Currently, memmap_on_memory feature is only supported with memory block
sizes that result in vmemmap pages covering full page blocks. This is
because memory onlining/offlining code requires applicable ranges to be
pageblock-aligned, for example, to set the migratetypes properly.
This patch helps to lift that restriction by reserving more pages than
required for vmemmap space. This helps the start address to be page block
aligned with different memory block sizes. Using this facility implies
the kernel will be reserving some pages for every memoryblock. This
allows the memmap on memory feature to be widely useful with different
memory block size values.
For ex: with 64K page size and 256MiB memory block size, we require 4
pages to map vmemmap pages, To align things correctly we end up adding a
reserve of 28 pages. ie, for every 4096 pages 28 pages get reserved.
Link: https://lkml.kernel.org/r/20230808091501.287660-5-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's update the documentation that any signal is sufficient, and add a
comment that not only checking for fatal signals is historical baggage:
changing it now could break existing user space. although unlikely.
For example, when an app provides a custom SIGALRM handler and triggers
memory offlining, the timeout cmd would no longer stop memory offlining,
because SIGALRM would no longer be considered a fatal signal.
Note that using signal_pending() instead of fatal_signal_pending() is
an anti-pattern, but slowly deprecating that behavior to eventually
change it in the far future is probably not worth the effort. If this
ever becomes relevant for user-space, we might want to rethink.
Link: https://lkml.kernel.org/r/20230711174050.603820-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kmem.limit_in_bytes (v1 way to limit kernel memory usage) has been
deprecated since 58056f7750 ("memcg, kmem: further deprecate
kmem.limit_in_bytes") merged in 5.16. We haven't heard about any serious
users since then but it seems that the mere presence of the file is
causing more harm thatn good. We (SUSE) have had several bug reports from
customers where Docker based containers started to fail because a write to
kmem.limit_in_bytes has failed.
This was unexpected because runc code only expects ENOENT (kmem disabled)
or EBUSY (tasks already running within cgroup). So a new error code was
unexpected and the whole container startup failed. This has been later
addressed by
52390d6804
so current Docker runtimes do not suffer from the problem anymore. There
are still older version of Docker in use and likely hard to get rid of
completely.
Address this by wiping out the file completely and effectively get back to
pre 4.5 era and CONFIG_MEMCG_KMEM=n configuration.
I would recommend backporting to stable trees which have picked up
58056f7750 ("memcg, kmem: further deprecate kmem.limit_in_bytes").
[mhocko@suse.com: restore _KMEM switch case]
Link: https://lkml.kernel.org/r/ZKe5wxdbvPi5Cwd7@dhcp22.suse.cz
Link: https://lkml.kernel.org/r/20230704115240.14672-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
As pages_sharing and pages_shared don't include the number of zero pages
merged by KSM, we cannot know how many pages are zero pages placed by KSM
when enabling use_zero_pages, which leads to KSM not being transparent
with all actual merged pages by KSM. In the early days of use_zero_pages,
zero-pages was unable to get unshared by the ways like MADV_UNMERGEABLE so
it's hard to count how many times one of those zeropages was then
unmerged.
But now, unsharing KSM-placed zero page accurately has been achieved, so
we can easily count both how many times a page full of zeroes was merged
with zero-page and how many times one of those pages was then unmerged.
and so, it helps to estimate memory demands when each and every shared
page could get unshared.
So we add ksm_zero_pages under /sys/kernel/mm/ksm/ to show the number
of all zero pages placed by KSM. Meanwhile, we update the Documentation.
Link: https://lkml.kernel.org/r/20230613030934.185944-1-yang.yang29@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn>
Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn>
Reviewed-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This patch enables config option GENERIC_IDLE_POLL_SETUP for arch
powerpc. This adds support for kernel param 'nohlt'.
Powerpc kernel also supports another kernel boot-time param called
'powersave' which can also be used to disable all cpu idle-states and
forces CPU to an idle-loop similar to what cpu_idle_poll() does. This
patch however makes powerpc kernel-parameters better aligned to the
generic boot-time parameters.
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230818050739.827851-1-vaibhav@linux.ibm.com
Since for MMIO driver using FIFO registers, also known as tpm_tis, the
default (and tbh recommended) behaviour is now the polling mode, the
"tristate" workaround is no longer for benefit.
If someone wants to explicitly enable IRQs for a TPM chip that should be
without question allowed. It could very well be a piece hardware in the
existing deny list because of e.g. firmware update or something similar.
While at it, document the module parameter, as this was not done in 2006
when it first appeared in the mainline.
Link: https://lore.kernel.org/linux-integrity/20201015214430.17937-1-jsnitsel@redhat.com/
Link: https://lore.kernel.org/all/1145393776.4829.19.camel@localhost.localdomain/
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Add an optional timeout arg to 'rootwait' as the maximum time in
seconds to wait for the root device to show up before attempting
forced mount of the root filesystem.
Use case:
In case of device mapper usage for the rootfs (e.g. root=/dev/dm-0),
if the mapper is not able to create the virtual block for any reason
(wrong arguments, bad dm-verity signature, etc), the `rootwait` param
causes the kernel to wait forever. It may however be desirable to only
wait for a given time and then panic (force mount) to cause device reset.
This gives the bootloader a chance to detect the problem and to take some
measures, such as marking the booted partition as bad (for A/B case) or
entering a recovery mode.
In success case, mounting happens as soon as the root device is ready,
unlike the existing 'rootdelay' parameter which performs an unconditional
pause.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Message-Id: <20230813082349.513386-1-loic.poulain@linaro.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit adds a module parameter that causes the locktorture writer
to run at real-time priority.
To use it:
insmod /lib/modules/torture.ko random_shuffle=1
insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3 writer_fifo=1
^^^^^^^^^^^^^
A predecessor to this patch has been helpful to uncover issues with the
proxy-execution series.
[ paulmck: Remove locktorture-specific code from kernel/torture.c. ]
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: kernel-team@android.com
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
[jstultz: Include header change to build, reword commit message]
Signed-off-by: John Stultz <jstultz@google.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
While workqueue.default_affinity_scope is writable, it only affects
workqueues which are created afterwards and isn't very useful. Instead,
let's introduce explicit "default" scope and update the effective scope
dynamically when workqueue.default_affinity_scope is changed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Add three more affinity scopes - WQ_AFFN_CPU, SMT and CACHE - and make CACHE
the default. The code changes to actually add the additional scopes are
trivial.
Also add module parameter "workqueue.default_affinity_scope" to override the
default scope and "affinity_scope" sysfs file to configure it per workqueue.
wq_dump.py and documentations are updated accordingly.
This enables significant flexibility in configuring how unbound workqueues
behave. If affinity scope is set to "cpu", it'll behave close to a per-cpu
workqueue. On the other hand, "system" removes all locality boundaries.
Many modern machines have multiple L3 caches often while being mostly
uniform in terms of memory access. Thus, workqueue's previous behavior of
spreading work items in each NUMA node had negative performance implications
from unncessarily crossing L3 boundaries between issue and execution.
However, picking a finer grained affinity scope also has a downside in that
an issuer in one group can't utilize CPUs in other groups.
While dependent on the specifics of workload, there's usually a noticeable
penalty in crossing L3 boundaries, so let's default to CACHE. This issue
will be further addressed and documented with examples in future patches.
Signed-off-by: Tejun Heo <tj@kernel.org>
Unbound workqueue CPU affinity is going to receive an overhaul and the NUMA
specific knobs won't make sense anymore. Remove them. Also, the pool_ids
knob was used for debugging and not really meaningful given that there is no
visibility into the pools associated with those IDs. Remove it too. A future
patch will improve overall visibility.
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull x86/gds fixes from Dave Hansen:
"Mitigate Gather Data Sampling issue:
- Add Base GDS mitigation
- Support GDS_NO under KVM
- Fix a documentation typo"
* tag 'gds-for-linus-2023-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Documentation/x86: Fix backwards on/off logic about YMM support
KVM: Add GDS_NO support to KVM
x86/speculation: Add Kconfig option for GDS
x86/speculation: Add force option to GDS mitigation
x86/speculation: Add Gather Data Sampling mitigation
Pull x86/srso fixes from Borislav Petkov:
"Add a mitigation for the speculative RAS (Return Address Stack)
overflow vulnerability on AMD processors.
In short, this is yet another issue where userspace poisons a
microarchitectural structure which can then be used to leak privileged
information through a side channel"
* tag 'x86_bugs_srso' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/srso: Tie SBPB bit setting to microcode patch detection
x86/srso: Add a forgotten NOENDBR annotation
x86/srso: Fix return thunks in generated code
x86/srso: Add IBPB on VMEXIT
x86/srso: Add IBPB
x86/srso: Add SRSO_NO support
x86/srso: Add IBPB_BRTYPE support
x86/srso: Add a Speculative RAS Overflow mitigation
x86/bugs: Increase the x86 bugs vector size to two u32s
Pull RISC-V fixes from Palmer Dabbelt:
- A pair of fixes for build-related failures in the selftests
- A fix for a sparse warning in acpi_os_ioremap()
- A fix to restore the kernel PA offset in vmcoreinfo, to fix crash
handling
* tag 'riscv-for-linus-6.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
Documentation: kdump: Add va_kernel_pa_offset for RISCV64
riscv: Export va_kernel_pa_offset in vmcoreinfo
RISC-V: ACPI: Fix acpi_os_ioremap to return iomem address
selftests: riscv: Fix compilation error with vstate_exec_nolibc.c
selftests/riscv: fix potential build failure during the "emit_tests" step
Printing the line number without the file is of limited usefulness.
Knowing the filename also makes it also easier to relate the logged
information to the controlfile.
Example:
# modprobe test_dynamic_debug
# echo 'file test_dynamic_debug.c =pfsl' > /proc/dynamic_debug/control
# echo 1 > /sys/module/test_dynamic_debug/parameters/do_prints
# dmesg | tail -2
[ 71.802212] do_cats:lib/test_dynamic_debug.c:103: test_dd: doing categories
[ 71.802227] do_levels:lib/test_dynamic_debug.c:123: test_dd: doing levels
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@akamai.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230709-dyndbg-filename-v2-3-fd83beef0925@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for HOTPLUG_SMT, which enables the generic sysfs SMT support
files in /sys/devices/system/cpu/smt, as well as the "nosmt" boot
parameter.
Implement the recently added hooks to allow partial SMT states, allow
any number of threads per core.
Tie the config symbol to HOTPLUG_CPU, which enables it on the major
platforms that support SMT. If there are other platforms that want the
SMT support that can be tweaked in future.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[ldufour: remove topology_smt_supported]
[ldufour: remove topology_smt_threads_supported]
[ldufour: select CONFIG_SMT_NUM_THREADS_DYNAMIC]
[ldufour: update kernel-parameters.txt]
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Link: https://msgid.link/20230705145143.40545-10-ldufour@linux.ibm.com
These options clearly turn *off* XSAVE YMM support. Correct the
typo.
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Fixes: 553a5c03e9 ("x86/speculation: Add force option to GDS mitigation")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Commit e55b9f9686 ("mm: memcontrol: drop dead CONFIG_MEMCG_SWAP
config symbol") removed MEMCG_SWAP as it was just a shorthand for
CONFIG_MEMCG && CONFIG_SWAP.
The commit also adjusted the documentation but missed reference to
CONFIG_MEM_RES_CTRL_SWAP, which was the previous name of
CONFIG_MEMCG_SWAP before renaming in commit c255a45805 ("memcg: rename
config variables").
Update the reference to the current state.
Signed-off-by: Krzysztof Pawlaczyk <krzpaw@gmail.com>
Reviewed-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230728105723.251892-1-krzpaw@gmail.com
The kernel parameter 'cma_pernuma=' only supports reserving the same
size of CMA area for each node. We need to reserve different sizes of
CMA area for specified nodes if these devices belong to different nodes.
Adding another kernel parameter 'numa_cma=' to reserve CMA area for
the specified node. If we want to use one of these parameters, we need to
enable DMA_NUMA_CMA.
At the same time, print the node id in cma_declare_contiguous_nid() if
CONFIG_NUMA is enabled.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: Christoph Hellwig <hch@lst.de>
In the commit b7176c261c ("dma-contiguous: provide the ability to
reserve per-numa CMA"), Barry adds DMA_PERNUMA_CMA for ARM64.
But this feature is architecture independent, so support per-numa CMA
for all architectures, and enable it by default if NUMA.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Tested-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Pull tty/serial fixes from Greg KH:
"Here are some small TTY and serial driver fixes for 6.5-rc4 for some
reported problems. Included in here is:
- TIOCSTI fix for braille readers
- documentation fix for minor numbers
- MAINTAINERS update for new serial files in -rc1
- minor serial driver fixes for reported problems
All of these have been in linux-next with no reported problems"
* tag 'tty-6.5-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial: 8250_dw: Preserve original value of DLF register
tty: serial: sh-sci: Fix sleeping in atomic context
serial: sifive: Fix sifive_serial_console_setup() section
Documentation: devices.txt: reconcile serial/ucc_uart minor numers
MAINTAINERS: Update TTY layer for lists and recently added files
tty: n_gsm: fix UAF in gsm_cleanup_mux
TIOCSTI: always enable for CAP_SYS_ADMIN
Add a mitigation for the speculative return address stack overflow
vulnerability found on AMD processors.
The mitigation works by ensuring all RET instructions speculate to
a controlled location, similar to how speculation is controlled in the
retpoline sequence. To accomplish this, the __x86_return_thunk forces
the CPU to mispredict every function return using a 'safe return'
sequence.
To ensure the safety of this mitigation, the kernel must ensure that the
safe return sequence is itself free from attacker interference. In Zen3
and Zen4, this is accomplished by creating a BTB alias between the
untraining function srso_untrain_ret_alias() and the safe return
function srso_safe_ret_alias() which results in evicting a potentially
poisoned BTB entry and using that safe one for all function returns.
In older Zen1 and Zen2, this is accomplished using a reinterpretation
technique similar to Retbleed one: srso_untrain_ret() and
srso_safe_ret().
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
