Instead of requiring architecture code to interact with the scheduler's
locking implementation, provide a couple of defines that can be used by the
architecture to request runqueue unlocked context switches, and ask for
interrupts to be enabled over the context switch.
Also replaces the "switch_lock" used by these architectures with an oncpu
flag (note, not a potentially slow bitflag). This eliminates one bus
locked memory operation when context switching, and simplifies the
task_running function.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Reimplement the balance on exec balancing to be sched-domains aware. Use this
to also do balance on fork balancing. Make x86_64 do balance on fork over the
NUMA domain.
The problem that the non sched domains aware blancing became apparent on dual
core, multi socket opterons. What we want is for the new tasks to be sent to
a different socket, but more often than not, we would first load up our
sibling core, or fill two cores of a single remote socket before selecting a
new one.
This gives large improvements to STREAM on such systems.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove the very aggressive idle stuff that has recently gone into 2.6 - it is
going against the direction we are trying to go. Hopefully we can regain
performance through other methods.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Do less affine wakeups. We're trying to reduce dbt2-pgsql idle time
regressions here... make sure we don't don't move tasks the wrong way in an
imbalance condition. Also, remove the cache coldness requirement from the
calculation - this seems to induce sharp cutoff points where behaviour will
suddenly change on some workloads if the load creeps slightly over or under
some point. It is good for periodic balancing because in that case have
otherwise have no other context to determine what task to move.
But also make a minor tweak to "wake balancing" - the imbalance tolerance is
now set at half the domain's imbalance, so we get the opportunity to do wake
balancing before the more random periodic rebalancing gets preformed.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Do CPU load averaging over a number of different intervals. Allow each
interval to be chosen by sending a parameter to source_load and target_load.
0 is instantaneous, idx > 0 returns a decaying average with the most recent
sample weighted at 2^(idx-1). To a maximum of 3 (could be easily increased).
So generally a higher number will result in more conservative balancing.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove the special casing for idle CPU balancing. Things like this are
hurting for example on SMT, where are single sibling being idle doesn't really
warrant a really aggressive pull over the NUMA domain, for example.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
These conditions should now be impossible, and we need to fix them if they
happen.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
SMT balancing has a couple of problems. Firstly, active_load_balance is too
complex - basically it should be a dumb helper for when the periodic balancer
has determined there is an imbalance, but gets stuck because the task is
running.
So rip out all its "smarts", and just make it move one task to the target CPU.
Second, the busy CPU's sched-domain tree was being used for active balancing.
This means that it may not see that nr_balance_failed has reached a critical
level. So use the target CPU's sched-domain tree for this. We can do this
because we hold its runqueue lock.
Lastly, reset nr_balance_failed to a point where we allow cache hot migration.
This will help ensure active load balancing is successful.
Thanks to Suresh Siddha for pointing out these issues.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix up active load balancing a bit so it doesn't get called when it shouldn't.
Reset the nr_balance_failed counter at more points where we have found
conditions to be balanced. This reduces too aggressive active balancing seen
on some workloads.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
John Hawkes explained the problem best:
A large number of processes that are pinned to a single CPU results
in every other CPU's load_balance() seeing this overloaded CPU as
"busiest", yet move_tasks() never finds a task to pull-migrate. This
condition occurs during module unload, but can also occur as a
denial-of-service using sys_sched_setaffinity(). Several hundred
CPUs performing this fruitless load_balance() will livelock on the
busiest CPU's runqueue lock. A smaller number of CPUs will livelock
if the pinned task count gets high.
Expanding slightly on John's patch, this one attempts to work out whether the
balancing failure has been due to too many tasks pinned on the runqueue. This
allows it to be basically invisible to the regular blancing paths (ie. when
there are no pinned tasks). We can use this extra knowledge to shut down the
balancing faster, and ensure the migration threads don't start running which
is another problem observed in the wild.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
New sched-domains code means we don't get spans with offline CPUs in
them.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Show swsuspend only on .config where it can compile. I got this on PPC32 &&
SMP:
kernel/power/smp.c:24: error: storage size of `ctxt' isn't known
Also mark swsusp as no longer experimental.
Signed-off-by: Olaf Hering <olh@suse.de>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In the cpu hotplug case, per-cpu data possibly isn't initialized even the
system state is 'running'. As the comments say in the original code, some
console drivers assume per-cpu resources have been allocated. radeon fb is
one such driver, which uses kmalloc. After a CPU is down, the per-cpu data
of slab is freed, so the system crashed when printing some info.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The following patch moves the recalculation of nr_copy_pages so that the right
number is used in the calculation of the size of memory and swap needed.
It prevents swsusp from attempting to suspend if there is not enough memory
and/or swap (which is unlikely anyway).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The following patch cleans up whitespace in swsusp.c (a bit):
- removes any trailing whitespace
- adds spaces after if, for, for_each_pbe, for_each_zone etc., wherever
necessary.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The following patch removes the unnecessary function does_collide_order().
This function is no longer necessary, as currently there are only 0-order
allocations in swsusp, and the use of it is confusing.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Without this patch, Linux provokes emergency disk shutdowns and
similar nastiness. It was in SuSE kernels for some time, IIRC.
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Using CPU hotplug to support suspend/resume SMP. Both S3 and S4 use
disable/enable_nonboot_cpus API. The S4 part is based on Pavel's original S4
SMP patch.
Signed-off-by: Li Shaohua<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
(The i386 CPU hotplug patch provides infrastructure for some work which Pavel
is doing as well as for ACPI S3 (suspend-to-RAM) work which Li Shaohua
<shaohua.li@intel.com> is doing)
The following provides i386 architecture support for safely unregistering and
registering processors during runtime, updated for the current -mm tree. In
order to avoid dumping cpu hotplug code into kernel/irq/* i dropped the
cpu_online check in do_IRQ() by modifying fixup_irqs(). The difference being
that on cpu offline, fixup_irqs() is called before we clear the cpu from
cpu_online_map and a long delay in order to ensure that we never have any
queued external interrupts on the APICs. There are additional changes to s390
and ppc64 to account for this change.
1) Add CONFIG_HOTPLUG_CPU
2) disable local APIC timer on dead cpus.
3) Disable preempt around irq balancing to prevent CPUs going down.
4) Print irq stats for all possible cpus.
5) Debugging check for interrupts on offline cpus.
6) Hacky fixup_irqs() to redirect irqs when cpus go off/online.
7) play_dead() for offline cpus to spin inside.
8) Handle offline cpus set in flush_tlb_others().
9) Grab lock earlier in smp_call_function() to prevent CPUs going down.
10) Implement __cpu_disable() and __cpu_die().
11) Enable local interrupts in cpu_enable() after fixup_irqs()
12) Don't fiddle with NMI on dead cpu, but leave intact on other cpus.
13) Program IRQ affinity whilst cpu is still in cpu_online_map on offline.
Signed-off-by: Zwane Mwaikambo <zwane@linuxpower.ca>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Don't look up the task by its pid and then use the syscall filtering
helper. Just implement our own filter helper which operates solely on
the information in the netlink_skb_parms.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
When the task refcounting was added to audit_filter_rules() it became
more of a problem that this function was violating the 'only one
return from each function' rule. In fixing it to use a variable to store
'ret' I stupidly neglected to actually change the 'return 1;' at the
end. This makes it not work very well.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Another rollup of patches which give various symbols static scope
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
