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  1. 24 9月, 2009 1 次提交
  3. 11 9月, 2009 1 次提交
  5. 27 8月, 2009 1 次提交
    • G
      powerpc/pseries: Reduce the polling interval in __cpu_up() · 67764263
      由 Gautham R Shenoy 提交于 
      Time time taken for a single cpu online operation on a pseries machine
is as follows:
Dedicated LPAR (POWER6): ~220ms.
Shared LPAR (POWER5)   : ~240ms.

Of this time, approximately 200ms is taken up by __cpu_up(). This is because
we poll every 200ms to check if the new cpu has notified it's presence
through the cpu_callin_map. We repeat this operation until the new cpu sets
the value in cpu_callin_map or 5 seconds elapse, whichever comes earlier.

However, using completion_structs instead of polling loops,
the time taken by the new processor to indicate it's presence has
found to be less than 1ms on pseries. This method however may not
work on all powerpc platforms due to the time-base synchronization code.

Keeping this in mind, we could reduce msleep polling interval from
200ms to 1ms while retaining the 5 second timeout.

With this, the time taken for a cpu online operation changes as follows:
Dedicated LPAR (POWER6): 20-25ms.
Shared LPAR (POWER5)   : 60-80ms.

In both these cases, it was found that the code polls through the loop
only once indicating that 1ms is a reasonable value, atleast on pseries.

The code needs testing on other powerpc platforms.
Signed-off-by: NGautham R Shenoy <ego@in.ibm.com>
Acked-by: NJoel Schopp <jschopp@austin.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      67764263
  7. 26 6月, 2009 1 次提交
    • B
      powerpc/pmac: Fix issues with PowerMac "PowerSurge" SMP · 7ccbe504
      由 Benjamin Herrenschmidt 提交于 
      The old PowerSurge SMP (ie, dual or quad 604 machines) code has
numerous issues in modern world.

One is cpu_possible_map is set too late (the device-tree is bogus)
so we fail to allocate the interrupt stacks and crash. Another
problem is the fact the timebase is frozen by the bringup of the
second CPU so the delays in the generic code will hang, we need
to move some of the calling procedure to inside the powermac code.

This makes it boot again for me
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      7ccbe504
  9. 21 12月, 2008 1 次提交
  11. 16 12月, 2008 1 次提交
  13. 13 12月, 2008 1 次提交
    • R
      cpumask: centralize cpu_online_map and cpu_possible_map · 98a79d6a
      由 Rusty Russell 提交于 
      Impact: cleanup

Each SMP arch defines these themselves.  Move them to a central
location.

Twists:
1) Some archs (m32, parisc, s390) set possible_map to all 1, so we add a
   CONFIG_INIT_ALL_POSSIBLE for this rather than break them.

2) mips and sparc32 '#define cpu_possible_map phys_cpu_present_map'.
   Those archs simply have phys_cpu_present_map replaced everywhere.

3) Alpha defined cpu_possible_map to cpu_present_map; this is tricky
   so I just manipulate them both in sync.

4) IA64, cris and m32r have gratuitous 'extern cpumask_t cpu_possible_map'
   declarations.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Reviewed-by: NGrant Grundler <grundler@parisc-linux.org>
Tested-by: NTony Luck <tony.luck@intel.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Cc: Mike Travis <travis@sgi.com>
Cc: ink@jurassic.park.msu.ru
Cc: rmk@arm.linux.org.uk
Cc: starvik@axis.com
Cc: tony.luck@intel.com
Cc: takata@linux-m32r.org
Cc: ralf@linux-mips.org
Cc: grundler@parisc-linux.org
Cc: paulus@samba.org
Cc: schwidefsky@de.ibm.com
Cc: lethal@linux-sh.org
Cc: wli@holomorphy.com
Cc: davem@davemloft.net
Cc: jdike@addtoit.com
Cc: mingo@redhat.com
      98a79d6a
  15. 19 11月, 2008 1 次提交
    • M
      powerpc: Provide a separate handler for each IPI action · 25ddd738
      由 Milton Miller 提交于 
      With the new generic smp call function helpers, I noticed the code in
smp_message_recv was a single function call in many cases.  While
getting the message number from the ipi data is easy, we can reduce
the path length by a function and data-dependent switch by registering
seperate IPI actions for these simple calls.

Originally I left the ipi action array exposed, but then I realized the
registration code should be common too.

The three users each had their own name array, so I made a fourth
to convert all users to use a common one.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      25ddd738
  17. 13 10月, 2008 1 次提交
  19. 09 9月, 2008 1 次提交
    • M
      kernel/cpu.c: create a CPU_STARTING cpu_chain notifier · e545a614
      由 Manfred Spraul 提交于 
      Right now, there is no notifier that is called on a new cpu, before the new
cpu begins processing interrupts/softirqs.
Various kernel function would need that notification, e.g. kvm works around
by calling smp_call_function_single(), rcu polls cpu_online_map.

The patch adds a CPU_STARTING notification. It also adds a helper function
that sends the message to all cpu_chain handlers.

Tested on x86-64.
All other archs are untested. Especially on sparc, I'm not sure if I got
it right.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      e545a614
  21. 28 7月, 2008 3 次提交
  23. 26 6月, 2008 2 次提交
  25. 14 5月, 2008 1 次提交
    • M
      [POWERPC] Fix sparse warnings in arch/powerpc/kernel · 1c21a293
      由 Michael Ellerman 提交于 
      Make a few things static in lparcfg.c
Make init and exit routines static in rtas_flash.c
Make things static in rtas_pci.c
Make some functions static in rtas.c
Make fops static in rtas-proc.c
Remove unneeded extern for do_gtod in smp.c
Make clocksource_init() static in time.c
Make last_tick_len and ticklen_to_xs static in time.c
Move the declaration of the pvr per-cpu into smp.h
Make kexec_smp_down() and kexec_stack static in machine_kexec_64.c
Don't return void in arch_teardown_msi_irqs() in msi.c
Move declaration of GregorianDay()into asm/time.h
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      1c21a293
  27. 02 5月, 2008 1 次提交
    • P
      [POWERPC] Bolt in SLB entry for kernel stack on secondary cpus · 3b575064
      由 Paul Mackerras 提交于 
      This fixes a regression reported by Kamalesh Bulabel where a POWER4
machine would crash because of an SLB miss at a point where the SLB
miss exception was unrecoverable.  This regression is tracked at:

http://bugzilla.kernel.org/show_bug.cgi?id=10082

SLB misses at such points shouldn't happen because the kernel stack is
the only memory accessed other than things in the first segment of the
linear mapping (which is mapped at all times by entry 0 of the SLB).
The context switch code ensures that SLB entry 2 covers the kernel
stack, if it is not already covered by entry 0.  None of entries 0
to 2 are ever replaced by the SLB miss handler.

Where this went wrong is that the context switch code assumes it
doesn't have to write to SLB entry 2 if the new kernel stack is in the
same segment as the old kernel stack, since entry 2 should already be
correct.  However, when we start up a secondary cpu, it calls
slb_initialize, which doesn't set up entry 2.  This is correct for
the boot cpu, where we will be using a stack in the kernel BSS at this
point (i.e. init_thread_union), but not necessarily for secondary
cpus, whose initial stack can be allocated anywhere.  This doesn't
cause any immediate problem since the SLB miss handler will just
create an SLB entry somewhere else to cover the initial stack.

In fact it's possible for the cpu to go quite a long time without SLB
entry 2 being valid.  Eventually, though, the entry created by the SLB
miss handler will get overwritten by some other entry, and if the next
access to the stack is at an unrecoverable point, we get the crash.

This fixes the problem by making slb_initialize create a suitable
entry for the kernel stack, if we are on a secondary cpu and the stack
isn't covered by SLB entry 0.  This requires initializing the
get_paca()->kstack field earlier, so I do that in smp_create_idle
where the current field is initialized.  This also abstracts a bit of
the computation that mk_esid_data in slb.c does so that it can be used
in slb_initialize.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      3b575064
  29. 25 1月, 2008 2 次提交
    • O
      [POWERPC] Make smp_send_stop() handle panic and xmon reboot · e057d985
      由 Olof Johansson 提交于 
      smp_send_stop() will send an IPI to all other cpus to shut them down.
However, for the case of xmon-based reboots (as well as potentially some
panics), the other cpus are (or might be) spinning with interrupts off,
and won't take the IPI.

Current code will drop us into the debugger when the IPI fails, which
means we're in an infinite loop that we can't get out of without an
external reset of some sort.

Instead, make the smp_send_stop() IPI call path just print the warning
about being unable to send IPIs, but make it return so the rest of the
shutdown sequence can continue. It's not perfect, but the lesser of
two evils.

Also move the call_lock handling outside of smp_call_function_map so we
can avoid deadlocks in smp_send_stop().
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      e057d985
    • O
      [POWERPC] Make smp_call_function_map static · b616de5e
      由 Olof Johansson 提交于 
      smp_call_function_map should be static, and for consistency prepend it
with __ like other local helper functions in the same file.
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      b616de5e
  31. 17 10月, 2007 1 次提交
  33. 03 10月, 2007 1 次提交
  35. 22 9月, 2007 1 次提交
    • S
      [POWERPC] Avoid pointless WARN_ON(irqs_disabled()) from panic codepath · 8fd7675c
      由 Satyam Sharma 提交于 
      > ------------[ cut here ]------------
> Badness at arch/powerpc/kernel/smp.c:202

comes when smp_call_function_map() has been called with irqs disabled,
which is illegal. However, there is a special case, the panic() codepath,
when we do not want to warn about this -- warning at that time is pointless
anyway, and only serves to scroll away the *real* cause of the panic and
distracts from the real bug.

* So let's extract the WARN_ON() from smp_call_function_map() into all its
  callers -- smp_call_function() and smp_call_function_single()

* Also, introduce another caller of smp_call_function_map(), namely
  __smp_call_function() (and make smp_call_function() a wrapper over this)
  which does *not* warn about disabled irqs

* Use this __smp_call_function() from the panic codepath's smp_send_stop()

We also end having to move code of smp_send_stop() below the definition
of __smp_call_function().
Signed-off-by: NSatyam Sharma <satyam@infradead.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      8fd7675c
  37. 03 8月, 2007 1 次提交
  39. 22 7月, 2007 1 次提交
  41. 22 5月, 2007 1 次提交
  43. 07 5月, 2007 1 次提交
  45. 13 4月, 2007 1 次提交
    • B
      [POWERPC] Make tlb flush batch use lazy MMU mode · a741e679
      由 Benjamin Herrenschmidt 提交于 
      The current tlb flush code on powerpc 64 bits has a subtle race since we
lost the page table lock due to the possible faulting in of new PTEs
after a previous one has been removed but before the corresponding hash
entry has been evicted, which can leads to all sort of fatal problems.

This patch reworks the batch code completely. It doesn't use the mmu_gather
stuff anymore. Instead, we use the lazy mmu hooks that were added by the
paravirt code. They have the nice property that the enter/leave lazy mmu
mode pair is always fully contained by the PTE lock for a given range
of PTEs. Thus we can guarantee that all batches are flushed on a given
CPU before it drops that lock.

We also generalize batching for any PTE update that require a flush.

Batching is now enabled on a CPU by arch_enter_lazy_mmu_mode() and
disabled by arch_leave_lazy_mmu_mode(). The code epects that this is
always contained within a PTE lock section so no preemption can happen
and no PTE insertion in that range from another CPU. When batching
is enabled on a CPU, every PTE updates that need a hash flush will
use the batch for that flush.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      a741e679
  47. 14 2月, 2007 1 次提交
  49. 12 1月, 2007 1 次提交
    • G
      [PATCH] Change cpu_up and co from __devinit to __cpuinit · b282b6f8
      由 Gautham R Shenoy 提交于 
      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: NGautham 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: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      b282b6f8
  51. 25 10月, 2006 1 次提交
  53. 05 10月, 2006 1 次提交
    • D
      IRQ: Maintain regs pointer globally rather than passing to IRQ handlers · 7d12e780
      由 David Howells 提交于 
      Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.
Signed-Off-By: NDavid Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
      7d12e780
  55. 25 7月, 2006 1 次提交
  57. 07 7月, 2006 1 次提交
  59. 01 7月, 2006 1 次提交
  61. 21 6月, 2006 1 次提交
  63. 29 3月, 2006 1 次提交
  65. 24 2月, 2006 1 次提交
    • P
      powerpc: Implement accurate task and CPU time accounting · c6622f63
      由 Paul Mackerras 提交于 
      This implements accurate task and cpu time accounting for 64-bit
powerpc kernels.  Instead of accounting a whole jiffy of time to a
task on a timer interrupt because that task happened to be running at
the time, we now account time in units of timebase ticks according to
the actual time spent by the task in user mode and kernel mode.  We
also count the time spent processing hardware and software interrupts
accurately.  This is conditional on CONFIG_VIRT_CPU_ACCOUNTING.  If
that is not set, we do tick-based approximate accounting as before.

To get this accurate information, we read either the PURR (processor
utilization of resources register) on POWER5 machines, or the timebase
on other machines on

* each entry to the kernel from usermode
* each exit to usermode
* transitions between process context, hard irq context and soft irq
  context in kernel mode
* context switches.

On POWER5 systems with shared-processor logical partitioning we also
read both the PURR and the timebase at each timer interrupt and
context switch in order to determine how much time has been taken by
the hypervisor to run other partitions ("steal" time).  Unfortunately,
since we need values of the PURR on both threads at the same time to
accurately calculate the steal time, and since we can only calculate
steal time on a per-core basis, the apportioning of the steal time
between idle time (time which we ceded to the hypervisor in the idle
loop) and actual stolen time is somewhat approximate at the moment.

This is all based quite heavily on what s390 does, and it uses the
generic interfaces that were added by the s390 developers,
i.e. account_system_time(), account_user_time(), etc.

This patch doesn't add any new interfaces between the kernel and
userspace, and doesn't change the units in which time is reported to
userspace by things such as /proc/stat, /proc/<pid>/stat, getrusage(),
times(), etc.  Internally the various task and cpu times are stored in
timebase units, but they are converted to USER_HZ units (1/100th of a
second) when reported to userspace.  Some precision is therefore lost
but there should not be any accumulating error, since the internal
accumulation is at full precision.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      c6622f63
  67. 07 2月, 2006 1 次提交
  69. 13 1月, 2006 1 次提交
  71. 09 1月, 2006 1 次提交