The description of reg[1] says that register is optional. Adjust
minItems to make it truly optional.

Fixes: 4260ddfb ("dt-bindings: arm: msm: Convert and split kpss-acc driver Documentation to yaml")
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230627-topic-more_bindings-v1-9-6b4b6cd081e5@linaro.orgSigned-off-by: Bjorn Andersson <andersson@kernel.org>

in gsbi_probe(), the return value of function clk_prepare_enable()
should be checked, since it may fail. using devm_clk_get_enabled()
instead of devm_clk_get() and clk_prepare_enable() can avoid this
problem.
Signed-off-by: Yuanjun Gong <ruc_gongyuanjun@163.com>
Link: https://lore.kernel.org/r/20230720140834.33557-1-ruc_gongyuanjun@163.com
[bjorn: Dropped unnecessary "ret" variable]
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Update the SoC SM8[2345]50 entries to use the new
generic RPMHPD bindings.
Signed-off-by: Rohit Agarwal <quic_rohiagar@quicinc.com>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/1689744162-9421-3-git-send-email-quic_rohiagar@quicinc.comSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Merge the new generic RPMHPD defines from a topic branch, to alow them
being used in DeviceTree source, and the driver.

Add Generic RPMh Power Domain indexes that can be used
for all the Qualcomm SoC henceforth.
The power domain indexes of these bindings are based on compatibility
with current targets like SM8[2345]50 targets.
Signed-off-by: Rohit Agarwal <quic_rohiagar@quicinc.com>
Suggested-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/1689744162-9421-2-git-send-email-quic_rohiagar@quicinc.comSigned-off-by: Bjorn Andersson <andersson@kernel.org>

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230714175142.4067795-1-robh@kernel.orgSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Add a simple driver for the qcom,rpm-proc compatible that registers the
"smd-edge" and populates other children defined in the device tree.

Note that the DT schema belongs to the remoteproc subsystem while this
driver is added inside soc/qcom. I argue that the RPM *is* a remoteproc,
but as an implementation detail in Linux it can currently not benefit
from anything provided by the remoteproc subsystem. The RPM firmware is
usually already loaded and started by earlier components in the boot
chain and is not meant to be ever restarted.

To avoid breaking existing kernel configurations the driver is always
built when smd-rpm.c is also built. They belong closely together anyway.
To avoid build errors CONFIG_RPMSG_QCOM_SMD must be also built-in if
rpm-proc is.
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20230531-rpm-rproc-v3-9-a07dcdefd918@gerhold.netSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Rather than looking up a dummy item from SMEM, use the new
qcom_smem_is_available() function to make the code more clear
(and reduce the overhead slightly).

Add the same check to qcom_smd_register_edge() as well to ensure that
it only succeeds if SMEM is already available - if a driver calls the
function and SMEM is not available yet then the initial state will be
read incorrectly and the RPMSG devices might never become available.
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20230531-rpm-rproc-v3-8-a07dcdefd918@gerhold.netSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Avoid having to look up a dummy item from SMEM to detect if it is
already available or if we need to defer probing.
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20230531-rpm-rproc-v3-7-a07dcdefd918@gerhold.netSigned-off-by: Bjorn Andersson <andersson@kernel.org>

On Qualcomm platforms, most subsystems (e.g. audio/modem DSP) are
described as remote processors in the device tree, with a dedicated
node where properties and services related to them can be described.

The Resource Power Manager (RPM) is also such a subsystem, with a
remote processor that is running a special firmware. Unfortunately,
the RPM never got a dedicated node representing it properly in the
device tree. Most of the RPM services are described below a top-level
/smd or /rpm-glink node.

However, SMD/GLINK is just one of the communication channels to the RPM
firmware. For example, the MPM interrupt functionality provided by the
RPM does not use SMD/GLINK but writes directly to a special memory
region allocated by the RPM firmware in combination with a mailbox.
Currently there is no good place in the device tree to describe this
functionality. It doesn't belong below SMD/GLINK but it's not an
independent top-level device either.

Introduce a new "qcom,rpm-proc" compatible that allows describing the
RPM as a remote processor/subsystem like all others. The SMD/GLINK node
is moved to a "smd-edge"/"glink-edge" subnode consistent with other
existing bindings. Additional subnodes (e.g. interrupt-controller for
MPM, rpm-master-stats) can be also added there.

Deprecate using the old top-level /smd node since all SMD edges
are now specified as subnodes of the remote processor.
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230531-rpm-rproc-v3-6-a07dcdefd918@gerhold.netSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Semantically glink-edge and glink-rpm-edge are similar: Both describe
the communication channels to a remote processor. The RPM glink-edge is
a special case that needs slightly different properties but otherwise
it is used exactly the same.

To improve consistency use the same "glink-edge" node name also for
glink-rpm-edge. Drop the $nodename from qcom,glink-edge.yaml to avoid
matching the wrong schema. qcom,glink-edge.yaml is always referenced
explicitly from other schemas. This will already ensure that the nodes
are being checked, so it's not necessary to bind to all nodes named
"glink-edge".
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230531-rpm-rproc-v3-5-a07dcdefd918@gerhold.netSigned-off-by: Bjorn Andersson <andersson@kernel.org>

There is an ever growing list of compatibles in the smd-rpm.c driver.
A fallback compatible would help here but would still require keeping
the current list around for backwards compatibility.

As an alternative, let's switch the driver to match the rpmsg_device_id
instead, which is always "rpm_requests" on all platforms. Add a check
to ensure that there is a device tree node defined for the device since
otherwise the of_platform_populate() call will operate on the root node (/).

Similar approaches with matching rpmsg_device_id are already used in
qcom_sysmon, qcom_glink_ssr, qrtr, and rpmsg_wwan_ctrl.

Tested-by: Konrad Dybcio <konrad.dybcio@linaro.org> # SM6375 (G-Link)
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20230531-rpm-rproc-v3-4-a07dcdefd918@gerhold.netSigned-off-by: Bjorn Andersson <andersson@kernel.org>

To avoid several more small patches adding new RPM compatibles in the
future, add MDM9607, MSM8610, MSM8917, MSM8937 and MSM8952 at once.
All of these have been worked on over the time by some people and are
definitely compatible as-is with the smd-rpm driver.
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20230531-rpm-rproc-v3-3-a07dcdefd918@gerhold.netSigned-off-by: Bjorn Andersson <andersson@kernel.org>

MSM8909 is using qcom,smd-channels but is missing in the list, add it
there as well.

Fixes: 709d473d ("dt-bindings: soc: qcom: smd-rpm: Add MSM8909")
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20230531-rpm-rproc-v3-2-a07dcdefd918@gerhold.netSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Some of the enum entries are not properly ordered, fix that.
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20230531-rpm-rproc-v3-1-a07dcdefd918@gerhold.netSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Use struct_size() instead of hand-writing it, when allocating a structure
with a flex array.

This is less verbose.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/f74328551cfab0262ba353f37d047ac74bf616e1.1689194490.git.christophe.jaillet@wanadoo.frSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Use devm_platform_ioremap_resource() to simplify code.
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Link: https://lore.kernel.org/r/20230705122644.32236-3-frank.li@vivo.comSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Just like all other Qualcomm SoCs, SC8280XP SCM should be fed an
interconnect path. Do so.
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20230622-topic-8280scmicc-v1-1-6ef318919ea5@linaro.orgSigned-off-by: Bjorn Andersson <andersson@kernel.org>

When tracing messages written to the RSC it's very useful to know the
type of TCS being targeted, in particular if/when the code borrows a
WAKE TCS for ACTIVE votes.

Add the "state" of the message to the traced information.

While at it, drop the "send-msg:" substring, as this is already captured
by the trace event itself.
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230620230058.428833-1-quic_bjorande@quicinc.comSigned-off-by: Bjorn Andersson <andersson@kernel.org>

The debugfs dump of Command DB relies uses %*pEp to print the resource
identifiers, with escaping of non-printable characters.
But p (ESCAPE_NP) does not escape NUL characters, so for identifiers
less than 8 bytes in length the output will retain these.

This does not cause an issue while looking at the dump in the terminal
(no known complaints at least), but when programmatically consuming the
debugfs output the extra characters are unwanted.

Change the fixed 8-byte sizeof() to a dynamic strnlen() to avoid
printing these NUL characters.
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230620213703.283583-1-quic_bjorande@quicinc.comSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Add a sync_state implementation, very similar to the one already present
in the RPMhPD driver.
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230619-topic-rpmpd_syncstate-v1-1-54f986cf9444@linaro.orgSigned-off-by: Bjorn Andersson <andersson@kernel.org>

The msm8226 SoC also contains OCMEM but with one region only.
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20230506-msm8226-ocmem-v3-5-79da95a2581f@z3ntu.xyzSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Add the compatible for the OCMEM found on msm8226 which compared to
msm8974 only has a core clock and no iface clock.
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20230506-msm8226-ocmem-v3-4-79da95a2581f@z3ntu.xyzSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Some platforms such as msm8226 do not have an iface clk. Since clk_bulk
APIs don't offer to a way to treat some clocks as optional simply add
core_clk and iface_clk members to our drvdata.
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20230506-msm8226-ocmem-v3-3-79da95a2581f@z3ntu.xyzSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Use dev_err_probe in the driver probe function where useful, to simplify
getting PTR_ERR and to ensure the underlying errors are included in the
error message.
Reviewed-by: Caleb Connolly <caleb.connolly@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20230506-msm8226-ocmem-v3-2-79da95a2581f@z3ntu.xyzSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Since we're using these two macros to read a value from a register, we
need to use the FIELD_GET instead of the FIELD_PREP macro, otherwise
we're getting wrong values.

So instead of:

  [    3.111779] ocmem fdd00000.sram: 2 ports, 1 regions, 512 macros, not interleaved

we now get the correct value of:

  [    3.129672] ocmem fdd00000.sram: 2 ports, 1 regions, 2 macros, not interleaved

Fixes: 88c1e940 ("soc: qcom: add OCMEM driver")
Reviewed-by: Caleb Connolly <caleb.connolly@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20230506-msm8226-ocmem-v3-1-79da95a2581f@z3ntu.xyzSigned-off-by: Bjorn Andersson <andersson@kernel.org>

Currently we use predefined initial threshold values. This works, but
does not really scale well with more and more SoCs gaining bwmon support,
as the necessary kickoff values may differ between platforms due to memory
type and/or controller setup.
All of the data we need for that is already provided in the device tree,
anyway.

Change the thresholds to:
* low = 0 (as we've been doing up until now)
* med = high = BW_MIN

Throughput going below the med threshold nudges bwmon into signaling
that we should slow down (e.g. if we inherited too high bandwidth
from the bootloader).

Throughput going above the high threshold nudges bwmon into signaling
that we should speed up so as not to choke the bus traffic due to
insufficient transfer rates.

F_MIN is a perfect initial value for both of these cases - if we go
above it (and there's a 99.99% chance it'll happen at boot time), we
should definitely make the memory go faster, whereas if we go below it,
we should slow down, no matter what performance state we were at before
(it's only possible for them to be >= FMIN).

This only changes the values programmed at probe time, as high and med
thresholds are updated at interrupt, also based on the OPP table from DT.
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230610-topic-bwmon_opp-v2-1-0d25c1ce7dca@linaro.orgSigned-off-by: Bjorn Andersson <andersson@kernel.org>

We just sorted the entries and fields last release, so just out of a
perverse sense of curiosity, I decided to see if we can keep things
ordered for even just one release.

The answer is "No. No we cannot".

I suggest that all kernel developers will need weekly training sessions,
involving a lot of Big Bird and Sesame Street.  And at the yearly
maintainer summit, we will all sing the alphabet song together.

I doubt I will keep doing this.  At some point "perverse sense of
curiosity" turns into just a cold dark place filled with sadness and
despair.

Repeats: 80e62bc8 ("MAINTAINERS: re-sort all entries and fields")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull dma-mapping fixes from Christoph Hellwig:

 - swiotlb area sizing fixes (Petr Tesarik)

* tag 'dma-mapping-6.5-2023-07-09' of git://git.infradead.org/users/hch/dma-mapping:
  swiotlb: reduce the number of areas to match actual memory pool size
  swiotlb: always set the number of areas before allocating the pool

Pull irq update from Borislav Petkov:

 - Optimize IRQ domain's name assignment

* tag 'irq_urgent_for_v6.5_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqdomain: Use return value of strreplace()

Pull x86 fpu fix from Borislav Petkov:

 - Do FPU AP initialization on Xen PV too which got missed by the recent
   boot reordering work

* tag 'x86_urgent_for_v6.5_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/xen: Fix secondary processors' FPU initialization

Pull x86 fix from Thomas Gleixner:
 "A single fix for the mechanism to park CPUs with an INIT IPI.

  On shutdown or kexec, the kernel tries to park the non-boot CPUs with
  an INIT IPI. But the same code path is also used by the crash utility.
  If the CPU which panics is not the boot CPU then it sends an INIT IPI
  to the boot CPU which resets the machine.

  Prevent this by validating that the CPU which runs the stop mechanism
  is the boot CPU. If not, leave the other CPUs in HLT"

* tag 'x86-core-2023-07-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/smp: Don't send INIT to boot CPU

Pull MIPS fixes from Thomas Bogendoerfer:

 - fixes for KVM

 - fix for loongson build and cpu probing

 - DT fixes

* tag 'mips_6.5_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: kvm: Fix build error with KVM_MIPS_DEBUG_COP0_COUNTERS enabled
  MIPS: dts: add missing space before {
  MIPS: Loongson: Fix build error when make modules_install
  MIPS: KVM: Fix NULL pointer dereference
  MIPS: Loongson: Fix cpu_probe_loongson() again

Pull xfs fix from Darrick Wong:
 "Nothing exciting here, just getting rid of a gcc warning that I got
  tired of seeing when I turn on gcov"

* tag 'xfs-6.5-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: fix uninit warning in xfs_growfs_data

Pull more smb client updates from Steve French:

 - fix potential use after free in unmount

 - minor cleanup

 - add worker to cleanup stale directory leases

* tag '6.5-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: Add a laundromat thread for cached directories
  smb: client: remove redundant pointer 'server'
  cifs: fix session state transition to avoid use-after-free issue

Pull NTB updates from Jon Mason:
 "Fixes for pci_clean_master, error handling in driver inits, and
  various other issues/bugs"

* tag 'ntb-6.5' of https://github.com/jonmason/ntb:
  ntb: hw: amd: Fix debugfs_create_dir error checking
  ntb.rst: Fix copy and paste error
  ntb_netdev: Fix module_init problem
  ntb: intel: Remove redundant pci_clear_master
  ntb: epf: Remove redundant pci_clear_master
  ntb_hw_amd: Remove redundant pci_clear_master
  ntb: idt: drop redundant pci_enable_pcie_error_reporting()
  MAINTAINERS: git://github -> https://github.com for jonmason
  NTB: EPF: fix possible memory leak in pci_vntb_probe()
  NTB: ntb_tool: Add check for devm_kcalloc
  NTB: ntb_transport: fix possible memory leak while device_register() fails
  ntb: intel: Fix error handling in intel_ntb_pci_driver_init()
  NTB: amd: Fix error handling in amd_ntb_pci_driver_init()
  ntb: idt: Fix error handling in idt_pci_driver_init()

Lockdep is certainly right to complain about

  (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_write+0x2d/0x3f
                 but task is already holding lock:
  (&mapping->i_mmap_rwsem){+.+.}-{3:3}, at: mmap_region+0x4dc/0x6db

Invert those to the usual ordering.

Fixes: 33313a74 ("mm: lock newly mapped VMA which can be modified after it becomes visible")
Cc: stable@vger.kernel.org
Signed-off-by: Hugh Dickins <hughd@google.com>
Tested-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'mm-hotfixes-stable-2023-07-08-10-43' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull hotfixes from Andrew Morton:
 "16 hotfixes. Six are cc:stable and the remainder address post-6.4
  issues"

The merge undoes the disabling of the CONFIG_PER_VMA_LOCK feature, since
it was all hopefully fixed in mainline.

* tag 'mm-hotfixes-stable-2023-07-08-10-43' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  lib: dhry: fix sleeping allocations inside non-preemptable section
  kasan, slub: fix HW_TAGS zeroing with slub_debug
  kasan: fix type cast in memory_is_poisoned_n
  mailmap: add entries for Heiko Stuebner
  mailmap: update manpage link
  bootmem: remove the vmemmap pages from kmemleak in free_bootmem_page
  MAINTAINERS: add linux-next info
  mailmap: add Markus Schneider-Pargmann
  writeback: account the number of pages written back
  mm: call arch_swap_restore() from do_swap_page()
  squashfs: fix cache race with migration
  mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
  docs: update ocfs2-devel mailing list address
  MAINTAINERS: update ocfs2-devel mailing list address
  mm: disable CONFIG_PER_VMA_LOCK until its fixed
  fork: lock VMAs of the parent process when forking

When forking a child process, the parent write-protects anonymous pages
and COW-shares them with the child being forked using copy_present_pte().

We must not take any concurrent page faults on the source vma's as they
are being processed, as we expect both the vma and the pte's behind it
to be stable.  For example, the anon_vma_fork() expects the parents
vma->anon_vma to not change during the vma copy.

A concurrent page fault on a page newly marked read-only by the page
copy might trigger wp_page_copy() and a anon_vma_prepare(vma) on the
source vma, defeating the anon_vma_clone() that wasn't done because the
parent vma originally didn't have an anon_vma, but we now might end up
copying a pte entry for a page that has one.

Before the per-vma lock based changes, the mmap_lock guaranteed
exclusion with concurrent page faults.  But now we need to do a
vma_start_write() to make sure no concurrent faults happen on this vma
while it is being processed.

This fix can potentially regress some fork-heavy workloads.  Kernel
build time did not show noticeable regression on a 56-core machine while
a stress test mapping 10000 VMAs and forking 5000 times in a tight loop
shows ~5% regression.  If such fork time regression is unacceptable,
disabling CONFIG_PER_VMA_LOCK should restore its performance.  Further
optimizations are possible if this regression proves to be problematic.
Suggested-by: David Hildenbrand <david@redhat.com>
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Closes: https://lore.kernel.org/all/dbdef34c-3a07-5951-e1ae-e9c6e3cdf51b@kernel.org/Reported-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Closes: https://lore.kernel.org/all/b198d649-f4bf-b971-31d0-e8433ec2a34c@applied-asynchrony.com/Reported-by: Jacob Young <jacobly.alt@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217624
Fixes: 0bff0aae ("x86/mm: try VMA lock-based page fault handling first")
Cc: stable@vger.kernel.org
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>