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* cpusets: prevent PF_THREAD_BOUND tasks from attaching to non-root cpusetsDavid Rientjes2009-04-031-8/+11
| | | | | | | | | | | | | | | | | | | | | | 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 <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpusets: allow cpusets to be configured/built on non-SMP systemsPaul Menage2009-04-031-0/+15
| | | | | | | | | | | | | | | | | | 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 <lizf@cn.fujitsu.com> Signed-off-by: Paul Menage <menage@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpusets: replace zone allowed functions with node allowedDavid Rientjes2009-04-031-34/+25
| | | | | | | | | | | | | | The cpuset_zone_allowed() variants are actually only a function of the zone's node. Cc: Paul Menage <menage@google.com> Acked-by: Christoph Lameter <cl@linux-foundation.org> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: remove struct cpuset_hotplug_scannerLi Zefan2009-04-031-14/+9
| | | | | | | | | | | | Use cgroup_scanner.data, instead of introducing cpuset_hotplug_scanner. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: avoid changing cpuset's mems when errno returnedLi Zefan2009-04-031-9/+16
| | | | | | | | | | | | | | | | | 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 <lizf@cn.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: rewrite update_tasks_nodemask()Li Zefan2009-04-031-70/+39
| | | | | | | | | | | | | | | | | | This patch uses cgroup_scan_tasks() to rebind tasks' vmas to new cpuset's mems_allowed. Not only simplify the code largely, but also avoid allocating an array to hold mm pointers of all the tasks in the cpuset. This array can be big (size > PAGESIZE) if we have lots of tasks in that cpuset, thus has a chance to fail the allocation when under memory stress. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: fix possible races in cpu/memory hotplugLi Zefan2009-04-031-3/+6
| | | | | | | | | | | | | Change to cpuset->cpus_allowed and cpuset->mems_allowed should be protected by callback_mutex, otherwise the reader may read wrong cpus/mems. This is cpuset's lock rule. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: show correct file modeLi Zefan2009-04-031-0/+1
| | | | | | | | | | | | | | | | We have some read-only files and write-only files, but currently they are all set to 0644, which is counter-intuitive and cause trouble for some cgroup tools like libcgroup. This patch adds 'mode' to struct cftype to allow cgroup subsys to set it's own files' file mode, and for the most cases cft->mode can be default to 0 and cgroup will figure out proper mode. Acked-by: Paul Menage <menage@google.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: fix possible deadlock in async_rebuild_sched_domainsMiao Xie2009-01-191-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Lockdep reported some possible circular locking info when we tested cpuset on NUMA/fake NUMA box. ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.29-rc1-00224-ga652504 #111 ------------------------------------------------------- bash/2968 is trying to acquire lock: (events){--..}, at: [<ffffffff8024c8cd>] flush_work+0x24/0xd8 but task is already holding lock: (cgroup_mutex){--..}, at: [<ffffffff8026ad1e>] cgroup_lock_live_group+0x12/0x29 which lock already depends on the new lock. ...... ------------------------------------------------------- Steps to reproduce: # mkdir /dev/cpuset # mount -t cpuset xxx /dev/cpuset # mkdir /dev/cpuset/0 # echo 0 > /dev/cpuset/0/cpus # echo 0 > /dev/cpuset/0/mems # echo 1 > /dev/cpuset/0/memory_migrate # cat /dev/zero > /dev/null & # echo $! > /dev/cpuset/0/tasks This is because async_rebuild_sched_domains has the following lock sequence: run_workqueue(async_rebuild_sched_domains) -> do_rebuild_sched_domains -> cgroup_lock But, attaching tasks when memory_migrate is set has following: cgroup_lock_live_group(cgroup_tasks_write) -> do_migrate_pages -> flush_work This patch fixes it by using a separate workqueue thread. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cgroups: consolidate cgroup documentsLi Zefan2009-01-161-1/+1
| | | | | | | | | | | | Move Documentation/cpusets.txt and Documentation/controllers/* to Documentation/cgroups/ Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: remove remaining pointers to cpumask_tLi Zefan2009-01-081-13/+15
| | | | | | | | | | | | | | | | | | Impact: cleanups, use new cpumask API Final trivial cleanups: mainly s/cpumask_t/struct cpumask Note there is a FIXME in generate_sched_domains(). A future patch will change struct cpumask *doms to struct cpumask *doms[]. (I suppose Rusty will do this.) Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Mike Travis <travis@sgi.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: convert cpuset->cpus_allowed to cpumask_var_tLi Zefan2009-01-081-40/+60
| | | | | | | | | | | | | | | | | | Impact: use new cpumask API This patch mainly does the following things: - change cs->cpus_allowed from cpumask_t to cpumask_var_t - call alloc_bootmem_cpumask_var() for top_cpuset in cpuset_init_early() - call alloc_cpumask_var() for other cpusets - replace cpus_xxx() to cpumask_xxx() Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Mike Travis <travis@sgi.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: don't allocate trial cpuset on stackLi Zefan2009-01-081-33/+60
| | | | | | | | | | | | | | | | | | | Impact: cleanups, reduce stack usage This patch prepares for the next patch. When we convert cpuset.cpus_allowed to cpumask_var_t, (trialcs = *cs) no longer works. Another result of this patch is reducing stack usage of trialcs. sizeof(*cs) can be as large as 148 bytes on x86_64, so it's really not good to have it on stack. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Mike Travis <travis@sgi.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: convert cpuset_attach() to use cpumask_var_tLi Zefan2009-01-081-5/+9
| | | | | | | | | | | | | | | Impact: reduce stack usage Allocate a global cpumask_var_t at boot, and use it in cpuset_attach(), so we won't fail cpuset_attach(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Mike Travis <travis@sgi.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: remove on stack cpumask_t in cpuset_can_attach()Li Zefan2009-01-081-6/+5
| | | | | | | | | | | | | | Impact: reduce stack usage Just use cs->cpus_allowed, and no need to allocate a cpumask_var_t. Signed-off-by: Li Zefan <lizf@cn.fujistu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Mike Travis <travis@sgi.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: remove on stack cpumask_t in cpuset_sprintf_cpulist()Li Zefan2009-01-081-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patchset converts cpuset to use new cpumask API, and thus remove on stack cpumask_t to reduce stack usage. Before: # cat kernel/cpuset.c include/linux/cpuset.h | grep -c cpumask_t 21 After: # cat kernel/cpuset.c include/linux/cpuset.h | grep -c cpumask_t 0 This patch: Impact: reduce stack usage It's safe to call cpulist_scnprintf inside callback_mutex, and thus we can just remove the cpumask_t and no need to allocate a cpumask_var_t. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Mike Travis <travis@sgi.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpusets: set task's cpu_allowed to cpu_possible_map when attaching it into ↵Miao Xie2009-01-081-3/+7
| | | | | | | | | | | | | | | | | | | | | top cpuset I found a bug on my dual-cpu box. I created a sub cpuset in top cpuset and assign 1 to its cpus. And then we attach some tasks into this sub cpuset. After this, we offline CPU1. Now, the tasks in this new cpuset are moved into top cpuset automatically because there is no cpu in sub cpuset. Then we online CPU1, we find all the tasks which doesn't belong to top cpuset originally just run on CPU0. We fix this bug by setting task's cpu_allowed to cpu_possible_map when attaching it into top cpuset. This method needn't modify the current behavior of cpusets on CPU hotplug, and all of tasks in top cpuset use cpu_possible_map to initialize their cpu_allowed. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: rcu_read_lock() to protect task_cs()Lai Jiangshan2009-01-081-8/+3
| | | | | | | | | | | | | | | | | | | task_cs() calls task_subsys_state(). We must use rcu_read_lock() to protect cgroup_subsys_state(). It's correct that top_cpuset is never freed, but cgroup_subsys_state() accesses css_set, this css_set maybe freed when task_cs() called. We use use rcu_read_lock() to protect it. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* oom: print triggering task's cpuset and mems allowedDavid Rientjes2009-01-071-0/+34
| | | | | | | | | | | | | | When cpusets are enabled, it's necessary to print the triggering task's set of allowable nodes so the subsequently printed meminfo can be interpreted correctly. We also print the task's cpuset name for informational purposes. [rientjes@google.com: task lock current before dereferencing cpuset] Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpumask: change cpumask_scnprintf, cpumask_parse_user, cpulist_parse, and ↵Rusty Russell2008-12-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | cpulist_scnprintf to take pointers. Impact: change calling convention of existing cpumask APIs Most cpumask functions started with cpus_: these have been replaced by cpumask_ ones which take struct cpumask pointers as expected. These four functions don't have good replacement names; fortunately they're rarely used, so we just change them over. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: paulus@samba.org Cc: mingo@redhat.com Cc: tony.luck@intel.com Cc: ralf@linux-mips.org Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: cl@linux-foundation.org Cc: srostedt@redhat.com
* sched, cpusets: fix warning in kernel/cpuset.cIngo Molnar2008-11-291-1/+1
| | | | | | | | | | | | | | | | | | this warning: kernel/cpuset.c: In function ‘generate_sched_domains’: kernel/cpuset.c:588: warning: ‘ndoms’ may be used uninitialized in this function triggers because GCC does not recognize that ndoms stays uninitialized only if doms is NULL - but that flow is covered at the end of generate_sched_domains(). Help out GCC by initializing this variable to 0. (that's prudent anyway) Also, this function needs a splitup and code flow simplification: with 160 lines length it's clearly too long. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cpuset: update top cpuset's mems after adding a nodeMiao Xie2008-11-201-3/+16
| | | | | | | | | | | | | | | | | | | | | | | After adding a node into the machine, top cpuset's mems isn't updated. By reviewing the code, we found that the update function cpuset_track_online_nodes() was invoked after node_states[N_ONLINE] changes. It is wrong because N_ONLINE just means node has pgdat, and if node has/added memory, we use N_HIGH_MEMORY. So, We should invoke the update function after node_states[N_HIGH_MEMORY] changes, just like its commit says. This patch fixes it. And we use notifier of memory hotplug instead of direct calling of cpuset_track_online_nodes(). Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Acked-by: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Paul Menage <menage@google.com Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: fix regression when failed to generate sched domainsLi Zefan2008-11-181-4/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | Impact: properly rebuild sched-domains on kmalloc() failure When cpuset failed to generate sched domains due to kmalloc() failure, the scheduler should fallback to the single partition 'fallback_doms' and rebuild sched domains, but now it only destroys but not rebuilds sched domains. The regression was introduced by: | commit dfb512ec4834116124da61d6c1ee10fd0aa32bd6 | Author: Max Krasnyansky <maxk@qualcomm.com> | Date: Fri Aug 29 13:11:41 2008 -0700 | | sched: arch_reinit_sched_domains() must destroy domains to force rebuild After the above commit, partition_sched_domains(0, NULL, NULL) will only destroy sched domains and partition_sched_domains(1, NULL, NULL) will create the default sched domain. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cpuset: use seq_*mask_* to print masksLai Jiangshan2008-10-201-8/+4
| | | | | | | | | | | | | | | 1) seq_file excepts that m->count == m->size when it's buf is full, so current code will causes bugs when buf is overflow. 2) There is not too good that cpuset accesses struct seq_file's fields directly. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset.c: remove extra variableRakib Mullick2008-10-201-3/+2
| | | | | | | | | Remove the use of int cpus_nonempty variable from 'update_flag' function. Signed-off-by: Md.Rakib H. Mullick <rakib.mullick@gmail.com> Acked-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpusets: scan_for_empty_cpusets(), cpuset doesn't seem to be so constFrederic Weisbecker2008-10-031-1/+1
| | | | | | | | | | | | | | This fixes a warning on latest -tip: kernel/cpuset.c: Dans la fonction «scan_for_empty_cpusets» : kernel/cpuset.c:1932: attention : passing argument 1 of «list_add_tail» discards qualifiers from pointer target type Actually the struct cpuset *root passed in parameter to scan_for_empty_cpusets is not supposed to be const since an entry is added on the tail of its list. Just correct the qualifier. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cpuset: avoid changing cpuset's cpus when -errno returnedLi Zefan2008-09-131-22/+15
| | | | | | | | | | | | | | | | | | | | | | | After the patch: commit 0b2f630a28d53b5a2082a5275bc3334b10373508 Author: Miao Xie <miaox@cn.fujitsu.com> Date: Fri Jul 25 01:47:21 2008 -0700 cpusets: restructure the function update_cpumask() and update_nodemask() It might happen that 'echo 0 > /cpuset/sub/cpus' returned failure but 'cpus' has been changed, because cpus was changed before calling heap_init() which may return -ENOMEM. This patch restores the orginal behavior. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched, cpuset: rework sched domains and CPU hotplug handling (v4)Max Krasnyansky2008-08-141-130/+182
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is an updated version of my previous cpuset patch on top of the latest mainline git. The patch fixes CPU hotplug handling issues in the current cpusets code. Namely circular locking in rebuild_sched_domains() and unsafe access to the cpu_online_map in the cpuset cpu hotplug handler. This version includes changes suggested by Paul Jackson (naming, comments, style, etc). I also got rid of the separate workqueue thread because it is now safe to call get_online_cpus() from workqueue callbacks. Here are some more details: rebuild_sched_domains() is the only way to rebuild sched domains correctly based on the current cpuset settings. What this means is that we need to be able to call it from different contexts, like cpu hotplug for example. Also latest scheduler code in -tip now calls rebuild_sched_domains() directly from functions like arch_reinit_sched_domains(). In order to support that properly we need to rework cpuset locking rules to avoid circular dependencies, which is what this patch does. New lock nesting rules are explained in the comments. We can now safely call rebuild_sched_domains() from virtually any context. The only requirement is that it needs to be called under get_online_cpus(). This allows cpu hotplug handlers and the scheduler to call rebuild_sched_domains() directly. The rest of the cpuset code now offloads sched domains rebuilds to a workqueue (async_rebuild_sched_domains()). This version of the patch addresses comments from the previous review. I fixed all miss-formated comments and trailing spaces. I also factored out the code that builds domain masks and split up CPU and memory hotplug handling. This was needed to simplify locking, to avoid unsafe access to the cpu_online_map from mem hotplug handler, and in general to make things cleaner. The patch passes moderate testing (building kernel with -j 16, creating & removing domains and bringing cpus off/online at the same time) on the quad-core2 based machine. It passes lockdep checks, even with preemptable RCU enabled. This time I also tested in with suspend/resume path and everything is working as expected. Signed-off-by: Max Krasnyansky <maxk@qualcomm.com> Acked-by: Paul Jackson <pj@sgi.com> Cc: menage@google.com Cc: a.p.zijlstra@chello.nl Cc: vegard.nossum@gmail.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cpuset: clean up cpuset hierarchy traversal codeLi Zefan2008-07-301-13/+8
| | | | | | | | | | | | | | | Use cpuset.stack_list rather than kfifo, so we avoid memory allocation for kfifo. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: fix wrong calculation of relax domain levelLi Zefan2008-07-301-1/+1
| | | | | | | | | | | | | | | | | | | | When multiple cpusets are overlapping in their 'cpus' and hence they form a single sched domain, the largest sched_relax_domain_level among those should be used. But when top_cpuset's sched_load_balance is set, its sched_relax_domain_level is used regardless other sub-cpusets'. This patch fixes it by walking the cpuset hierarchy to find the largest sched_relax_domain_level. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: speed up sched domain partitionLai Jiangshan2008-07-301-4/+37
| | | | | | | | | | | | | | | | All child cpusets contain a subset of the parent's cpus, so we can skip them when partitioning sched domains. This decreases 'csa' greately for cpusets with multi-level hierarchy. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: a bit cleanup for scan_for_empty_cpusets()Li Zefan2008-07-301-5/+2
| | | | | | | | | | | | | | clean up hierarchy traversal code Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Jackson <pj@sgi.com> Cc: Cliff Wickman <cpw@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: two minor code-cleanupsLai Jiangshan2008-07-251-2/+2
| | | | | | | | | | | | | | | | | | | In cpuset_update_task_memory_state() local variable struct task_struct *tsk = current; And local variable tsk is used 14 times and statement task_cs(tsk) is used twice in this function. So using task_cs(tsk) instead of task_cs(current) is better for readability. And "(struct cgroup_scanner *)&scan" is not good for readability also. (and "container_of" is used in cpuset_do_move_task(), not "(cpuset_hotplug_scanner *)scan") Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: code-cleanup for started_afterLai Jiangshan2008-07-251-31/+6
| | | | | | | | | | | cgroup(cgroup_scan_tasks) will initialize heap->gt for us. This patch removes started_after() and its helper-function. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: don't pass empty cpumasks to partition_sched_domains()Lai Jiangshan2008-07-251-0/+5
| | | | | | | | | | | | | | | | | | I create lots of empty cpusets(empty cpumasks) and turn off the "sched_load_balance" in top cpuset. I found that all these empty cpumasks are passed to partition_sched_domains() in rebuild_sched_domains(), it's very time-consuming for partition_sched_domains() and it's not need. It also reduce memory consumed and some works in rebuild_sched_domains() too. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: avoid unnecessary sched domains rebuildingLi Zefan2008-07-251-6/+12
| | | | | | | | | | | | | | When changing 'sched_relax_domain_level', don't rebuild sched domains if 'cpus' is empty or 'sched_load_balance' is not set. Also make the comments of rebuild_sched_domains() more readable. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Paul Jackson <pj@sgi.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpusets: update task's cpus_allowed and mems_allowed after CPU/NODE ↵Miao Xie2008-07-251-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | offline/online The bug is that a task may run on the cpu/node which is not in its cpuset.cpus/ cpuset.mems. It can be reproduced by the following commands: ----------------------------------- # mkdir /dev/cpuset # mount -t cpuset xxx /dev/cpuset # mkdir /dev/cpuset/0 # echo 0-1 > /dev/cpuset/0/cpus # echo 0 > /dev/cpuset/0/mems # echo $$ > /dev/cpuset/0/tasks # echo 0 > /sys/devices/system/cpu/cpu1/online # echo 1 > /sys/devices/system/cpu/cpu1/online ----------------------------------- There is only CPU0 in cpuset.cpus, but the task in this cpuset runs on both CPU0 and CPU1. It is because the task's cpu_allowed didn't get updated after we did CPU offline/online manipulation. Similar for mem_allowed. This patch fixes this bug expect for root cpuset. Because there is a problem about root cpuset, in that whether it is necessary to update all the tasks in root cpuset or not after cpu/node offline/online. If updating, some kernel threads which is bound into a specified cpu will be unbound. If not updating, there is a bug in root cpuset. This bug is also caused by offline/online manipulation. For example, there is a dual-cpu machine. we create a sub cpuset in root cpuset and assign 1 to its cpus. And then we attach some tasks into this sub cpuset. After this, we offline CPU1. Now, the tasks in this new cpuset are moved into root cpuset automatically because there is no cpu in sub cpuset. Then we online CPU1, we find all the tasks which doesn't belong to root cpuset originally just run on CPU0. Maybe we need to add a flag in the task_struct to mark which task can't be unbound? Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Acked-by: Paul Jackson <pj@sgi.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Jackson <pj@sgi.com> Cc: Paul Menage <menage@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpusets: restructure the function update_cpumask() and update_nodemask()Miao Xie2008-07-251-72/+109
| | | | | | | | | | | | | | Extract two functions from update_cpumask() and update_nodemask().They will be used later for updating tasks' cpus_allowed and mems_allowed after CPU/NODE offline/online. [lizf@cn.fujitsu.com: build fix] Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Acked-by: Paul Jackson <pj@sgi.com> Cc: David Rientjes <rientjes@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup files: remove cpuset_common_file_write()Paul Menage2008-07-251-74/+35
| | | | | | | | | | | | | | | | | This patch tweaks the signatures of the update_cpumask() and update_nodemask() functions so that they can be called directly as handlers for the new cgroups write_string() method. This allows cpuset_common_file_write() to be removed. Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: 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>
* Merge branch 'sched/for-linus' of ↵Linus Torvalds2008-07-241-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: hrtick_enabled() should use cpu_active() sched, x86: clean up hrtick implementation sched: fix build error, provide partition_sched_domains() unconditionally sched: fix warning in inc_rt_tasks() to not declare variable 'rq' if it's not needed cpu hotplug: Make cpu_active_map synchronization dependency clear cpu hotplug, sched: Introduce cpu_active_map and redo sched domain managment (take 2) sched: rework of "prioritize non-migratable tasks over migratable ones" sched: reduce stack size in isolated_cpu_setup() Revert parts of "ftrace: do not trace scheduler functions" Fixed up conflicts in include/asm-x86/thread_info.h (due to the TIF_SINGLESTEP unification vs TIF_HRTICK_RESCHED removal) and kernel/sched_fair.c (due to cpu_active_map vs for_each_cpu_mask_nr() introduction).
| * cpu hotplug, sched: Introduce cpu_active_map and redo sched domain managment ↵Max Krasnyansky2008-07-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | (take 2) This is based on Linus' idea of creating cpu_active_map that prevents scheduler load balancer from migrating tasks to the cpu that is going down. It allows us to simplify domain management code and avoid unecessary domain rebuilds during cpu hotplug event handling. Please ignore the cpusets part for now. It needs some more work in order to avoid crazy lock nesting. Although I did simplfy and unify domain reinitialization logic. We now simply call partition_sched_domains() in all the cases. This means that we're using exact same code paths as in cpusets case and hence the test below cover cpusets too. Cpuset changes to make rebuild_sched_domains() callable from various contexts are in the separate patch (right next after this one). This not only boots but also easily handles while true; do make clean; make -j 8; done and while true; do on-off-cpu 1; done at the same time. (on-off-cpu 1 simple does echo 0/1 > /sys/.../cpu1/online thing). Suprisingly the box (dual-core Core2) is quite usable. In fact I'm typing this on right now in gnome-terminal and things are moving just fine. Also this is running with most of the debug features enabled (lockdep, mutex, etc) no BUG_ONs or lockdep complaints so far. I believe I addressed all of the Dmitry's comments for original Linus' version. I changed both fair and rt balancer to mask out non-active cpus. And replaced cpu_is_offline() with !cpu_active() in the main scheduler code where it made sense (to me). Signed-off-by: Max Krasnyanskiy <maxk@qualcomm.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Gregory Haskins <ghaskins@novell.com> Cc: dmitry.adamushko@gmail.com Cc: pj@sgi.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | cpusets: fix wrong domain attr updatesMiao Xie2008-07-221-1/+3
|/ | | | | | | | | | | | | | Fix wrong domain attr updates, or we will always update the first sched domain attr. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Paul Jackson <pj@sgi.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> [2.6.26.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge commit 'v2.6.26' into sched/develIngo Molnar2008-07-141-6/+18
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| * cpusets, hotplug, scheduler: fix scheduler domain breakageDmitry Adamushko2008-07-131-6/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit f18f982ab ("sched: CPU hotplug events must not destroy scheduler domains created by the cpusets") introduced a hotplug-related problem as described below: Upon CPU_DOWN_PREPARE, update_sched_domains() -> detach_destroy_domains(&cpu_online_map) does the following: /* * Force a reinitialization of the sched domains hierarchy. The domains * and groups cannot be updated in place without racing with the balancing * code, so we temporarily attach all running cpus to the NULL domain * which will prevent rebalancing while the sched domains are recalculated. */ The sched-domains should be rebuilt when a CPU_DOWN ops. has been completed, effectively either upon CPU_DEAD{_FROZEN} (upon success) or CPU_DOWN_FAILED{_FROZEN} (upon failure -- restore the things to their initial state). That's what update_sched_domains() also does but only for !CPUSETS case. With f18f982ab, sched-domains' reinitialization is delegated to CPUSETS code: cpuset_handle_cpuhp() -> common_cpu_mem_hotplug_unplug() -> rebuild_sched_domains() Being called for CPU_UP_PREPARE and if its callback is called after update_sched_domains()), it just negates all the work done by update_sched_domains() -- i.e. a soon-to-be-offline cpu is included in the sched-domains and that makes it visible for the load-balancer while the CPU_DOWN ops. is in progress. __migrate_live_tasks() moves the tasks off a 'dead' cpu (it's already "offline" when this function is called). try_to_wake_up() is called for one of these tasks from another CPU -> the load-balancer (wake_idle()) picks up a "dead" CPU and places the task on it. Then e.g. BUG_ON(rq->nr_running) detects this a bit later -> oops. Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com> Tested-by: Vegard Nossum <vegard.nossum@gmail.com> Cc: Paul Menage <menage@google.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: miaox@cn.fujitsu.com Cc: rostedt@goodmis.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Merge branch 'linus' into sched/develIngo Molnar2008-06-231-2/+2
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| * Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds2008-06-201-2/+2
| |\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: softlockup: fix NMI hangs due to lock race - 2.6.26-rc regression rcupreempt: remove export of rcu_batches_completed_bh cpuset: limit the input of cpuset.sched_relax_domain_level
| | * cpuset: limit the input of cpuset.sched_relax_domain_levelLi Zefan2008-06-191-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We allow the inputs to be [-1 ... SD_LV_MAX), and return -EINVAL for inputs outside this range. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Acked-by: Paul Jackson <pj@sgi.com> Acked-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | sched: CPU hotplug events must not destroy scheduler domains created by the ↵Max Krasnyansky2008-06-191-0/+6
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cpusets First issue is not related to the cpusets. We're simply leaking doms_cur. It's allocated in arch_init_sched_domains() which is called for every hotplug event. So we just keep reallocation doms_cur without freeing it. I introduced free_sched_domains() function that cleans things up. Second issue is that sched domains created by the cpusets are completely destroyed by the CPU hotplug events. For all CPU hotplug events scheduler attaches all CPUs to the NULL domain and then puts them all into the single domain thereby destroying domains created by the cpusets (partition_sched_domains). The solution is simple, when cpusets are enabled scheduler should not create default domain and instead let cpusets do that. Which is exactly what the patch does. Signed-off-by: Max Krasnyansky <maxk@qualcomm.com> Cc: pj@sgi.com Cc: menage@google.com Cc: rostedt@goodmis.org Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'linus' into sched-develIngo Molnar2008-06-161-3/+7
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| * cpusets: fix bug when adding nonexistent cpu or memLai Jiangshan2008-06-061-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adding a nonexistent cpu to a cpuset will be omitted quietly. It should return -EINVAL. Example: (real_nr_cpus <= 4 < NR_CPUS or cpu#4 was just offline) # cat cpus 0-1 # /bin/echo 4 > cpus # /bin/echo $? 0 # cat cpus # The same occurs when add a nonexistent mem. This patch will fix this bug. And when *buf == "", the check is unneeded. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Jackson <pj@sgi.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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