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This patch fixes a long-standing performance bug in classic RCU that
results in massive internal-to-RCU lock contention on systems with
more than a few hundred CPUs. Although this patch creates a separate
flavor of RCU for ease of review and patch maintenance, it is intended
to replace classic RCU.
This patch still handles stress better than does mainline, so I am still
calling it ready for inclusion. This patch is against the -tip tree.
Nevertheless, experience on an actual 1000+ CPU machine would still be
most welcome.
Most of the changes noted below were found while creating an rcutiny
(which should permit ejecting the current rcuclassic) and while doing
detailed line-by-line documentation.
Updates from v9 (http://lkml.org/lkml/2008/12/2/334):
o Fixes from remainder of line-by-line code walkthrough,
including comment spelling, initialization, undesirable
narrowing due to type conversion, removing redundant memory
barriers, removing redundant local-variable initialization,
and removing redundant local variables.
I do not believe that any of these fixes address the CPU-hotplug
issues that Andi Kleen was seeing, but please do give it a whirl
in case the machine is smarter than I am.
A writeup from the walkthrough may be found at the following
URL, in case you are suffering from terminal insomnia or
masochism:
http://www.kernel.org/pub/linux/kernel/people/paulmck/tmp/rcutree-walkthrough.2008.12.16a.pdf
o Made rcutree tracing use seq_file, as suggested some time
ago by Lai Jiangshan.
o Added a .csv variant of the rcudata debugfs trace file, to allow
people having thousands of CPUs to drop the data into
a spreadsheet. Tested with oocalc and gnumeric. Updated
documentation to suit.
Updates from v8 (http://lkml.org/lkml/2008/11/15/139):
o Fix a theoretical race between grace-period initialization and
force_quiescent_state() that could occur if more than three
jiffies were required to carry out the grace-period
initialization. Which it might, if you had enough CPUs.
o Apply Ingo's printk-standardization patch.
o Substitute local variables for repeated accesses to global
variables.
o Fix comment misspellings and redundant (but harmless) increments
of ->n_rcu_pending (this latter after having explicitly added it).
o Apply checkpatch fixes.
Updates from v7 (http://lkml.org/lkml/2008/10/10/291):
o Fixed a number of problems noted by Gautham Shenoy, including
the cpu-stall-detection bug that he was having difficulty
convincing me was real. ;-)
o Changed cpu-stall detection to wait for ten seconds rather than
three in order to reduce false positive, as suggested by Ingo
Molnar.
o Produced a design document (http://lwn.net/Articles/305782/).
The act of writing this document uncovered a number of both
theoretical and "here and now" bugs as noted below.
o Fix dynticks_nesting accounting confusion, simplify WARN_ON()
condition, fix kerneldoc comments, and add memory barriers
in dynticks interface functions.
o Add more data to tracing.
o Remove unused "rcu_barrier" field from rcu_data structure.
o Count calls to rcu_pending() from scheduling-clock interrupt
to use as a surrogate timebase should jiffies stop counting.
o Fix a theoretical race between force_quiescent_state() and
grace-period initialization. Yes, initialization does have to
go on for some jiffies for this race to occur, but given enough
CPUs...
Updates from v6 (http://lkml.org/lkml/2008/9/23/448):
o Fix a number of checkpatch.pl complaints.
o Apply review comments from Ingo Molnar and Lai Jiangshan
on the stall-detection code.
o Fix several bugs in !CONFIG_SMP builds.
o Fix a misspelled config-parameter name so that RCU now announces
at boot time if stall detection is configured.
o Run tests on numerous combinations of configurations parameters,
which after the fixes above, now build and run correctly.
Updates from v5 (http://lkml.org/lkml/2008/9/15/92, bad subject line):
o Fix a compiler error in the !CONFIG_FANOUT_EXACT case (blew a
changeset some time ago, and finally got around to retesting
this option).
o Fix some tracing bugs in rcupreempt that caused incorrect
totals to be printed.
o I now test with a more brutal random-selection online/offline
script (attached). Probably more brutal than it needs to be
on the people reading it as well, but so it goes.
o A number of optimizations and usability improvements:
o Make rcu_pending() ignore the grace-period timeout when
there is no grace period in progress.
o Make force_quiescent_state() avoid going for a global
lock in the case where there is no grace period in
progress.
o Rearrange struct fields to improve struct layout.
o Make call_rcu() initiate a grace period if RCU was
idle, rather than waiting for the next scheduling
clock interrupt.
o Invoke rcu_irq_enter() and rcu_irq_exit() only when
idle, as suggested by Andi Kleen. I still don't
completely trust this change, and might back it out.
o Make CONFIG_RCU_TRACE be the single config variable
manipulated for all forms of RCU, instead of the prior
confusion.
o Document tracing files and formats for both rcupreempt
and rcutree.
Updates from v4 for those missing v5 given its bad subject line:
o Separated dynticks interface so that NMIs and irqs call separate
functions, greatly simplifying it. In particular, this code
no longer requires a proof of correctness. ;-)
o Separated dynticks state out into its own per-CPU structure,
avoiding the duplicated accounting.
o The case where a dynticks-idle CPU runs an irq handler that
invokes call_rcu() is now correctly handled, forcing that CPU
out of dynticks-idle mode.
o Review comments have been applied (thank you all!!!).
For but one example, fixed the dynticks-ordering issue that
Manfred pointed out, saving me much debugging. ;-)
o Adjusted rcuclassic and rcupreempt to handle dynticks changes.
Attached is an updated patch to Classic RCU that applies a hierarchy,
greatly reducing the contention on the top-level lock for large machines.
This passes 10-hour concurrent rcutorture and online-offline testing on
128-CPU ppc64 without dynticks enabled, and exposes some timekeeping
bugs in presence of dynticks (exciting working on a system where
"sleep 1" hangs until interrupted...), which were fixed in the
2.6.27 kernel. It is getting more reliable than mainline by some
measures, so the next version will be against -tip for inclusion.
See also Manfred Spraul's recent patches (or his earlier work from
2004 at http://marc.info/?l=linux-kernel&m=108546384711797&w=2).
We will converge onto a common patch in the fullness of time, but are
currently exploring different regions of the design space. That said,
I have already gratefully stolen quite a few of Manfred's ideas.
This patch provides CONFIG_RCU_FANOUT, which controls the bushiness
of the RCU hierarchy. Defaults to 32 on 32-bit machines and 64 on
64-bit machines. If CONFIG_NR_CPUS is less than CONFIG_RCU_FANOUT,
there is no hierarchy. By default, the RCU initialization code will
adjust CONFIG_RCU_FANOUT to balance the hierarchy, so strongly NUMA
architectures may choose to set CONFIG_RCU_FANOUT_EXACT to disable
this balancing, allowing the hierarchy to be exactly aligned to the
underlying hardware. Up to two levels of hierarchy are permitted
(in addition to the root node), allowing up to 16,384 CPUs on 32-bit
systems and up to 262,144 CPUs on 64-bit systems. I just know that I
am going to regret saying this, but this seems more than sufficient
for the foreseeable future. (Some architectures might wish to set
CONFIG_RCU_FANOUT=4, which would limit such architectures to 64 CPUs.
If this becomes a real problem, additional levels can be added, but I
doubt that it will make a significant difference on real hardware.)
In the common case, a given CPU will manipulate its private rcu_data
structure and the rcu_node structure that it shares with its immediate
neighbors. This can reduce both lock and memory contention by multiple
orders of magnitude, which should eliminate the need for the strange
manipulations that are reported to be required when running Linux on
very large systems.
Some shortcomings:
o More bugs will probably surface as a result of an ongoing
line-by-line code inspection.
Patches will be provided as required.
o There are probably hangs, rcutorture failures, &c. Seems
quite stable on a 128-CPU machine, but that is kind of small
compared to 4096 CPUs. However, seems to do better than
mainline.
Patches will be provided as required.
o The memory footprint of this version is several KB larger
than rcuclassic.
A separate UP-only rcutiny patch will be provided, which will
reduce the memory footprint significantly, even compared
to the old rcuclassic. One such patch passes light testing,
and has a memory footprint smaller even than rcuclassic.
Initial reaction from various embedded guys was "it is not
worth it", so am putting it aside.
Credits:
o Manfred Spraul for ideas, review comments, and bugs spotted,
as well as some good friendly competition. ;-)
o Josh Triplett, Ingo Molnar, Peter Zijlstra, Mathieu Desnoyers,
Lai Jiangshan, Andi Kleen, Andy Whitcroft, and Andrew Morton
for reviews and comments.
o Thomas Gleixner for much-needed help with some timer issues
(see patches below).
o Jon M. Tollefson, Tim Pepper, Andrew Theurer, Jose R. Santos,
Andy Whitcroft, Darrick Wong, Nishanth Aravamudan, Anton
Blanchard, Dave Kleikamp, and Nathan Lynch for keeping machines
alive despite my heavy abuse^Wtesting.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Commit d015fe995 'powerpc/cell/axon-msi: Retry on missing interrupt'
has turned a rare failure to kexec on QS22 into a reproducible
error, which we have now analysed.
The problem is that after a kexec, the MSIC hardware still points
into the middle of the old ring buffer. We set up the ring buffer
during reboot, but not the offset into it. On older kernels, this
would cause a storm of thousands of spurious interrupts after a
kexec, which would most of the time get dropped silently.
With the new code, we time out on each interrupt, waiting for
it to become valid. If more interrupts come in that we time
out on, this goes on indefinitely, which eventually leads to
a hard crash.
The solution in this commit is to read the current offset from
the MSIC when reinitializing it. This now works correctly, as
expected.
Reported-by: Dirk Herrendoerfer <d.herrendoerfer@de.ibm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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An earlier patch from Jens Osterkamp attempted to fix GDB
watchpoints by enabling the DABRX register at boot time.
Unfortunately, this did not work on SMP setups, where
secondary CPUs were still using the power-on DABRX value.
This introduces the same change for secondary CPUs on cell
as well.
Reported-by: Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
Tested-by: Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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The MSI capture logic for the axon bridge can sometimes
lose interrupts in case of high DMA and interrupt load,
when it signals an MSI interrupt to the MPIC interrupt
controller while we are already handling another MSI.
Each MSI vector gets written into a FIFO buffer in main
memory using DMA, and that DMA access is normally flushed
by the actual interrupt packet on the IOIF. An MMIO
register in the MSIC holds the position of the last
entry in the FIFO buffer that was written. However,
reading that position does not flush the DMA, so that
we can observe stale data in the buffer.
In a stress test, we have observed the DMA to arrive
up to 14 microseconds after reading the register.
This patch works around this problem by retrying the
access to the FIFO buffer.
We can reliably detect the conditioning by writing
an invalid MSI vector into the FIFO buffer after
reading from it, assuming that all MSIs we get
are valid. After detecting an invalid MSI vector,
we udelay(1) in the interrupt cascade for up to
100 times before giving up.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jk/spufs into merge
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Currently, we can end up in an infinite loop if we get a signal
while the kernel has faulted in spufs_ps_fault. Eg:
alarm(1);
write(fd, some_spu_psmap_register_address, 4);
- the write's copy_from_user will fault on the ps mapping, and
signal_pending will be non-zero. Because returning from the fault
handler will never clear TIF_SIGPENDING, so we'll just keep faulting,
resulting in an unkillable process using 100% of CPU.
This change returns VM_FAULT_SIGBUS if there's a fatal signal pending,
letting us escape the loop.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
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This gets rid of this build warning:
arch/powerpc/platforms/pseries/pci_dlpar.c: In function 'init_phb_dynamic':
arch/powerpc/platforms/pseries/pci_dlpar.c:192: warning: unused variable 'b'
This is one of the very few warnings left in a ppc64_defconfig build and
getting rid of it will make it easier to see future introduced ones (in
fact this was introduced very recently).
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This fixes this error on Cell when CONFIG_KEXEC = n:
arch/powerpc/platforms/cell/ras.c:299: error: implicit declaration of function 'crash_shutdown_register'
We have to include <asm/kexec.h> because it contains the dummy
definition of crash_shutdown_register that is used when
CONFIG_KEXEC=n, but <linux/kexec.h> doesn't include <asm/kexec.h> in
that case.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: (23 commits)
Revert "powerpc: Sync RPA note in zImage with kernel's RPA note"
powerpc: Fix compile errors with CONFIG_BUG=n
powerpc: Fix format string warning in arch/powerpc/boot/main.c
powerpc: Fix bug in kernel copy of libfdt's fdt_subnode_offset_namelen()
powerpc: Remove duplicate DMA entry from mpc8313erdb device tree
powerpc/cell/OProfile: Fix on-stack array size in activate spu profiling function
powerpc/mpic: Fix regression caused by change of default IRQ affinity
powerpc: Update remaining dma_mapping_ops to use map/unmap_page
powerpc/pci: Fix unmapping of IO space on 64-bit
powerpc/pci: Properly allocate bus resources for hotplug PHBs
OF-device: Don't overwrite numa_node in device registration
powerpc: Fix swapcontext system for VSX + old ucontext size
powerpc: Fix compiler warning for the relocatable kernel
powerpc: Work around ld bug in older binutils
powerpc/ppc64/kdump: Better flag for running relocatable
powerpc: Use is_kdump_kernel()
powerpc: Kexec exit should not use magic numbers
powerpc/44x: Update 44x defconfigs
powerpc/40x: Update 40x defconfigs
powerpc: enable heap randomization for linkstations
...
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The Freescale implementation of MPIC only allows a single CPU destination
for non-IPI interrupts. We add a flag to the mpic_init to distinquish
these variants of MPIC. We pull in the irq_choose_cpu from sparc64 to
select a single CPU as the destination of the interrupt.
This is to deal with the fact that the default smp affinity was
changed by commit 18404756765c713a0be4eb1082920c04822ce588 ("genirq:
Expose default irq affinity mask (take 3)") to be all CPUs.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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After the merge of the 32 and 64bit DMA code, dma_direct_ops lost
their map/unmap_single() functions but gained map/unmap_page(). This
caused a problem for Cell because Cell's dma_iommu_fixed_ops called
the dma_direct_ops if the fixed linear mapping was to be used or the
iommu ops if the dynamic window was to be used. So in order to fix
this problem we need to update the 64bit DMA code to use
map/unmap_page.
First, we update the generic IOMMU code so that iommu_map_single()
becomes iommu_map_page() and iommu_unmap_single() becomes
iommu_unmap_page(). Then we propagate these changes up through all
the callers of these two functions and in the process update all the
dma_mapping_ops so that they have map/unmap_page rahter than
map/unmap_single. We can do this because on 64bit there is no HIGHMEM
memory so map/unmap_page ends up performing exactly the same function
as map/unmap_single, just taking different arguments.
This has no affect on drivers because the dma_map_single_attrs() just
ends up calling the map_page() function of the appropriate
dma_mapping_ops and similarly the dma_unmap_single_attrs() calls
unmap_page().
This fixes an oops on Cell blades, which oops on boot without this
because they call dma_direct_ops.map_single, which is NULL.
Signed-off-by: Mark Nelson <markn@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Resources for PHB's that are dynamically added to a system are not
properly allocated in the resource tree.
Not having these resources allocated causes an oops when removing
the PHB when we try to release them.
The diff appears a bit messy, this is mainly due to moving everything
one tab to the left in the pcibios_allocate_bus_resources routine.
The functionality change in this routine is only that the
list_for_each_entry() loop is pulled out and moved to the necessary
calling routine.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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linux/crash_dump.h defines is_kdump_kernel() to be used by code that
needs to know if the previous kernel crashed instead of a (clean) boot
or reboot.
This updates the just added powerpc code to use it. This is needed
for the next commit, which will remove __kdump_flag.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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master.kernel.org:/pub/scm/linux/kernel/git/jwboyer/powerpc-4xx into merge
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The i2c bus defn is broken on linkstation / kurobox machines since at
least 2.6.27. Fix it. Also remove CONFIG_SERIAL_OF_PLATFORM, which, if
enabled, breaks the serial console after the
"console handover: boot [udbg0] -> real [ttyS1]" message.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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Fix the HCU4 Kconfig option to 'default n'. We don't want the
board to always be enabled for other board defconfigs.
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (46 commits)
[PATCH] fs: add a sanity check in d_free
[PATCH] i_version: remount support
[patch] vfs: make security_inode_setattr() calling consistent
[patch 1/3] FS_MBCACHE: don't needlessly make it built-in
[PATCH] move executable checking into ->permission()
[PATCH] fs/dcache.c: update comment of d_validate()
[RFC PATCH] touch_mnt_namespace when the mount flags change
[PATCH] reiserfs: add missing llseek method
[PATCH] fix ->llseek for more directories
[PATCH vfs-2.6 6/6] vfs: add LOOKUP_RENAME_TARGET intent
[PATCH vfs-2.6 5/6] vfs: remove LOOKUP_PARENT from non LOOKUP_PARENT lookup
[PATCH vfs-2.6 4/6] vfs: remove unnecessary fsnotify_d_instantiate()
[PATCH vfs-2.6 3/6] vfs: add __d_instantiate() helper
[PATCH vfs-2.6 2/6] vfs: add d_ancestor()
[PATCH vfs-2.6 1/6] vfs: replace parent == dentry->d_parent by IS_ROOT()
[PATCH] get rid of on-stack dentry in udf
[PATCH 2/2] anondev: switch to IDA
[PATCH 1/2] anondev: init IDR statically
[JFFS2] Use d_splice_alias() not d_add() in jffs2_lookup()
[PATCH] Optimise NFS readdir hack slightly.
...
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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This adds relocatable kernel support for kdump. With this one can
use the same regular kernel to capture the kdump. A signature (0xfeed1234)
is passed in r6 from panic code to the next kernel through kexec_sequence
and purgatory code. The signature is used to differentiate between
kdump kernel and non-kdump kernels.
The purgatory code compares the signature and sets the __kdump_flag in
head_64.S. During the boot up, kernel code checks __kdump_flag and if it
is set, the kernel will behave as relocatable kdump kernel. This kernel
will boot at the address where it was loaded by kexec-tools ie. at the
address reserved through crashkernel boot parameter.
CONFIG_CRASH_DUMP depends on CONFIG_RELOCATABLE option to build kdump
kernel as relocatable. So the same kernel can be used as production and
kdump kernel.
This patch incorporates the changes suggested by Paul Mackerras to avoid
GOT use and to avoid two copies of the code.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Mohan Kumar M <mohan@in.ibm.com>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Most of the platforms were printing the size of the memory
in their show_cpuinfo implementations. This moves that to
the common show_cpuinfo, so that all 32-bit platforms will
now print the size of memory. I also update the code
to deal with the fact that total_memory is now a phys_addr_t.
Signed-off-by: Becky Bruce <becky.bruce@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Manual merge of:
arch/powerpc/Kconfig
arch/powerpc/include/asm/page.h
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We used to assume that even numbered threads were the primary
threads, ie those that would be listed and started as a cpu from
open firmware. Replace a left over is even (% 2) check with a check
for it being a primary thread and update the comments.
Tested with a debug print on pseries, identical code found for cell.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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The pfn of the memory to be removed should be validated prior to
attempting to remove the memory. In cases where the probe of a
memory section fails during hotplug add, the pfn for the lmb may
not be valid.
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This patch adds a comment to clarify why atomic_dec_if_positive is being used
to decrement gang's aff_sched_count on SPU context unbind.
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
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This patch improves redability of the code responsible for trying to find
a node with enough SPUs not committed to other affinity gangs.
An additional check is also added, to avoid taking into account gangs that
have no SPU affinity.
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
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No need to zero the entire buffer, just the head and tail indices.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
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With most file readers (eg cat, dd), reading a context's regs file will
result in two reads: the first to read the data, and the second to
return EOF. Because each read performs a spu_acquire_saved, we end up
descheduling and re-scheduling the context twice.
This change does a simple check to see if we'd return EOF before
calling spu_acquire_saved(), saving the extra schedule operation.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
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Currently, read() on the sputrace log will block until the read buffer
is full. This makes it difficult to retrieve the end of the buffer, as
the user will need to read with the right-sized buffer.
In a similar method as 91553a1b5e0df006a3573a88d98ee7cd48a3818a, this
change makes the switch_log return if there has already been data
read.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
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openers
Currently, we use ctx->mapping_lock and ctx->switch_log->lock for the
context switch log. The mapping lock only prevents concurrent open()s,
so we require the switch_lock->lock for reads.
Since writes to the switch log buffer occur on context switches, we're
better off synchronising with the state_mutex, which is held during a
switch. Since we're serialised througout the buffer reads and writes,
we can use the state mutex to protect open and release too, and
can now kfree() the log buffer on release. This allows us to perform
the switch log notify without taking any extra locks.
Because the buffer is only present while the file is open, we can use
it to prevent multiple simultaneous openers.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
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Currently, read() on the sputrace buffer will only return data when
the user buffer is exhausted. This may mean that we never see the
end of the event log, unless we read() with exactly the right-sized
buffer.
This change makes sputrace_read not block if we have data ready to
return.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
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Currently, sputrace will start logging to the event buffer before the
log buffer has been open()ed. This results in a heap of "lost samples"
warnings if the sputrace file hasn't yet been opened.
Since the buffer is reset on open() anyway, there's no need to enable
logging when no-one has opened the log.
Because open clears the log, make it return EBUSY for mutliple open
calls.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (131 commits)
tracing/fastboot: improve help text
tracing/stacktrace: improve help text
tracing/fastboot: fix initcalls disposition in bootgraph.pl
tracing/fastboot: fix bootgraph.pl initcall name regexp
tracing/fastboot: fix issues and improve output of bootgraph.pl
tracepoints: synchronize unregister static inline
tracepoints: tracepoint_synchronize_unregister()
ftrace: make ftrace_test_p6nop disassembler-friendly
markers: fix synchronize marker unregister static inline
tracing/fastboot: add better resolution to initcall debug/tracing
trace: add build-time check to avoid overrunning hex buffer
ftrace: fix hex output mode of ftrace
tracing/fastboot: fix initcalls disposition in bootgraph.pl
tracing/fastboot: fix printk format typo in boot tracer
ftrace: return an error when setting a nonexistent tracer
ftrace: make some tracers reentrant
ring-buffer: make reentrant
ring-buffer: move page indexes into page headers
tracing/fastboot: only trace non-module initcalls
ftrace: move pc counter in irqtrace
...
Manually fix conflicts:
- init/main.c: initcall tracing
- kernel/module.c: verbose level vs tracepoints
- scripts/bootgraph.pl: fallout from cherry-picking commits.
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Due to confusion between the ftrace infrastructure and the gcc profiling
tracer "ftrace", this patch renames the config options from FTRACE to
FUNCTION_TRACER. The other two names that are offspring from FTRACE
DYNAMIC_FTRACE and FTRACE_MCOUNT_RECORD will stay the same.
This patch was generated mostly by script, and partially by hand.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Conflicts:
init/main.c
kernel/module.c
scripts/bootgraph.pl
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This patch adds support for the GPIO functions of PPC40x and PPC44x
SOCs.
Signed-off-by: Steve Falco <sfalco@harris.com>
Acked-by: Stefan Roese <sr@denx.de>
Acked-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
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Adds support for a HCU4 PPC405GPr based board from Netstal Maschinen AG.
Signed-off-by: Niklaus Giger <niklaus.giger@member.fsf.org>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
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This adds a common board file for almost all of the "simple" PowerPC 40x
boards that exist today. This is intended to be a single place to add
support for boards that do not differ in platform support from most of the
evaluation boards that are used as reference platforms. Boards that have
specific requirements or custom hardware setup should still have their own
board.c file.
The first board ported to this is the AMCC PowerPC 405EZ Acadia board.
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
do_generic_file_read: s/EINTR/EIO/ if lock_page_killable() fails
softirq, warning fix: correct a format to avoid a warning
softirqs, debug: preemption check
x86, pci-hotplug, calgary / rio: fix EBDA ioremap()
IO resources, x86: ioremap sanity check to catch mapping requests exceeding, fix
IO resources, x86: ioremap sanity check to catch mapping requests exceeding the BAR sizes
softlockup: Documentation/sysctl/kernel.txt: fix softlockup_thresh description
dmi scan: warn about too early calls to dmi_check_system()
generic: redefine resource_size_t as phys_addr_t
generic: make PFN_PHYS explicitly return phys_addr_t
generic: add phys_addr_t for holding physical addresses
softirq: allocate less vectors
IO resources: fix/remove printk
printk: robustify printk, update comment
printk: robustify printk, fix #2
printk: robustify printk, fix
printk: robustify printk
Fixed up conflicts in:
arch/powerpc/include/asm/types.h
arch/powerpc/platforms/Kconfig.cputype
manually.
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MPC5200 needs to have pipelining disabled for ATA to work. MPC5200B does not.
So, for the latter, don't touch the original setting from the bootloader.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
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'core/printk' and 'core/misc' into core-v28-for-linus
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Manual fixup of conflicts on:
arch/powerpc/include/asm/dcr-regs.h
drivers/net/ibm_newemac/core.h
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Recently, indirect_pci was changed to test if the bus number requested
is the one hanging straight off the PHB, then it substitutes the bus
number with another one contained in a new "self_busno" field of the
pci_controller structure.
However, this breaks CHRP which didn't initialize this new field, and
which relies on having the right bus number passed to the hardware.
This fixes it by initializing this variable properly for all CHRP bridges
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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The detection of the IBM "Python" PCI host bridge on IBM CHRP
machines such as old RS6000 was broken when we changed
of_device_is_compatible() from strncasecmp to strcasecmp (dropped
the "n" variant) due to the way IBM encodes the chip version.
We fix that by instead doing a match on the model property like
we do for others bridges in that file. It should be good enough
for those machines. If yours is still broken, let me know.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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We need a marker_synchronize_unregister() before the end of exit() to make sure
every probe callers have exited the non preemptible section and thus are not
executing the probe code anymore.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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This is a much better version of a previous patch to make the parser
tables constant. Rather than changing the typedef, we put the "const" in
all the various places where its required, allowing the __initconst
exception for nfsroot which was the cause of the previous trouble.
This was posted for review some time ago and I believe its been in -mm
since then.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Alexander Viro <aviro@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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