WSL2-Linux-Kernel/mm
Tejun Heo 48ddbe1946 cgroup: make css->refcnt clearing on cgroup removal optional
Currently, cgroup removal tries to drain all css references.  If there
are active css references, the removal logic waits and retries
->pre_detroy() until either all refs drop to zero or removal is
cancelled.

This semantics is unusual and adds non-trivial complexity to cgroup
core and IMHO is fundamentally misguided in that it couples internal
implementation details (references to internal data structure) with
externally visible operation (rmdir).  To userland, this is a behavior
peculiarity which is unnecessary and difficult to expect (css refs is
otherwise invisible from userland), and, to policy implementations,
this is an unnecessary restriction (e.g. blkcg wants to hold css refs
for caching purposes but can't as that becomes visible as rmdir hang).

Unfortunately, memcg currently depends on ->pre_destroy() retrials and
cgroup removal vetoing and can't be immmediately switched to the new
behavior.  This patch introduces the new behavior of not waiting for
css refs to drain and maintains the old behavior for subsystems which
have __DEPRECATED_clear_css_refs set.

Once, memcg is updated, we can drop the code paths for the old
behavior as proposed in the following patch.  Note that the following
patch is incorrect in that dput work item is in cgroup and may lose
some of dputs when multiples css's are released back-to-back, and
__css_put() triggers check_for_release() when refcnt reaches 0 instead
of 1; however, it shows what part can be removed.

  http://thread.gmane.org/gmane.linux.kernel.containers/22559/focus=75251

Note that, in not-too-distant future, cgroup core will start emitting
warning messages for subsys which require the old behavior, so please
get moving.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
2012-04-01 12:09:56 -07:00
..
Kconfig Merge branch 'master' into x86/memblock 2011-11-28 09:46:22 -08:00
Kconfig.debug mm: more intensive memory corruption debugging 2012-01-10 16:30:42 -08:00
Makefile Cross Memory Attach 2011-10-31 17:30:44 -07:00
backing-dev.c backing-dev: fix wakeup timer races with bdi_unregister() 2012-02-01 16:52:49 +08:00
bootmem.c bootmem/sparsemem: remove limit constraint in alloc_bootmem_section 2012-03-21 17:54:58 -07:00
bounce.c mm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:27 +08:00
cleancache.c mm: cleancache: Use __read_mostly as appropiate. 2012-01-23 16:08:09 -05:00
compaction.c mm: compaction: make compact_control order signed 2012-03-21 17:54:56 -07:00
debug-pagealloc.c mm, x86: Remove debug_pagealloc_enabled 2011-12-06 09:24:07 +01:00
dmapool.c mm: fix implicit stat.h usage in dmapool.c 2011-10-31 09:20:12 -04:00
fadvise.c fadvise: only initiate writeback for specified range with FADV_DONTNEED 2012-01-10 16:30:43 -08:00
failslab.c switch debugfs to umode_t 2012-01-03 22:54:56 -05:00
filemap.c radix-tree: use iterators in find_get_pages* functions 2012-03-28 17:14:37 -07:00
filemap_xip.c mm/filemap_xip.c: fix race condition in xip_file_fault() 2012-02-03 16:16:41 -08:00
fremap.c mm: delete various needless include <linux/module.h> 2011-10-31 09:20:11 -04:00
highmem.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
huge_memory.c thp: optimize away unnecessary page table locking 2012-03-21 17:54:57 -07:00
hugetlb.c mm: hugetlb: cleanup duplicated code in unmapping vm range 2012-03-23 16:58:31 -07:00
hwpoison-inject.c HWPOISON: Clean up memory_failure() vs. __memory_failure() 2012-01-03 12:06:32 -08:00
init-mm.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
internal.h mm: thp: tail page refcounting fix 2011-11-02 16:06:57 -07:00
kmemcheck.c kmemcheck: Fix build errors due to missing slab.h 2010-03-30 22:02:32 +09:00
kmemleak-test.c kmemleak: remove memset by using kzalloc 2011-01-27 18:31:51 +00:00
kmemleak.c kmemleak: Disable early logging when kmemleak is off by default 2012-01-20 16:57:05 +00:00
ksm.c ksm: cleanup: introduce find_mergeable_vma() 2012-03-21 17:54:59 -07:00
maccess.c mm: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
madvise.c coredump: add VM_NODUMP, MADV_NODUMP, MADV_CLEAR_NODUMP 2012-03-23 16:58:42 -07:00
memblock.c memblock: Fix size aligning of memblock_alloc_base_nid() 2012-03-01 10:53:18 +01:00
memcontrol.c cgroup: make css->refcnt clearing on cgroup removal optional 2012-04-01 12:09:56 -07:00
memory-failure.c Merge branch 'x86-mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-22 09:42:04 -07:00
memory.c coredump: remove VM_ALWAYSDUMP flag 2012-03-23 16:58:42 -07:00
memory_hotplug.c mm: compaction: introduce sync-light migration for use by compaction 2012-01-12 20:13:09 -08:00
mempolicy.c cpuset: mm: reduce large amounts of memory barrier related damage v3 2012-03-21 17:54:59 -07:00
mempool.c mempool: fix first round failure behavior 2012-01-10 16:30:45 -08:00
migrate.c mm: fix move/migrate_pages() race on task struct 2012-03-21 17:54:58 -07:00
mincore.c mm: thp: fix pmd_bad() triggering in code paths holding mmap_sem read mode 2012-03-21 17:54:54 -07:00
mlock.c vm: avoid using find_vma_prev() unnecessarily 2012-03-06 18:23:36 -08:00
mm_init.c mm: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
mmap.c Merge branch 'akpm' (Andrew's patch-bomb) 2012-03-22 09:04:48 -07:00
mmu_context.c mm, counters: remove task argument to sync_mm_rss() and __sync_task_rss_stat() 2012-03-21 17:54:59 -07:00
mmu_notifier.c mm: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
mmzone.c mm: delete various needless include <linux/module.h> 2011-10-31 09:20:11 -04:00
mprotect.c Merge branch 'akpm' (Andrew's patch-bomb) 2012-03-22 09:04:48 -07:00
mremap.c mm: collapse security_vm_enough_memory() variants into a single function 2012-02-14 10:45:39 +11:00
msync.c sanitize vfs_fsync calling conventions 2010-05-21 18:31:21 -04:00
nobootmem.c Merge branch 'master' into x86/memblock 2011-11-28 09:46:22 -08:00
nommu.c NOMMU: Don't need to clear vm_mm when deleting a VMA 2012-02-24 08:59:04 -08:00
oom_kill.c signal: oom_kill_task: use SEND_SIG_FORCED instead of force_sig() 2012-03-23 16:58:41 -07:00
page-writeback.c Ext4 commits for 3.3 merge window; mostly cleanups and bug fixes 2012-03-28 10:02:55 -07:00
page_alloc.c mm: only IPI CPUs to drain local pages if they exist 2012-03-28 17:14:35 -07:00
page_cgroup.c page_cgroup: fix horrid swap accounting regression 2012-03-06 08:18:23 -08:00
page_io.c block: kill off REQ_UNPLUG 2011-03-10 08:52:27 +01:00
page_isolation.c mm: page_isolation: codeclean fix comment and rm unneeded val init 2010-10-26 16:52:11 -07:00
pagewalk.c mm: thp: fix pmd_bad() triggering in code paths holding mmap_sem read mode 2012-03-21 17:54:54 -07:00
percpu-km.c percpu: clear memory allocated with the km allocator 2010-10-02 10:28:42 +03:00
percpu-vm.c percpu: use bitmap_clear 2012-01-20 09:23:16 -08:00
percpu.c Kmemleak patches 2012-01-14 18:11:11 -08:00
pgtable-generic.c thp: add HPAGE_PMD_* definitions for !CONFIG_TRANSPARENT_HUGEPAGE 2012-03-21 17:55:02 -07:00
prio_tree.c sanitize <linux/prefetch.h> usage 2011-05-20 12:50:29 -07:00
process_vm_access.c Fix race in process_vm_rw_core 2012-02-02 12:55:17 -08:00
quicklist.c mm: delete various needless include <linux/module.h> 2011-10-31 09:20:11 -04:00
readahead.c mm: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
rmap.c memcg: use new logic for page stat accounting 2012-03-21 17:55:01 -07:00
shmem.c Merge branch 'akpm' (Andrew's patch-bomb) 2012-03-22 09:04:48 -07:00
slab.c Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux 2012-03-28 15:04:26 -07:00
slob.c mm: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
slub.c Merge branch 'akpm' (Andrew's patch-bomb) 2012-03-28 17:19:28 -07:00
sparse-vmemmap.c mm: delete various needless include <linux/module.h> 2011-10-31 09:20:11 -04:00
sparse.c bootmem/sparsemem: remove limit constraint in alloc_bootmem_section 2012-03-21 17:54:58 -07:00
swap.c mm: drain percpu lru add/rotate page-vectors on cpu hot-unplug 2012-03-21 17:54:58 -07:00
swap_state.c mm: make swapin readahead skip over holes 2012-03-21 17:54:56 -07:00
swapfile.c swapon: check validity of swap_flags 2012-03-28 17:14:35 -07:00
thrash.c mm/thrash.c: quiet sparse noise 2011-10-31 17:30:50 -07:00
truncate.c mm for fs: add truncate_pagecache_range() 2012-03-28 17:14:35 -07:00
util.c procfs: mark thread stack correctly in proc/<pid>/maps 2012-03-21 17:54:58 -07:00
vmalloc.c mm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:27 +08:00
vmscan.c Fix potential endless loop in kswapd when compaction is not enabled 2012-03-24 12:18:32 -07:00
vmstat.c mm,x86,um: move CMPXCHG_LOCAL config option 2012-01-12 20:13:03 -08:00