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This patch adds lpspi driver to support new i.MX products which use
lpspi instead of ecspi.
The lpspi can continue operating in stop mode when an appropriate
clock is available. It is also designed for low CPU overhead with
DMA offloading of FIFO register accesses.
Signed-off-by: Gao Pan <pandy.gao@nxp.com>
Reviewed-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Right now we switch the host fprs/vrs in kvm_arch_vcpu_load and switch
back in kvm_arch_vcpu_put. This process is already optimized
since commit 9977e886cbbc7 ("s390/kernel: lazy restore fpu registers")
avoiding double save/restores on schedule. We still reload the pointers
and test the guest fpc on each context switch, though.
We can minimize the cost of vcpu_load/put by doing the test in the
VCPU_RUN ioctl itself. As most VCPU threads almost never exit to
userspace in the common fast path, this allows to avoid this overhead
for the common case (eventfd driven I/O, all exits including sleep
handled in the kernel) - making kvm_arch_vcpu_load/put basically
disappear in perf top.
Also adapt the fpu get/set ioctls.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
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Right now we save the host access registers in kvm_arch_vcpu_load
and load them in kvm_arch_vcpu_put. Vice versa for the guest access
registers. On schedule this means, that we load/save access registers
multiple times.
e.g. VCPU_RUN with just one reschedule and then return does
[from user space via VCPU_RUN]
- save the host registers in kvm_arch_vcpu_load (via ioctl)
- load the guest registers in kvm_arch_vcpu_load (via ioctl)
- do guest stuff
- decide to schedule/sleep
- save the guest registers in kvm_arch_vcpu_put (via sched)
- load the host registers in kvm_arch_vcpu_put (via sched)
- save the host registers in switch_to (via sched)
- schedule
- return
- load the host registers in switch_to (via sched)
- save the host registers in kvm_arch_vcpu_load (via sched)
- load the guest registers in kvm_arch_vcpu_load (via sched)
- do guest stuff
- decide to go to userspace
- save the guest registers in kvm_arch_vcpu_put (via ioctl)
- load the host registers in kvm_arch_vcpu_put (via ioctl)
[back to user space]
As the kernel does not use access registers, we can avoid
this reloading and simply piggy back on switch_to (let it save
the guest values instead of host values in thread.acrs) by
moving the host/guest switch into the VCPU_RUN ioctl function.
We now do
[from user space via VCPU_RUN]
- save the host registers in kvm_arch_vcpu_ioctl_run
- load the guest registers in kvm_arch_vcpu_ioctl_run
- do guest stuff
- decide to schedule/sleep
- save the guest registers in switch_to
- schedule
- return
- load the guest registers in switch_to (via sched)
- do guest stuff
- decide to go to userspace
- save the guest registers in kvm_arch_vcpu_ioctl_run
- load the host registers in kvm_arch_vcpu_ioctl_run
This seems to save about 10% of the vcpu_put/load functions
according to perf.
As vcpu_load no longer switches the acrs, We can also loading
the acrs in kvm_arch_vcpu_ioctl_set_sregs.
Suggested-by: Fan Zhang <zhangfan@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
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All conflicts were simple overlapping changes except perhaps
for the Thunder driver.
That driver has a change_mtu method explicitly for sending
a message to the hardware. If that fails it returns an
error.
Normally a driver doesn't need an ndo_change_mtu method becuase those
are usually just range changes, which are now handled generically.
But since this extra operation is needed in the Thunder driver, it has
to stay.
However, if the message send fails we have to restore the original
MTU before the change because the entire call chain expects that if
an error is thrown by ndo_change_mtu then the MTU did not change.
Therefore code is added to nicvf_change_mtu to remember the original
MTU, and to restore it upon nicvf_update_hw_max_frs() failue.
Signed-off-by: David S. Miller <davem@davemloft.net>
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Change unimplemented msrs messages to use pr_debug.
If CONFIG_DYNAMIC_DEBUG is set, then these messages can be
enabled at run time or else -DDEBUG can be used at compile
time to enable them. These messages will still be printed if
ignore_msrs=1.
Signed-off-by: Bandan Das <bsd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Current DMA implementation was not handling the continuous selection
format viz. SPI chip select would be deasserted even between sequential
serial transfers.
Use existing dspi_data_to_pushr function to restructure the transmit
code path and set or reset the CONT bit on same lines as code path
in EOQ mode does. This correctly implements continuous selection format
while also correcting and cleaning up the transmit code path.
Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Currently dmaengine_prep_slave_single was being called with length
set to the complete DMA buffer size. This resulted in unwanted bytes
being transferred to the SPI register leading to clock and MOSI lines
having unwanted data even after chip select got deasserted and the
required bytes having been transferred.
While at it also clean up the use of curr_xfer_len which is central
to the DMA setup, from bytes to DMA transfers for every use.
Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Buffers allocated with a call to dma_alloc_coherent should be
freed with dma_free_coherent instead of the currently used
devm_kfree.
Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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A null dereference or Oops exception might occurs when reading at once the
whole content of an spi-nor of big enough size that requires an scatterlist
table that does not fit into one single page.
The spi_map_buf function is ignoring the chained sg case by dereferenceing
the scatterlist elements in an array fashion. This wrongly assumes that
the allocation of the scatterlist elements are contiguous. This is true as
long as the scatterlist table fits within a PAGE_SIZE. However, for
allocation where the scatter table is bigger than that, the pages allocated
by sg_alloc might not be contigous.
The sg table can be properly walked by sg_next instead of using an array.
Signed-off-by: Juan Gutierrez <juan.gutierrez@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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- Expose all invalidation types to the L1
- Reject invvpid instruction, if L1 passed zero vpid value to single
context invalidations
Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
Tested-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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- Remove VMX_EPT_EXTENT_INDIVIDUAL_ADDR, since there is no such type of
EPT invalidation
- Add missing VPID types names
Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
Tested-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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blkcg allocates some per-cgroup data structures with GFP_NOWAIT and
when that fails falls back to operations which aren't specific to the
cgroup. Occassional failures are expected under pressure and falling
back to non-cgroup operation is the right thing to do.
Unfortunately, I forgot to add __GFP_NOWARN to these allocations and
these expected failures end up creating a lot of noise. Add
__GFP_NOWARN.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Marc MERLIN <marc@merlins.org>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
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The check on bio->bi_vcnt doesn't make sense in erase_end_io().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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Also code gets simplified a bit.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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Also this patch simplify the code a bit.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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Always bio_add_page() is the standard and preferred way to
do the task.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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Instead we use standard iterator way to do that.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
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When the bio is full, bio_add_pc_page() will return zero,
so use this information tell when the bio is full.
Also replace access to .bi_vcnt for pr_debug() with bio_segments().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
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Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
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For a non-cloned bio, bio_add_page() only returns failure when
the io vec table is full, but in that case, bio->bi_vcnt can't
be zero at all.
So remove the impossible failure handling.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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Some drivers often use external bvec table, so introduce
this helper for this case. It is always safe to access the
bio->bi_io_vec in this way for this case.
After converting to this usage, it will becomes a bit easier
to evaluate the remaining direct access to bio->bi_io_vec,
so it can help to prepare for the following multipage bvec
support.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Fixed up the new O_DIRECT cases.
Signed-off-by: Jens Axboe <axboe@fb.com>
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We store the bits in the bdev sector size locally, but we don't use
the calculation anymore. All we do with it is shift it back up to
the bdev sector size. So let's just use that directly and kill the
variable and bits calculation.
Signed-off-by: Jens Axboe <axboe@fb.com>
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We now pass the device to the debug messages, but on non-x86,
this is an invalid pointer in vga_arb_device_init:
drivers/gpu/vga/vgaarb.c: In function 'vga_arb_device_init':
drivers/gpu/vga/vgaarb.c:1467:4: error: 'dev' may be used uninitialized in this function [-Werror=maybe-uninitialized]
This moves the initialization of the dev pointer outside of the
architecture #ifdef.
Fixes: a75d68f62106 ("vgaarb: Use dev_printk() when possible")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161122143445.1896558-1-arnd@arndb.de
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A direct I/O alignment must be always checked against the device blocks size,
but the I/O offset (bio->bi_iter.bi_sector must always use 512B sector unit, and
not the actual logical block size.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
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Both of these drivers won't work on 64-bit architectures unless they
are redesigned, since they store a virtual address pointer in a 32-bit
field of the descriptors:
drivers/net/ethernet/marvell/mvneta_bm.c: In function 'mvneta_bm_construct':
drivers/net/ethernet/marvell/mvneta_bm.c:103:16: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
drivers/net/ethernet/marvell/mvpp2.c: In function 'mvpp2_prs_vlan_init':
drivers/net/ethernet/marvell/mvpp2.c:2563:32: error: large integer implicitly truncated to unsigned type [-Werror=overflow]
This limits the COMPILE_TEST option for the two drivers again to
only build them on 32-bit. This seems nicer than shutting up the
warnings, in case we ever actually want to use them on 64-bit,
as the warnings indicate which parts of the driver are currently
broken there.
Fixes: a0627f776a45 ("net: marvell: Allow drivers to be built with COMPILE_TEST")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jiri Pirko says:
====================
mlxsw: core: Implement thermal zone
Implement thermal zone for mlxsw based HW.
The first patch is just a register dependency for the second patch.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Implement thermal zone for mlxsw based HW. It uses temperature sensor
provided by ASIC (the same as mlxsw hwmon interface) to report current
temp to thermal core. The ASIC's PWM is then used to control speed
of system fans registered as cooling devices.
Signed-off-by: Ivan Vecera <cera@cera.cz>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The MFSL register is used to configure the fan speed event / interrupt
notification mechanism. Fan speed threshold are defined for both
under-speed and over-speed.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Andrew Lunn says:
====================
Start adding support for mv88e6390
This is the first patchset implementing support for the mv88e6390
family. This is a new generation of switch devices and has numerous
incompatible changes to the registers. These patches allow the switch
to the detected during probe, and makes the statistics unit work.
These patches are insufficient to make the mv88e6390 functional. More
patches will follow.
v2:
Move stats code into global1
Change DT compatible string to mv88e6190
Fixed mv88e6351 stats which v1 had broken
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Move the stats functions which access global 1 registers into
global1.c.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The mv88e6390 uses a different bit to select between bank0 and bank1
of the statistics. So implement an ops function for this, and pass the
selector bit to the generic stats read function. Also, the histogram
selection has moved for the mv88e6390, so abstract its selection as
well.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Different families have different sets of statistics. Abstract this
using a stats_get_stats op. The mv88e6390 needs a different
implementation, which will be added later.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Different families have different sets of statistics. Abstract this
using a stats_get_sset_count and stats_get_strings op. Each stat has a
bitmap, and the ops implementer uses a bit map mask to count the
statistics which apply for the family, or return the list of strings.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
v2:
Rename functions to avoid _ prefix.
Signed-off-by: David S. Miller <davem@davemloft.net>
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The statistics unit on the mv88e6390 needs the histogram mode to be
configured in a different register compared to other devices. Add an
ops to do this.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
v2:
Rename to mv88e6390_g1_stats_set_histogram
Move into global1.c
Signed-off-by: David S. Miller <davem@davemloft.net>
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The MV88E6390 has a control register for what the histogram statistics
actually contain. This means the stat_snapshot method should not set
this information. So implement the 6390 stats_snapshot function without
these bits.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Knowing the family of device belongs to helps with picking the ops
implementation which is appropriate to the device. So add a comment to
each structure of ops.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Taking a stats snapshot differs between same families. Abstract this
into an ops member. At the same time, move the code into global1.[ch],
since the registers are in the global1 range.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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With the devices added to the tables, the probe will recognize the
switch. This however is not sufficient to make it work properly, other
changes are needed because of incompatibilities.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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_mv88e6xxx_stats_wait() did not check the return value from
mv88e6xxx_g1_read(), so the compiler complained about set but unused
err.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The switch needs to be taken out of reset before we can read its ID
register on the MDIO bus.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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While testing HDMI with Xorg on the Juno board, I find that when Xorg
starts up or shuts down, the display is shifted significantly to the
right and wrapped in the active region. (No sync bars are visible.)
The timings are correct, it behaves as if the start address has been
shifted many pixels _into_ the framebuffer.
This occurs whenever the display mode size is changed - using xrandr
in Xorg shows that changing the resolution triggers the problem
almost every time, but changing the refresh rate does not.
Using devmem2 to disable and re-enable the HDLCD resolves the issue,
and repeated disable/enable cycles do not make the issue re-appear.
Further debugging shows that we try to update the controller
configuration while enabled.
Alwys ensure that the HDLCD is disabled prior to updating the
controller timings, and use drm_crtc_vblank_off()/drm_crtc_vblank_on()
so that DRM knows whether it can expect vblank interrupts.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
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Reviews have found that sun5i was a better prefix after all for the GR8.
Rename the relevant device trees before it's too late.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
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From the Intel SDM, volume 3, section 10.4.3, "Enabling or Disabling the
Local APIC,"
When IA32_APIC_BASE[11] is 0, the processor is functionally equivalent
to an IA-32 processor without an on-chip APIC. The CPUID feature flag
for the APIC (see Section 10.4.2, "Presence of the Local APIC") is
also set to 0.
Signed-off-by: Jim Mattson <jmattson@google.com>
[Changed subject tag from nVMX to x86.]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd into linux-leds/for-next
Pull PM8XXX namespace cleanup from Lee Jones.
* tag 'ib-mfd-arm-leds-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd:
mfd: qcom-pm8xxx: Clean up PM8XXX namespace
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Avoid the pointless function call to pv_lock_ops.vcpu_is_preempted()
when a paravirt spinlock enabled kernel is ran on native hardware.
Do this by patching out the CALL instruction with "XOR %RAX,%RAX"
which has the same effect (0 return value).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: benh@kernel.crashing.org
Cc: boqun.feng@gmail.com
Cc: borntraeger@de.ibm.com
Cc: bsingharora@gmail.com
Cc: dave@stgolabs.net
Cc: jgross@suse.com
Cc: kernellwp@gmail.com
Cc: konrad.wilk@oracle.com
Cc: mpe@ellerman.id.au
Cc: paulmck@linux.vnet.ibm.com
Cc: paulus@samba.org
Cc: pbonzini@redhat.com
Cc: rkrcmar@redhat.com
Cc: will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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{mutex,rwsem}_spin_on_owner() when owner vCPU is preempted
An over-committed guest with more vCPUs than pCPUs has a heavy overload
in the two spin_on_owner. This blames on the lock holder preemption
issue.
Break out of the loop if the vCPU is preempted: if vcpu_is_preempted(cpu)
is true.
test-case:
perf record -a perf bench sched messaging -g 400 -p && perf report
before patch:
20.68% sched-messaging [kernel.vmlinux] [k] mutex_spin_on_owner
8.45% sched-messaging [kernel.vmlinux] [k] mutex_unlock
4.12% sched-messaging [kernel.vmlinux] [k] system_call
3.01% sched-messaging [kernel.vmlinux] [k] system_call_common
2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7
2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
2.00% sched-messaging [kernel.vmlinux] [k] osq_lock
after patch:
9.99% sched-messaging [kernel.vmlinux] [k] mutex_unlock
5.28% sched-messaging [unknown] [H] 0xc0000000000768e0
4.27% sched-messaging [kernel.vmlinux] [k] __copy_tofrom_user_power7
3.77% sched-messaging [kernel.vmlinux] [k] copypage_power7
3.24% sched-messaging [kernel.vmlinux] [k] _raw_write_lock_irq
3.02% sched-messaging [kernel.vmlinux] [k] system_call
2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task
Tested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: benh@kernel.crashing.org
Cc: boqun.feng@gmail.com
Cc: bsingharora@gmail.com
Cc: dave@stgolabs.net
Cc: kernellwp@gmail.com
Cc: konrad.wilk@oracle.com
Cc: linuxppc-dev@lists.ozlabs.org
Cc: mpe@ellerman.id.au
Cc: paulmck@linux.vnet.ibm.com
Cc: paulus@samba.org
Cc: rkrcmar@redhat.com
Cc: virtualization@lists.linux-foundation.org
Cc: will.deacon@arm.com
Cc: xen-devel-request@lists.xenproject.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1478077718-37424-4-git-send-email-xinhui.pan@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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in osq_lock()
An over-committed guest with more vCPUs than pCPUs has a heavy overload
in osq_lock().
This is because if vCPU-A holds the osq lock and yields out, vCPU-B ends
up waiting for per_cpu node->locked to be set. IOW, vCPU-B waits for
vCPU-A to run and unlock the osq lock.
Use the new vcpu_is_preempted(cpu) interface to detect if a vCPU is
currently running or not, and break out of the spin-loop if so.
test case:
$ perf record -a perf bench sched messaging -g 400 -p && perf report
before patch:
18.09% sched-messaging [kernel.vmlinux] [k] osq_lock
12.28% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
5.27% sched-messaging [kernel.vmlinux] [k] mutex_unlock
3.89% sched-messaging [kernel.vmlinux] [k] wait_consider_task
3.64% sched-messaging [kernel.vmlinux] [k] _raw_write_lock_irq
3.41% sched-messaging [kernel.vmlinux] [k] mutex_spin_on_owner.is
2.49% sched-messaging [kernel.vmlinux] [k] system_call
after patch:
20.68% sched-messaging [kernel.vmlinux] [k] mutex_spin_on_owner
8.45% sched-messaging [kernel.vmlinux] [k] mutex_unlock
4.12% sched-messaging [kernel.vmlinux] [k] system_call
3.01% sched-messaging [kernel.vmlinux] [k] system_call_common
2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7
2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
2.00% sched-messaging [kernel.vmlinux] [k] osq_lock
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: benh@kernel.crashing.org
Cc: bsingharora@gmail.com
Cc: dave@stgolabs.net
Cc: kernellwp@gmail.com
Cc: konrad.wilk@oracle.com
Cc: linuxppc-dev@lists.ozlabs.org
Cc: mpe@ellerman.id.au
Cc: paulmck@linux.vnet.ibm.com
Cc: paulus@samba.org
Cc: rkrcmar@redhat.com
Cc: virtualization@lists.linux-foundation.org
Cc: will.deacon@arm.com
Cc: xen-devel-request@lists.xenproject.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1478077718-37424-3-git-send-email-xinhui.pan@linux.vnet.ibm.com
[ Translated to English. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Commit ("x86/kvm: support vCPU preemption check") added a new
struct kvm_steal_time::preempted field. This field tells us if
a vCPU is running or not.
It is zero if some old KVM does not support this field or if the vCPU
is not preempted. Other values means the vCPU has been preempted.
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Radim Krčmář <rkrcmar@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: benh@kernel.crashing.org
Cc: boqun.feng@gmail.com
Cc: borntraeger@de.ibm.com
Cc: bsingharora@gmail.com
Cc: dave@stgolabs.net
Cc: jgross@suse.com
Cc: kernellwp@gmail.com
Cc: konrad.wilk@oracle.com
Cc: linuxppc-dev@lists.ozlabs.org
Cc: mpe@ellerman.id.au
Cc: paulmck@linux.vnet.ibm.com
Cc: paulus@samba.org
Cc: virtualization@lists.linux-foundation.org
Cc: will.deacon@arm.com
Cc: xen-devel-request@lists.xenproject.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1478077718-37424-12-git-send-email-xinhui.pan@linux.vnet.ibm.com
[ Various typo fixes. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Support the vcpu_is_preempted() functionality under Xen. This will
enhance lock performance on overcommitted hosts (more runnable vCPUs
than physical CPUs in the system) as doing busy waits for preempted
vCPUs will hurt system performance far worse than early yielding.
A quick test (4 vCPUs on 1 physical CPU doing a parallel build job
with "make -j 8") reduced system time by about 5% with this patch.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: benh@kernel.crashing.org
Cc: boqun.feng@gmail.com
Cc: borntraeger@de.ibm.com
Cc: bsingharora@gmail.com
Cc: dave@stgolabs.net
Cc: kernellwp@gmail.com
Cc: konrad.wilk@oracle.com
Cc: linuxppc-dev@lists.ozlabs.org
Cc: mpe@ellerman.id.au
Cc: paulmck@linux.vnet.ibm.com
Cc: paulus@samba.org
Cc: pbonzini@redhat.com
Cc: rkrcmar@redhat.com
Cc: virtualization@lists.linux-foundation.org
Cc: will.deacon@arm.com
Cc: xen-devel-request@lists.xenproject.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1478077718-37424-11-git-send-email-xinhui.pan@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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