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* tracehook_notify_death: use task_detached() helperOleg Nesterov2009-04-02
| | | | | | | | | | | | Now that task_detached() is exported, change tracehook_notify_death() to use this helper, nobody else checks ->exit_signal == -1 by hand. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Metzger, Markus T" <markus.t.metzger@intel.com> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* forget_original_parent: do not abuse child->ptrace_entryOleg Nesterov2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | By discussion with Roland. - Use ->sibling instead of ->ptrace_entry to chain the need to be release_task'd childs. Nobody else can use ->sibling, this task is EXIT_DEAD and nobody can find it on its own list. - rename ptrace_dead to dead_childs. - Now that we don't have the "parallel" untrace code, change back reparent_thread() to return void, pass dead_childs as an argument. Actually, I don't understand why do we notify /sbin/init when we reparent a zombie, probably it is better to reap it unconditionally. [akpm@linux-foundation.org: s/childs/children/] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Metzger, Markus T" <markus.t.metzger@intel.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* forget_original_parent: split out the un-ptrace partOleg Nesterov2009-04-02
| | | | | | | | | | | | | | | | | | | By discussion with Roland. - Rename ptrace_exit() to exit_ptrace(), and change it to do all the necessary work with ->ptraced list by its own. - Move this code from exit.c to ptrace.c - Update the comment in ptrace_detach() to explain the rechecking of the child->ptrace. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Metzger, Markus T" <markus.t.metzger@intel.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* reparent_thread: fix a zombie leak if /sbin/init ignores SIGCHLDOleg Nesterov2009-04-02
| | | | | | | | | | | | | | | | | | | | If /sbin/init ignores SIGCHLD and we re-parent a zombie, it is leaked. reparent_thread() does do_notify_parent() which sets ->exit_signal = -1 in this case. This means that nobody except us can reap it, the detached task is not visible to do_wait(). Change reparent_thread() to return a boolean (like __pthread_detach) to indicate that the thread is dead and must be released. Also change forget_original_parent() to add the child to ptrace_dead list in this case. The naming becomes insane, the next patch does the cleanup. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* reparent_thread: fix the "is it traced" checkOleg Nesterov2009-04-02
| | | | | | | | | | | | | | | | | | reparent_thread() uses ptrace_reparented() to check whether this thread is ptraced, in that case we should not notify the new parent. But ptrace_reparented() is not exactly correct when the reparented thread is traced by /sbin/init, because forget_original_parent() has already changed ->real_parent. Currently, the only problem is the false notification. But with the next patch the kernel crash in this (yes, pathological) case. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* reparent_thread: don't call kill_orphaned_pgrp() if task_detached()Oleg Nesterov2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | If task_detached(p) == T, then either a) p is not the main thread, we will find the group leader on the ->children list. or b) p is the group leader but its ->exit_state = EXIT_DEAD. This can only happen when the last sub-thread has died, but in that case that thread has already called kill_orphaned_pgrp() from exit_notify(). In both cases kill_orphaned_pgrp() looks bogus. Move the task_detached() check up and simplify the code, this is also right from the "common sense" pov: we should do nothing with the detached childs, except move them to the new parent's ->children list. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ptrace: fix possible zombie leak on PTRACE_DETACHOleg Nesterov2009-04-02
| | | | | | | | | | | | | | | | | When ptrace_detach() takes tasklist, the tracee can be SIGKILL'ed. If it has already passed exit_notify() we can leak a zombie, because a) ptracing disables the auto-reaping logic, and b) ->real_parent was not notified about the child's death. ptrace_detach() should follow the ptrace_exit's logic, change the code accordingly. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Roland McGrath <roland@redhat.com> Tested-by: Denys Vlasenko <dvlasenk@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ptrace: reintroduce __ptrace_detach() as a callee of ptrace_exit()Oleg Nesterov2009-04-02
| | | | | | | | | | | | | | No functional changes, preparation for the next patch. Move the "should we release this child" logic into the separate handler, __ptrace_detach(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ptrace: simplify ptrace_exit()->ignoring_children() pathOleg Nesterov2009-04-02
| | | | | | | | | | | | | | | | | | | | | ignoring_children() takes parent->sighand->siglock and checks k_sigaction[SIGCHLD] atomically. But this buys nothing, we can't get the "really" wrong result even if we race with sigaction(SIGCHLD). If we read the "stale" sa_handler/sa_flags we can pretend it was changed right after the check. Remove spin_lock(->siglock), and kill "int ign" which caches the result of ignoring_children() which becomes rather trivial. Perhaps it makes sense to export this helper, do_notify_parent() can use it too. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ptrace: kill __ptrace_detach(), fix ->exit_state checkOleg Nesterov2009-04-02
| | | | | | | | | | | | | | | | Move the code from __ptrace_detach() to its single caller and kill this helper. Also, fix the ->exit_state check, we shouldn't wake up EXIT_DEAD tasks. Actually, I think task_is_stopped_or_traced() makes more sense, but this needs another patch. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: SI_USER: Masquerade si_pid when crossing pid ns boundarySukadev Bhattiprolu2009-04-02
| | | | | | | | | | | | | | | | | | When sending a signal to a descendant namespace, set ->si_pid to 0 since the sender does not have a pid in the receiver's namespace. Note: - If rt_sigqueueinfo() sets si_code to SI_USER when sending a signal across a pid namespace boundary, the value in ->si_pid will be cleared to 0. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: protect cinit from blocked fatal signalsSukadev Bhattiprolu2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Normally SIG_DFL signals to global and container-init are dropped early. But if a signal is blocked when it is posted, we cannot drop the signal since the receiver may install a handler before unblocking the signal. Once this signal is queued however, the receiver container-init has no way of knowing if the signal was sent from an ancestor or descendant namespace. This patch ensures that contianer-init drops all SIG_DFL signals in get_signal_to_deliver() except SIGKILL/SIGSTOP. If SIGSTOP/SIGKILL originate from a descendant of container-init they are never queued (i.e dropped in sig_ignored() in an earler patch). If SIGSTOP/SIGKILL originate from parent namespace, the signal is queued and container-init processes the signal. IOW, if get_signal_to_deliver() sees a sig_kernel_only() signal for global or container-init, the signal must have been generated internally or must have come from an ancestor ns and we process the signal. Further, the signal_group_exit() check was needed to cover the case of a multi-threaded init sending SIGKILL to other threads when doing an exit() or exec(). But since the new sig_kernel_only() check covers the SIGKILL, the signal_group_exit() check is no longer needed and can be removed. Finally, now that we have all pieces in place, set SIGNAL_UNKILLABLE for container-inits. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: zap_pid_ns_process() should use force_sig()Sukadev Bhattiprolu2009-04-02
| | | | | | | | | | | | | | | | | | | send_signal() assumes that signals with SEND_SIG_PRIV are generated from within the same namespace. So any nested container-init processes become immune to the SIGKILL generated by kill_proc_info() in zap_pid_ns_processes(). Use force_sig() in zap_pid_ns_processes() instead - force_sig() clears the SIGNAL_UNKILLABLE flag ensuring the signal is processed by container-inits. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: protect cinit from unblocked SIG_DFL signalsSukadev Bhattiprolu2009-04-02
| | | | | | | | | | | | | | | | | | | | | | Drop early any SIG_DFL or SIG_IGN signals to container-init from within the same container. But queue SIGSTOP and SIGKILL to the container-init if they are from an ancestor container. Blocked, fatal signals (i.e when SIG_DFL is to terminate) from within the container can still terminate the container-init. That will be addressed in the next patch. Note: To be bisect-safe, SIGNAL_UNKILLABLE will be set for container-inits in a follow-on patch. Until then, this patch is just a preparatory step. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: add from_ancestor_ns parameter to send_signal()Sukadev Bhattiprolu2009-04-02
| | | | | | | | | | | | | | | | | | | send_signal() (or its helper) needs to determine the pid namespace of the sender. But a signal sent via kill_pid_info_as_uid() comes from within the kernel and send_signal() does not need to determine the pid namespace of the sender. So define a helper for send_signal() which takes an additional parameter, 'from_ancestor_ns' and have kill_pid_info_as_uid() use that helper directly. The 'from_ancestor_ns' parameter will be used in a follow-on patch. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: protect init from unwanted signals moreOleg Nesterov2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | (This is a modified version of the patch submitted by Oleg Nesterov http://lkml.org/lkml/2008/11/18/249 and tries to address comments that came up in that discussion) init ignores the SIG_DFL signals but we queue them anyway, including SIGKILL. This is mostly OK, the signal will be dropped silently when dequeued, but the pending SIGKILL has 2 bad implications: - it implies fatal_signal_pending(), so we confuse things like wait_for_completion_killable/lock_page_killable. - for the sub-namespace inits, the pending SIGKILL can mask (legacy_queue) the subsequent SIGKILL from the parent namespace which must kill cinit reliably. (preparation, cinits don't have SIGNAL_UNKILLABLE yet) The patch can't help when init is ptraced, but ptracing of init is not "safe" anyway. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: remove 'handler' parameter to tracehook functionsOleg Nesterov2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Container-init must behave like global-init to processes within the container and hence it must be immune to unhandled fatal signals from within the container (i.e SIG_DFL signals that terminate the process). But the same container-init must behave like a normal process to processes in ancestor namespaces and so if it receives the same fatal signal from a process in ancestor namespace, the signal must be processed. Implementing these semantics requires that send_signal() determine pid namespace of the sender but since signals can originate from workqueues/ interrupt-handlers, determining pid namespace of sender may not always be possible or safe. This patchset implements the design/simplified semantics suggested by Oleg Nesterov. The simplified semantics for container-init are: - container-init must never be terminated by a signal from a descendant process. - container-init must never be immune to SIGKILL from an ancestor namespace (so a process in parent namespace must always be able to terminate a descendant container). - container-init may be immune to unhandled fatal signals (like SIGUSR1) even if they are from ancestor namespace. SIGKILL/SIGSTOP are the only reliable signals to a container-init from ancestor namespace. This patch: Based on an earlier patch submitted by Oleg Nesterov and comments from Roland McGrath (http://lkml.org/lkml/2008/11/19/258). The handler parameter is currently unused in the tracehook functions. Besides, the tracehook functions are called with siglock held, so the functions can check the handler if they later need to. Removing the parameter simiplifies changes to sig_ignored() in a follow-on patch. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Daniel Lezcano <daniel.lezcano@free.fr> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* do_wait: fix waiting for the group stop with the dead leaderOleg Nesterov2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | do_wait(WSTOPPED) assumes that p->state must be == TASK_STOPPED, this is not true if the leader is already dead. Check SIGNAL_STOP_STOPPED instead and use signal->group_exit_code. Trivial test-case: void *tfunc(void *arg) { pause(); return NULL; } int main(void) { pthread_t thr; pthread_create(&thr, NULL, tfunc, NULL); pthread_exit(NULL); return 0; } It doesn't react to ^Z (and then to ^C or ^\). The task is stopped, but bash can't see this. The bug is very old, and it was reported multiple times. This patch was sent more than a year ago (http://marc.info/?t=119713920000003) but it was ignored. This change also fixes other oddities (but not all) in this area. For example, before this patch: $ sleep 100 ^Z [1]+ Stopped sleep 100 $ strace -p `pidof sleep` Process 11442 attached - interrupt to quit strace hangs in do_wait(), because ->exit_code was already consumed by bash. After this patch, strace happily proceeds: --- SIGTSTP (Stopped) @ 0 (0) --- restart_syscall(<... resuming interrupted call ...> To me, this looks much more "natural" and correct. Another example. Let's suppose we have the main thread M and sub-thread T, the process is stopped, and its parent did wait(WSTOPPED). Now we can ptrace T but not M. This looks at least strange to me. Imho, do_wait() should not confuse the per-thread ptrace stops with the per-process job control stops. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Kaz Kylheku <kkylheku@gmail.com> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Roland McGrath <roland@redhat.com> Cc: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpusets: prevent PF_THREAD_BOUND tasks from attaching to non-root cpusetsDavid Rientjes2009-04-02
| | | | | | | | | | | | | | | | | | | | | | 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 Menage2009-04-02
| | | | | | | | | | | | | | | | | | 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 Rientjes2009-04-02
| | | | | | | | | | | | | | 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 Zefan2009-04-02
| | | | | | | | | | | | 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 Zefan2009-04-02
| | | | | | | | | | | | | | | | | 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 Zefan2009-04-02
| | | | | | | | | | | | | | | | | | 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>
* cgroups: add 'data' field to struct cgroup_scannerLi Zefan2009-04-02
| | | | | | | | | | | We need to pass some data to test_task() or process_task() in some cases. Will be used later. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.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: fix possible races in cpu/memory hotplugLi Zefan2009-04-02
| | | | | | | | | | | | | 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>
* memcg: cleanup cache_chargeDaisuke Nishimura2009-04-02
| | | | | | | | | | | | Current mem_cgroup_cache_charge is a bit complicated especially in the case of shmem's swap-in. This patch cleans it up by using try_charge_swapin and commit_charge_swapin. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: 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>
* memcg: remove redundant message at swaponKAMEZAWA Hiroyuki2009-04-02
| | | | | | | | | | | | | | | | | | It's pointed out that swap_cgroup's message at swapon() is nonsense. Because * It can be calculated very easily if all necessary information is written in Kconfig. * It's not necessary to annoying people at every swapon(). In other view, now, memory usage per swp_entry is reduced to 2bytes from 8bytes(64bit) and I think it's reasonably small. Reported-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: 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>
* cgroups: use css id in swap cgroup for saving memory v5KAMEZAWA Hiroyuki2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Try to use CSS ID for records in swap_cgroup. By this, on 64bit machine, size of swap_cgroup goes down to 2 bytes from 8bytes. This means, when 2GB of swap is equipped, (assume the page size is 4096bytes) From size of swap_cgroup = 2G/4k * 8 = 4Mbytes. To size of swap_cgroup = 2G/4k * 2 = 1Mbytes. Reduction is large. Of course, there are trade-offs. This CSS ID will add overhead to swap-in/swap-out/swap-free. But in general, - swap is a resource which the user tend to avoid use. - If swap is never used, swap_cgroup area is not used. - Reading traditional manuals, size of swap should be proportional to size of memory. Memory size of machine is increasing now. I think reducing size of swap_cgroup makes sense. Note: - ID->CSS lookup routine has no locks, it's under RCU-Read-Side. - memcg can be obsolete at rmdir() but not freed while refcnt from swap_cgroup is available. Changelog v4->v5: - reworked on to memcg-charge-swapcache-to-proper-memcg.patch Changlog ->v4: - fixed not configured case. - deleted unnecessary comments. - fixed NULL pointer bug. - fixed message in dmesg. [nishimura@mxp.nes.nec.co.jp: css_tryget can be called twice in !PageCgroupUsed case] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: charge swapcache to proper memcgDaisuke Nishimura2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | memcg_test.txt says at 4.1: This swap-in is one of the most complicated work. In do_swap_page(), following events occur when pte is unchanged. (1) the page (SwapCache) is looked up. (2) lock_page() (3) try_charge_swapin() (4) reuse_swap_page() (may call delete_swap_cache()) (5) commit_charge_swapin() (6) swap_free(). Considering following situation for example. (A) The page has not been charged before (2) and reuse_swap_page() doesn't call delete_from_swap_cache(). (B) The page has not been charged before (2) and reuse_swap_page() calls delete_from_swap_cache(). (C) The page has been charged before (2) and reuse_swap_page() doesn't call delete_from_swap_cache(). (D) The page has been charged before (2) and reuse_swap_page() calls delete_from_swap_cache(). memory.usage/memsw.usage changes to this page/swp_entry will be Case (A) (B) (C) (D) Event Before (2) 0/ 1 0/ 1 1/ 1 1/ 1 =========================================== (3) +1/+1 +1/+1 +1/+1 +1/+1 (4) - 0/ 0 - -1/ 0 (5) 0/-1 0/ 0 -1/-1 0/ 0 (6) - 0/-1 - 0/-1 =========================================== Result 1/ 1 1/ 1 1/ 1 1/ 1 In any cases, charges to this page should be 1/ 1. In case of (D), mem_cgroup_try_get_from_swapcache() returns NULL (because lookup_swap_cgroup() returns NULL), so "+1/+1" at (3) means charges to the memcg("foo") to which the "current" belongs. OTOH, "-1/0" at (4) and "0/-1" at (6) means uncharges from the memcg("baa") to which the page has been charged. So, if the "foo" and "baa" is different(for example because of task move), this charge will be moved from "baa" to "foo". I think this is an unexpected behavior. This patch fixes this by modifying mem_cgroup_try_get_from_swapcache() to return the memcg to which the swapcache has been charged if PCG_USED bit is set. IIUC, checking PCG_USED bit of swapcache is safe under page lock. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: remove mem_cgroup_reclaim_imbalance() remnantsKOSAKI Motohiro2009-04-02
| | | | | | | | | | | | commit 4f98a2fee8acdb4ac84545df98cccecfd130f8db (vmscan: split LRU lists into anon & file sets) removed mem_cgroup_reclaim_imbalance(), but there are some leftovers in memcontrol.h. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: remove mem_cgroup_calc_mapped_ratio()KOSAKI Motohiro2009-04-02
| | | | | | | | | | | | Currently, mem_cgroup_calc_mapped_ratio() is unused at all. it can be removed and KAMEZAWA-san suggested it. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: show memcg information during OOMBalbir Singh2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add RSS and swap to OOM output from memcg Display memcg values like failcnt, usage and limit when an OOM occurs due to memcg. Thanks to Johannes Weiner, Li Zefan, David Rientjes, Kamezawa Hiroyuki, Daisuke Nishimura and KOSAKI Motohiro for review. Sample output ------------- Task in /a/x killed as a result of limit of /a memory: usage 1048576kB, limit 1048576kB, failcnt 4183 memory+swap: usage 1400964kB, limit 9007199254740991kB, failcnt 0 [akpm@linux-foundation.org: compilation fix] [akpm@linux-foundation.org: fix kerneldoc and whitespace] [akpm@linux-foundation.org: add printk facility level] Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Li Zefan <lizf@cn.fujitsu.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>
* memcg: fix OOM killer under memcgKAMEZAWA Hiroyuki2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch tries to fix OOM Killer problems caused by hierarchy. Now, memcg itself has OOM KILL function (in oom_kill.c) and tries to kill a task in memcg. But, when hierarchy is used, it's broken and correct task cannot be killed. For example, in following cgroup /groupA/ hierarchy=1, limit=1G, 01 nolimit 02 nolimit All tasks' memory usage under /groupA, /groupA/01, groupA/02 is limited to groupA's 1Gbytes but OOM Killer just kills tasks in groupA. This patch provides makes the bad process be selected from all tasks under hierarchy. BTW, currently, oom_jiffies is updated against groupA in above case. oom_jiffies of tree should be updated. To see how oom_jiffies is used, please check mem_cgroup_oom_called() callers. [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: const fix] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: fix shrinking memory to return -EBUSY by fixing retry algorithmKAMEZAWA Hiroyuki2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As pointed out, shrinking memcg's limit should return -EBUSY after reasonable retries. This patch tries to fix the current behavior of shrink_usage. Before looking into "shrink should return -EBUSY" problem, we should fix hierarchical reclaim code. It compares current usage and current limit, but it only makes sense when the kernel reclaims memory because hit limits. This is also a problem. What this patch does are. 1. add new argument "shrink" to hierarchical reclaim. If "shrink==true", hierarchical reclaim returns immediately and the caller checks the kernel should shrink more or not. (At shrinking memory, usage is always smaller than limit. So check for usage < limit is useless.) 2. For adjusting to above change, 2 changes in "shrink"'s retry path. 2-a. retry_count depends on # of children because the kernel visits the children under hierarchy one by one. 2-b. rather than checking return value of hierarchical_reclaim's progress, compares usage-before-shrink and usage-after-shrink. If usage-before-shrink <= usage-after-shrink, retry_count is decremented. Reported-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: hierarchical statKAMEZAWA Hiroyuki2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clean up memory.stat file routine and show "total" hierarchical stat. This patch does - renamed get_all_zonestat to be get_local_zonestat. - remove old mem_cgroup_stat_desc, which is only for per-cpu stat. - add mcs_stat to cover both of per-cpu/per-lru stat. - add "total" stat of hierarchy (*) - add a callback system to scan all memcg under a root. == "total" is added. [kamezawa@localhost ~]$ cat /opt/cgroup/xxx/memory.stat cache 0 rss 0 pgpgin 0 pgpgout 0 inactive_anon 0 active_anon 0 inactive_file 0 active_file 0 unevictable 0 hierarchical_memory_limit 50331648 hierarchical_memsw_limit 9223372036854775807 total_cache 65536 total_rss 192512 total_pgpgin 218 total_pgpgout 155 total_inactive_anon 0 total_active_anon 135168 total_inactive_file 61440 total_active_file 4096 total_unevictable 0 == (*) maybe the user can do calc hierarchical stat by his own program in userland but if it can be written in clean way, it's worth to be shown, I think. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: use CSS IDKAMEZAWA Hiroyuki2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Assigning CSS ID for each memcg and use css_get_next() for scanning hierarchy. Assume folloing tree. group_A (ID=3) /01 (ID=4) /0A (ID=7) /02 (ID=10) group_B (ID=5) and task in group_A/01/0A hits limit at group_A. reclaim will be done in following order (round-robin). group_A(3) -> group_A/01 (4) -> group_A/01/0A (7) -> group_A/02(10) -> group_A -> ..... Round robin by ID. The last visited cgroup is recorded and restart from it when it start reclaim again. (More smart algorithm can be implemented..) No cgroup_mutex or hierarchy_mutex is required. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* devcgroup: avoid using cgroup_lockLi Zefan2009-04-02
| | | | | | | | | | | | | There is nothing special that has to be protected by cgroup_lock, so introduce devcgroup_mtuex for it's own use. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Balbir Singh <balbir@in.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>
* debug cgroup: remove unneeded cgroup_lockLi Zefan2009-04-02
| | | | | | | | | | | Since we are in cgroup write handler, so the cgrp is valid, so we don't have to hold cgroup_mutex when calling cgroup_task_count(). One similar example is in cgroup_tasks_open(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.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>
* cgroups: don't change release_agent when remount failedLi Zefan2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remount can fail in either case: - wrong mount options is specified, or option 'noprefix' is changed. - a to-be-added subsys is already mounted/active. When using remount to change 'release_agent', for the above former failure case, remount will return errno with release_agent unchanged, but for the latter case, remount will return EBUSY with relase_agent changed, which is unexpected I think: # mount -t cgroup -o cpu xxx /cgrp1 # mount -t cgroup -o cpuset,release_agent=agent1 yyy /cgrp2 # cat /cgrp2/release_agent agent1 # mount -t cgroup -o remount,cpuset,noprefix,release_agent=agent2 yyy /cgrp2 mount: /cgrp2 not mounted already, or bad option # cat /cgrp2/release_agent agent1 <-- ok # mount -t cgroup -o remount,cpu,cpuset,release_agent=agent2 yyy /cgrp2 mount: /cgrp2 is busy # cat /cgrp2/release_agent agent2 <-- unexpected! Signed-off-by: Li Zefan <lizf@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>
* cgroups: show correct file modeLi Zefan2009-04-02
| | | | | | | | | | | | | | | | 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>
* cgroups: more documentation for remount and release_agentLi Zefan2009-04-02
| | | | | | | | | | | | | | | | | | | | This won't remove cpuacct from the mounted hierachy: # mount -t cgroup -o cpu,cpuacct xxx /mnt # mount -o remount,cpu /mnt Because for this usage mount(8) will append the new options to the original options. And this will get you right: # mount [-t cgroup] -o remount,cpu xxx /mnt Also document how to specify or change release_agent. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Reviewd-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.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>
* kernel/cgroup.c: kfree(NULL) is legalJesper Juhl2009-04-02
| | | | | | | | | | | | | | | | | | Reduces object file size a bit: Before: $ size kernel/cgroup.o text data bss dec hex filename 21593 7804 4924 34321 8611 kernel/cgroup.o After: $ size kernel/cgroup.o text data bss dec hex filename 21537 7744 4924 34205 859d kernel/cgroup.o Signed-off-by: Jesper Juhl <jj@chaosbits.net> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: fix frequent -EBUSY at rmdirKAMEZAWA Hiroyuki2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In following situation, with memory subsystem, /groupA use_hierarchy==1 /01 some tasks /02 some tasks /03 some tasks /04 empty When tasks under 01/02/03 hit limit on /groupA, hierarchical reclaim is triggered and the kernel walks tree under groupA. In this case, rmdir /groupA/04 fails with -EBUSY frequently because of temporal refcnt from the kernel. In general. cgroup can be rmdir'd if there are no children groups and no tasks. Frequent fails of rmdir() is not useful to users. (And the reason for -EBUSY is unknown to users.....in most cases) This patch tries to modify above behavior, by - retries if css_refcnt is got by someone. - add "return value" to pre_destroy() and allows subsystem to say "we're really busy!" Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: CSS ID supportKAMEZAWA Hiroyuki2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch for Per-CSS(Cgroup Subsys State) ID and private hierarchy code. This patch attaches unique ID to each css and provides following. - css_lookup(subsys, id) returns pointer to struct cgroup_subysys_state of id. - css_get_next(subsys, id, rootid, depth, foundid) returns the next css under "root" by scanning When cgroup_subsys->use_id is set, an id for css is maintained. The cgroup framework only parepares - css_id of root css for subsys - id is automatically attached at creation of css. - id is *not* freed automatically. Because the cgroup framework don't know lifetime of cgroup_subsys_state. free_css_id() function is provided. This must be called by subsys. There are several reasons to develop this. - Saving space .... For example, memcg's swap_cgroup is array of pointers to cgroup. But it is not necessary to be very fast. By replacing pointers(8bytes per ent) to ID (2byes per ent), we can reduce much amount of memory usage. - Scanning without lock. CSS_ID provides "scan id under this ROOT" function. By this, scanning css under root can be written without locks. ex) do { rcu_read_lock(); next = cgroup_get_next(subsys, id, root, &found); /* check sanity of next here */ css_tryget(); rcu_read_unlock(); id = found + 1 } while(...) Characteristics: - Each css has unique ID under subsys. - Lifetime of ID is controlled by subsys. - css ID contains "ID" and "Depth in hierarchy" and stack of hierarchy - Allowed ID is 1-65535, ID 0 is UNUSED ID. Design Choices: - scan-by-ID v.s. scan-by-tree-walk. As /proc's pid scan does, scan-by-ID is robust when scanning is done by following kind of routine. scan -> rest a while(release a lock) -> conitunue from interrupted memcg's hierarchical reclaim does this. - When subsys->use_id is set, # of css in the system is limited to 65535. [bharata@linux.vnet.ibm.com: remove rcu_read_lock() from css_get_next()] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: relax ns_can_attach checks to allow attaching to grandchild cgroupsGrzegorz Nosek2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | The ns_proxy cgroup allows moving processes to child cgroups only one level deep at a time. This commit relaxes this restriction and makes it possible to attach tasks directly to grandchild cgroups, e.g.: ($pid is in the root cgroup) echo $pid > /cgroup/CG1/CG2/tasks Previously this operation would fail with -EPERM and would have to be performed as two steps: echo $pid > /cgroup/CG1/tasks echo $pid > /cgroup/CG1/CG2/tasks Also, the target cgroup no longer needs to be empty to move a task there. Signed-off-by: Grzegorz Nosek <root@localdomain.pl> Acked-by: Serge Hallyn <serue@us.ibm.com> Reviewed-by: Li Zefan <lizf@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>
* cgroups: fix cgroup.h commentsPaul Menage2009-04-02
| | | | | | | | | Fix the style of some multi-line comments in cgroup.h to match Documentation/CodingStyle Signed-off-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* documentation: fix unix_dgram_qlen descriptionLi Xiaodong2009-04-02
| | | | | | | | | | | Previous description about system parameter in /proc/sys/net/unix/ is wrong (or missed). Simply add a new description about unix_dgram_qlen according to latest kernel. Signed-off-by: Li Xiaodong <lixd@cn.fujitsu.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* documentation: update Documentation/filesystem/proc.txt and ↵Shen Feng2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Documentation/sysctls Now /proc/sys is described in many places and much information is redundant. This patch updates the proc.txt and move the /proc/sys desciption out to the files in Documentation/sysctls. Details are: merge - 2.1 /proc/sys/fs - File system data - 2.11 /proc/sys/fs/mqueue - POSIX message queues filesystem - 2.17 /proc/sys/fs/epoll - Configuration options for the epoll interface with Documentation/sysctls/fs.txt. remove - 2.2 /proc/sys/fs/binfmt_misc - Miscellaneous binary formats since it's not better then the Documentation/binfmt_misc.txt. merge - 2.3 /proc/sys/kernel - general kernel parameters with Documentation/sysctls/kernel.txt remove - 2.5 /proc/sys/dev - Device specific parameters since it's obsolete the sysfs is used now. remove - 2.6 /proc/sys/sunrpc - Remote procedure calls since it's not better then the Documentation/sysctls/sunrpc.txt move - 2.7 /proc/sys/net - Networking stuff - 2.9 Appletalk - 2.10 IPX to newly created Documentation/sysctls/net.txt. remove - 2.8 /proc/sys/net/ipv4 - IPV4 settings since it's not better then the Documentation/networking/ip-sysctl.txt. add - Chapter 3 Per-Process Parameters to descibe /proc/<pid>/xxx parameters. Signed-off-by: Shen Feng <shen@cn.fujitsu.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* documentation: ignore byproducts from latexHenrik Austad2009-04-02
| | | | | | | | | When using 'make pdfdocs', auto-generated files should be ignored Signed-off-by: Henrik Austad <henrik@austad.us> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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