linux-toradex.git/kernel/cgroup.c, branch tegra-11.2.6

cgroup: leave cg_list valid upon cgroup_exit

2011-01-11T00:16:51+00:00

A thread/process in cgroup_attach_task() could have called
list_del(&tsk->cg_list) after cgroup_exit() had already called
list_del() on the same list. Since it only checked for
!list_empty(&tsk->cg_list) before doing this, the list_del()
call would thus be made twice.

The solution is to leave tsk->cg_list in a valid state in
cgroup_exit() with list_del_init(&tsk->cg_list), which leaves
an empty list.

Change-Id: I4e7c1d0665fced629f5ca033c18dd98afe080e0c
Signed-off-by: Simon Wilson

cgroup: Remove call to synchronize_rcu in cgroup_attach_task

2010-12-18T01:01:51+00:00

synchronize_rcu can be very expensive, averaging 100 ms in
some cases.  In cgroup_attach_task, it is used to prevent
a task->cgroups pointer dereferenced in an RCU read side
critical section from being invalidated, by delaying the
call to put_css_set until after an RCU grace period.

To avoid the call to synchronize_rcu, make the put_css_set
call rcu-safe by moving the deletion of the css_set links
into free_css_set_work, scheduled by the rcu callback
free_css_set_rcu.

The decrement of the cgroup refcount is no longer
synchronous with the call to put_css_set, which can result
in the cgroup refcount staying positive after the last call
to cgroup_attach_task returns.  To allow the cgroup to be
deleted with cgroup_rmdir synchronously after
cgroup_attach_task, have rmdir check the refcount of all
associated css_sets.  If cgroup_rmdir is called on a cgroup
for which the css_sets all have refcount zero but the
cgroup refcount is nonzero, reuse the rmdir waitqueue to
block the rmdir until free_css_set_work is called.

Signed-off-by: Colin Cross

cgroup: Set CGRP_RELEASABLE when adding to a cgroup

2010-12-18T01:01:49+00:00

Changes the meaning of CGRP_RELEASABLE to be set on any cgroup
that has ever had a task or cgroup in it, or had css_get called
on it.  The bit is set in cgroup_attach_task, cgroup_create,
and __css_get.  It is not necessary to set the bit in
cgroup_fork, as the task is either in the root cgroup, in
which can never be released, or the task it was forked from
already set the bit in croup_attach_task.

Signed-off-by: Colin Cross

Fix cgroup: Add generic cgroup subsystem permission checks.

2010-09-30T00:49:18+00:00

Change-Id: Ib82f6a716686a3ebb4592112400fc5e4a2ce066c
Signed-off-by: Colin Cross

cgroup: Add generic cgroup subsystem permission checks.

2010-09-30T00:49:18+00:00

    Rather than using explicit euid == 0 checks when trying to move
tasks into a cgroup via CFS, move permission checks into each
specific cgroup subsystem. If a subsystem does not specify a
'can_attach' handler, then we fall back to doing our checks the old way.

    This way non-root processes can add arbitrary processes to
a cgroup if all the registered subsystems on that cgroup agree.

    Also change explicit euid == 0 check to CAP_SYS_ADMIN

Signed-off-by: San Mehat

cgroups: fix API thinko

2010-09-10T01:57:23+00:00

Add cgroup_attach_task_all()

The existing cgroup_attach_task_current_cg() API is called by a thread to
attach another thread to all of its cgroups; this is unsuitable for cases
where a privileged task wants to attach itself to the cgroups of a less
privileged one, since the call must be made from the context of the target
task.

This patch adds a more generic cgroup_attach_task_all() API that allows
both the source task and to-be-moved task to be specified.
cgroup_attach_task_current_cg() becomes a specialization of the more
generic new function.

[menage@google.com: rewrote changelog]
[akpm@linux-foundation.org: address reviewer comments]
Signed-off-by: Michael S. Tsirkin 
Tested-by: Alex Williamson 
Acked-by: Paul Menage 
Cc: Li Zefan 
Cc: Ben Blum 
Cc: Sridhar Samudrala 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: save space for the terminator

2010-08-11T15:59:18+00:00

The original code didn't leave enough space for a NULL terminator.  These
strings are copied with strcpy() into fixed length buffers in
cgroup_root_from_opts().

Signed-off-by: Dan Carpenter 
Acked-by: Serge E. Hallyn 
Reviewd-by: KAMEZAWA Hiroyuki 
Cc: Paul Menage 
Cc: Li Zefan 
Cc: Ben Blum 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroupfs: create /sys/fs/cgroup to mount cgroupfs on

2010-08-05T20:53:35+00:00

We really shouldn't be asking userspace to create new root filesystems.
So follow along with all of the other in-kernel filesystems, and provide
a mount point in sysfs.

For cgroupfs, this should be in /sys/fs/cgroup/  This change provides
that mount point when the cgroup filesystem is registered in the kernel.

Acked-by: Paul Menage 
Acked-by: Dhaval Giani 
Cc: Li Zefan 
Cc: Lennart Poettering 
Cc: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6

2010-08-04T18:47:58+00:00

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1443 commits)
  phy/marvell: add 88ec048 support
  igb: Program MDICNFG register prior to PHY init
  e1000e: correct MAC-PHY interconnect register offset for 82579
  hso: Add new product ID
  can: Add driver for esd CAN-USB/2 device
  l2tp: fix export of header file for userspace
  can-raw: Fix skb_orphan_try handling
  Revert "net: remove zap_completion_queue"
  net: cleanup inclusion
  phy/marvell: add 88e1121 interface mode support
  u32: negative offset fix
  net: Fix a typo from "dev" to "ndev"
  igb: Use irq_synchronize per vector when using MSI-X
  ixgbevf: fix null pointer dereference due to filter being set for VLAN 0
  e1000e: Fix irq_synchronize in MSI-X case
  e1000e: register pm_qos request on hardware activation
  ip_fragment: fix subtracting PPPOE_SES_HLEN from mtu twice
  net: Add getsockopt support for TCP thin-streams
  cxgb4: update driver version
  cxgb4: add new PCI IDs
  ...

Manually fix up conflicts in:
 - drivers/net/e1000e/netdev.c: due to pm_qos registration
   infrastructure changes
 - drivers/net/phy/marvell.c: conflict between adding 88ec048 support
   and cleaning up the IDs
 - drivers/net/wireless/ipw2x00/ipw2100.c: trivial ipw2100_pm_qos_req
   conflict (registration change vs marking it static)

cgroups: Add an API to attach a task to current task's cgroup

2010-07-28T12:45:12+00:00

Add a new kernel API to attach a task to current task's cgroup
in all the active hierarchies.

Signed-off-by: Sridhar Samudrala 
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Paul Menage 
Acked-by: Li Zefan