Applications with a large number of memory mappings result in application specific poor performance or stall events

Issue

• An application that makes use of a very large number of small memory regions begins to slow at scale. When profiling the application via perf, the following codepath is seen to be that which the system is spending the majority of it's time within:

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 32.92%          <comm>  [kernel.kallsyms]                      [k] find_vma                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
                    |
                    --- find_vma
                       |         
                       |--98.51%-- arch_get_unmapped_area_topdown
                       |          get_unmapped_area_prot
                       |          |         
                       |          |--99.99%-- do_mmap_pgoff
                       |          |          sys_mmap_pgoff
                       |          |          sys_mmap
                       |          |          system_call_fastpath
                       |          |          __GI___mmap64
                       |          |          |         
<snip>