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Pull compiler attributes updates from Miguel Ojeda:
- Fix __has_attribute(__no_sanitize_coverage__) for GCC 4 (Marco Elver)
- Add Nick as Reviewer for compiler_attributes.h (Nick Desaulniers)
- Move __compiletime_{error|warning} (Nick Desaulniers)
* tag 'compiler-attributes-for-linus-v5.15-rc1-v2' of git://github.com/ojeda/linux:
compiler_attributes.h: move __compiletime_{error|warning}
MAINTAINERS: add Nick as Reviewer for compiler_attributes.h
Compiler Attributes: fix __has_attribute(__no_sanitize_coverage__) for GCC 4
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Pull CPU hotplug updates from Thomas Gleixner:
"Updates for the SMP and CPU hotplug:
- Remove DEFINE_SMP_CALL_CACHE_FUNCTION() which is a left over of the
original hotplug code and now causing trouble with the ARM64 cache
topology setup due to the pointless SMP function call.
It's not longer required as the hotplug callbacks are guaranteed to
be invoked on the upcoming CPU.
- Remove the deprecated and now unused CPU hotplug functions
- Rewrite the CPU hotplug API documentation"
* tag 'smp-urgent-2021-09-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Documentation: core-api/cpuhotplug: Rewrite the API section
cpu/hotplug: Remove deprecated CPU-hotplug functions.
thermal: Replace deprecated CPU-hotplug functions.
drivers: base: cacheinfo: Get rid of DEFINE_SMP_CALL_CACHE_FUNCTION()
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Pull locking fixes from Borislav Petkov:
- Fix the futex PI requeue machinery to not return to userspace in
inconsistent state
- Avoid a potential null pointer dereference in the ww_mutex deadlock
check
- Other smaller cleanups and optimizations
* tag 'locking_urgent_for_v5.15_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rtmutex: Fix ww_mutex deadlock check
futex: Remove unused variable 'vpid' in futex_proxy_trylock_atomic()
futex: Avoid redundant task lookup
futex: Clarify comment for requeue_pi_wake_futex()
futex: Prevent inconsistent state and exit race
futex: Return error code instead of assigning it without effect
locking/rwsem: Add missing __init_rwsem() for PREEMPT_RT
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Pull timer fix from Borislav Petkov:
- Handle negative second values properly when converting a timespec64
to nanoseconds.
* tag 'timers_urgent_for_v5.15_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time: Handle negative seconds correctly in timespec64_to_ns()
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Pull virtio updates from Michael Tsirkin:
- vduse driver ("vDPA Device in Userspace") supporting emulated virtio
block devices
- virtio-vsock support for end of record with SEQPACKET
- vdpa: mac and mq support for ifcvf and mlx5
- vdpa: management netlink for ifcvf
- virtio-i2c, gpio dt bindings
- misc fixes and cleanups
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (39 commits)
Documentation: Add documentation for VDUSE
vduse: Introduce VDUSE - vDPA Device in Userspace
vduse: Implement an MMU-based software IOTLB
vdpa: Support transferring virtual addressing during DMA mapping
vdpa: factor out vhost_vdpa_pa_map() and vhost_vdpa_pa_unmap()
vdpa: Add an opaque pointer for vdpa_config_ops.dma_map()
vhost-iotlb: Add an opaque pointer for vhost IOTLB
vhost-vdpa: Handle the failure of vdpa_reset()
vdpa: Add reset callback in vdpa_config_ops
vdpa: Fix some coding style issues
file: Export receive_fd() to modules
eventfd: Export eventfd_wake_count to modules
iova: Export alloc_iova_fast() and free_iova_fast()
virtio-blk: remove unneeded "likely" statements
virtio-balloon: Use virtio_find_vqs() helper
vdpa: Make use of PFN_PHYS/PFN_UP/PFN_DOWN helper macro
vsock_test: update message bounds test for MSG_EOR
af_vsock: rename variables in receive loop
virtio/vsock: support MSG_EOR bit processing
vhost/vsock: support MSG_EOR bit processing
...
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Pull tracing fixes from Steven Rostedt:
"Minor fixes to the processing of the bootconfig tree"
* tag 'trace-v5.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
bootconfig: Rename xbc_node_find_child() to xbc_node_find_subkey()
tracing/boot: Fix to check the histogram control param is a leaf node
tracing/boot: Fix trace_boot_hist_add_array() to check array is value
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Pull pwm updates from Thierry Reding:
"The changes this time around are mostly janitorial in nature. A lot of
this is simplifications of drivers using device-managed functions and
improving compilation coverage.
The Mediatek display PWM driver now supports the atomic API.
Cleanups and minor fixes make up the remainder of this set"
* tag 'pwm/for-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (54 commits)
pwm: mtk-disp: Implement atomic API .get_state()
pwm: mtk-disp: Fix overflow in period and duty calculation
pwm: mtk-disp: Implement atomic API .apply()
pwm: mtk-disp: Adjust the clocks to avoid them mismatch
dt-bindings: pwm: rockchip: Add description for rk3568
pwm: Make pwmchip_remove() return void
pwm: sun4i: Don't check the return code of pwmchip_remove()
pwm: sifive: Don't check the return code of pwmchip_remove()
pwm: samsung: Don't check the return code of pwmchip_remove()
pwm: renesas-tpu: Don't check the return code of pwmchip_remove()
pwm: rcar: Don't check the return code of pwmchip_remove()
pwm: pca9685: Don't check the return code of pwmchip_remove()
pwm: omap-dmtimer: Don't check the return code of pwmchip_remove()
pwm: mtk-disp: Don't check the return code of pwmchip_remove()
pwm: imx-tpm: Don't check the return code of pwmchip_remove()
pwm: img: Don't check the return code of pwmchip_remove()
pwm: cros-ec: Don't check the return code of pwmchip_remove()
pwm: brcmstb: Don't check the return code of pwmchip_remove()
pwm: atmel-tcb: Don't check the return code of pwmchip_remove()
pwm: atmel-hlcdc: Don't check the return code of pwmchip_remove()
...
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Pull thermal updates from Daniel Lezcano:
- Add the tegra3 thermal sensor and fix the compilation testing on
tegra by adding a dependency on ARCH_TEGRA along with COMPILE_TEST
(Dmitry Osipenko)
- Fix the error code for the exynos when devm_get_clk() fails (Dan
Carpenter)
- Add the TCC cooling support for AlderLake platform (Sumeet Pawnikar)
- Add support for hardware trip points for the rcar gen3 thermal driver
and store TSC id as unsigned int (Niklas Söderlund)
- Replace the deprecated CPU-hotplug functions get_online_cpus() and
put_online_cpus (Sebastian Andrzej Siewior)
- Add the thermal tools directory in the MAINTAINERS file (Daniel
Lezcano)
- Fix the Makefile and the cross compilation flags for the userspace
'tmon' tool (Rolf Eike Beer)
- Allow to use the IMOK independently from the GDDV on Int340x (Sumeet
Pawnikar)
- Fix the stub thermal_cooling_device_register() function prototype
which does not match the real function (Arnd Bergmann)
- Make the thermal trip point optional in the DT bindings (Maxime
Ripard)
- Fix a typo in a comment in the core code (Geert Uytterhoeven)
- Reduce the verbosity of the trace in the SoC thermal tegra driver
(Dmitry Osipenko)
- Add the support for the LMh (Limit Management hardware) driver on the
QCom platforms (Thara Gopinath)
- Allow processing of HWP interrupt by adding a weak function in the
Intel driver (Srinivas Pandruvada)
- Prevent an abort of the sensor probe is a channel is not used
(Matthias Kaehlcke)
* tag 'thermal-v5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux:
thermal/drivers/qcom/spmi-adc-tm5: Don't abort probing if a sensor is not used
thermal/drivers/intel: Allow processing of HWP interrupt
dt-bindings: thermal: Add dt binding for QCOM LMh
thermal/drivers/qcom: Add support for LMh driver
firmware: qcom_scm: Introduce SCM calls to access LMh
thermal/drivers/tegra-soctherm: Silence message about clamped temperature
thermal: Spelling s/scallbacks/callbacks/
dt-bindings: thermal: Make trips node optional
thermal/core: Fix thermal_cooling_device_register() prototype
thermal/drivers/int340x: Use IMOK independently
tools/thermal/tmon: Add cross compiling support
thermal/tools/tmon: Improve the Makefile
MAINTAINERS: Add missing userspace thermal tools to the thermal section
thermal/drivers/intel_powerclamp: Replace deprecated CPU-hotplug functions.
thermal/drivers/rcar_gen3_thermal: Store TSC id as unsigned int
thermal/drivers/rcar_gen3_thermal: Add support for hardware trip points
drivers/thermal/intel: Add TCC cooling support for AlderLake platform
thermal/drivers/exynos: Fix an error code in exynos_tmu_probe()
thermal/drivers/tegra: Correct compile-testing of drivers
thermal/drivers/tegra: Add driver for Tegra30 thermal sensor
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Dave stumbled over the incomplete and confusing documentation of the CPU
hotplug API.
Rewrite it, add the missing function documentations and correct the
existing ones.
Reported-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210909123212.489059409@linutronix.de
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No users in tree use the deprecated CPU-hotplug functions anymore.
Remove them.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210803141621.780504-39-bigeasy@linutronix.de
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Ensure that all usage sites of get/put_online_cpus() except for the
struggler in drivers/thermal are gone. So the last user and the deprecated
inlines can be removed.
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Pull more power management updates from Rafael Wysocki:
"These improve hybrid processors support in intel_pstate, fix an issue
in the core devices PM code, clean up the handling of dedicated wake
IRQs, update the Energy Model documentation and update MAINTAINERS.
Specifics:
- Make the HWP performance levels calibration on hybrid processors in
intel_pstate more straightforward (Rafael Wysocki).
- Prevent the PM core from leaving devices in suspend after a failing
system-wide suspend transition in some cases when driver PM flags
are used (Prasad Sodagudi).
- Drop unused function argument from the dedicated wake IRQs handling
code (Sergey Shtylyov).
- Fix up Energy Model kerneldoc comments and include them in the
Energy Model documentation (Lukasz Luba).
- Use my kernel.org address in MAINTAINERS insead of the personal one
(Rafael Wysocki)"
* tag 'pm-5.15-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
MAINTAINERS: Change Rafael's e-mail address
PM: sleep: core: Avoid setting power.must_resume to false
Documentation: power: include kernel-doc in Energy Model doc
PM: EM: fix kernel-doc comments
cpufreq: intel_pstate: hybrid: Rework HWP calibration
ACPI: CPPC: Introduce cppc_get_nominal_perf()
PM: sleep: wakeirq: drop useless parameter from dev_pm_attach_wake_irq()
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* pm-cpufreq:
cpufreq: intel_pstate: hybrid: Rework HWP calibration
ACPI: CPPC: Introduce cppc_get_nominal_perf()
* pm-sleep:
PM: sleep: core: Avoid setting power.must_resume to false
PM: sleep: wakeirq: drop useless parameter from dev_pm_attach_wake_irq()
* pm-em:
Documentation: power: include kernel-doc in Energy Model doc
PM: EM: fix kernel-doc comments
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Rename xbc_node_find_child() to xbc_node_find_subkey() for
clarifying that function returns a key node (no value node).
Since there are xbc_node_for_each_child() (loop on all child
nodes) and xbc_node_for_each_subkey() (loop on only subkey
nodes), this name distinction is necessary to avoid confusing
users.
Link: https://lkml.kernel.org/r/163119459826.161018.11200274779483115300.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Pull ARM development updates from Russell King:
- Rename "mod_init" and "mod_exit" so that initcall debug output is
actually useful (Randy Dunlap)
- Update maintainers entries for linux-arm-kernel to indicate it is
moderated for non-subscribers (Randy Dunlap)
- Move install rules to arch/arm/Makefile (Masahiro Yamada)
- Drop unnecessary ARCH_NR_GPIOS definition (Linus Walleij)
- Don't warn about atags_to_fdt() stack size (David Heidelberg)
- Speed up unaligned copy_{from,to}_kernel_nofault (Arnd Bergmann)
- Get rid of set_fs() usage (Arnd Bergmann)
- Remove checks for GCC prior to v4.6 (Geert Uytterhoeven)
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 9118/1: div64: Remove always-true __div64_const32_is_OK() duplicate
ARM: 9117/1: asm-generic: div64: Remove always-true __div64_const32_is_OK()
ARM: 9116/1: unified: Remove check for gcc < 4
ARM: 9110/1: oabi-compat: fix oabi epoll sparse warning
ARM: 9113/1: uaccess: remove set_fs() implementation
ARM: 9112/1: uaccess: add __{get,put}_kernel_nofault
ARM: 9111/1: oabi-compat: rework fcntl64() emulation
ARM: 9114/1: oabi-compat: rework sys_semtimedop emulation
ARM: 9108/1: oabi-compat: rework epoll_wait/epoll_pwait emulation
ARM: 9107/1: syscall: always store thread_info->abi_syscall
ARM: 9109/1: oabi-compat: add epoll_pwait handler
ARM: 9106/1: traps: use get_kernel_nofault instead of set_fs()
ARM: 9115/1: mm/maccess: fix unaligned copy_{from,to}_kernel_nofault
ARM: 9105/1: atags_to_fdt: don't warn about stack size
ARM: 9103/1: Drop ARCH_NR_GPIOS definition
ARM: 9102/1: move theinstall rules to arch/arm/Makefile
ARM: 9100/1: MAINTAINERS: mark all linux-arm-kernel@infradead list as moderated
ARM: 9099/1: crypto: rename 'mod_init' & 'mod_exit' functions to be module-specific
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Pull gfs2 setattr updates from Al Viro:
"Make it possible for filesystems to use a generic 'may_setattr()' and
switch gfs2 to using it"
* 'work.gfs2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
gfs2: Switch to may_setattr in gfs2_setattr
fs: Move notify_change permission checks into may_setattr
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Pull root filesystem type handling updates from Al Viro:
"Teach init/do_mounts.c to handle non-block filesystems, hopefully
preventing even more special-cased kludges (such as root=/dev/nfs,
etc)"
* 'work.init' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: simplify get_filesystem_list / get_all_fs_names
init: allow mounting arbitrary non-blockdevice filesystems as root
init: split get_fs_names
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Pull iov_iter fixes from Al Viro:
"Fixes for io-uring handling of iov_iter reexpands"
* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
io_uring: reexpand under-reexpanded iters
iov_iter: track truncated size
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Pull libnvdimm updates from Dan Williams:
- Fix a race condition in the teardown path of raw mode pmem
namespaces.
- Cleanup the code that filesystems use to detect filesystem-dax
capabilities of their underlying block device.
* tag 'libnvdimm-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
dax: remove bdev_dax_supported
xfs: factor out a xfs_buftarg_is_dax helper
dax: stub out dax_supported for !CONFIG_FS_DAX
dax: remove __generic_fsdax_supported
dax: move the dax_read_lock() locking into dax_supported
dax: mark dax_get_by_host static
dm: use fs_dax_get_by_bdev instead of dax_get_by_host
dax: stop using bdevname
fsdax: improve the FS_DAX Kconfig description and help text
libnvdimm/pmem: Fix crash triggered when I/O in-flight during unbind
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Pull dmaengine updates from Vinod Koul:
"New drivers/devices
- Support for Renesas RZ/G2L dma controller
- New driver for AMD PTDMA controller
Updates:
- Big pile of idxd updates
- Updates for Altera driver, stm32-dma, dw etc"
* tag 'dmaengine-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine: (83 commits)
dmaengine: sh: fix some NULL dereferences
dmaengine: sh: Fix unused initialization of pointer lmdesc
MAINTAINERS: Fix AMD PTDMA DRIVER entry
dmaengine: ptdma: remove PT_OFFSET to avoid redefnition
dmaengine: ptdma: Add debugfs entries for PTDMA
dmaengine: ptdma: register PTDMA controller as a DMA resource
dmaengine: ptdma: Initial driver for the AMD PTDMA
dmaengine: fsl-dpaa2-qdma: Fix spelling mistake "faile" -> "failed"
dmaengine: idxd: remove interrupt disable for dev_lock
dmaengine: idxd: remove interrupt disable for cmd_lock
dmaengine: idxd: fix setting up priv mode for dwq
dmaengine: xilinx_dma: Set DMA mask for coherent APIs
dmaengine: ti: k3-psil-j721e: Add entry for CSI2RX
dmaengine: sh: Add DMAC driver for RZ/G2L SoC
dmaengine: Extend the dma_slave_width for 128 bytes
dt-bindings: dma: Document RZ/G2L bindings
dmaengine: ioat: depends on !UML
dmaengine: idxd: set descriptor allocation size to threshold for swq
dmaengine: idxd: make submit failure path consistent on desc freeing
dmaengine: idxd: remove interrupt flag for completion list spinlock
...
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Merge yet more updates and hotfixes from Andrew Morton:
"Post-linux-next material, based upon latest upstream to catch the
now-merged dependencies:
- 10 patches.
Subsystems affected by this patch series: mm (vmstat and migration)
and compat.
And bunch of hotfixes, mostly cc:stable:
- 8 patches.
Subsystems affected by this patch series: mm (hmm, hugetlb, vmscan,
pagealloc, pagemap, kmemleak, mempolicy, and memblock)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
arch: remove compat_alloc_user_space
compat: remove some compat entry points
mm: simplify compat numa syscalls
mm: simplify compat_sys_move_pages
kexec: avoid compat_alloc_user_space
kexec: move locking into do_kexec_load
mm: migrate: change to use bool type for 'page_was_mapped'
mm: migrate: fix the incorrect function name in comments
mm: migrate: introduce a local variable to get the number of pages
mm/vmstat: protect per cpu variables with preempt disable on RT
* emailed hotfixes from Andrew Morton <akpm@linux-foundation.org>:
nds32/setup: remove unused memblock_region variable in setup_memory()
mm/mempolicy: fix a race between offset_il_node and mpol_rebind_task
mm/kmemleak: allow __GFP_NOLOCKDEP passed to kmemleak's gfp
mmap_lock: change trace and locking order
mm/page_alloc.c: avoid accessing uninitialized pcp page migratetype
mm,vmscan: fix divide by zero in get_scan_count
mm/hugetlb: initialize hugetlb_usage in mm_init
mm/hmm: bypass devmap pte when all pfn requested flags are fulfilled
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Print to the trace log before releasing the lock to avoid racing with
other trace log printers of the same lock type.
Link: https://lkml.kernel.org/r/20210903022041.1843024-1-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michel Lespinasse <walken.cr@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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After fork, the child process will get incorrect (2x) hugetlb_usage. If
a process uses 5 2MB hugetlb pages in an anonymous mapping,
HugetlbPages: 10240 kB
and then forks, the child will show,
HugetlbPages: 20480 kB
The reason for double the amount is because hugetlb_usage will be copied
from the parent and then increased when we copy page tables from parent
to child. Child will have 2x actual usage.
Fix this by adding hugetlb_count_init in mm_init.
Link: https://lkml.kernel.org/r/20210826071742.877-1-liuzixian4@huawei.com
Fixes: 5d317b2b6536 ("mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status")
Signed-off-by: Liu Zixian <liuzixian4@huawei.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull more power management updates from Rafael Wysocki:
"These are mostly ARM cpufreq driver updates, including one new
MediaTek driver that has just passed all of the reviews, with the
addition of a revert of a recent intel_pstate commit, some core
cpufreq changes and a DT-related update of the operating performance
points (OPP) support code.
Specifics:
- Add new cpufreq driver for the MediaTek MT6779 platform called
mediatek-hw along with corresponding DT bindings (Hector.Yuan).
- Add DCVS interrupt support to the qcom-cpufreq-hw driver (Thara
Gopinath).
- Make the qcom-cpufreq-hw driver set the dvfs_possible_from_any_cpu
policy flag (Taniya Das).
- Blocklist more Qualcomm platforms in cpufreq-dt-platdev (Bjorn
Andersson).
- Make the vexpress cpufreq driver set the CPUFREQ_IS_COOLING_DEV
flag (Viresh Kumar).
- Add new cpufreq driver callback to allow drivers to register with
the Energy Model in a consistent way and make several drivers use
it (Viresh Kumar).
- Change the remaining users of the .ready() cpufreq driver callback
to move the code from it elsewhere and drop it from the cpufreq
core (Viresh Kumar).
- Revert recent intel_pstate change adding HWP guaranteed performance
change notification support to it that led to problems, because the
notification in question is triggered prematurely on some systems
(Rafael Wysocki).
- Convert the OPP DT bindings to DT schema and clean them up while at
it (Rob Herring)"
* tag 'pm-5.15-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (23 commits)
Revert "cpufreq: intel_pstate: Process HWP Guaranteed change notification"
cpufreq: mediatek-hw: Add support for CPUFREQ HW
cpufreq: Add of_perf_domain_get_sharing_cpumask
dt-bindings: cpufreq: add bindings for MediaTek cpufreq HW
cpufreq: Remove ready() callback
cpufreq: sh: Remove sh_cpufreq_cpu_ready()
cpufreq: acpi: Remove acpi_cpufreq_cpu_ready()
cpufreq: qcom-hw: Set dvfs_possible_from_any_cpu cpufreq driver flag
cpufreq: blocklist more Qualcomm platforms in cpufreq-dt-platdev
cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support
cpufreq: scmi: Use .register_em() to register with energy model
cpufreq: vexpress: Use .register_em() to register with energy model
cpufreq: scpi: Use .register_em() to register with energy model
dt-bindings: opp: Convert to DT schema
dt-bindings: Clean-up OPP binding node names in examples
ARM: dts: omap: Drop references to opp.txt
cpufreq: qcom-cpufreq-hw: Use .register_em() to register with energy model
cpufreq: omap: Use .register_em() to register with energy model
cpufreq: mediatek: Use .register_em() to register with energy model
cpufreq: imx6q: Use .register_em() to register with energy model
...
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Pull more ACPI updates from Rafael Wysocki:
"These add ACPI support to the PCI VMD driver, improve suspend-to-idle
support for AMD platforms and update documentation.
Specifics:
- Add ACPI support to the PCI VMD driver (Rafael Wysocki)
- Rearrange suspend-to-idle support code to reflect the platform
firmware expectations on some AMD platforms (Mario Limonciello)
- Make SSDT overlays documentation follow the code documented by it
more closely (Andy Shevchenko)"
* tag 'acpi-5.15-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: PM: s2idle: Run both AMD and Microsoft methods if both are supported
Documentation: ACPI: Align the SSDT overlays file with the code
PCI: VMD: ACPI: Make ACPI companion lookup work for VMD bus
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Clang 14 will add support for __attribute__((__error__(""))) and
__attribute__((__warning__(""))). To make use of these in
__compiletime_error and __compiletime_warning (as used by BUILD_BUG and
friends) for newer clang and detect/fallback for older versions of
clang, move these to compiler_attributes.h and guard them with
__has_attribute preprocessor guards.
Link: https://reviews.llvm.org/D106030
Link: https://bugs.llvm.org/show_bug.cgi?id=16428
Link: https://github.com/ClangBuiltLinux/linux/issues/1173
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
[Reworded, landed in Clang 14]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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Include Christoph's rework of the dax_supported() helpers in the v5.15
libnvdimm update. This supports the ongoing dax-reflink enabling effort.
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Pull ceph updates from Ilya Dryomov:
- a set of patches to address fsync stalls caused by depending on
periodic rather than triggered MDS journal flushes in some cases
(Xiubo Li)
- a fix for mtime effectively not getting updated in case of competing
writers (Jeff Layton)
- a couple of fixes for inode reference leaks and various WARNs after
"umount -f" (Xiubo Li)
- a new ceph.auth_mds extended attribute (Jeff Layton)
- a smattering of fixups and cleanups from Jeff, Xiubo and Colin.
* tag 'ceph-for-5.15-rc1' of git://github.com/ceph/ceph-client:
ceph: fix dereference of null pointer cf
ceph: drop the mdsc_get_session/put_session dout messages
ceph: lockdep annotations for try_nonblocking_invalidate
ceph: don't WARN if we're forcibly removing the session caps
ceph: don't WARN if we're force umounting
ceph: remove the capsnaps when removing caps
ceph: request Fw caps before updating the mtime in ceph_write_iter
ceph: reconnect to the export targets on new mdsmaps
ceph: print more information when we can't find snaprealm
ceph: add ceph_change_snap_realm() helper
ceph: remove redundant initializations from mdsc and session
ceph: cancel delayed work instead of flushing on mdsc teardown
ceph: add a new vxattr to return auth mds for an inode
ceph: remove some defunct forward declarations
ceph: flush the mdlog before waiting on unsafe reqs
ceph: flush mdlog before umounting
ceph: make iterate_sessions a global symbol
ceph: make ceph_create_session_msg a global symbol
ceph: fix comment about short copies in ceph_write_end
ceph: fix memory leak on decode error in ceph_handle_caps
|
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All users of compat_alloc_user_space() and copy_in_user() have been
removed from the kernel, only a few functions in sparc remain that can be
changed to calling arch_copy_in_user() instead.
Link: https://lkml.kernel.org/r/20210727144859.4150043-7-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
These are all handled correctly when calling the native system call entry
point, so remove the special cases.
Link: https://lkml.kernel.org/r/20210727144859.4150043-6-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The compat implementations for mbind, get_mempolicy, set_mempolicy and
migrate_pages are just there to handle the subtly different layout of
bitmaps on 32-bit hosts.
The compat implementation however lacks some of the checks that are
present in the native one, in particular for checking that the extra bits
are all zero when user space has a larger mask size than the kernel.
Worse, those extra bits do not get cleared when copying in or out of the
kernel, which can lead to incorrect data as well.
Unify the implementation to handle the compat bitmap layout directly in
the get_nodes() and copy_nodes_to_user() helpers. Splitting out the
get_bitmap() helper from get_nodes() also helps readability of the native
case.
On x86, two additional problems are addressed by this: compat tasks can
pass a bitmap at the end of a mapping, causing a fault when reading across
the page boundary for a 64-bit word. x32 tasks might also run into
problems with get_mempolicy corrupting data when an odd number of 32-bit
words gets passed.
On parisc the migrate_pages() system call apparently had the wrong calling
convention, as big-endian architectures expect the words inside of a
bitmap to be swapped. This is not a problem though since parisc has no
NUMA support.
[arnd@arndb.de: fix mempolicy crash]
Link: https://lkml.kernel.org/r/20210730143417.3700653-1-arnd@kernel.org
Link: https://lore.kernel.org/lkml/YQPLG20V3dmOfq3a@osiris/
Link: https://lkml.kernel.org/r/20210727144859.4150043-5-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Merge more updates from Andrew Morton:
"147 patches, based on 7d2a07b769330c34b4deabeed939325c77a7ec2f.
Subsystems affected by this patch series: mm (memory-hotplug, rmap,
ioremap, highmem, cleanups, secretmem, kfence, damon, and vmscan),
alpha, percpu, procfs, misc, core-kernel, MAINTAINERS, lib,
checkpatch, epoll, init, nilfs2, coredump, fork, pids, criu, kconfig,
selftests, ipc, and scripts"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (94 commits)
scripts: check_extable: fix typo in user error message
mm/workingset: correct kernel-doc notations
ipc: replace costly bailout check in sysvipc_find_ipc()
selftests/memfd: remove unused variable
Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH
configs: remove the obsolete CONFIG_INPUT_POLLDEV
prctl: allow to setup brk for et_dyn executables
pid: cleanup the stale comment mentioning pidmap_init().
kernel/fork.c: unexport get_{mm,task}_exe_file
coredump: fix memleak in dump_vma_snapshot()
fs/coredump.c: log if a core dump is aborted due to changed file permissions
nilfs2: use refcount_dec_and_lock() to fix potential UAF
nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group
nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group
nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group
nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group
nilfs2: fix NULL pointer in nilfs_##name##_attr_release
nilfs2: fix memory leak in nilfs_sysfs_create_device_group
trap: cleanup trap_init()
init: move usermodehelper_enable() to populate_rootfs()
...
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Pull SLUB updates from Vlastimil Babka:
"SLUB: reduce irq disabled scope and make it RT compatible
This series was initially inspired by Mel's pcplist local_lock
rewrite, and also interest to better understand SLUB's locking and the
new primitives and RT variants and implications. It makes SLUB
compatible with PREEMPT_RT and generally more preemption-friendly,
apparently without significant regressions, as the fast paths are not
affected.
The main changes to SLUB by this series:
- irq disabling is now only done for minimum amount of time needed to
protect the strict kmem_cache_cpu fields, and as part of spin lock,
local lock and bit lock operations to make them irq-safe
- SLUB is fully PREEMPT_RT compatible
The series should now be sufficiently tested in both RT and !RT
configs, mainly thanks to Mike.
The RFC/v1 version also got basic performance screening by Mel that
didn't show major regressions. Mike's testing with hackbench of v2 on
!RT reported negligible differences [6]:
virgin(ish) tip
5.13.0.g60ab3ed-tip
7,320.67 msec task-clock # 7.792 CPUs utilized ( +- 0.31% )
221,215 context-switches # 0.030 M/sec ( +- 3.97% )
16,234 cpu-migrations # 0.002 M/sec ( +- 4.07% )
13,233 page-faults # 0.002 M/sec ( +- 0.91% )
27,592,205,252 cycles # 3.769 GHz ( +- 0.32% )
8,309,495,040 instructions # 0.30 insn per cycle ( +- 0.37% )
1,555,210,607 branches # 212.441 M/sec ( +- 0.42% )
5,484,209 branch-misses # 0.35% of all branches ( +- 2.13% )
0.93949 +- 0.00423 seconds time elapsed ( +- 0.45% )
0.94608 +- 0.00384 seconds time elapsed ( +- 0.41% ) (repeat)
0.94422 +- 0.00410 seconds time elapsed ( +- 0.43% )
5.13.0.g60ab3ed-tip +slub-local-lock-v2r3
7,343.57 msec task-clock # 7.776 CPUs utilized ( +- 0.44% )
223,044 context-switches # 0.030 M/sec ( +- 3.02% )
16,057 cpu-migrations # 0.002 M/sec ( +- 4.03% )
13,164 page-faults # 0.002 M/sec ( +- 0.97% )
27,684,906,017 cycles # 3.770 GHz ( +- 0.45% )
8,323,273,871 instructions # 0.30 insn per cycle ( +- 0.28% )
1,556,106,680 branches # 211.901 M/sec ( +- 0.31% )
5,463,468 branch-misses # 0.35% of all branches ( +- 1.33% )
0.94440 +- 0.00352 seconds time elapsed ( +- 0.37% )
0.94830 +- 0.00228 seconds time elapsed ( +- 0.24% ) (repeat)
0.93813 +- 0.00440 seconds time elapsed ( +- 0.47% ) (repeat)
RT configs showed some throughput regressions, but that's expected
tradeoff for the preemption improvements through the RT mutex. It
didn't prevent the v2 to be incorporated to the 5.13 RT tree [7],
leading to testing exposure and bugfixes.
Before the series, SLUB is lockless in both allocation and free fast
paths, but elsewhere, it's disabling irqs for considerable periods of
time - especially in allocation slowpath and the bulk allocation,
where IRQs are re-enabled only when a new page from the page allocator
is needed, and the context allows blocking. The irq disabled sections
can then include deactivate_slab() which walks a full freelist and
frees the slab back to page allocator or unfreeze_partials() going
through a list of percpu partial slabs. The RT tree currently has some
patches mitigating these, but we can do much better in mainline too.
Patches 1-6 are straightforward improvements or cleanups that could
exist outside of this series too, but are prerequsities.
Patches 7-9 are also preparatory code changes without functional
changes, but not so useful without the rest of the series.
Patch 10 simplifies the fast paths on systems with preemption, based
on (hopefully correct) observation that the current loops to verify
tid are unnecessary.
Patches 11-20 focus on reducing irq disabled scope in the allocation
slowpath:
- patch 11 moves disabling of irqs into ___slab_alloc() from its
callers, which are the allocation slowpath, and bulk allocation.
Instead these callers only disable preemption to stabilize the cpu.
- The following patches then gradually reduce the scope of disabled
irqs in ___slab_alloc() and the functions called from there. As of
patch 14, the re-enabling of irqs based on gfp flags before calling
the page allocator is removed from allocate_slab(). As of patch 17,
it's possible to reach the page allocator (in case of existing
slabs depleted) without disabling and re-enabling irqs a single
time.
Pathces 21-26 reduce the scope of disabled irqs in functions related
to unfreezing percpu partial slab.
Patch 27 is preparatory. Patch 28 is adopted from the RT tree and
converts the flushing of percpu slabs on all cpus from using IPI to
workqueue, so that the processing isn't happening with irqs disabled
in the IPI handler. The flushing is not performance critical so it
should be acceptable.
Patch 29 also comes from RT tree and makes object_map_lock RT
compatible.
Patch 30 make slab_lock irq-safe on RT where we cannot rely on having
irq disabled from the list_lock spin lock usage.
Patch 31 changes kmem_cache_cpu->partial handling in put_cpu_partial()
from cmpxchg loop to a short irq disabled section, which is used by
all other code modifying the field. This addresses a theoretical race
scenario pointed out by Jann, and makes the critical section safe wrt
with RT local_lock semantics after the conversion in patch 35.
Patch 32 changes preempt disable to migrate disable, so that the
nested list_lock spinlock is safe to take on RT. Because
migrate_disable() is a function call even on !RT, a small set of
private wrappers is introduced to keep using the cheaper
preempt_disable() on !PREEMPT_RT configurations. As of this patch,
SLUB should be already compatible with RT's lock semantics.
Finally, patch 33 changes irq disabled sections that protect
kmem_cache_cpu fields in the slow paths, with a local lock. However on
PREEMPT_RT it means the lockless fast paths can now preempt slow paths
which don't expect that, so the local lock has to be taken also in the
fast paths and they are no longer lockless. RT folks seem to not mind
this tradeoff. The patch also updates the locking documentation in the
file's comment"
Mike Galbraith and Mel Gorman verified that their earlier testing
observations still hold for the final series:
Link: https://lore.kernel.org/lkml/89ba4f783114520c167cc915ba949ad2c04d6790.camel@gmx.de/
Link: https://lore.kernel.org/lkml/20210907082010.GB3959@techsingularity.net/
* tag 'mm-slub-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux: (33 commits)
mm, slub: convert kmem_cpu_slab protection to local_lock
mm, slub: use migrate_disable() on PREEMPT_RT
mm, slub: protect put_cpu_partial() with disabled irqs instead of cmpxchg
mm, slub: make slab_lock() disable irqs with PREEMPT_RT
mm: slub: make object_map_lock a raw_spinlock_t
mm: slub: move flush_cpu_slab() invocations __free_slab() invocations out of IRQ context
mm, slab: split out the cpu offline variant of flush_slab()
mm, slub: don't disable irqs in slub_cpu_dead()
mm, slub: only disable irq with spin_lock in __unfreeze_partials()
mm, slub: separate detaching of partial list in unfreeze_partials() from unfreezing
mm, slub: detach whole partial list at once in unfreeze_partials()
mm, slub: discard slabs in unfreeze_partials() without irqs disabled
mm, slub: move irq control into unfreeze_partials()
mm, slub: call deactivate_slab() without disabling irqs
mm, slub: make locking in deactivate_slab() irq-safe
mm, slub: move reset of c->page and freelist out of deactivate_slab()
mm, slub: stop disabling irqs around get_partial()
mm, slub: check new pages with restored irqs
mm, slub: validate slab from partial list or page allocator before making it cpu slab
mm, slub: restore irqs around calling new_slab()
...
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pidmap_init() has already been replaced with pid_idr_init() in the commit
95846ecf9dac ("pid: replace pid bitmap implementation with IDR API").
Cleanup the stale comment which still mentions it.
Link: https://lkml.kernel.org/r/20210714120713.19825-1-itazur@amazon.com
Signed-off-by: Takahiro Itazuri <itazur@amazon.com>
Cc: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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This counter tracks the number of watches a user has, to compare against
the 'max_user_watches' limit. This causes a scalability bottleneck on
SPECjbb2015 on large systems as there is only one user. Changing to a
per-cpu counter increases throughput of the benchmark by about 30% on a
16-socket, > 1000 thread system.
[rdunlap@infradead.org: fix build errors in kernel/user.c when CONFIG_EPOLL=n]
[npiggin@gmail.com: move ifdefs into wrapper functions, slightly improve panic message]
Link: https://lkml.kernel.org/r/1628051945.fens3r99ox.astroid@bobo.none
[akpm@linux-foundation.org: tweak user_epoll_alloc(), per Guenter]
Link: https://lkml.kernel.org/r/20210804191421.GA1900577@roeck-us.net
Link: https://lkml.kernel.org/r/20210802032013.2751916-1-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reported-by: Anton Blanchard <anton@ozlabs.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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The macros for the unit conversion for frequency are duplicated in
different places.
Provide these macros in the 'units' header, so they can be reused.
Link: https://lkml.kernel.org/r/20210816114732.1834145-3-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Christian Eggers <ceggers@arri.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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Patch series "Add Hz macros", v3.
There are multiple definitions of the HZ_PER_MHZ or HZ_PER_KHZ in the
different drivers. Instead of duplicating this definition again and
again, add one in the units.h header to be reused in all the place the
redefiniton occurs.
At the same time, change the type of the Watts, as they can not be
negative.
This patch (of 10):
The users of the macros are safe to be assigned with an unsigned instead
of signed as the variables using them are themselves unsigned.
Link: https://lkml.kernel.org/r/20210816114732.1834145-1-daniel.lezcano@linaro.org
Link: https://lkml.kernel.org/r/20210816114732.1834145-2-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Christian Eggers <ceggers@arri.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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Fix trivia typo Not -> Note in the comment to DO_ONCE().
Link: https://lkml.kernel.org/r/20210722184349.76290-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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DAMON is designed to be used by kernel space code such as the memory
management subsystems, and therefore it provides only kernel space API.
That said, letting the user space control DAMON could provide some
benefits to them. For example, it will allow user space to analyze their
specific workloads and make their own special optimizations.
For such cases, this commit implements a simple DAMON application kernel
module, namely 'damon-dbgfs', which merely wraps the DAMON api and exports
those to the user space via the debugfs.
'damon-dbgfs' exports three files, ``attrs``, ``target_ids``, and
``monitor_on`` under its debugfs directory, ``<debugfs>/damon/``.
Attributes
----------
Users can read and write the ``sampling interval``, ``aggregation
interval``, ``regions update interval``, and min/max number of monitoring
target regions by reading from and writing to the ``attrs`` file. For
example, below commands set those values to 5 ms, 100 ms, 1,000 ms, 10,
1000 and check it again::
# cd <debugfs>/damon
# echo 5000 100000 1000000 10 1000 > attrs
# cat attrs
5000 100000 1000000 10 1000
Target IDs
----------
Some types of address spaces supports multiple monitoring target. For
example, the virtual memory address spaces monitoring can have multiple
processes as the monitoring targets. Users can set the targets by writing
relevant id values of the targets to, and get the ids of the current
targets by reading from the ``target_ids`` file. In case of the virtual
address spaces monitoring, the values should be pids of the monitoring
target processes. For example, below commands set processes having pids
42 and 4242 as the monitoring targets and check it again::
# cd <debugfs>/damon
# echo 42 4242 > target_ids
# cat target_ids
42 4242
Note that setting the target ids doesn't start the monitoring.
Turning On/Off
--------------
Setting the files as described above doesn't incur effect unless you
explicitly start the monitoring. You can start, stop, and check the
current status of the monitoring by writing to and reading from the
``monitor_on`` file. Writing ``on`` to the file starts the monitoring of
the targets with the attributes. Writing ``off`` to the file stops those.
DAMON also stops if every targets are invalidated (in case of the virtual
memory monitoring, target processes are invalidated when terminated).
Below example commands turn on, off, and check the status of DAMON::
# cd <debugfs>/damon
# echo on > monitor_on
# echo off > monitor_on
# cat monitor_on
off
Please note that you cannot write to the above-mentioned debugfs files
while the monitoring is turned on. If you write to the files while DAMON
is running, an error code such as ``-EBUSY`` will be returned.
[akpm@linux-foundation.org: remove unneeded "alloc failed" printks]
[akpm@linux-foundation.org: replace macro with static inline]
Link: https://lkml.kernel.org/r/20210716081449.22187-8-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
This commit introduces a reference implementation of the address space
specific low level primitives for the virtual address space, so that users
of DAMON can easily monitor the data accesses on virtual address spaces of
specific processes by simply configuring the implementation to be used by
DAMON.
The low level primitives for the fundamental access monitoring are defined
in two parts:
1. Identification of the monitoring target address range for the address
space.
2. Access check of specific address range in the target space.
The reference implementation for the virtual address space does the works
as below.
PTE Accessed-bit Based Access Check
-----------------------------------
The implementation uses PTE Accessed-bit for basic access checks. That
is, it clears the bit for the next sampling target page and checks whether
it is set again after one sampling period. This could disturb the reclaim
logic. DAMON uses ``PG_idle`` and ``PG_young`` page flags to solve the
conflict, as Idle page tracking does.
VMA-based Target Address Range Construction
-------------------------------------------
Only small parts in the super-huge virtual address space of the processes
are mapped to physical memory and accessed. Thus, tracking the unmapped
address regions is just wasteful. However, because DAMON can deal with
some level of noise using the adaptive regions adjustment mechanism,
tracking every mapping is not strictly required but could even incur a
high overhead in some cases. That said, too huge unmapped areas inside
the monitoring target should be removed to not take the time for the
adaptive mechanism.
For the reason, this implementation converts the complex mappings to three
distinct regions that cover every mapped area of the address space. Also,
the two gaps between the three regions are the two biggest unmapped areas
in the given address space. The two biggest unmapped areas would be the
gap between the heap and the uppermost mmap()-ed region, and the gap
between the lowermost mmap()-ed region and the stack in most of the cases.
Because these gaps are exceptionally huge in usual address spaces,
excluding these will be sufficient to make a reasonable trade-off. Below
shows this in detail::
<heap>
<BIG UNMAPPED REGION 1>
<uppermost mmap()-ed region>
(small mmap()-ed regions and munmap()-ed regions)
<lowermost mmap()-ed region>
<BIG UNMAPPED REGION 2>
<stack>
[akpm@linux-foundation.org: mm/damon/vaddr.c needs highmem.h for kunmap_atomic()]
[sjpark@amazon.de: remove unnecessary PAGE_EXTENSION setup]
Link: https://lkml.kernel.org/r/20210806095153.6444-2-sj38.park@gmail.com
[sjpark@amazon.de: safely walk page table]
Link: https://lkml.kernel.org/r/20210831161800.29419-1-sj38.park@gmail.com
Link: https://lkml.kernel.org/r/20210716081449.22187-6-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
PG_idle and PG_young allow the two PTE Accessed bit users, Idle Page
Tracking and the reclaim logic concurrently work while not interfering
with each other. That is, when they need to clear the Accessed bit, they
set PG_young to represent the previous state of the bit, respectively.
And when they need to read the bit, if the bit is cleared, they further
read the PG_young to know whether the other has cleared the bit meanwhile
or not.
For yet another user of the PTE Accessed bit, we could add another page
flag, or extend the mechanism to use the flags. For the DAMON usecase,
however, we don't need to do that just yet. IDLE_PAGE_TRACKING and DAMON
are mutually exclusive, so there's only ever going to be one user of the
current set of flags.
In this commit, we split out the CONFIG options to allow for the use of
PG_young and PG_idle outside of idle page tracking.
In the next commit, DAMON's reference implementation of the virtual memory
address space monitoring primitives will use it.
[sjpark@amazon.de: set PAGE_EXTENSION for non-64BIT]
Link: https://lkml.kernel.org/r/20210806095153.6444-1-sj38.park@gmail.com
[akpm@linux-foundation.org: tweak Kconfig text]
[sjpark@amazon.de: hide PAGE_IDLE_FLAG from users]
Link: https://lkml.kernel.org/r/20210813081238.34705-1-sj38.park@gmail.com
Link: https://lkml.kernel.org/r/20210716081449.22187-5-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Even somehow the initial monitoring target regions are well constructed to
fulfill the assumption (pages in same region have similar access
frequencies), the data access pattern can be dynamically changed. This
will result in low monitoring quality. To keep the assumption as much as
possible, DAMON adaptively merges and splits each region based on their
access frequency.
For each ``aggregation interval``, it compares the access frequencies of
adjacent regions and merges those if the frequency difference is small.
Then, after it reports and clears the aggregated access frequency of each
region, it splits each region into two or three regions if the total
number of regions will not exceed the user-specified maximum number of
regions after the split.
In this way, DAMON provides its best-effort quality and minimal overhead
while keeping the upper-bound overhead that users set.
Link: https://lkml.kernel.org/r/20210716081449.22187-4-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
To avoid the unbounded increase of the overhead, DAMON groups adjacent
pages that are assumed to have the same access frequencies into a
region. As long as the assumption (pages in a region have the same
access frequencies) is kept, only one page in the region is required to
be checked. Thus, for each ``sampling interval``,
1. the 'prepare_access_checks' primitive picks one page in each region,
2. waits for one ``sampling interval``,
3. checks whether the page is accessed meanwhile, and
4. increases the access count of the region if so.
Therefore, the monitoring overhead is controllable by adjusting the
number of regions. DAMON allows both the underlying primitives and user
callbacks to adjust regions for the trade-off. In other words, this
commit makes DAMON to use not only time-based sampling but also
space-based sampling.
This scheme, however, cannot preserve the quality of the output if the
assumption is not guaranteed. Next commit will address this problem.
Link: https://lkml.kernel.org/r/20210716081449.22187-3-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "Introduce Data Access MONitor (DAMON)", v34.
Introduction
============
DAMON is a data access monitoring framework for the Linux kernel. The
core mechanisms of DAMON called 'region based sampling' and 'adaptive
regions adjustment' (refer to 'mechanisms.rst' in the 11th patch of this
patchset for the detail) make it
- accurate (The monitored information is useful for DRAM level memory
management. It might not appropriate for Cache-level accuracy,
though.),
- light-weight (The monitoring overhead is low enough to be applied
online while making no impact on the performance of the target
workloads.), and
- scalable (the upper-bound of the instrumentation overhead is
controllable regardless of the size of target workloads.).
Using this framework, therefore, several memory management mechanisms such
as reclamation and THP can be optimized to aware real data access
patterns. Experimental access pattern aware memory management
optimization works that incurring high instrumentation overhead will be
able to have another try.
Though DAMON is for kernel subsystems, it can be easily exposed to the
user space by writing a DAMON-wrapper kernel subsystem. Then, user space
users who have some special workloads will be able to write personalized
tools or applications for deeper understanding and specialized
optimizations of their systems.
DAMON is also merged in two public Amazon Linux kernel trees that based on
v5.4.y[1] and v5.10.y[2].
[1] https://github.com/amazonlinux/linux/tree/amazon-5.4.y/master/mm/damon
[2] https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon
The userspace tool[1] is available, released under GPLv2, and actively
being maintained. I am also planning to implement another basic user
interface in perf[2]. Also, the basic test suite for DAMON is available
under GPLv2[3].
[1] https://github.com/awslabs/damo
[2] https://lore.kernel.org/linux-mm/20210107120729.22328-1-sjpark@amazon.com/
[3] https://github.com/awslabs/damon-tests
Long-term Plan
--------------
DAMON is a part of a project called Data Access-aware Operating System
(DAOS). As the name implies, I want to improve the performance and
efficiency of systems using fine-grained data access patterns. The
optimizations are for both kernel and user spaces. I will therefore
modify or create kernel subsystems, export some of those to user space and
implement user space library / tools. Below shows the layers and
components for the project.
---------------------------------------------------------------------------
Primitives: PTE Accessed bit, PG_idle, rmap, (Intel CMT), ...
Framework: DAMON
Features: DAMOS, virtual addr, physical addr, ...
Applications: DAMON-debugfs, (DARC), ...
^^^^^^^^^^^^^^^^^^^^^^^ KERNEL SPACE ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Raw Interface: debugfs, (sysfs), (damonfs), tracepoints, (sys_damon), ...
vvvvvvvvvvvvvvvvvvvvvvv USER SPACE vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Library: (libdamon), ...
Tools: DAMO, (perf), ...
---------------------------------------------------------------------------
The components in parentheses or marked as '...' are not implemented yet
but in the future plan. IOW, those are the TODO tasks of DAOS project.
For more detail, please refer to the plans:
https://lore.kernel.org/linux-mm/20201202082731.24828-1-sjpark@amazon.com/
Evaluations
===========
We evaluated DAMON's overhead, monitoring quality and usefulness using 24
realistic workloads on my QEMU/KVM based virtual machine running a kernel
that v24 DAMON patchset is applied.
DAMON is lightweight. It increases system memory usage by 0.39% and slows
target workloads down by 1.16%.
DAMON is accurate and useful for memory management optimizations. An
experimental DAMON-based operation scheme for THP, namely 'ethp', removes
76.15% of THP memory overheads while preserving 51.25% of THP speedup.
Another experimental DAMON-based 'proactive reclamation' implementation,
'prcl', reduces 93.38% of residential sets and 23.63% of system memory
footprint while incurring only 1.22% runtime overhead in the best case
(parsec3/freqmine).
NOTE that the experimental THP optimization and proactive reclamation are
not for production but only for proof of concepts.
Please refer to the official document[1] or "Documentation/admin-guide/mm:
Add a document for DAMON" patch in this patchset for detailed evaluation
setup and results.
[1] https://damonitor.github.io/doc/html/latest-damon/admin-guide/mm/damon/eval.html
Real-world User Story
=====================
In summary, DAMON has used on production systems and proved its usefulness.
DAMON as a profiler
-------------------
We analyzed characteristics of a large scale production systems of our
customers using DAMON. The systems utilize 70GB DRAM and 36 CPUs. From
this, we were able to find interesting things below.
There were obviously different access pattern under idle workload and
active workload. Under the idle workload, it accessed large memory
regions with low frequency, while the active workload accessed small
memory regions with high freuqnecy.
DAMON found a 7GB memory region that showing obviously high access
frequency under the active workload. We believe this is the
performance-effective working set and need to be protected.
There was a 4KB memory region that showing highest access frequency under
not only active but also idle workloads. We think this must be a hottest
code section like thing that should never be paged out.
For this analysis, DAMON used only 0.3-1% of single CPU time. Because we
used recording-based analysis, it consumed about 3-12 MB of disk space per
20 minutes. This is only small amount of disk space, but we can further
reduce the disk usage by using non-recording-based DAMON features. I'd
like to argue that only DAMON can do such detailed analysis (finding 4KB
highest region in 70GB memory) with the light overhead.
DAMON as a system optimization tool
-----------------------------------
We also found below potential performance problems on the systems and made
DAMON-based solutions.
The system doesn't want to make the workload suffer from the page
reclamation and thus it utilizes enough DRAM but no swap device. However,
we found the system is actively reclaiming file-backed pages, because the
system has intensive file IO. The file IO turned out to be not
performance critical for the workload, but the customer wanted to ensure
performance critical file-backed pages like code section to not mistakenly
be evicted.
Using direct IO should or `mlock()` would be a straightforward solution,
but modifying the user space code is not easy for the customer.
Alternatively, we could use DAMON-based operation scheme[1]. By using it,
we can ask DAMON to track access frequency of each region and make
'process_madvise(MADV_WILLNEED)[2]' call for regions having specific size
and access frequency for a time interval.
We also found the system is having high number of TLB misses. We tried
'always' THP enabled policy and it greatly reduced TLB misses, but the
page reclamation also been more frequent due to the THP internal
fragmentation caused memory bloat. We could try another DAMON-based
operation scheme that applies 'MADV_HUGEPAGE' to memory regions having
>=2MB size and high access frequency, while applying 'MADV_NOHUGEPAGE' to
regions having <2MB size and low access frequency.
We do not own the systems so we only reported the analysis results and
possible optimization solutions to the customers. The customers satisfied
about the analysis results and promised to try the optimization guides.
[1] https://lore.kernel.org/linux-mm/20201006123931.5847-1-sjpark@amazon.com/
[2] https://lore.kernel.org/linux-api/20200622192900.22757-4-minchan@kernel.org/
Comparison with Idle Page Tracking
==================================
Idle Page Tracking allows users to set and read idleness of pages using a
bitmap file which represents each page with each bit of the file. One
recommended usage of it is working set size detection. Users can do that
by
1. find PFN of each page for workloads in interest,
2. set all the pages as idle by doing writes to the bitmap file,
3. wait until the workload accesses its working set, and
4. read the idleness of the pages again and count pages became not idle.
NOTE: While Idle Page Tracking is for user space users, DAMON is primarily
designed for kernel subsystems though it can easily exposed to the user
space. Hence, this section only assumes such user space use of DAMON.
For what use cases Idle Page Tracking would be better?
------------------------------------------------------
1. Flexible usecases other than hotness monitoring.
Because Idle Page Tracking allows users to control the primitive (Page
idleness) by themselves, Idle Page Tracking users can do anything they
want. Meanwhile, DAMON is primarily designed to monitor the hotness of
each memory region. For this, DAMON asks users to provide sampling
interval and aggregation interval. For the reason, there could be some
use case that using Idle Page Tracking is simpler.
2. Physical memory monitoring.
Idle Page Tracking receives PFN range as input, so natively supports
physical memory monitoring.
DAMON is designed to be extensible for multiple address spaces and use
cases by implementing and using primitives for the given use case.
Therefore, by theory, DAMON has no limitation in the type of target
address space as long as primitives for the given address space exists.
However, the default primitives introduced by this patchset supports only
virtual address spaces.
Therefore, for physical memory monitoring, you should implement your own
primitives and use it, or simply use Idle Page Tracking.
Nonetheless, RFC patchsets[1] for the physical memory address space
primitives is already available. It also supports user memory same to
Idle Page Tracking.
[1] https://lore.kernel.org/linux-mm/20200831104730.28970-1-sjpark@amazon.com/
For what use cases DAMON is better?
-----------------------------------
1. Hotness Monitoring.
Idle Page Tracking let users know only if a page frame is accessed or not.
For hotness check, the user should write more code and use more memory.
DAMON do that by itself.
2. Low Monitoring Overhead
DAMON receives user's monitoring request with one step and then provide
the results. So, roughly speaking, DAMON require only O(1) user/kernel
context switches.
In case of Idle Page Tracking, however, because the interface receives
contiguous page frames, the number of user/kernel context switches
increases as the monitoring target becomes complex and huge. As a result,
the context switch overhead could be not negligible.
Moreover, DAMON is born to handle with the monitoring overhead. Because
the core mechanism is pure logical, Idle Page Tracking users might be able
to implement the mechanism on their own, but it would be time consuming
and the user/kernel context switching will still more frequent than that
of DAMON. Also, the kernel subsystems cannot use the logic in this case.
3. Page granularity working set size detection.
Until v22 of this patchset, this was categorized as the thing Idle Page
Tracking could do better, because DAMON basically maintains additional
metadata for each of the monitoring target regions. So, in the page
granularity working set size detection use case, DAMON would incur (number
of monitoring target pages * size of metadata) memory overhead. Size of
the single metadata item is about 54 bytes, so assuming 4KB pages, about
1.3% of monitoring target pages will be additionally used.
All essential metadata for Idle Page Tracking are embedded in 'struct
page' and page table entries. Therefore, in this use case, only one
counter variable for working set size accounting is required if Idle Page
Tracking is used.
There are more details to consider, but roughly speaking, this is true in
most cases.
However, the situation changed from v23. Now DAMON supports arbitrary
types of monitoring targets, which don't use the metadata. Using that,
DAMON can do the working set size detection with no additional space
overhead but less user-kernel context switch. A first draft for the
implementation of monitoring primitives for this usage is available in a
DAMON development tree[1]. An RFC patchset for it based on this patchset
will also be available soon.
Since v24, the arbitrary type support is dropped from this patchset
because this patchset doesn't introduce real use of the type. You can
still get it from the DAMON development tree[2], though.
[1] https://github.com/sjp38/linux/tree/damon/pgidle_hack
[2] https://github.com/sjp38/linux/tree/damon/master
4. More future usecases
While Idle Page Tracking has tight coupling with base primitives (PG_Idle
and page table Accessed bits), DAMON is designed to be extensible for many
use cases and address spaces. If you need some special address type or
want to use special h/w access check primitives, you can write your own
primitives for that and configure DAMON to use those. Therefore, if your
use case could be changed a lot in future, using DAMON could be better.
Can I use both Idle Page Tracking and DAMON?
--------------------------------------------
Yes, though using them concurrently for overlapping memory regions could
result in interference to each other. Nevertheless, such use case would
be rare or makes no sense at all. Even in the case, the noise would bot
be really significant. So, you can choose whatever you want depending on
the characteristics of your use cases.
More Information
================
We prepared a showcase web site[1] that you can get more information.
There are
- the official documentations[2],
- the heatmap format dynamic access pattern of various realistic workloads for
heap area[3], mmap()-ed area[4], and stack[5] area,
- the dynamic working set size distribution[6] and chronological working set
size changes[7], and
- the latest performance test results[8].
[1] https://damonitor.github.io/_index
[2] https://damonitor.github.io/doc/html/latest-damon
[3] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.0.png.html
[4] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.1.png.html
[5] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.2.png.html
[6] https://damonitor.github.io/test/result/visual/latest/rec.wss_sz.png.html
[7] https://damonitor.github.io/test/result/visual/latest/rec.wss_time.png.html
[8] https://damonitor.github.io/test/result/perf/latest/html/index.html
Baseline and Complete Git Trees
===============================
The patches are based on the latest -mm tree, specifically
v5.14-rc1-mmots-2021-07-15-18-47 of https://github.com/hnaz/linux-mm. You can
also clone the complete git tree:
$ git clone git://github.com/sjp38/linux -b damon/patches/v34
The web is also available:
https://github.com/sjp38/linux/releases/tag/damon/patches/v34
Development Trees
-----------------
There are a couple of trees for entire DAMON patchset series and features
for future release.
- For latest release: https://github.com/sjp38/linux/tree/damon/master
- For next release: https://github.com/sjp38/linux/tree/damon/next
Long-term Support Trees
-----------------------
For people who want to test DAMON but using LTS kernels, there are another
couple of trees based on two latest LTS kernels respectively and
containing the 'damon/master' backports.
- For v5.4.y: https://github.com/sjp38/linux/tree/damon/for-v5.4.y
- For v5.10.y: https://github.com/sjp38/linux/tree/damon/for-v5.10.y
Amazon Linux Kernel Trees
-------------------------
DAMON is also merged in two public Amazon Linux kernel trees that based on
v5.4.y[1] and v5.10.y[2].
[1] https://github.com/amazonlinux/linux/tree/amazon-5.4.y/master/mm/damon
[2] https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon
Git Tree for Diff of Patches
============================
For easy review of diff between different versions of each patch, I
prepared a git tree containing all versions of the DAMON patchset series:
https://github.com/sjp38/damon-patches
You can clone it and use 'diff' for easy review of changes between
different versions of the patchset. For example:
$ git clone https://github.com/sjp38/damon-patches && cd damon-patches
$ diff -u damon/v33 damon/v34
Sequence Of Patches
===================
First three patches implement the core logics of DAMON. The 1st patch
introduces basic sampling based hotness monitoring for arbitrary types of
targets. Following two patches implement the core mechanisms for control
of overhead and accuracy, namely regions based sampling (patch 2) and
adaptive regions adjustment (patch 3).
Now the essential parts of DAMON is complete, but it cannot work unless
someone provides monitoring primitives for a specific use case. The
following two patches make it just work for virtual address spaces
monitoring. The 4th patch makes 'PG_idle' can be used by DAMON and the
5th patch implements the virtual memory address space specific monitoring
primitives using page table Accessed bits and the 'PG_idle' page flag.
Now DAMON just works for virtual address space monitoring via the kernel
space api. To let the user space users can use DAMON, following four
patches add interfaces for them. The 6th patch adds a tracepoint for
monitoring results. The 7th patch implements a DAMON application kernel
module, namely damon-dbgfs, that simply wraps DAMON and exposes DAMON
interface to the user space via the debugfs interface. The 8th patch
further exports pid of monitoring thread (kdamond) to user space for
easier cpu usage accounting, and the 9th patch makes the debugfs interface
to support multiple contexts.
Three patches for maintainability follows. The 10th patch adds
documentations for both the user space and the kernel space. The 11th
patch provides unit tests (based on the kunit) while the 12th patch adds
user space tests (based on the kselftest).
Finally, the last patch (13th) updates the MAINTAINERS file.
This patch (of 13):
DAMON is a data access monitoring framework for the Linux kernel. The
core mechanisms of DAMON make it
- accurate (the monitoring output is useful enough for DRAM level
performance-centric memory management; It might be inappropriate for
CPU cache levels, though),
- light-weight (the monitoring overhead is normally low enough to be
applied online), and
- scalable (the upper-bound of the overhead is in constant range
regardless of the size of target workloads).
Using this framework, hence, we can easily write efficient kernel space
data access monitoring applications. For example, the kernel's memory
management mechanisms can make advanced decisions using this.
Experimental data access aware optimization works that incurring high
access monitoring overhead could again be implemented on top of this.
Due to its simple and flexible interface, providing user space interface
would be also easy. Then, user space users who have some special
workloads can write personalized applications for better understanding and
optimizations of their workloads and systems.
===
Nevertheless, this commit is defining and implementing only basic access
check part without the overhead-accuracy handling core logic. The basic
access check is as below.
The output of DAMON says what memory regions are how frequently accessed
for a given duration. The resolution of the access frequency is
controlled by setting ``sampling interval`` and ``aggregation interval``.
In detail, DAMON checks access to each page per ``sampling interval`` and
aggregates the results. In other words, counts the number of the accesses
to each region. After each ``aggregation interval`` passes, DAMON calls
callback functions that previously registered by users so that users can
read the aggregated results and then clears the results. This can be
described in below simple pseudo-code::
init()
while monitoring_on:
for page in monitoring_target:
if accessed(page):
nr_accesses[page] += 1
if time() % aggregation_interval == 0:
for callback in user_registered_callbacks:
callback(monitoring_target, nr_accesses)
for page in monitoring_target:
nr_accesses[page] = 0
if time() % update_interval == 0:
update()
sleep(sampling interval)
The target regions constructed at the beginning of the monitoring and
updated after each ``regions_update_interval``, because the target regions
could be dynamically changed (e.g., mmap() or memory hotplug). The
monitoring overhead of this mechanism will arbitrarily increase as the
size of the target workload grows.
The basic monitoring primitives for actual access check and dynamic target
regions construction aren't in the core part of DAMON. Instead, it allows
users to implement their own primitives that are optimized for their use
case and configure DAMON to use those. In other words, users cannot use
current version of DAMON without some additional works.
Following commits will implement the core mechanisms for the
overhead-accuracy control and default primitives implementations.
Link: https://lkml.kernel.org/r/20210716081449.22187-1-sj38.park@gmail.com
Link: https://lkml.kernel.org/r/20210716081449.22187-2-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Marco Elver <elver@google.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Joe Perches <joe@perches.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Instead of hard-coding ((1UL << NR_PAGEFLAGS) - 1) everywhere, introducing
PAGEFLAGS_MASK to make the code clear to get the page flags.
Link: https://lkml.kernel.org/r/20210819150712.59948-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
kmap_atomic() disables preemption and pagefaults for historical reasons.
The conversion to kmap_local(), which only disables migration, cannot be
done wholesale because quite some call sites need to be updated to
accommodate with the changed semantics.
On PREEMPT_RT enabled kernels the kmap_atomic() semantics are problematic
due to the implicit disabling of preemption which makes it impossible to
acquire 'sleeping' spinlocks within the kmap atomic sections.
PREEMPT_RT replaces the preempt_disable() with a migrate_disable() for
more than a decade. It could be argued that this is a justification to do
this unconditionally, but PREEMPT_RT covers only a limited number of
architectures and it disables some functionality which limits the coverage
further.
Limit the replacement to PREEMPT_RT for now.
Link: https://lkml.kernel.org/r/20210810091116.pocdmaatdcogvdso@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "small ioremap cleanups".
The first patch moves a little code around the vmalloc/ioremap boundary
following a bigger move by Nick earlier. The second enforces
non-executable mapping on ioremap just like we do for vmap. No driver
currently uses executable mappings anyway, as they should.
This patch (of 2):
This keeps it together with the implementation, and to remove the
vmap_range wrapper.
Link: https://lkml.kernel.org/r/20210824091259.1324527-1-hch@lst.de
Link: https://lkml.kernel.org/r/20210824091259.1324527-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
There is a READ_ONCE() in the macro of compound_head(), which will prevent
compiler from optimizing the code when there are more than once calling of
it in a function. Remove the redundant calling of compound_head() from
page_to_index() and page_add_file_rmap() for better code generation.
Link: https://lkml.kernel.org/r/20210811101431.83940-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Currently, the "auto-movable" online policy does not allow for hotplugged
KERNEL (ZONE_NORMAL) memory to increase the amount of MOVABLE memory we
can have, primarily, because there is no coordiantion across memory
devices and we don't want to create zone-imbalances accidentially when
unplugging memory.
However, within a single memory device it's different. Let's allow for
KERNEL memory within a dynamic memory group to allow for more MOVABLE
within the same memory group. The only thing we have to take care of is
that the managing driver avoids zone imbalances by unplugging MOVABLE
memory first, otherwise there can be corner cases where unplug of memory
could result in (accidential) zone imbalances.
virtio-mem is the only user of dynamic memory groups and recently added
support for prioritizing unplug of ZONE_MOVABLE over ZONE_NORMAL, so we
don't need a new toggle to enable it for dynamic memory groups.
We limit this handling to dynamic memory groups, because:
* We want to keep the runtime overhead for collecting stats when
onlining a single memory block small. We tend to have only a handful of
dynamic memory groups, but we can have quite some static memory groups
(e.g., 256 DIMMs).
* It doesn't make too much sense for static memory groups, as we try
onlining all applicable memory blocks either completely to ZONE_MOVABLE
or not. In ordinary operation, we won't have a mixture of zones within
a static memory group.
When adding memory to a dynamic memory group, we'll first online memory to
ZONE_MOVABLE as long as early KERNEL memory allows for it. Then, we'll
online the next unit(s) to ZONE_NORMAL, until we can online the next
unit(s) to ZONE_MOVABLE.
For a simple virtio-mem device with a MOVABLE:KERNEL ratio of 3:1, it will
result in a layout like:
[M][M][M][M][M][M][M][M][N][M][M][M][N][M][M][M]...
^ movable memory due to early kernel memory
^ allows for more movable memory ...
^-----^ ... here
^ allows for more movable memory ...
^-----^ ... here
While the created layout is sub-optimal when it comes to contiguous zones,
it gives us the maximum flexibility when dynamically growing/shrinking a
device; we can grow small VMs really big in small steps, and still shrink
reliably to e.g., 1/4 of the maximum VM size in this example, removing
full memory blocks along with meta data more reliably.
Mark dynamic memory groups in the xarray such that we can efficiently
iterate over them when collecting stats. In usual setups, we have one
virtio-mem device per NUMA node, and usually only a small number of NUMA
nodes.
Note: for now, there seems to be no compelling reason to make this
behavior configurable.
Link: https://lkml.kernel.org/r/20210806124715.17090-10-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hui Zhu <teawater@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Marek Kedzierski <mkedzier@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Use memory groups to improve our "auto-movable" onlining policy:
1. For static memory groups (e.g., a DIMM), online a memory block MOVABLE
only if all other memory blocks in the group are either MOVABLE or could
be onlined MOVABLE. A DIMM will either be MOVABLE or not, not a mixture.
2. For dynamic memory groups (e.g., a virtio-mem device), online a
memory block MOVABLE only if all other memory blocks inside the
current unit are either MOVABLE or could be onlined MOVABLE. For a
virtio-mem device with a device block size with 512 MiB, all 128 MiB
memory blocks wihin a 512 MiB unit will either be MOVABLE or not, not
a mixture.
We have to pass the memory group to zone_for_pfn_range() to take the
memory group into account.
Note: for now, there seems to be no compelling reason to make this
behavior configurable.
Link: https://lkml.kernel.org/r/20210806124715.17090-9-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hui Zhu <teawater@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Marek Kedzierski <mkedzier@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
Linus Torvalds
Thomas Gleixner
Sebastian Andrzej Siewior
Rafael J. Wysocki
Masami Hiramatsu
Liam Howlett
Liu Zixian
Nick Desaulniers
Dan Williams
Arnd Bergmann
Takahiro Itazuri
Nicholas Piggin
Daniel Lezcano
Andy Shevchenko
SeongJae Park
Muchun Song
Christoph Hellwig
David Hildenbrand