linux/include
Kirill A. Shutemov 0dea116876 cgroup: implement eventfd-based generic API for notifications
This patchset introduces eventfd-based API for notifications in cgroups
and implements memory notifications on top of it.

It uses statistics in memory controler to track memory usage.

Output of time(1) on building kernel on tmpfs:

Root cgroup before changes:
	make -j2  506.37 user 60.93s system 193% cpu 4:52.77 total
Non-root cgroup before changes:
	make -j2  507.14 user 62.66s system 193% cpu 4:54.74 total
Root cgroup after changes (0 thresholds):
	make -j2  507.13 user 62.20s system 193% cpu 4:53.55 total
Non-root cgroup after changes (0 thresholds):
	make -j2  507.70 user 64.20s system 193% cpu 4:55.70 total
Root cgroup after changes (1 thresholds, never crossed):
	make -j2  506.97 user 62.20s system 193% cpu 4:53.90 total
Non-root cgroup after changes (1 thresholds, never crossed):
	make -j2  507.55 user 64.08s system 193% cpu 4:55.63 total

This patch:

Introduce the write-only file "cgroup.event_control" in every cgroup.

To register new notification handler you need:
- create an eventfd;
- open a control file to be monitored. Callbacks register_event() and
  unregister_event() must be defined for the control file;
- write "<event_fd> <control_fd> <args>" to cgroup.event_control.
  Interpretation of args is defined by control file implementation;

eventfd will be woken up by control file implementation or when the
cgroup is removed.

To unregister notification handler just close eventfd.

If you need notification functionality for a control file you have to
implement callbacks register_event() and unregister_event() in the
struct cftype.

[kamezawa.hiroyu@jp.fujitsu.com: Kconfig fix]
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Dan Malek <dan@embeddedalley.com>
Cc: Vladislav Buzov <vbuzov@embeddedalley.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Alexander Shishkin <virtuoso@slind.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:37 -08:00
..
acpi Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu 2010-03-03 07:34:18 -08:00
asm-generic gpio: introduce gpio_request_one() and friends 2010-03-06 11:26:48 -08:00
crypto crypto: md5 - Add export support 2010-01-17 21:55:31 +11:00
drm Merge branch 'drm-radeon-testing' of /ssd/git/drm-radeon-next into drm-next-stage 2010-03-01 16:08:57 +10:00
keys
linux cgroup: implement eventfd-based generic API for notifications 2010-03-12 15:52:37 -08:00
math-emu
media V4L/DVB: tuner-types: Add Sony BTF-Pxn01Z tuner type used on GigaPocket cards 2010-02-26 15:11:07 -03:00
mtd
net 9P2010.L handshake: Remove "dotu" variable 2010-03-05 15:04:42 -06:00
pcmcia Merge branch 'master' of /home/davem/src/GIT/linux-2.6/ 2010-02-28 19:23:06 -08:00
rdma Merge branch 'misc' into for-next 2010-03-01 23:52:31 -08:00
rxrpc
scsi [SCSI] scsi_transport_sas: add support for transport layer retries (TLR) 2010-02-08 17:15:19 -06:00
sound Merge branch 'topic/misc' into for-linus 2010-03-08 09:35:50 +01:00
trace Merge branch 'kvm-updates/2.6.34' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2010-03-05 13:12:34 -08:00
video broadsheetfb: support storing waveform 2010-03-12 15:52:34 -08:00
xen
Kbuild