linux-toradex.git/kernel/cpuset.c, branch T20_LinuxImageV2.0Beta1_20121218

atomic: use

2011-07-26T23:49:47+00:00

This allows us to move duplicated code in 
(atomic_inc_not_zero() for now) to 

Signed-off-by: Arun Sharma 
Reviewed-by: Eric Dumazet 
Cc: Ingo Molnar 
Cc: David Miller 
Cc: Eric Dumazet 
Acked-by: Mike Frysinger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpusets: randomize node rotor used in cpuset_mem_spread_node()

2011-07-26T23:49:43+00:00

[ This patch has already been accepted as commit 0ac0c0d0f837 but later
  reverted (commit 35926ff5fba8) because it itroduced arch specific
  __node_random which was defined only for x86 code so it broke other
  archs.  This is a followup without any arch specific code.  Other than
  that there are no functional changes.]

Some workloads that create a large number of small files tend to assign
too many pages to node 0 (multi-node systems).  Part of the reason is
that the rotor (in cpuset_mem_spread_node()) used to assign nodes starts
at node 0 for newly created tasks.

This patch changes the rotor to be initialized to a random node number
of the cpuset.

[akpm@linux-foundation.org: fix layout]
[Lee.Schermerhorn@hp.com: Define stub numa_random() for !NUMA configuration]
[mhocko@suse.cz: Make it arch independent]
[akpm@linux-foundation.org: fix CONFIG_NUMA=y, MAX_NUMNODES>1 build]
Signed-off-by: Jack Steiner 
Signed-off-by: Lee Schermerhorn 
Signed-off-by: Michal Hocko 
Reviewed-by: KOSAKI Motohiro 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: Paul Menage 
Cc: Jack Steiner 
Cc: Robin Holt 
Cc: David Rientjes 
Cc: Christoph Lameter 
Cc: David Rientjes 
Cc: Jack Steiner 
Cc: KOSAKI Motohiro 
Cc: Lee Schermerhorn 
Cc: Michal Hocko 
Cc: Paul Menage 
Cc: Pekka Enberg 
Cc: Robin Holt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowed

2011-05-28T15:02:57+00:00

The rule is, we have to update tsk->rt.nr_cpus_allowed if we change
tsk->cpus_allowed. Otherwise RT scheduler may confuse.

Signed-off-by: KOSAKI Motohiro 
Cc: Oleg Nesterov 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/4DD4B3FA.5060901@jp.fujitsu.com
Signed-off-by: Ingo Molnar

cgroup: remove the ns_cgroup

2011-05-27T00:12:34+00:00

The ns_cgroup is an annoying cgroup at the namespace / cgroup frontier and
leads to some problems:

  * cgroup creation is out-of-control
  * cgroup name can conflict when pids are looping
  * it is not possible to have a single process handling a lot of
    namespaces without falling in a exponential creation time
  * we may want to create a namespace without creating a cgroup

  The ns_cgroup was replaced by a compatibility flag 'clone_children',
  where a newly created cgroup will copy the parent cgroup values.
  The userspace has to manually create a cgroup and add a task to
  the 'tasks' file.

This patch removes the ns_cgroup as suggested in the following thread:

https://lists.linux-foundation.org/pipermail/containers/2009-June/018616.html

The 'cgroup_clone' function is removed because it is no longer used.

This is a userspace-visible change.  Commit 45531757b45c ("cgroup: notify
ns_cgroup deprecated") (merged into 2.6.27) caused the kernel to emit a
printk warning users that the feature is planned for removal.  Since that
time we have heard from XXX users who were affected by this.

Signed-off-by: Daniel Lezcano 
Signed-off-by: Serge E. Hallyn 
Cc: Eric W. Biederman 
Cc: Jamal Hadi Salim 
Reviewed-by: Li Zefan 
Acked-by: Paul Menage 
Acked-by: Matt Helsley 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: add per-thread subsystem callbacks

2011-05-27T00:12:34+00:00

Add cgroup subsystem callbacks for per-thread attachment in atomic contexts

Add can_attach_task(), pre_attach(), and attach_task() as new callbacks
for cgroups's subsystem interface.  Unlike can_attach and attach, these
are for per-thread operations, to be called potentially many times when
attaching an entire threadgroup.

Also, the old "bool threadgroup" interface is removed, as replaced by
this.  All subsystems are modified for the new interface - of note is
cpuset, which requires from/to nodemasks for attach to be globally scoped
(though per-cpuset would work too) to persist from its pre_attach to
attach_task and attach.

This is a pre-patch for cgroup-procs-writable.patch.

Signed-off-by: Ben Blum 
Cc: "Eric W. Biederman" 
Cc: Li Zefan 
Cc: Matt Helsley 
Reviewed-by: Paul Menage 
Cc: Oleg Nesterov 
Cc: David Rientjes 
Cc: Miao Xie 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sched: Dynamic sched_domain::level

2011-04-11T12:09:32+00:00

Remove the SD_LV_ enum and use dynamic level assignments.

Signed-off-by: Peter Zijlstra 
Cc: Mike Galbraith 
Cc: Nick Piggin 
Cc: Linus Torvalds 
Cc: Andrew Morton 
Link: http://lkml.kernel.org/r/20110407122942.969433965@chello.nl
Signed-off-by: Ingo Molnar

cpuset: hold callback_mutex in cpuset_post_clone()

2011-03-24T02:46:35+00:00

Chaning cpuset->mems/cpuset->cpus should be protected under
callback_mutex.

cpuset_clone() doesn't follow this rule. It's ok because it's
called when creating and initializing a cgroup, but we'd better
hold the lock to avoid subtil break in the future.

Signed-off-by: Li Zefan 
Acked-by: Paul Menage 
Acked-by: David Rientjes 
Cc: Miao Xie 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpuset: fix unchecked calls to NODEMASK_ALLOC()

2011-03-24T02:46:35+00:00

Those functions that use NODEMASK_ALLOC() can't propagate errno
to users, but will fail silently.

Fix it by using a static nodemask_t variable for each function, and
those variables are protected by cgroup_mutex;

[akpm@linux-foundation.org: fix comment spelling, strengthen cgroup_lock comment]
Signed-off-by: Li Zefan 
Cc: Paul Menage 
Acked-by: David Rientjes 
Cc: Miao Xie 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpuset: remove unneeded NODEMASK_ALLOC() in cpuset_attach()

2011-03-24T02:46:34+00:00

oldcs->mems_allowed is not modified during cpuset_attach(), so we don't
have to copy it to a buffer allocated by NODEMASK_ALLOC().  Just pass it
to cpuset_migrate_mm().

Signed-off-by: Li Zefan 
Cc: Paul Menage 
Acked-by: David Rientjes 
Cc: Miao Xie 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpuset: remove unneeded NODEMASK_ALLOC() in cpuset_sprintf_memlist()

2011-03-24T02:46:34+00:00

It's not necessary to copy cpuset->mems_allowed to a buffer allocated by
NODEMASK_ALLOC().  Just pass it to nodelist_scnprintf().

As spotted by Paul, a side effect is we fix a bug that the function can
return -ENOMEM but the caller doesn't expect negative return value.
Therefore change the return value of cpuset_sprintf_cpulist() and
cpuset_sprintf_memlist() from int to size_t.

Signed-off-by: Li Zefan 
Acked-by: Paul Menage 
Acked-by: David Rientjes 
Cc: Miao Xie 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds