Re: regression caused by cgroups optimization in 3.17-rc2

[Johannes Weiner]

On Tue, Sep 02, 2014 at 03:36:29PM -0700, Dave Hansen wrote:
> 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.

That looks like a partial profile, where did the page allocator, page
zeroing etc. go?  Because the distribution among these listed symbols
doesn't seem all that crazy:

>    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%-- [...]

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/