linux/kernel/cpuset.c, branch v4.1

kernel, cpuset: remove exception for __GFP_THISNODE

2015-04-14T23:49:03Z

Nothing calls __cpuset_node_allowed() with __GFP_THISNODE set anymore, so remove the obscure comment about it and its special-case exception. Signed-off-by: David Rientjes Acked-by: Vlastimil Babka Cc: Christoph Lameter Cc: Pekka Enberg Cc: Joonsoo Kim Cc: Johannes Weiner Cc: Mel Gorman Cc: Pravin Shelar Cc: Jarno Rajahalme Cc: Li Zefan Cc: Greg Thelen Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

cpusets, isolcpus: exclude isolcpus from load balancing in cpusets

2015-03-19T18:28:19Z

Ensure that cpus specified with the isolcpus= boot commandline option stay outside of the load balancing in the kernel scheduler. Operations like load balancing can introduce unwanted latencies, which is exactly what the isolcpus= commandline is there to prevent. Previously, simply creating a new cpuset, without even touching the cpuset.cpus field inside the new cpuset, would undo the effects of isolcpus=, by creating a scheduler domain spanning the whole system, and setting up load balancing inside that domain. The cpuset root cpuset.cpus file is read-only, so there was not even a way to undo that effect. This does not impact the majority of cpusets users, since isolcpus= is a fairly specialized feature used for realtime purposes. Cc: Peter Zijlstra Cc: Clark Williams Cc: Li Zefan Cc: Ingo Molnar Cc: Luiz Capitulino Cc: Mike Galbraith Cc: cgroups@vger.kernel.org Signed-off-by: Rik van Riel Tested-by: David Rientjes Acked-by: Peter Zijlstra (Intel) Acked-by: David Rientjes Acked-by: Zefan Li Signed-off-by: Tejun Heo

cpuset: Fix cpuset sched_relax_domain_level

2015-03-02T16:55:04Z

The cpuset.sched_relax_domain_level can control how far we do immediate load balancing on a system. However, it was found on recent kernels that echo'ing a value into cpuset.sched_relax_domain_level did not reduce any immediate load balancing. The reason this occurred was because the update_domain_attr_tree() traversal did not update for the "top_cpuset". This resulted in nothing being changed when modifying the sched_relax_domain_level parameter. This patch is able to address that problem by having update_domain_attr_tree() allow updates for the root in the cpuset traversal. Fixes: fc560a26acce ("cpuset: replace cpuset->stack_list with cpuset_for_each_descendant_pre()") Cc: # 3.9+ Signed-off-by: Jason Low Signed-off-by: Zefan Li Signed-off-by: Tejun Heo Tested-by: Serge Hallyn

cpuset: fix a warning when clearing configured masks in old hierarchy

2015-03-02T16:55:04Z

When we clear cpuset.cpus, cpuset.effective_cpus won't be cleared: # mount -t cgroup -o cpuset xxx /mnt # mkdir /mnt/tmp # echo 0 > /mnt/tmp/cpuset.cpus # echo > /mnt/tmp/cpuset.cpus # cat cpuset.cpus # cat cpuset.effective_cpus 0-15 And a kernel warning in update_cpumasks_hier() is triggered: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 4028 at kernel/cpuset.c:894 update_cpumasks_hier+0x471/0x650() Cc: # 3.17+ Signed-off-by: Zefan Li Signed-off-by: Tejun Heo Tested-by: Serge Hallyn

cpuset: initialize effective masks when clone_children is enabled

2015-03-02T16:55:04Z

If clone_children is enabled, effective masks won't be initialized due to the bug: # mount -t cgroup -o cpuset xxx /mnt # echo 1 > cgroup.clone_children # mkdir /mnt/tmp # cat /mnt/tmp/ # cat cpuset.effective_cpus # cat cpuset.cpus 0-15 And then this cpuset won't constrain the tasks in it. Either the bug or the fix has no effect on unified hierarchy, as there's no clone_chidren flag there any more. Reported-by: Christian Brauner Reported-by: Serge Hallyn Cc: # 3.17+ Signed-off-by: Zefan Li Signed-off-by: Tejun Heo Tested-by: Serge Hallyn

cpuset: use %*pb[l] to print bitmaps including cpumasks and nodemasks

2015-02-14T05:21:37Z

printk and friends can now format bitmaps using '%*pb[l]'. cpumask and nodemask also provide cpumask_pr_args() and nodemask_pr_args() respectively which can be used to generate the two printf arguments necessary to format the specified cpu/nodemask. * kernel/cpuset.c::cpuset_print_task_mems_allowed() used a static buffer which is protected by a dedicated spinlock. Removed. Signed-off-by: Tejun Heo Cc: Li Zefan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/cpuset.c: Mark cpuset_init_current_mems_allowed as __init

2015-02-13T02:54:11Z

The only caller of cpuset_init_current_mems_allowed is the __init annotated build_all_zonelists_init, so we can also make the former __init. Signed-off-by: Rasmus Villemoes Cc: Vlastimil Babka Cc: Rik van Riel Cc: Joonsoo Kim Cc: David Rientjes Cc: Vishnu Pratap Singh Cc: Pintu Kumar Cc: Michal Nazarewicz Cc: Mel Gorman Cc: Paul Gortmaker Cc: Peter Zijlstra Cc: Tim Chen Cc: Hugh Dickins Cc: Li Zefan Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2014-12-12T02:57:19Z

Pull cgroup update from Tejun Heo: "cpuset got simplified a bit. cgroup core got a fix on unified hierarchy and grew some effective css related interfaces which will be used for blkio support for writeback IO traffic which is currently being worked on" * 'for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: implement cgroup_get_e_css() cgroup: add cgroup_subsys->css_e_css_changed() cgroup: add cgroup_subsys->css_released() cgroup: fix the async css offline wait logic in cgroup_subtree_control_write() cgroup: restructure child_subsys_mask handling in cgroup_subtree_control_write() cgroup: separate out cgroup_calc_child_subsys_mask() from cgroup_refresh_child_subsys_mask() cpuset: lock vs unlock typo cpuset: simplify cpuset_node_allowed API cpuset: convert callback_mutex to a spinlock

sched/deadline: Ensure that updates to exclusive cpusets don't break AC

2014-10-28T09:48:00Z

How we deal with updates to exclusive cpusets is currently broken. As an example, suppose we have an exclusive cpuset composed of two cpus: A[cpu0,cpu1]. We can assign SCHED_DEADLINE task to it up to the allowed bandwidth. If we want now to modify cpusetA's cpumask, we have to check that removing a cpu's amount of bandwidth doesn't break AC guarantees. This thing isn't checked in the current code. This patch fixes the problem above, denying an update if the new cpumask won't have enough bandwidth for SCHED_DEADLINE tasks that are currently active. Signed-off-by: Juri Lelli Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Li Zefan Cc: cgroups@vger.kernel.org Link: http://lkml.kernel.org/r/5433E6AF.5080105@arm.com Signed-off-by: Ingo Molnar

sched/deadline: Fix bandwidth check/update when migrating tasks between exclusive cpusets

2014-10-28T09:47:58Z

Exclusive cpusets are the only way users can restrict SCHED_DEADLINE tasks affinity (performing what is commonly called clustered scheduling). Unfortunately, such thing is currently broken for two reasons: - No check is performed when the user tries to attach a task to an exlusive cpuset (recall that exclusive cpusets have an associated maximum allowed bandwidth). - Bandwidths of source and destination cpusets are not correctly updated after a task is migrated between them. This patch fixes both things at once, as they are opposite faces of the same coin. The check is performed in cpuset_can_attach(), as there aren't any points of failure after that function. The updated is split in two halves. We first reserve bandwidth in the destination cpuset, after we pass the check in cpuset_can_attach(). And we then release bandwidth from the source cpuset when the task's affinity is actually changed. Even if there can be time windows when sched_setattr() may erroneously fail in the source cpuset, we are fine with it, as we can't perfom an atomic update of both cpusets at once. Reported-by: Daniel Wagner Reported-by: Vincent Legout Signed-off-by: Juri Lelli Signed-off-by: Peter Zijlstra (Intel) Cc: Dario Faggioli Cc: Michael Trimarchi Cc: Fabio Checconi Cc: michael@amarulasolutions.com Cc: luca.abeni@unitn.it Cc: Li Zefan Cc: Linus Torvalds Cc: cgroups@vger.kernel.org Link: http://lkml.kernel.org/r/1411118561-26323-3-git-send-email-juri.lelli@arm.com Signed-off-by: Ingo Molnar