linux/kernel/cgroup
Yu Zhao 354ed59744 mm: multi-gen LRU: kill switch
Add /sys/kernel/mm/lru_gen/enabled as a kill switch. Components that
can be disabled include:
  0x0001: the multi-gen LRU core
  0x0002: walking page table, when arch_has_hw_pte_young() returns
          true
  0x0004: clearing the accessed bit in non-leaf PMD entries, when
          CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG=y
  [yYnN]: apply to all the components above
E.g.,
  echo y >/sys/kernel/mm/lru_gen/enabled
  cat /sys/kernel/mm/lru_gen/enabled
  0x0007
  echo 5 >/sys/kernel/mm/lru_gen/enabled
  cat /sys/kernel/mm/lru_gen/enabled
  0x0005

NB: the page table walks happen on the scale of seconds under heavy memory
pressure, in which case the mmap_lock contention is a lesser concern,
compared with the LRU lock contention and the I/O congestion.  So far the
only well-known case of the mmap_lock contention happens on Android, due
to Scudo [1] which allocates several thousand VMAs for merely a few
hundred MBs.  The SPF and the Maple Tree also have provided their own
assessments [2][3].  However, if walking page tables does worsen the
mmap_lock contention, the kill switch can be used to disable it.  In this
case the multi-gen LRU will suffer a minor performance degradation, as
shown previously.

Clearing the accessed bit in non-leaf PMD entries can also be disabled,
since this behavior was not tested on x86 varieties other than Intel and
AMD.

[1] https://source.android.com/devices/tech/debug/scudo
[2] https://lore.kernel.org/r/20220128131006.67712-1-michel@lespinasse.org/
[3] https://lore.kernel.org/r/20220426150616.3937571-1-Liam.Howlett@oracle.com/

Link: https://lkml.kernel.org/r/20220918080010.2920238-11-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Acked-by: Steven Barrett <steven@liquorix.net>
Acked-by: Suleiman Souhlal <suleiman@google.com>
Tested-by: Daniel Byrne <djbyrne@mtu.edu>
Tested-by: Donald Carr <d@chaos-reins.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
Tested-by: Shuang Zhai <szhai2@cs.rochester.edu>
Tested-by: Sofia Trinh <sofia.trinh@edi.works>
Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-26 19:46:10 -07:00
..
cgroup-internal.h mm: multi-gen LRU: kill switch 2022-09-26 19:46:10 -07:00
cgroup-v1.c cgroup: Add missing cpus_read_lock() to cgroup_attach_task_all() 2022-08-25 07:36:30 -10:00
cgroup.c cgroup: Fix race condition at rebind_subsystems() 2022-08-23 08:11:06 -10:00
cpuset.c cgroup: Fix threadgroup_rwsem <-> cpus_read_lock() deadlock 2022-08-17 07:36:05 -10:00
debug.c
freezer.c cgroup: cleanup comments 2022-03-13 19:19:27 -10:00
legacy_freezer.c
Makefile cgroup: Add misc cgroup controller 2021-04-04 13:34:46 -04:00
misc.c misc_cgroup: remove error log to avoid log flood 2021-09-20 07:35:38 -10:00
namespace.c memcg: enable accounting for new namesapces and struct nsproxy 2021-09-03 09:58:12 -07:00
pids.c clone3: allow spawning processes into cgroups 2020-02-12 17:57:51 -05:00
rdma.c cgroup: fix spelling mistakes 2021-05-24 12:45:26 -04:00
rstat.c sched/core: add forced idle accounting for cgroups 2022-07-04 09:23:07 +02:00