Revert "update defconfig"

This reverts commit c5654202cbd92d5e8b0edd962b30d57a4732b581.
Revert "introduce for_each_thread() to replace the buggy while_each_thread() (fix)"

This reverts commit 1186c6c81b0771e301d16a2aaa4127956beaa018.
Revert "lowmemorykiller.c: convert to use for_each_thread"

This reverts commit d90c4510b6e862f5fb42ceefc026f2b92f5699c0.
Revert "introduce for_each_thread() to replace the buggy while_each_thread()"

This reverts commit 0fb66c5b6395e2ed7d1b8684166859dab9463e00.
Revert "mm, oom: base root bonus on current usage"

This reverts commit 5aff3ca30d87194939261390a57ecabd02264120.
Revert "mm, oom: prefer thread group leaders for display purposes"

This reverts commit e30ded55f5f44d5b8a6fb316eafe44165a3f9e73.
Revert "oom_kill: add rcu_read_lock() into find_lock_task_mm()"

This reverts commit 9b7e71ba35a62fc2b04b83d045572870cff231f7.
Revert "oom_kill: has_intersects_mems_allowed() needs rcu_read_lock()"

This reverts commit 477ec52204cd5a504309718ed93ef78e59745f59.
Revert "oom_kill: change oom_kill.c to use for_each_thread()"

This reverts commit 5b858caf37df4e1a0f1251ce6e849b81706d9959.
Revert "mm/oom_kill: remove weird use of ERR_PTR()/PTR_ERR()."

This reverts commit 8ab5e01359fbef681b95bf05037841635c36ef08.
Revert "mm, oom: cleanup pagefault oom handler"

This reverts commit 513237b1e423fcae8bcb272b432a9bf1cad05e1c.
Revert "oom: use N_MEMORY instead N_HIGH_MEMORY"

This reverts commit f587c480dd19366eca8dc9f412a69a23ac7af642.
Revert "mm, oom: allow exiting threads to have access to memory reserves"

This reverts commit 1458b8436c5e2b8a78d94a4bc16c8add9f753cff.
Revert "mm, memcg: move all oom handling to memcontrol.c"

This reverts commit b717f4425122bd3459e6796d91c140f3127566c6.
Revert "mm, oom: reduce dependency on tasklist_lock"

This reverts commit 2c49816252c1a72c5c5e4f68813e3f684b7e0bae.
Revert "mm, memcg: introduce own oom handler to iterate only over its own threads"

This reverts commit e5142267781fdc56c822bedde5bf3be4d10c4823.
Revert "mm, oom: introduce helper function to process threads during scan"

This reverts commit 64df34584a260f644231487c8612c8f0077e31a1.
Revert "mm, oom: move declaration for mem_cgroup_out_of_memory to oom.h"

This reverts commit 020ad9b478dba6dde4c10a1521143f87a2b3400c.
Revert "mm, oom: fix and cleanup oom score calculations"

This reverts commit ab1f81dc6df3f239cf4aaef50a102cb63020a9da.
Revert "mm, oom: fix badness score underflow"

This reverts commit 6a9909b666c85202fd64b9ce2db1ca5d9056f38d.