linux-toradex.git/kernel/cpuset.c, branch v2.6.32-rc3

cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time

2009-09-24T14:20:58+00:00

Alter the ss->can_attach and ss->attach functions to be able to deal with
a whole threadgroup at a time, for use in cgroup_attach_proc.  (This is a
pre-patch to cgroup-procs-writable.patch.)

Currently, new mode of the attach function can only tell the subsystem
about the old cgroup of the threadgroup leader.  No subsystem currently
needs that information for each thread that's being moved, but if one were
to be added (for example, one that counts tasks within a group) this bit
would need to be reworked a bit to tell the subsystem the right
information.

[hidave.darkstar@gmail.com: fix build]
Signed-off-by: Ben Blum 
Signed-off-by: Paul Menage 
Acked-by: Li Zefan 
Reviewed-by: Matt Helsley 
Cc: "Eric W. Biederman" 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Dave Young 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpuset,mm: update tasks' mems_allowed in time

2009-06-17T02:47:31+00:00

Fix allocating page cache/slab object on the unallowed node when memory
spread is set by updating tasks' mems_allowed after its cpuset's mems is
changed.

In order to update tasks' mems_allowed in time, we must modify the code of
memory policy.  Because the memory policy is applied in the process's
context originally.  After applying this patch, one task directly
manipulates anothers mems_allowed, and we use alloc_lock in the
task_struct to protect mems_allowed and memory policy of the task.

But in the fast path, we didn't use lock to protect them, because adding a
lock may lead to performance regression.  But if we don't add a lock,the
task might see no nodes when changing cpuset's mems_allowed to some
non-overlapping set.  In order to avoid it, we set all new allowed nodes,
then clear newly disallowed ones.

[lee.schermerhorn@hp.com:
  The rework of mpol_new() to extract the adjusting of the node mask to
  apply cpuset and mpol flags "context" breaks set_mempolicy() and mbind()
  with MPOL_PREFERRED and a NULL nodemask--i.e., explicit local
  allocation.  Fix this by adding the check for MPOL_PREFERRED and empty
  node mask to mpol_new_mpolicy().

  Remove the now unneeded 'nodes = NULL' from mpol_new().

  Note that mpol_new_mempolicy() is always called with a non-NULL
  'nodes' parameter now that it has been removed from mpol_new().
  Therefore, we don't need to test nodes for NULL before testing it for
  'empty'.  However, just to be extra paranoid, add a VM_BUG_ON() to
  verify this assumption.]
[lee.schermerhorn@hp.com:

  I don't think the function name 'mpol_new_mempolicy' is descriptive
  enough to differentiate it from mpol_new().

  This function applies cpuset set context, usually constraining nodes
  to those allowed by the cpuset.  However, when the 'RELATIVE_NODES flag
  is set, it also translates the nodes.  So I settled on
  'mpol_set_nodemask()', because the comment block for mpol_new() mentions
  that we need to call this function to "set nodes".

  Some additional minor line length, whitespace and typo cleanup.]
Signed-off-by: Miao Xie 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Christoph Lameter 
Cc: Paul Menage 
Cc: Nick Piggin 
Cc: Yasunori Goto 
Cc: Pekka Enberg 
Cc: David Rientjes 
Signed-off-by: Lee Schermerhorn 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpusets: update tasks' page/slab spread flags in time

2009-06-17T02:47:31+00:00

Fix the bug that the kernel didn't spread page cache/slab object evenly
over all the allowed nodes when spread flags were set by updating tasks'
page/slab spread flags in time.

Signed-off-by: Miao Xie 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Christoph Lameter 
Cc: Paul Menage 
Cc: Nick Piggin 
Cc: Yasunori Goto 
Cc: Pekka Enberg 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpusets: restructure the function cpuset_update_task_memory_state()

2009-06-17T02:47:31+00:00

The kernel still allocates the page caches on old node after modifying its
cpuset's mems when 'memory_spread_page' was set, or it didn't spread the
page cache evenly over all the nodes that faulting task is allowed to usr
after memory_spread_page was set.  it is caused by the old mem_allowed and
flags of the task, the current kernel doesn't updates them unless some
function invokes cpuset_update_task_memory_state(), it is too late
sometimes.We must update the mem_allowed and the flags of the tasks in
time.

Slab has the same problem.

The following patches fix this bug by updating tasks' mem_allowed and
spread flag after its cpuset's mems or spread flag is changed.

This patch:

Extract a function from cpuset_update_task_memory_state().  It will be
used later for update tasks' page/slab spread flags after its cpuset's
flag is set

Signed-off-by: Miao Xie 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Christoph Lameter 
Cc: Paul Menage 
Cc: Nick Piggin 
Cc: Yasunori Goto 
Cc: Pekka Enberg 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86: remove some alloc_bootmem_cpumask_var calling

2009-06-11T16:27:07+00:00

Now that we set up the slab allocator earlier, we can get rid of some
alloc_bootmem_cpumask_var() calls in boot code.

Cc: Ingo Molnar 
Cc: Johannes Weiner 
Cc: Linus Torvalds 
Signed-off-by: Yinghai Lu 
Signed-off-by: Pekka Enberg

cpusets: prevent PF_THREAD_BOUND tasks from attaching to non-root cpusets

2009-04-03T02:04:57+00:00

Kthreads that have the PF_THREAD_BOUND bit set in their flags are bound to a
specific cpu.  Thus, their set of allowed cpus shall not change.

This patch prevents such threads from attaching to non-root cpusets.  They do
not have mempolicies that restrict them to a subset of system nodes and, since
their cpumask may never change, they cannot use any of the features of
cpusets.

The tasks will forever be a member of the root cpuset and will be returned
when listing the tasks attached to that cpuset.

Cc: Paul Menage 
Cc: Peter Zijlstra 
Cc: Dhaval Giani 
Signed-off-by: David Rientjes 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpusets: allow cpusets to be configured/built on non-SMP systems

2009-04-03T02:04:57+00:00

Allow cpusets to be configured/built on non-SMP systems

Currently it's impossible to build cpusets under UML on x86-64, since
cpusets depends on SMP and x86-64 UML doesn't support SMP.

There's code in cpusets that doesn't depend on SMP.  This patch surrounds
the minimum amount of cpusets code with #ifdef CONFIG_SMP in order to
allow cpusets to build/run on UP systems (for testing purposes under UML).

Reviewed-by: Li Zefan 
Signed-off-by: Paul Menage 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpusets: replace zone allowed functions with node allowed

2009-04-03T02:04:57+00:00

The cpuset_zone_allowed() variants are actually only a function of the
zone's node.

Cc: Paul Menage 
Acked-by: Christoph Lameter 
Cc: Randy Dunlap 
Signed-off-by: David Rientjes 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpuset: remove struct cpuset_hotplug_scanner

2009-04-03T02:04:57+00:00

Use cgroup_scanner.data, instead of introducing cpuset_hotplug_scanner.

Signed-off-by: Li Zefan 
Cc: KAMEZAWA Hiroyuki 
Cc: Paul Menage 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpuset: avoid changing cpuset's mems when errno returned

2009-04-03T02:04:57+00:00

When writing to cpuset.mems, cpuset has to update its mems_allowed before
calling update_tasks_nodemask(), but this function might return -ENOMEM.

To avoid this rare case, we allocate the memory before changing
mems_allowed, and then pass to update_tasks_nodemask().  Similar to what
update_cpumask() does.

Signed-off-by: Li Zefan 
Cc: KAMEZAWA Hiroyuki 
Cc: Paul Menage 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds