linux/kernel
Paul Jackson 4c4d50f7b3 [PATCH] cpuset: top_cpuset tracks hotplug changes to cpu_online_map
Change the list of cpus allowed to tasks in the top (root) cpuset to
dynamically track what cpus are online, using a CPU hotplug notifier.  Make
this top cpus file read-only.

On systems that have cpusets configured in their kernel, but that aren't
actively using cpusets (for some distros, this covers the majority of
systems) all tasks end up in the top cpuset.

If that system does support CPU hotplug, then these tasks cannot make use
of CPUs that are added after system boot, because the CPUs are not allowed
in the top cpuset.  This is a surprising regression over earlier kernels
that didn't have cpusets enabled.

In order to keep the behaviour of cpusets consistent between systems
actively making use of them and systems not using them, this patch changes
the behaviour of the 'cpus' file in the top (root) cpuset, making it read
only, and making it automatically track the value of cpu_online_map.  Thus
tasks in the top cpuset will have automatic use of hot plugged CPUs allowed
by their cpuset.

Thanks to Anton Blanchard and Nathan Lynch for reporting this problem,
driving the fix, and earlier versions of this patch.

Signed-off-by: Paul Jackson <pj@sgi.com>
Cc: Nathan Lynch <ntl@pobox.com>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-08-27 11:01:32 -07:00
..
irq [PATCH] genirq: {en,dis}able_irq_wake() need refcounting too 2006-07-31 13:28:36 -07:00
power [PATCH] Make suspend possible with a traced process at a breakpoint 2006-08-06 08:57:45 -07:00
time [PATCH] time: rename clocksource functions 2006-06-26 09:58:21 -07:00
.gitignore gitignore: ignore more generated files 2006-01-03 11:35:26 +01:00
Kconfig.hz [PATCH] i386: Selectable Frequency of the Timer Interrupt 2005-06-23 09:45:10 -07:00
Kconfig.preempt [PATCH] sched: voluntary kernel preemption 2005-06-25 16:24:45 -07:00
Makefile [PATCH] per-task-delay-accounting: taskstats interface 2006-07-14 21:53:56 -07:00
acct.c [PATCH] Fix sighand->siglock usage in kernel/acct.c 2006-07-14 21:53:54 -07:00
audit.c [PATCH] fix oops with CONFIG_AUDIT and !CONFIG_AUDITSYSCALL 2006-08-03 10:50:39 -04:00
audit.h [PATCH] add rule filterkey 2006-07-01 05:43:06 -04:00
auditfilter.c [PATCH] introduce audit rules counter 2006-08-03 10:55:18 -04:00
auditsc.c [PATCH] take filling ->pid, etc. out of audit_get_context() 2006-08-03 10:59:51 -04:00
capability.c [PATCH] sched: cleanup, remove task_t, convert to struct task_struct 2006-07-03 15:27:11 -07:00
compat.c [PATCH] N32 sigset and __COMPAT_ENDIAN_SWAP__ 2006-06-25 10:01:15 -07:00
configs.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
cpu.c cpu hotplug: simplify and hopefully fix locking 2006-07-23 12:12:16 -07:00
cpuset.c [PATCH] cpuset: top_cpuset tracks hotplug changes to cpu_online_map 2006-08-27 11:01:32 -07:00
delayacct.c [PATCH] delay accounting: temporarily enable by default 2006-07-31 13:28:37 -07:00
dma.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
exec_domain.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
exit.c [PATCH] per-task delay accounting taskstats interface: control exit data through cpumasks 2006-07-14 21:53:57 -07:00
extable.c [PATCH] symbol_put_addr() locks kernel 2006-05-15 11:20:55 -07:00
fork.c [PATCH] ptrace: make pid of child process available for PTRACE_EVENT_VFORK_DONE 2006-08-06 08:57:46 -07:00
futex.c [PATCH] futex_find_get_task(): remove an obscure EXIT_ZOMBIE check 2006-08-27 11:01:30 -07:00
futex_compat.c [PATCH] futex: Apply recent futex fixes to futex_compat 2006-08-06 08:57:49 -07:00
hrtimer.c [PATCH] fix hrtimer percpu usage typo 2006-08-14 12:54:28 -07:00
itimer.c [PATCH] hrtimers: remove data field 2006-03-26 08:57:03 -08:00
kallsyms.c [PATCH] null-terminate over-long /proc/kallsyms symbols 2006-07-14 21:53:52 -07:00
kexec.c [POWERPC] Add the use of the firmware soft-reset-nmi to kdump. 2006-06-28 15:18:52 +10:00
kfifo.c [PATCH] gfp flags annotations - part 1 2005-10-08 15:00:57 -07:00
kmod.c [PATCH] lockdep: annotate on-stack completions 2006-07-03 15:27:09 -07:00
kprobes.c [PATCH] IA64: kprobe invalidate icache of jump buffer 2006-07-31 13:28:38 -07:00
ksysfs.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
kthread.c [PATCH] remove kernel/kthread.c:kthread_stop_sem() 2006-07-14 21:53:52 -07:00
lockdep.c [PATCH] lockdep: core, reduce per-lock class-cache size 2006-07-10 13:24:14 -07:00
lockdep_internals.h [PATCH] lockdep: core 2006-07-03 15:27:03 -07:00
lockdep_proc.c [PATCH] lockdep: procfs 2006-07-03 15:27:04 -07:00
module.c [PATCH] null-terminate over-long /proc/kallsyms symbols 2006-07-14 21:53:52 -07:00
mutex-debug.c [PATCH] lockdep: prove mutex locking correctness 2006-07-03 15:27:04 -07:00
mutex-debug.h [PATCH] lockdep: better lock debugging 2006-07-03 15:27:01 -07:00
mutex.c [PATCH] lockdep: prove mutex locking correctness 2006-07-03 15:27:04 -07:00
mutex.h [PATCH] lockdep: prove mutex locking correctness 2006-07-03 15:27:04 -07:00
panic.c [PATCH] panic.c build fix 2006-08-14 12:54:28 -07:00
params.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
pid.c [PATCH] sched: cleanup, remove task_t, convert to struct task_struct 2006-07-03 15:27:11 -07:00
posix-cpu-timers.c [PATCH] arm_timer: remove a racy and obsolete PF_EXITING check 2006-06-17 10:52:13 -07:00
posix-timers.c [PATCH] hrtimers: remove data field 2006-03-26 08:57:03 -08:00
printk.c [PATCH] vt: printk: Fix framebuffer console triggering might_sleep assertion 2006-08-06 08:57:47 -07:00
profile.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
ptrace.c [PATCH] sched: cleanup, remove task_t, convert to struct task_struct 2006-07-03 15:27:11 -07:00
rcupdate.c [PATCH] cpu hotplug: replace __devinit* with __cpuinit* for cpu notifications 2006-07-31 13:28:39 -07:00
rcutorture.c [PATCH] rcutorture: add call_rcu_bh() operations 2006-06-27 17:32:40 -07:00
relay.c [PATCH] relay: consolidate sendfile() and read() code 2006-03-23 19:58:45 +01:00
resource.c [PATCH] memory hotadd fixes: find_next_system_ram catch range fix 2006-08-06 08:57:48 -07:00
rtmutex-debug.c [PATCH] sched: cleanup, remove task_t, convert to struct task_struct 2006-07-03 15:27:11 -07:00
rtmutex-debug.h [PATCH] lockdep: better lock debugging 2006-07-03 15:27:01 -07:00
rtmutex-tester.c [PATCH] Add try_to_freeze() to rt-test kthreads 2006-07-14 21:53:53 -07:00
rtmutex.c [PATCH] reference rt-mutex-design in rtmutex.c 2006-07-31 13:28:43 -07:00
rtmutex.h [PATCH] lockdep: better lock debugging 2006-07-03 15:27:01 -07:00
rtmutex_common.h [PATCH] pi-futex: futex_lock_pi/futex_unlock_pi support 2006-06-27 17:32:47 -07:00
rwsem.c [PATCH] lockdep: prove rwsem locking correctness 2006-07-03 15:27:04 -07:00
sched.c [PATCH] revert "Drop tasklist lock in do_sched_setscheduler" 2006-08-27 11:01:29 -07:00
seccomp.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
signal.c Fix force_sig_info() semantics after cleanups 2006-08-02 20:17:49 -07:00
softirq.c [PATCH] Reducing local_bh_enable/disable overhead in irqtrace 2006-07-31 13:28:42 -07:00
softlockup.c [PATCH] cpu hotplug: replace __devinit* with __cpuinit* for cpu notifications 2006-07-31 13:28:39 -07:00
spinlock.c [PATCH] lockdep: prove spinlock rwlock locking correctness 2006-07-03 15:27:04 -07:00
stacktrace.c [PATCH] lockdep: stacktrace subsystem, core 2006-07-03 15:27:02 -07:00
stop_machine.c [PATCH] Remove redundant up() in stop_machine() 2006-08-27 11:01:31 -07:00
sys.c [PATCH] Fix prctl privilege escalation and suid_dumpable (CVE-2006-2451) 2006-07-12 12:50:25 -07:00
sys_ni.c [PATCH] sys_move_pages: 32bit support (i386, x86_64) 2006-06-23 07:42:53 -07:00
sysctl.c [PATCH] ZVC/zone_reclaim: Leave 1% of unmapped pagecache pages for file I/O 2006-07-03 15:26:59 -07:00
taskstats.c [PATCH] taskstats: free skb, avoid returns in send_cpu_listeners 2006-07-31 13:28:37 -07:00
time.c [PATCH] Time: Introduce arch generic time accessors 2006-06-26 09:58:20 -07:00
timer.c [PATCH] sys_getppid oopses on debug kernel 2006-08-14 12:54:29 -07:00
uid16.c [PATCH] Add more prevent_tail_call() 2006-04-19 16:27:18 -07:00
unwind.c [PATCH] x86_64: allow unwinder to build without module support 2006-06-26 10:48:18 -07:00
user.c [PATCH] selinux: add hooks for key subsystem 2006-06-22 15:05:55 -07:00
wait.c [PATCH] uninline init_waitqueue_head() 2006-07-10 13:24:25 -07:00
workqueue.c [PATCH] workqueue: remove lock_cpu_hotplug() 2006-08-14 12:54:29 -07:00