This reverts commit e4f0ae0ea6.
It's not wrong, but it's not right either, and everybody seems to agree
that the right fix is probably to do the ccr3 write after the ccr4 one
(and that we also should clean it up a bit). And after that we need to
really validate that all the bits that we write to ccr4 actually do
work.
The old 2.6.19 code was insane, and basically didn't change ccr4 at all
(even though it certainly looks like it was the *intent* to do so). So
let's revert the change that may fix things, just because it's not what
was actually ever tested when the code was written, even if it _was_ the
intent.
There's a discussion on http://lkml.org/lkml/2007/1/9/63 that was
started by the patch that now gets reverted, and that discussion may
well contain the proper long-term fix.
Suggested-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
i386 boot/compressed/relocs checks for absolute symbols and warns about
unexpected ones. If you build with modversions, you get ~2500 warnings
about __crc_<symbol>. These suckers are really absolute symbols - we
do _not_ want to modify them on relocation.
They are generated by genksyms - EXPORT_... generates a weak alias, then
genksyms produces an ld script with __crc_<symbol> = <checksum> and it's
fed to ld to produce the final object file. Their only use is to match
kernel and module at modprobe time; they _must_ be absolute.
boot/compressed/relocs has a whitelist of known absolute symbols, but
it doesn't know about __crc_... stuff. As the result, we get shitloads
of false positives on any ld(1) version.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the world was a simple and static place setting up irqs was easy.
It sufficed to allocate a linux irq number and a find a free cpu
vector we could receive that linux irq on. In those days it was
a safe assumption that any allocated vector was actually in use
so after one global pass through all of the vectors we would have
none left.
These days things are much more dynamic with interrupt controllers
(in the form of MSI or MSI-X) appearing on plug in cards and linux
irqs appearing and disappearing. As these irqs come and go vectors
are allocated and freed, invalidating the ancient assumption that all
allocated vectors stayed in use forever.
So this patch modifies the vector allocator to walk through every
possible vector before giving up, and to check to see if a vector
is in use before assigning it. With these changes we stop leaking
freed vectors and it becomes possible to allocate and free irq vectors
all day long.
This changed was modeled after the vector allocator on x86_64 where
this limitation has already been removed. In essence we don't update
the static variables that hold the position of the last vector we
allocated until have successfully allocated another vector. This
allows us to detect if we have completed one complete scan through
all of the possible vectors.
Acked-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This workaround unnecessarily cripples functionality to work
around an errata that doesn't seem possible to hit due to
us using the automatic clock throttling in the p4 mcheck code.
See http://lkml.org/lkml/2006/10/28/148 for complete reasoning
and lack of disconsent.
Signed-off-by: Dave Jones <davej@redhat.com>
This patch fixes core dumps to include the vDSO vma, which is left out now.
It removes the special-case core writing macros, which were not doing the
right thing for the vDSO vma anyway. Instead, it uses VM_ALWAYSDUMP in the
vma; there is no need for the fixmap page to be installed. It handles the
CONFIG_COMPAT_VDSO case by making elf_core_dump use the fake vma from
get_gate_vma after real vmas in the same way the /proc/PID/maps code does.
This changes core dumps so they no longer include the non-PT_LOAD phdrs from
the vDSO. I made the change to add them in the first place, but in turned out
that nothing ever wanted them there since the advent of NT_AUXV. It's cleaner
to leave them out, and just let the phdrs inside the vDSO image speak for
themselves.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I wouldn't mind if CONFIG_COMPAT_VDSO went away entirely. But if it's there,
it should work properly. Currently it's quite haphazard: both real vma and
fixmap are mapped, both are put in the two different AT_* slots, sysenter
returns to the vma address rather than the fixmap address, and core dumps yet
are another story.
This patch makes CONFIG_COMPAT_VDSO disable the real vma and use the fixmap
area consistently. This makes it actually compatible with what the old vdso
implementation did.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The paravirt subsystem is still in flux so all exports from it are
definitely internal use only. The APIs around this /will/ change.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit f2802e7f57 and its x86 version
(b7471c6da9) adds nmi_known_cpu() check
while parsing boot options in x86_64 and i386.
With that, "nmi_watchdog=2" stops working for me on Intel Core 2 CPU
based system.
The problem is, setup_nmi_watchdog is called while parsing the boot
option and identify_cpu is not done yet. So, the return value of
nmi_known_cpu() is not valid at this point.
So revert that check. This should not have any adverse effect as the
nmi_known_cpu() check is done again later in enable_lapic_nmi_watchdog().
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current PDA code, which went in in post 2.6.19 has a flaw in that it
doesn't correctly cycle the GDT and %GS segment through the boot PDA,
the CPU PDA and finally the per-cpu PDA.
The bug generally doesn't show up if the boot CPU id is zero, but
everything falls apart for a non zero boot CPU id. The basically kills
voyager which is perfectly capable of doing non zero CPU id boots, so
voyager currently won't boot without this.
The fix is to be careful and actually do the GDT setups correctly.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We write back the wrong register when configuring the Geode processor.
Instead of storing to CCR4, it stores to CCR3.
Cc: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
o sched_clock() a non-init function is using init data tsc_disable. This
is flagged by MODPOST on i386 if CONFIG_RELOCATABLE=y
WARNING: vmlinux - Section mismatch: reference to .init.data:tsc_disable from .text between 'sched_clock' (at offset 0xc0109d58) and 'tsc_update_callback'
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
o Some functions which should have been in init sections as they are called
only once. Put them in init sections. Otherwise MODPOST generates warning
as these functions are placed in .text and they end up accessing something
in init sections.
WARNING: vmlinux - Section mismatch: reference to .init.text:migration_init
from .text between 'do_pre_smp_initcalls' (at offset 0xc01000d1) and
'run_init_process'
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Andi Kleen <ak@suse.de>
o struct genapic contains pointer to probe() function which is of type
__init. Hence MODPOST generates warning if kernel is compiled with
CONFIG_RELOCATABLE=y for i386.
WARNING: vmlinux - Section mismatch: reference to .init.text: from .data between 'apic_summit' (at offset 0xc058b504) and 'apic_bigsmp'
WARNING: vmlinux - Section mismatch: reference to .init.text: from .data between 'apic_bigsmp' (at offset 0xc058b5a4) and 'cpu.4471'
WARNING: vmlinux - Section mismatch: reference to .init.text: from .data between 'apic_es7000' (at offset 0xc058b644) and 'apic_default'
WARNING: vmlinux - Section mismatch: reference to .init.text: from .data between 'apic_default' (at offset 0xc058b6e4) and 'interrupt'
o One of the possible options is to put special case check in MODPOST to
not emit warnings for this case but I think it is not a very good option
in terms of maintenance.
o Another option is to make probe() function non __init. Anyway this function
is really small so not freeing this memory after init is not a big deal.
Secondly, from a programming perspective, probably genapic should not
provide pointers to functions which have been freed as genapic is non
__init and is used even after initialization is complete.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
o Misc smpboot/cpu hotplug path cleanups. I did those to supress the
warnings generated by MODPOST. These warnings are visible only
if CONFIG_RELOCATABLE=y.
o CONFIG_RELOCATABLE compiles the kernel with --emit-relocs option. This
option retains relocation information in vmlinux file and MODPOST
is quick to spit out "Section mismatch" warnings.
o This patch fixes some of those warnings. Many of the functions in
smpboot case are __devinit type and they in turn accesses text/data which
if of type __cpuinit. Now if CONFIG_HOTPLUG=y and CONFIG_HOTPLUG_CPU=n
then we end up in cases where a function in .text segment is calling
another function in .init.text segment and MODPOST emits warning.
WARNING: vmlinux - Section mismatch: reference to .init.text:identify_cpu from .text between 'smp_store_cpu_info' (at offset 0xc011020d) and 'do_boot_cpu'
WARNING: vmlinux - Section mismatch: reference to .init.text:init_gdt from .text between 'do_boot_cpu' (at offset 0xc01102ca) and '__cpu_up'
WARNING: vmlinux - Section mismatch: reference to .init.text:print_cpu_info from .text between 'do_boot_cpu' (at offset 0xc01105d0) and '__cpu_up'
o It also fixes the issues where CONFIG_HOTPLUG_CPU=y and start_secondary()
is calling smp_callin() which in-turn calls synchronize_tsc_ap() which is
of type __init. This should have meant broken CPU hotplug.
WARNING: vmlinux - Section mismatch: reference to .init.data: from .text between 'start_secondary' (at offset 0xc011603f) and 'initialize_secondary'
WARNING: vmlinux - Section mismatch: reference to .init.data: from .text between 'MP_processor_info' (at offset 0xc0116a4f) and 'mp_register_lapic'
WARNING: vmlinux - Section mismatch: reference to .init.data: from .text between 'MP_processor_info' (at offset 0xc0116a4f) and 'mp_register_lapic'
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Andi Kleen <ak@suse.de>
o Currently synchronize_tsc_ap() is of type __init. It is called by
smp_callin() which is of type __cpuinit. So synchronize_tsc_ap()
should be of type __cpuinit.
o Modpost generates warnings for i386 if CONFIG_RELOCATABLE=y and
CONFIG_HOTPLUG_CPU=y
WARNING: vmlinux - Section mismatch: reference to .init.data: from .text between 'start_secondary' (at offset 0xc01164dc) and 'initialize_secondary'
WARNING: vmlinux - Section mismatch: reference to .init.data: from .text between 'start_secondary' (at offset 0xc01164e8) and 'initialize_secondary'
o tsc is of type __initdata. It should be of type __cpuinitdata.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
o MODPOST generates warning for i386 if kernel is compiled with
CONFIG_RELOCATABLE=y
WARNING: vmlinux - Section mismatch: reference to .init.data: from .data between 'this_cpu' (at offset 0xc05194d0) and 'cpuinfo_op'
o this_cpu pointer should be of type __cpuinitdata.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
o MODPOST generates warning for i386 if kernel is compiled with
CONFIG_RELOCATABLE=y
WARNING: vmlinux - Section mismatch: reference to .init.text:startup_32_smp
from .data between 'trampoline_data' (at offset 0xc0519cf8) and 'boot_gdt'
o trampoline code/data can go into init section is CPU hotplug is not
enabled.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
o Relocatable bzImage support had got rid of CONFIG_PHYSICAL_START option
thinking that now this option is not required as people can build a
second kernel as relocatable and load it anywhere. So need of compiling
the kernel for a custom address was gone. But Magnus uses vmlinux images
for second kernel in Xen environment and he wants to continue to use
it.
o Restoring the CONFIG_PHYSICAL_START option for the time being. I think
down the line we can get rid of it.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
cmd.val was used uninitialized on the line below.
Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
This is patch that solves Ebox mini PC issue and make
FSB code more specification compilant. At start guess_fsb
function is guessing 200MHz FSB too. It is better to
make it in this way because, thanks to this function, driver
will fail for bogus FSB values caused by bogus multiplier
value. For PowerSaver processors we can't depend on Max /
MinMHzFSB because these values are only used for
PowerSaver 2.0 and 3.0. Most processors on which Longhaul
is used are PowerSaver 1.0 only. I'm changing code for older
CPU's too, but not so much as previously, and this code was
already used for Ezra. Using MinMHzBR for Ezra-T is outside
spec. It is for voltage scaling purpose and don't have to
be equal to minmult (but it is). Same for Nehemiah (it
isn't for sure). Added mult - current multiplier value.
Signed-off-by: Rafa³ Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>
Commit 968de4f026 ("i386: Relocatable
kernel support") caused problems for people with old binutils versions
that didn't mark ".text.*" sections automatically allocated.
So we should use .section command to specifically mark .text.head
section as AX (allocatable and executable) to solve the problem.
This should be unnecessary with binutils 2.15 and later, which is
already three years old, but it doesn't hurt supporting older toolchains
where possible.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Dunno why this pops out in only in the allmodconfig build.
Though the warning is accurate, all the callers of the flagged
non __init function are __init, this is not a functional change.
WARNING: vmlinux - Section mismatch: reference to .init.data:acpi_sci_flags from .text between 'acpi_sci_ioapic_setup' (at offset 0xc010f0a
6) and 'acpi_gsi_to_irq' WARNING: vmlinux - Section mismatch: reference to .init.text:mp_override_legacy_irq from .text between 'acpi_sci_ioapic_setup' (at offset 0
xc010f0de) and 'acpi_gsi_to_irq' WARNING: vmlinux - Section mismatch: reference to .init.data:acpi_sci_override_gsi from .text between 'acpi_sci_ioapic_setup' (at offset 0x
c010f0e4) and 'acpi_gsi_to_irq'
Signed-off-by: Len Brown <len.brown@intel.com>
The apple fn keys don't work anymore with 2.6.20-rc1.
The reason is that USB_HID_POWERBOOK appears in several files although
USB_HIDINPUT_POWERBOOK is the thing to be used.
The patch fixes this.
Cc: Greg KH <greg@kroah.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Due to the changes to make the kernel relocateable a new file is created
during the build process.
[jirislaby@gmail.com: The .gitigonre was intended to be in arch/ subtree]
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
ACPI PM2 register was fallback for "Longhaul ver. 1" CPU's.
My assumption that this register isn't present at
"PowerSaver" motherboards is so far true, but current code
will not work correctly in other case. There are three possible
supports: ACPI C3, PM2 and northbridge. That was my assumption
that ACPI C3 and northbridge is for PS and northbridge and PM2
is for V1. In current code we can only check if it is ACPI
support or not by port22_en. So remove port22_en and add
longhaul_flags. If USE_ACPI_C3 and USE_NORTHBRIDGE are both
clear then it means ACPI PM2 support. Also change order of
support probe from ACPI C3, PM2, northbridge to ACPI C3,
northbridge, ACPI PM2. Paranoid protection against port 0x22
cast as ACPI PM2 register. Bit 1 clear in such case - lockup
on AGP DMA. And obvious (now) fixup for do_powersaver. Use
cx->address only for ACPI C3 ("PowerSaver" processor using
PM2 support).
Signed-off-by: Rafa¿ Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>
We use the fixmap for accessing pci config space in pci_mmcfg_read/write().
The problem is in pci_exp_set_dev_base(). It is caching a last
accessed address to avoid calling set_fixmap_nocache() whenever
pci_mmcfg_read/write() is used.
static inline void pci_exp_set_dev_base(int bus, int devfn)
{
u32 dev_base = base | (bus << 20) | (devfn << 12);
if (dev_base != mmcfg_last_accessed_device) {
mmcfg_last_accessed_device = dev_base;
set_fixmap_nocache(FIX_PCIE_MCFG, dev_base);
}
}
cpu0 cpu1
---------------------------------------------------------------------------
pci_mmcfg_read("device-A")
pci_exp_set_dev_base()
set_fixmap_nocache()
pci_mmcfg_read("device-B")
pci_exp_set_dev_base()
set_fixmap_nocache()
pci_mmcfg_read("device-B")
pci_exp_set_dev_base()
/* doesn't flush tlb */
But if cpus accessed the above order, the second pci_mmcfg_read() on
cpu0 doesn't flush the TLB, because "mmcfg_last_accessed_device" is
device-B. So, second pci_mmcfg_read() on cpu0 accesses a device-A via
a previous TLB cache. This problem became the cause of several strange
behavior.
This patches fixes this situation by adds "mmcfg_last_accessed_cpu" check.
[ Alternatively, we could make a per-cpu mapping area or something. Not
that it's probably worth it, but if we wanted to avoid all locking and
instead just disable preemption, that would be the way to go. --Linus ]
Signed-off-by: OGAWA Hirofumi <hogawa@miraclelinux.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A space and a bracket are missing (and indentation is wrong).
Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org>
Signed-off-by: Dave Jones <davej@redhat.com>
Fixes the oops in cpufreq_stats with acpi_cpufreq driver. The issue was
that the frequency was reported as 0 in acpi-cpufreq.c. The bug is due to
different indicies for freq_table and ACPI perf table.
Also adds a check in cpufreq_stats to check for error return from
freq_table_get_index() and avoid using the error return value.
Patch fixes the issue reported at
http://www.ussg.iu.edu/hypermail/linux/kernel/0611.2/0629.html
and also other similar issue here
http://bugme.osdl.org/show_bug.cgi?id=7383 comment 53
Signed-off-by: Dhaval Giani <dhaval.giani@gmail.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>
Fernando Lopez-Lezcano reported frequent scheduling latencies and audio
xruns starting at the 2.6.18-rt kernel, and those problems persisted all
until current -rt kernels. The latencies were serious and unjustified by
system load, often in the milliseconds range.
After a patient and heroic multi-month effort of Fernando, where he
tested dozens of kernels, tried various configs, boot options,
test-patches of mine and provided latency traces of those incidents, the
following 'smoking gun' trace was captured by him:
_------=> CPU#
/ _-----=> irqs-off
| / _----=> need-resched
|| / _---=> hardirq/softirq
||| / _--=> preempt-depth
|||| /
||||| delay
cmd pid ||||| time | caller
\ / ||||| \ | /
IRQ_19-1479 1D..1 0us : __trace_start_sched_wakeup (try_to_wake_up)
IRQ_19-1479 1D..1 0us : __trace_start_sched_wakeup <<...>-5856> (37 0)
IRQ_19-1479 1D..1 0us : __trace_start_sched_wakeup (c01262ba 0 0)
IRQ_19-1479 1D..1 0us : resched_task (try_to_wake_up)
IRQ_19-1479 1D..1 0us : __spin_unlock_irqrestore (try_to_wake_up)
...
<idle>-0 1...1 11us!: default_idle (cpu_idle)
...
<idle>-0 0Dn.1 602us : smp_apic_timer_interrupt (c0103baf 1 0)
...
<...>-5856 0D..2 618us : __switch_to (__schedule)
<...>-5856 0D..2 618us : __schedule <<idle>-0> (20 162)
<...>-5856 0D..2 619us : __spin_unlock_irq (__schedule)
<...>-5856 0...1 619us : trace_stop_sched_switched (__schedule)
<...>-5856 0D..1 619us : trace_stop_sched_switched <<...>-5856> (37 0)
what is visible in this trace is that CPU#1 ran try_to_wake_up() for
PID:5856, it placed PID:5856 on CPU#0's runqueue and ran resched_task()
for CPU#0. But it decided to not send an IPI that no CPU - due to
TS_POLLING. But CPU#0 never woke up after its NEED_RESCHED bit was set,
and only rescheduled to PID:5856 upon the next lapic timer IRQ. The
result was a 600+ usecs latency and a missed wakeup!
the bug turned out to be an idle-wakeup bug introduced into the mainline
kernel this summer via an optimization in the x86_64 tree:
commit 495ab9c045
Author: Andi Kleen <ak@suse.de>
Date: Mon Jun 26 13:59:11 2006 +0200
[PATCH] i386/x86-64/ia64: Move polling flag into thread_info_status
During some profiling I noticed that default_idle causes a lot of
memory traffic. I think that is caused by the atomic operations
to clear/set the polling flag in thread_info. There is actually
no reason to make this atomic - only the idle thread does it
to itself, other CPUs only read it. So I moved it into ti->status.
the problem is this type of change:
if (!hlt_counter && boot_cpu_data.hlt_works_ok) {
- clear_thread_flag(TIF_POLLING_NRFLAG);
+ current_thread_info()->status &= ~TS_POLLING;
smp_mb__after_clear_bit();
while (!need_resched()) {
local_irq_disable();
this changes clear_thread_flag() to an explicit clearing of TS_POLLING.
clear_thread_flag() is defined as:
clear_bit(flag, &ti->flags);
and clear_bit() is a LOCK-ed atomic instruction on all x86 platforms:
static inline void clear_bit(int nr, volatile unsigned long * addr)
{
__asm__ __volatile__( LOCK_PREFIX
"btrl %1,%0"
hence smp_mb__after_clear_bit() is defined as a simple compile barrier:
#define smp_mb__after_clear_bit() barrier()
but the explicit TS_POLLING clearing introduced by the patch:
+ current_thread_info()->status &= ~TS_POLLING;
is not an atomic op! So the clearing of the TS_POLLING bit is freely
reorderable with the reading of the NEED_RESCHED bit - and both now
reside in different memory addresses.
CPU idle wakeup very much depends on ordered memory ops, the clearing of
the TS_POLLING flag must always be done before we test need_resched()
and hit the idle instruction(s). [Symmetrically, the wakeup code needs
to set NEED_RESCHED before it tests the TS_POLLING flag, so memory
ordering is paramount.]
Fernando's dual-core Athlon64 system has a sufficiently advanced memory
ordering model so that it triggered this scenario very often.
( And it also turned out that the reason why these latencies never
triggered on my testsystems is that i routinely use idle=poll, which
was the only idle variant not affected by this bug. )
The fix is to change the smp_mb__after_clear_bit() to an smp_mb(), to
act as an absolute barrier between the TS_POLLING write and the
NEED_RESCHED read. This affects almost all idling methods (default,
ACPI, APM), on all 3 x86 architectures: i386, x86_64, ia64.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The PDA patches introduced a bug in ptrace: it reads eflags from the wrong
place on the target's stack, but writes it back to the correct place. The
result is a corrupted eflags, which is most visible when it turns interrupts
off unexpectedly.
This patch fixes this by making the ptrace code a little less fragile. It
changes [gs]et_stack_long to take a straightforward byte offset into struct
pt_regs, rather than requiring all callers to do a sizeof(struct pt_regs)
offset adjustment. This means that the eflag's offset (EFL_OFFSET) on the
target stack can be simply computed with offsetof().
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Frederik Deweerdt <deweerdt@free.fr>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix compile error when config memory hotplug with numa on i386.
The cause of compile error was missing of arch_add_memory(),
remove_memory(), and memory_add_physaddr_to_nid().
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@cs.washington.edu>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
register_memory() becomes double definition in 2.6.20-rc1. It is defined
in arch/i386/kernel/setup.c as static definition in 2.6.19. But it is
moved to arch/i386/kernel/e820.c in 2.6.20-rc1. And same name function is
defined in driver/base/memory.c too. So, it becomes cause of compile error
of duplicate definition if memory hotplug option is on.
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch is designed to fix:
- Disk eating corruptor on KT7 after resume from RAM
- VIA IRQ handling
- VIA fixups for bus lockups after resume from RAM
The core of this is to add a table of resume fixups run at resume time.
We need to do this for a variety of boards and features, but particularly
we need to do this to get various critical VIA fixups done on resume.
The second part of the problem is to handle VIA IRQ number rules which
are a bit odd and need special handling for PIC interrupts. Various
patches broke various boxes and while this one may not be perfect
(hopefully it is) it ensures the workaround is applied to the right
devices only.
From: Jean Delvare <khali@linux-fr.org>
Now that PCI quirks are replayed on software resume, we can safely
re-enable the Asus SMBus unhiding quirk even when software suspend support
is enabled.
[akpm@osdl.org: fix const warning]
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Check the correct variable and set policy->cur upon acpi-cpufreq
initialization to allow the userspace governor to be used as default.
Signed-off-by: Mattia Dongili <malattia@linux.it>
Acked-by: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>
Alexey Starikovskiy