-- testcase
| --0.07%-- [...]
--10182230022.41%-- [...]
62.08% 0.26% [kernel] [k] handle_mm_fault
|
--- handle_mm_fault
|
|--114.28%-- __do_page_fault
| do_page_fault
| page_fault
| |
| |--99.94%-- testcase
| --0.06%-- [...]
--10210709377.69%-- [...]
44.32% 0.22% [kernel] [k] do_cow_fault
|
--- do_cow_fault
|
|--114.28%-- handle_mm_fault
| __do_page_fault
| do_page_fault
| page_fault
| testcase
--14302986980.21%-- [...]
35.23% 0.00% [kernel] [k] sys_munmap
|
--- sys_munmap
system_call_fastpath
__GI___munmap
34.84% 0.04% [kernel] [k] mem_cgroup_try_charge
|
--- mem_cgroup_try_charge
|
|--114.18%-- do_cow_fault
| handle_mm_fault
| __do_page_fault
| do_page_fault
| page_fault
| testcase
--18195666899.12%-- [...]
34.74% 0.49% [kernel] [k] unmap_single_vma
|
--- unmap_single_vma
unmap_vmas
unmap_region
do_munmap
vm_munmap
sys_munmap
system_call_fastpath
__GI___munmap
34.66% 0.00% [kernel] [k] tlb_flush_mmu_free
|
--- tlb_flush_mmu_free
|
|--112.70%-- unmap_single_vma
| unmap_vmas
| unmap_region
| do_munmap
| vm_munmap
| sys_munmap
| system_call_fastpath
| __GI___munmap
|
|--1.59%-- tlb_flush_mmu
| tlb_finish_mmu
| unmap_region
| do_munmap
| vm_munmap
| sys_munmap
| system_call_fastpath
| __GI___munmap
--18285481100.94%-- [...]
34.66% 0.12% [kernel] [k] free_pages_and_swap_cache
|
--- free_pages_and_swap_cache
tlb_flush_mmu_free
|
|--112.70%-- unmap_single_vma
| unmap_vmas
| unmap_region
| do_munmap
| vm_munmap
| sys_munmap
| system_call_fastpath
| __GI___munmap
|
|--1.59%-- tlb_flush_mmu
| tlb_finish_mmu
| unmap_region
| do_munmap
| vm_munmap
| sys_munmap
| system_call_fastpath
| __GI___munmap
--18286531934.97%-- [...]
34.61% 0.04% [kernel] [k] try_charge
|
--- try_charge
|
|--114.26%-- mem_cgroup_try_charge
| |
| |--99.93%-- do_cow_fault
| | handle_mm_fault
| | __do_page_fault
| | do_page_fault
| | page_fault
| | testcase
| --0.07%-- [...]
--18312751937.56%-- [...]
34.57% 0.00% [kernel] [k] res_counter_charge
|
--- res_counter_charge
|
|--114.27%-- try_charge
| mem_cgroup_try_charge
| |
| |--99.93%-- do_cow_fault
| | handle_mm_fault
| | __do_page_fault
| | do_page_fault
| | page_fault
| | testcase
| --0.07%-- [...]
--18334689838.42%-- [...]
34.56% 0.08% [kernel] [k] release_pages
|
--- release_pages
|
|--114.21%-- free_pages_and_swap_cache
| tlb_flush_mmu_free
| |
| |--98.61%-- unmap_single_vma
| | unmap_vmas
| | unmap_region
| | do_munmap
| | vm_munmap
| | sys_munmap
| | system_call_fastpath
| | __GI___munmap
| |
| --1.39%-- tlb_flush_mmu
| tlb_finish_mmu
| unmap_region
| do_munmap
| vm_munmap
| sys_munmap
| system_call_fastpath
| __GI___munmap
--18340488029.00%-- [...]
34.26% 0.08% [kernel] [k] __res_counter_charge
|
--- __res_counter_charge
|
|--114.28%-- res_counter_charge
| try_charge
| mem_cgroup_try_charge
| |
| |--99.93%-- do_cow_fault
| | handle_mm_fault
| | __do_page_fault
| | do_page_fault
| | page_fault
| | testcase
| --0.07%-- [...]
--18502823676.22%-- [...]
33.45% 0.00% [kernel] [k] mem_cgroup_uncharge_list
|
--- mem_cgroup_uncharge_list
|
|--114.28%-- release_pages
| free_pages_and_swap_cache
| tlb_flush_mmu_free
| |
| |--98.62%-- unmap_single_vma
| | unmap_vmas
| | unmap_region
| | do_munmap
| | vm_munmap
| | sys_munmap
| | system_call_fastpath
| | __GI___munmap
| |
| --1.38%-- tlb_flush_mmu
| tlb_finish_mmu
| unmap_region
| do_munmap
| vm_munmap
| sys_munmap
| system_call_fastpath
| __GI___munmap
--18949679654.78%-- [...]
33.45% 0.01% [kernel] [k] uncharge_list
|
--- uncharge_list
|
|--114.29%-- mem_cgroup_uncharge_list
| release_pages
| free_pages_and_swap_cache
| tlb_flush_mmu_free
| |
| |--98.62%-- unmap_single_vma
| | unmap_vmas
| | unmap_region
| | do_munmap
| | vm_munmap
| | sys_munmap
| | system_call_fastpath
| | __GI___munmap
| |
| --1.38%-- tlb_flush_mmu
| tlb_finish_mmu
| unmap_region
| do_munmap
| vm_munmap
| sys_munmap
| system_call_fastpath
| __GI___munmap
--18951232568.52%-- [...]
33.43% 0.02% [kernel] [k] uncharge_batch
|
--- uncharge_batch
|
|--114.28%-- uncharge_list
| mem_cgroup_uncharge_list
| release_pages
| free_pages_and_swap_cache
| tlb_flush_mmu_free
| |
| |--98.62%-- unmap_single_vma
| | unmap_vmas
| | unmap_region
| | do_munmap
| | vm_munmap
| | sys_munmap
| | system_call_fastpath
| | __GI___munmap
| |
| --1.38%-- tlb_flush_mmu
| tlb_finish_mmu
| unmap_region
| do_munmap
| vm_munmap
| sys_munmap
| system_call_fastpath
| __GI___munmap
--18962452122.61%-- [...]
32.43% 0.01% [kernel] [k] refill_stock
|
--- refill_stock
|
|--114.27%-- uncharge_batch
| uncharge_list
| mem_cgroup_uncharge_list
| release_pages
| free_pages_and_swap_cache
| tlb_flush_mmu_free
| |
| |--98.62%-- unmap_single_vma
| | unmap_vmas
| | unmap_region
| | do_munmap
| | vm_munmap
| | sys_munmap
| | system_call_fastpath
| | __GI___munmap
| |
| --1.38%-- tlb_flush_mmu
| tlb_finish_mmu
| unmap_region
| do_munmap
| vm_munmap
| sys_munmap
| system_call_fastpath
| __GI___munmap
--19543678319.29%-- [...]