Commit Graph

23 Commits

Author SHA1 Message Date
Ingo Molnar
0437e109e1 sched: zap the migration init / cache-hot balancing code
the SMP load-balancer uses the boot-time migration-cost estimation
code to attempt to improve the quality of balancing. The reason for
this code is that the discrete priority queues do not preserve
the order of scheduling accurately, so the load-balancer skips
tasks that were running on a CPU 'recently'.

this code is fundamental fragile: the boot-time migration cost detector
doesnt really work on systems that had large L3 caches, it caused boot
delays on large systems and the whole cache-hot concept made the
balancing code pretty undeterministic as well.

(and hey, i wrote most of it, so i can say it out loud that it sucks ;-)

under CFS the same purpose of cache affinity can be achieved without
any special cache-hot special-case: tasks are sorted in the 'timeline'
tree and the SMP balancer picks tasks from the left side of the
tree, thus the most cache-cold task is balanced automatically.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-07-09 18:51:57 +02:00
Ralf Baechle
4ebd5233f0 [MIPS] Fix modpost warnings by making start_secondary __cpuinit
WARNING: arch/mips/kernel/built-in.o(.text+0x9a58): Section mismatch: reference to .init.text:cpu_report (between 'start_secondary' and 'smp_prepare_boot_cpu')
WARNING: arch/mips/kernel/built-in.o(.text+0x9a60): Section mismatch: reference to .init.text:per_cpu_trap_init (between 'start_secondary' and 'smp_prepare_boot_cpu')
WARNING: arch/mips/kernel/built-in.o(.text+0x9adc): Section mismatch: reference to .init.text:cpu_probe (between 'start_secondary' and 'smp_prepare_boot_cpu')
mipsel-linux-objcopy -S -O srec --remove-section=.reginfo --remove-section=.mdebug --remove-section=.comment --remove-section=.note --remove-section=.pdr --remove-section=.options --remove-section=.MIPS.options vmlinux arch/mips/boot/vmlinux.srec

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-06-11 18:20:54 +01:00
Ralf Baechle
de7fa296b6 [MIPS] SMP: Get smp_tune_scheduling to do something useful.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-22 00:50:45 +00:00
Gautham R Shenoy
b282b6f8a8 [PATCH] Change cpu_up and co from __devinit to __cpuinit
Compiling the kernel with CONFIG_HOTPLUG = y and CONFIG_HOTPLUG_CPU = n
with CONFIG_RELOCATABLE = y generates the following modpost warnings

WARNING: vmlinux - Section mismatch: reference to .init.data: from
.text between '_cpu_up' (at offset 0xc0141b7d) and 'cpu_up'
WARNING: vmlinux - Section mismatch: reference to .init.data: from
.text between '_cpu_up' (at offset 0xc0141b9c) and 'cpu_up'
WARNING: vmlinux - Section mismatch: reference to .init.text:__cpu_up
from .text between '_cpu_up' (at offset 0xc0141bd8) and 'cpu_up'
WARNING: vmlinux - Section mismatch: reference to .init.data: from
.text between '_cpu_up' (at offset 0xc0141c05) and 'cpu_up'
WARNING: vmlinux - Section mismatch: reference to .init.data: from
.text between '_cpu_up' (at offset 0xc0141c26) and 'cpu_up'
WARNING: vmlinux - Section mismatch: reference to .init.data: from
.text between '_cpu_up' (at offset 0xc0141c37) and 'cpu_up'

This is because cpu_up, _cpu_up and __cpu_up (in some architectures) are
defined as __devinit
AND
__cpu_up calls some __cpuinit functions.

Since __cpuinit would map to __init with this kind of a configuration,
we get a .text refering .init.data warning.

This patch solves the problem by converting all of __cpu_up, _cpu_up
and cpu_up from __devinit to __cpuinit. The approach is justified since
the callers of cpu_up are either dependent on CONFIG_HOTPLUG_CPU or
are of __init type.

Thus when CONFIG_HOTPLUG_CPU=y, all these cpu up functions would land up
in .text section, and when CONFIG_HOTPLUG_CPU=n, all these functions would
land up in .init section.

Tested on a i386 SMP machine running linux-2.6.20-rc3-mm1.

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2007-01-11 18:18:20 -08:00
Ralf Baechle
0004a9dfea [MIPS] Cleanup memory barriers for weakly ordered systems.
Also the R4000 / R4600 LL/SC instructions imply a sync so no explicit sync
needed.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-12-04 22:43:14 +00:00
Ralf Baechle
f5d6c63a67 [MIPS] Do topology_init even on uniprocessor kernels.
Otherwise CPU 0 doesn't show up in sysfs which breaks some software.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-11-29 16:21:34 +00:00
Ralf Baechle
9a244b95dd [MIPS] Pass NULL not 0 for pointer value.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-10-11 19:31:00 +01:00
Ralf Baechle
0e8f8f54c1 [MIPS] NUMA: Register all nodes before cpus or sysfs will barf.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-10-09 23:20:46 +01:00
Ralf Baechle
25969354a3 [MIPS] Avoid interprocessor function calls.
On the 34K where multiple virtual processors are implemented in a single
core and share a single TLB, interprocessor function calls are not needed
to flush a cache, so avoid them.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-07-13 21:25:56 +01:00
KAMEZAWA Hiroyuki
76b67ed9dc [PATCH] node hotplug: register cpu: remove node struct
With Goto-san's patch, we can add new pgdat/node at runtime.  I'm now
considering node-hot-add with cpu + memory on ACPI.

I found acpi container, which describes node, could evaluate cpu before
memory. This means cpu-hot-add occurs before memory hot add.

In most part, cpu-hot-add doesn't depend on node hot add.  But register_cpu(),
which creates symbolic link from node to cpu, requires that node should be
onlined before register_cpu().  When a node is onlined, its pgdat should be
there.

This patch-set holds off creating symbolic link from node to cpu
until node is onlined.

This removes node arguments from register_cpu().

Now, register_cpu() requires 'struct node' as its argument.  But the array of
struct node is now unified in driver/base/node.c now (By Goto's node hotplug
patch).  We can get struct node in generic way.  So, this argument is not
necessary now.

This patch also guarantees add cpu under node only when node is onlined.  It
is necessary for node-hot-add vs.  cpu-hot-add patch following this.

Moreover, register_cpu calculates cpu->node_id by cpu_to_node() without regard
to its 'struct node *root' argument.  This patch removes it.

Also modify callers of register_cpu()/unregister_cpu, whose args are changed
by register-cpu-remove-node-struct patch.

[Brice.Goglin@ens-lyon.org: fix it]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 17:32:37 -07:00
Ralf Baechle
320e6aba26 [MIPS] Fix SMP now that fixup_cpu_present_map is gone.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-06-06 00:15:09 +01:00
Ralf Baechle
41c594ab65 [MIPS] MT: Improved multithreading support.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-04-19 04:14:28 +02:00
Ralf Baechle
e49ed7f591 [MIPS] Sort out duplicate exports.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-04-19 04:14:14 +02:00
Andrew Morton
394e3902c5 [PATCH] more for_each_cpu() conversions
When we stop allocating percpu memory for not-possible CPUs we must not touch
the percpu data for not-possible CPUs at all.  The correct way of doing this
is to test cpu_possible() or to use for_each_cpu().

This patch is a kernel-wide sweep of all instances of NR_CPUS.  I found very
few instances of this bug, if any.  But the patch converts lots of open-coded
test to use the preferred helper macros.

Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Kyle McMartin <kyle@parisc-linux.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Christian Zankel <chris@zankel.net>
Cc: Philippe Elie <phil.el@wanadoo.fr>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Jens Axboe <axboe@suse.de>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-23 07:38:17 -08:00
Ralf Baechle
9b6695a8ad [MIPS] SMP: Fix initialization order bug.
A recent change requires cpu_possible_map to be initialized before
smp_sched_init() but most MIPS platforms were initializing their
processors in the prom_prepare_cpus callback of smp_prepare_cpus.  The
simple fix of calling prom_prepare_cpus from one of the earlier SMP
initialization hooks doesn't work well either since IPIs may require
init_IRQ() to have completed, so bit the bullet and split
prom_prepare_cpus into two initialization functions, plat_smp_setup
which is called early from setup_arch and plat_prepare_cpus called where
prom_prepare_cpus used to be called.
    
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-02-27 17:30:36 +00:00
Rojhalat Ibrahim
1e35aabab8 [MIPS] Add topology_init.
A recent patch introduced cpu topology in sysfs.  When you run a kernel
with SMP and sysfs enabled, you now get an Oops on boot. The following
patch fixes that by adding topology_init to arch/mips/kernel/smp.c. The
code is copied from arch/s390/kernel/smp.c.
    
Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-02-21 16:58:23 +00:00
Nick Piggin
5bfb5d690f [PATCH] sched: disable preempt in idle tasks
Run idle threads with preempt disabled.

Also corrected a bugs in arm26's cpu_idle (make it actually call schedule()).
How did it ever work before?

Might fix the CPU hotplugging hang which Nigel Cunningham noted.

We think the bug hits if the idle thread is preempted after checking
need_resched() and before going to sleep, then the CPU offlined.

After calling stop_machine_run, the CPU eventually returns from preemption and
into the idle thread and goes to sleep.  The CPU will continue executing
previous idle and have no chance to call play_dead.

By disabling preemption until we are ready to explicitly schedule, this bug is
fixed and the idle threads generally become more robust.

From: alexs <ashepard@u.washington.edu>

  PPC build fix

From: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>

  MIPS build fix

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-09 07:56:33 -08:00
Ralf Baechle
3bffe736d9 Delete old junk.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2005-10-29 19:32:04 +01:00
Ralf Baechle
ae1b3d51c8 Make sure that the processor is actually online or die spectacularly.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2005-10-29 19:31:55 +01:00
Ralf Baechle
f03da6e28e Fix BogoMIPS display on UP and some minor cosmetical things.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2005-10-29 19:31:05 +01:00
Ralf Baechle
b727a60258 Merge do_boot_cpu() into the new style __cpu_up().
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2005-10-29 19:30:43 +01:00
Ralf Baechle
57f0060b8a Document why calling smp_call_function will deadlock when called with
interrupts disabled.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2005-10-29 19:30:30 +01:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00