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After a recent LLVM change [1] that deduces __cold on functions that only call
cold code (such as __init functions), there is a section mismatch warning from
__get_mem_config_intel(), which got moved to .text.unlikely. as a result of
that optimization:
WARNING: modpost: vmlinux: section mismatch in reference: \
__get_mem_config_intel+0x77 (section: .text.unlikely.) -> thread_throttle_mode_init (section: .init.text)
Mark __get_mem_config_intel() as __init as well since it is only called
from __init code, which clears up the warning.
While __rdt_get_mem_config_amd() does not exhibit a warning because it
does not call any __init code, it is a similar function that is only
called from __init code like __get_mem_config_intel(), so mark it __init
as well to keep the code symmetrical.
CONFIG_SECTION_MISMATCH_WARN_ONLY=n would turn this into a fatal error.
Fixes: 05b93417ce5b ("x86/intel_rdt/mba: Add primary support for Memory Bandwidth Allocation (MBA)")
Fixes: 4d05bf71f157 ("x86/resctrl: Introduce AMD QOS feature")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: <stable@kernel.org>
Link: https://github.com/llvm/llvm-project/commit/6b11573b8c5e3d36beee099dbe7347c2a007bf53 [1]
Link: https://lore.kernel.org/r/20240917-x86-restctrl-get_mem_config_intel-init-v3-1-10d521256284@kernel.org
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The resctrl schemata file supports specifying memory bandwidth associated with
the Memory Bandwidth Allocation (MBA) feature via a percentage (this is the
default) or bandwidth in MiBps (when resctrl is mounted with the "mba_MBps"
option).
The allowed range for the bandwidth percentage is from
/sys/fs/resctrl/info/MB/min_bandwidth to 100, using a granularity of
/sys/fs/resctrl/info/MB/bandwidth_gran. The supported range for the MiBps
bandwidth is 0 to U32_MAX.
There are two issues with parsing of MiBps memory bandwidth:
* The user provided MiBps is mistakenly rounded up to the granularity
that is unique to percentage input.
* The user provided MiBps is parsed using unsigned long (thus accepting
values up to ULONG_MAX), and then assigned to u32 that could result in
overflow.
Do not round up the MiBps value and parse user provided bandwidth as the u32
it is intended to be. Use the appropriate kstrtou32() that can detect out of
range values.
Fixes: 8205a078ba78 ("x86/intel_rdt/mba_sc: Add schemata support")
Fixes: 6ce1560d35f6 ("x86/resctrl: Switch over to the resctrl mbps_val list")
Co-developed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Martin Kletzander <nert.pinx@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
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no_llseek had been defined to NULL two years ago, in commit 868941b14441
("fs: remove no_llseek")
To quote that commit,
At -rc1 we'll need do a mechanical removal of no_llseek -
git grep -l -w no_llseek | grep -v porting.rst | while read i; do
sed -i '/\<no_llseek\>/d' $i
done
would do it.
Unfortunately, that hadn't been done. Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
.llseek = no_llseek,
so it's obviously safe.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When using resctrl on systems with Sub-NUMA Clustering enabled, monitoring
groups may be allocated RMID values which would overrun the
arch_mbm_{local,total} arrays.
This is due to inconsistencies in whether the SNC-adjusted num_rmid value or
the unadjusted value in resctrl_arch_system_num_rmid_idx() is used. The
num_rmid value for the L3 resource is currently:
resctrl_arch_system_num_rmid_idx() / snc_nodes_per_l3_cache
As a simple fix, make resctrl_arch_system_num_rmid_idx() return the
SNC-adjusted, L3 num_rmid value on x86.
Fixes: e13db55b5a0d ("x86/resctrl: Introduce snc_nodes_per_l3_cache")
Signed-off-by: Peter Newman <peternewman@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20240822190212.1848788-1-peternewman@google.com
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 resource control updates from Borislav Petkov:
- Enable Sub-NUMA clustering to work with resource control on Intel by
teaching resctrl to handle scopes due to the clustering which
partitions the L3 cache into sets. Modify and extend the subsystem to
handle such scopes properly
* tag 'x86_cache_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Update documentation with Sub-NUMA cluster changes
x86/resctrl: Detect Sub-NUMA Cluster (SNC) mode
x86/resctrl: Enable shared RMID mode on Sub-NUMA Cluster (SNC) systems
x86/resctrl: Make __mon_event_count() handle sum domains
x86/resctrl: Fill out rmid_read structure for smp_call*() to read a counter
x86/resctrl: Handle removing directories in Sub-NUMA Cluster (SNC) mode
x86/resctrl: Create Sub-NUMA Cluster (SNC) monitor files
x86/resctrl: Allocate a new field in union mon_data_bits
x86/resctrl: Refactor mkdir_mondata_subdir() with a helper function
x86/resctrl: Initialize on-stack struct rmid_read instances
x86/resctrl: Add a new field to struct rmid_read for summation of domains
x86/resctrl: Prepare for new Sub-NUMA Cluster (SNC) monitor files
x86/resctrl: Block use of mba_MBps mount option on Sub-NUMA Cluster (SNC) systems
x86/resctrl: Introduce snc_nodes_per_l3_cache
x86/resctrl: Add node-scope to the options for feature scope
x86/resctrl: Split the rdt_domain and rdt_hw_domain structures
x86/resctrl: Prepare for different scope for control/monitor operations
x86/resctrl: Prepare to split rdt_domain structure
x86/resctrl: Prepare for new domain scope
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 confidential computing updates from Borislav Petkov:
"Unrelated x86/cc changes queued here to avoid ugly cross-merges and
conflicts:
- Carve out CPU hotplug function declarations into a separate header
with the goal to be able to use the lockdep assertions in a more
flexible manner
- As a result, refactor cacheinfo code after carving out a function
to return the cache ID associated with a given cache level
- Cleanups
Add support to be able to kexec TDX guests:
- Expand ACPI MADT CPU offlining support
- Add machinery to prepare CoCo guests memory before kexec-ing into a
new kernel
- Cleanup, readjust and massage related code"
* tag 'x86_cc_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
ACPI: tables: Print MULTIPROC_WAKEUP when MADT is parsed
x86/acpi: Add support for CPU offlining for ACPI MADT wakeup method
x86/mm: Introduce kernel_ident_mapping_free()
x86/smp: Add smp_ops.stop_this_cpu() callback
x86/acpi: Do not attempt to bring up secondary CPUs in the kexec case
x86/acpi: Rename fields in the acpi_madt_multiproc_wakeup structure
x86/mm: Do not zap page table entries mapping unaccepted memory table during kdump
x86/mm: Make e820__end_ram_pfn() cover E820_TYPE_ACPI ranges
x86/tdx: Convert shared memory back to private on kexec
x86/mm: Add callbacks to prepare encrypted memory for kexec
x86/tdx: Account shared memory
x86/mm: Return correct level from lookup_address() if pte is none
x86/mm: Make x86_platform.guest.enc_status_change_*() return an error
x86/kexec: Keep CR4.MCE set during kexec for TDX guest
x86/relocate_kernel: Use named labels for less confusion
cpu/hotplug, x86/acpi: Disable CPU offlining for ACPI MADT wakeup
cpu/hotplug: Add support for declaring CPU offlining not supported
x86/apic: Mark acpi_mp_wake_* variables as __ro_after_init
x86/acpi: Extract ACPI MADT wakeup code into a separate file
x86/kexec: Remove spurious unconditional JMP from from identity_mapped()
...
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There isn't a simple hardware bit that indicates whether a CPU is running in
Sub-NUMA Cluster (SNC) mode. Infer the state by comparing the number of CPUs
sharing the L3 cache with CPU0 to the number of CPUs in the same NUMA node as
CPU0.
Add the missing definition of pr_fmt() to monitor.c. This wasn't noticed
before as there are only "can't happen" console messages from this file.
[ bp: Massage commit message. ]
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-19-tony.luck@intel.com
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Hardware has two RMID configuration options for SNC systems. The default
mode divides RMID counters between SNC nodes. E.g. with 200 RMIDs and
two SNC nodes per L3 cache RMIDs 0..99 are used on node 0, and 100..199
on node 1. This isn't compatible with Linux resctrl usage. On this
example system a process using RMID 5 would only update monitor counters
while running on SNC node 0.
The other mode is "RMID Sharing Mode". This is enabled by clearing bit
0 of the RMID_SNC_CONFIG (0xCA0) model specific register. In this mode
the number of logical RMIDs is the number of physical RMIDs (from CPUID
leaf 0xF) divided by the number of SNC nodes per L3 cache instance. A
process can use the same RMID across different SNC nodes.
See the "Intel Resource Director Technology Architecture Specification"
for additional details.
When SNC is enabled, update the MSR when a monitor domain is marked
online. Technically this is overkill. It only needs to be done once
per L3 cache instance rather than per SNC domain. But there is no harm
in doing it more than once, and this is not in a critical path.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20240702173820.90368-3-tony.luck@intel.com
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Legacy resctrl monitor files must provide the sum of event values across
all Sub-NUMA Cluster (SNC) domains that share an L3 cache instance.
There are now two cases:
1) A specific domain is provided in struct rmid_read
This is either a non-SNC system, or the request is to read data
from just one SNC node.
2) Domain pointer is NULL. In this case the cacheinfo field in struct
rmid_read indicates that all SNC nodes that share that L3 cache
instance should have the event read and return the sum of all
values.
Update the CPU sanity check. The existing check that an event is read
from a CPU in the requested domain still applies when reading a single
domain. But when summing across domains a more relaxed check that the
current CPU is in the scope of the L3 cache instance is appropriate
since the MSRs to read events are scoped at L3 cache level.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-17-tony.luck@intel.com
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mon_event_read() fills out most fields of the struct rmid_read that is passed
via an smp_call*() function to a CPU that is part of the correct domain to
read the monitor counters.
With Sub-NUMA Cluster (SNC) mode there are now two cases to handle:
1) Reading a file that returns a value for a single domain.
+ Choose the CPU to execute from the domain cpu_mask
2) Reading a file that must sum across domains sharing an L3 cache
instance.
+ Indicate to called code that a sum is needed by passing a NULL
rdt_mon_domain pointer.
+ Choose the CPU from the L3 shared_cpu_map.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-16-tony.luck@intel.com
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In SNC mode, there are multiple subdirectories in each L3 level monitor
directory (one for each SNC node). If all the CPUs in an SNC node are taken
offline, just remove the SNC directory for that node. In non-SNC mode, or when
the last SNC node directory is removed, remove the L3 monitor directory.
Add a helper function to avoid duplicated code.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20240702173820.90368-2-tony.luck@intel.com
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When SNC mode is enabled, create subdirectories and files to monitor at the SNC
node granularity. Legacy behavior is preserved by tagging the monitor files at
the L3 granularity with the "sum" attribute. When the user reads these files
the kernel will read monitor data from all SNC nodes that share the same L3
cache instance and return the aggregated value to the user.
Note that the "domid" field for files that must sum across SNC domains has the
L3 cache instance id, while non-summing files use the domain id.
The "sum" files do not need to make a call to mon_event_read() to initialize
the MBM counters. This will be handled by initializing the individual SNC nodes
that share the L3.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-14-tony.luck@intel.com
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When Sub-NUMA Cluster (SNC) mode is enabled, the legacy monitor reporting files
must report the sum of the data from all of the SNC nodes that share the L3
cache that is referenced by the monitor file.
Resctrl squeezes all the attributes of these files into 32 bits so they can be
stored in the "priv" field of struct kernfs_node.
Currently, only three monitor events are defined by enum resctrl_event_id so
reducing it from 8 bits to 7 bits still provides more than enough space to
represent all the known event types.
But note that this choice was arbitrary. The "rid" field is also far wider
than needed for the current number of resource id types. This structure is
purely internal to resctrl, no ABI issues with modifying it. Subsequent changes
may rearrange the allocation of bits between each of the fields as needed.
Give the bit to a new "sum" field that indicates that reading this file must
sum across SNC nodes. This bit also indicates that the domid field is the id of
an L3 cache (instead of a domain id) to find which domains must be summed.
Fix up other issues in the kerneldoc description for mon_data_bits.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-13-tony.luck@intel.com
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In Sub-NUMA Cluster (SNC) mode Linux must create the monitor
files in the original "mon_L3_XX" directories and also in each
of the "mon_sub_L3_YY" directories.
Refactor mkdir_mondata_subdir() to move the creation of monitoring files
into a helper function to avoid the need to duplicate code later.
No functional change.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-12-tony.luck@intel.com
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New semantics rely on some struct rmid_read members having NULL values to
distinguish between the SNC and non-SNC scenarios. resctrl can thus no longer
rely on this struct not being initialized properly.
Initialize all on-stack declarations of struct rmid_read:
rdtgroup_mondata_show()
mbm_update()
mkdir_mondata_subdir()
to ensure that garbage values from the stack are not passed down to other
functions.
[ bp: Massage commit message. ]
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-11-tony.luck@intel.com
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When a user reads a monitor file rdtgroup_mondata_show() calls mon_event_read()
to package up all the required details into an rmid_read structure which is
passed across the smp_call*() infrastructure to code that will read data from
hardware and return the value (or error status) in the rmid_read structure.
Sub-NUMA Cluster (SNC) mode adds files with new semantics. These require the
smp_call-ed code to sum event data from all domains that share an L3 cache.
Add a pointer to the L3 "cacheinfo" structure to struct rmid_read for the data
collection routines to use to pick the domains to be summed.
[ Reinette: the rmid_read structure has become complex enough so document each
of its fields and provide the kerneldoc documentation for struct rmid_read. ]
Co-developed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-10-tony.luck@intel.com
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When SNC is enabled, monitoring data is collected at the SNC node granularity,
but must be reported at L3-cache granularity for backwards compatibility in
addition to reporting at the node level.
Add a "ci" field to the rdt_mon_domain structure to save the cache information
about the enclosing L3 cache for the domain. This provides:
1) The cache id which is needed to compose the name of the legacy monitoring
directory, and to determine which domains should be summed to provide
L3-scoped data.
2) The shared_cpu_map which is needed to determine which CPUs can be used to
read the RMID counters with the MSR interface.
This is the first step to an eventual goal of monitor reporting files like this
(for a system with two SNC nodes per L3):
$ cd /sys/fs/resctrl/mon_data
$ tree mon_L3_00
mon_L3_00 <- 00 here is L3 cache id
├── llc_occupancy \ These files provide legacy support
├── mbm_local_bytes > for non-SNC aware monitor apps
├── mbm_total_bytes / that expect data at L3 cache level
├── mon_sub_L3_00 <- 00 here is SNC node id
│ ├── llc_occupancy \ These files are finer grained
│ ├── mbm_local_bytes > data from each SNC node
│ └── mbm_total_bytes /
└── mon_sub_L3_01
├── llc_occupancy \
├── mbm_local_bytes > As above, but for node 1.
└── mbm_total_bytes /
[ bp: Massage commit message. ]
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-9-tony.luck@intel.com
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systems
When SNC is enabled there is a mismatch between the MBA control function
which operates at L3 cache scope and the MBM monitor functions which
measure memory bandwidth on each SNC node.
Block use of the mba_MBps when scopes for MBA/MBM do not match.
Improve user diagnostics by adding invalfc() message when mba_MBps
is not supported.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-8-tony.luck@intel.com
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Intel Sub-NUMA Cluster (SNC) is a feature that subdivides the CPU cores
and memory controllers on a socket into two or more groups. These are
presented to the operating system as NUMA nodes.
This may enable some workloads to have slightly lower latency to memory
as the memory controller(s) in an SNC node are electrically closer to the
CPU cores on that SNC node. This cost may be offset by lower bandwidth
since the memory accesses for each core can only be interleaved between
the memory controllers on the same SNC node.
Resctrl monitoring on an Intel system depends upon attaching RMIDs to tasks
to track L3 cache occupancy and memory bandwidth. There is an MSR that
controls how the RMIDs are shared between SNC nodes.
The default mode divides them numerically. E.g. when there are two SNC
nodes on a socket the lower number half of the RMIDs are given to the
first node, the remainder to the second node. This would be difficult
to use with the Linux resctrl interface as specific RMID values assigned
to resctrl groups are not visible to users.
RMID sharing mode divides the physical RMIDs evenly between SNC nodes
but uses a logical RMID in the IA32_PQR_ASSOC MSR. For example a system
with 200 physical RMIDs (as enumerated by CPUID leaf 0xF) that has two
SNC nodes per L3 cache instance would have 100 logical RMIDs available
for Linux to use. A task running on SNC node 0 with RMID 5 would
accumulate LLC occupancy and MBM bandwidth data in physical RMID 5.
Another task using RMID 5, but running on SNC node 1 would accumulate
data in physical RMID 105.
Even with this renumbering SNC mode requires several changes in resctrl
behavior for correct operation.
Add a static global to arch/x86/kernel/cpu/resctrl/monitor.c to indicate
how many SNC domains share an L3 cache instance. Initialize this to
"1". Runtime detection of SNC mode will adjust this value.
Update all places to take appropriate action when SNC mode is enabled:
1) The number of logical RMIDs per L3 cache available for use is the
number of physical RMIDs divided by the number of SNC nodes.
2) Likewise the "mon_scale" value must be divided by the number of SNC
nodes.
3) Add a function to convert from logical RMID values (assigned to
tasks and loaded into the IA32_PQR_ASSOC MSR on context switch)
to physical RMID values to load into IA32_QM_EVTSEL MSR when
reading counters on each SNC node.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-7-tony.luck@intel.com
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Currently supported resctrl features are all domain scoped the same as the
scope of the L2 or L3 caches.
Add RESCTRL_L3_NODE as a new option for features that are scoped at the
same granularity as NUMA nodes. This is needed for Intel's Sub-NUMA
Cluster (SNC) feature where monitoring features are divided between
nodes that share an L3 cache.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-6-tony.luck@intel.com
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The same rdt_domain structure is used for both control and monitor
functions. But this results in wasted memory as some of the fields are
only used by control functions, while most are only used for monitor
functions.
Split into separate rdt_ctrl_domain and rdt_mon_domain structures with
just the fields required for control and monitoring respectively.
Similar split of the rdt_hw_domain structure into rdt_hw_ctrl_domain
and rdt_hw_mon_domain.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-5-tony.luck@intel.com
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Resctrl assumes that control and monitor operations on a resource are
performed at the same scope.
Prepare for systems that use different scope (specifically Intel needs
to split the RDT_RESOURCE_L3 resource to use L3 scope for cache control
and NODE scope for cache occupancy and memory bandwidth monitoring).
Create separate domain lists for control and monitor operations.
Note that errors during initialization of either control or monitor
functions on a domain would previously result in that domain being
excluded from both control and monitor operations. Now the domains are
allocated independently it is no longer required to disable both control
and monitor operations if either fail.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-4-tony.luck@intel.com
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The rdt_domain structure is used for both control and monitor features.
It is about to be split into separate structures for these two usages
because the scope for control and monitoring features for a resource
will be different for future resources.
To allow for common code that scans a list of domains looking for a
specific domain id, move all the common fields ("list", "id", "cpu_mask")
into their own structure within the rdt_domain structure.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-3-tony.luck@intel.com
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Resctrl resources operate on subsets of CPUs in the system with the
defining attribute of each subset being an instance of a particular
level of cache. E.g. all CPUs sharing an L3 cache would be part of the
same domain.
In preparation for features that are scoped at the NUMA node level,
change the code from explicit references to "cache_level" to a more
generic scope. At this point the only options for this scope are groups
of CPUs that share an L2 cache or L3 cache.
Clean up the error handling when looking up domains. Report invalid ids
before calling rdt_find_domain() in preparation for better messages when
scope can be other than cache scope. This means that rdt_find_domain()
will never return an error. So remove checks for error from the call sites.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-2-tony.luck@intel.com
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Commit
6791e0ea3071 ("x86/resctrl: Access per-rmid structures by index")
adds logic to map individual monitoring groups into a global index space used
for tracking allocated RMIDs.
Attempts to free the default RMID are ignored in free_rmid(), and this works
fine on x86.
With arm64 MPAM, there is a latent bug here however: on platforms with no
monitors exposed through resctrl, each control group still gets a different
monitoring group ID as seen by the hardware, since the CLOSID always forms part
of the monitoring group ID.
This means that when removing a control group, the code may try to free this
group's default monitoring group RMID for real. If there are no monitors
however, the RMID tracking table rmid_ptrs[] would be a waste of memory and is
never allocated, leading to a splat when free_rmid() tries to dereference the
table.
One option would be to treat RMID 0 as special for every CLOSID, but this would
be ugly since bookkeeping still needs to be done for these monitoring group IDs
when there are monitors present in the hardware.
Instead, add a gating check of resctrl_arch_mon_capable() in free_rmid(), and
just do nothing if the hardware doesn't have monitors.
This fix mirrors the gating checks already present in
mkdir_rdt_prepare_rmid_alloc() and elsewhere.
No functional change on x86.
[ bp: Massage commit message. ]
Fixes: 6791e0ea3071 ("x86/resctrl: Access per-rmid structures by index")
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20240618140152.83154-1-Dave.Martin@arm.com
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pseudo_lock_region_init() and rdtgroup_cbm_to_size() open code a search for
details of a particular cache level.
Replace with get_cpu_cacheinfo_level().
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20240610003927.341707-5-tony.luck@intel.com
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 resource control updates from Borislav Petkov:
- Add a tracepoint to read out LLC occupancy of resource monitor IDs
with the goal of freeing them sooner rather than later
- Other code improvements and cleanups
* tag 'x86_cache_for_v6.10_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Add tracepoint for llc_occupancy tracking
x86/resctrl: Rename pseudo_lock_event.h to trace.h
x86/resctrl: Simplify call convention for MSR update functions
x86/resctrl: Pass domain to target CPU
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New CPU #defines encode vendor and family as well as model.
[ bp: Squash two resctrl patches into one. ]
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/20240424181514.41848-1-tony.luck%40intel.com
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In our production environment, after removing monitor groups, those
unused RMIDs get stuck in the limbo list forever because their
llc_occupancy is always larger than the threshold. But the unused RMIDs
can be successfully freed by turning up the threshold.
In order to know how much the threshold should be, perf can be used to
acquire the llc_occupancy of RMIDs in each rdt domain.
Instead of using perf tool to track llc_occupancy and filter the log
manually, it is more convenient for users to use tracepoint to do this
work. So add a new tracepoint that shows the llc_occupancy of busy RMIDs
when scanning the limbo list.
Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20240408092303.26413-3-haifeng.xu@shopee.com
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Now only the pseudo-locking part uses tracepoints to do event tracking,
but other parts of resctrl may need new tracepoints. It is unnecessary
to create separate header files and define CREATE_TRACE_POINTS in
different c files which fragments the resctrl tracing.
Therefore, give the resctrl tracepoint header file a generic name to
support its use for tracepoints that are not specific to pseudo-locking.
No functional change.
Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20240408092303.26413-2-haifeng.xu@shopee.com
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The per-resource MSR update functions cat_wrmsr(), mba_wrmsr_intel(),
and mba_wrmsr_amd() all take three arguments:
(struct rdt_domain *d, struct msr_param *m, struct rdt_resource *r)
struct msr_param contains pointers to both struct rdt_resource and struct
rdt_domain, thus only struct msr_param is necessary.
Pass struct msr_param as a single parameter. Clean up formatting and
fix some fir tree declaration ordering.
No functional change.
Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Link: https://lore.kernel.org/r/20240308213846.77075-3-tony.luck@intel.com
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reset_all_ctrls() and resctrl_arch_update_domains() use on_each_cpu_mask()
to call rdt_ctrl_update() on potentially one CPU from each domain.
But this means rdt_ctrl_update() needs to figure out which domain to
apply changes to. Doing so requires a search of all domains in a resource,
which can only be done safely if cpus_lock is held. Both callers do hold
this lock, but there isn't a way for a function called on another CPU
via IPI to verify this.
Commit
c0d848fcb09d ("x86/resctrl: Remove lockdep annotation that triggers
false positive")
removed the incorrect assertions.
Add the target domain to the msr_param structure and call
rdt_ctrl_update() for each domain separately using
smp_call_function_single(). This means that rdt_ctrl_update() doesn't
need to search for the domain and get_domain_from_cpu() can safely
assert that the cpus_lock is held since the remaining callers do not use
IPI.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Link: https://lore.kernel.org/r/20240308213846.77075-2-tony.luck@intel.com
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Tony encountered this OOPS when the last CPU of a domain goes
offline while running a kernel built with CONFIG_NO_HZ_FULL:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
...
RIP: 0010:__find_nth_andnot_bit+0x66/0x110
...
Call Trace:
<TASK>
? __die()
? page_fault_oops()
? exc_page_fault()
? asm_exc_page_fault()
cpumask_any_housekeeping()
mbm_setup_overflow_handler()
resctrl_offline_cpu()
resctrl_arch_offline_cpu()
cpuhp_invoke_callback()
cpuhp_thread_fun()
smpboot_thread_fn()
kthread()
ret_from_fork()
ret_from_fork_asm()
</TASK>
The NULL pointer dereference is encountered while searching for another
online CPU in the domain (of which there are none) that can be used to
run the MBM overflow handler.
Because the kernel is configured with CONFIG_NO_HZ_FULL the search for
another CPU (in its effort to prefer those CPUs that aren't marked
nohz_full) consults the mask representing the nohz_full CPUs,
tick_nohz_full_mask. On a kernel with CONFIG_CPUMASK_OFFSTACK=y
tick_nohz_full_mask is not allocated unless the kernel is booted with
the "nohz_full=" parameter and because of that any access to
tick_nohz_full_mask needs to be guarded with tick_nohz_full_enabled().
Replace the IS_ENABLED(CONFIG_NO_HZ_FULL) with tick_nohz_full_enabled().
The latter ensures tick_nohz_full_mask can be accessed safely and can be
used whether kernel is built with CONFIG_NO_HZ_FULL enabled or not.
[ Use Ingo's suggestion that combines the two NO_HZ checks into one. ]
Fixes: a4846aaf3945 ("x86/resctrl: Add cpumask_any_housekeeping() for limbo/overflow")
Reported-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/ff8dfc8d3dcb04b236d523d1e0de13d2ef585223.1711993956.git.reinette.chatre@intel.com
Closes: https://lore.kernel.org/lkml/ZgIFT5gZgIQ9A9G7@agluck-desk3/
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get_domain_from_cpu() walks a list of domains to find the one that
contains the specified CPU. This needs to be protected against races
with CPU hotplug when the list is modified. It has recently gained
a lockdep annotation to check this.
The lockdep annotation causes false positives when called via IPI as the
lock is held, but by another process. Remove it.
[ bp: Refresh it ontop of x86/cache. ]
Fixes: fb700810d30b ("x86/resctrl: Separate arch and fs resctrl locks")
Reported-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/ZdUSwOM9UUNpw84Y@agluck-desk3
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resctrl has one mutex that is taken by the architecture-specific code, and the
filesystem parts. The two interact via cpuhp, where the architecture code
updates the domain list. Filesystem handlers that walk the domains list should
not run concurrently with the cpuhp callback modifying the list.
Exposing a lock from the filesystem code means the interface is not cleanly
defined, and creates the possibility of cross-architecture lock ordering
headaches. The interaction only exists so that certain filesystem paths are
serialised against CPU hotplug. The CPU hotplug code already has a mechanism to
do this using cpus_read_lock().
MPAM's monitors have an overflow interrupt, so it needs to be possible to walk
the domains list in irq context. RCU is ideal for this, but some paths need to
be able to sleep to allocate memory.
Because resctrl_{on,off}line_cpu() take the rdtgroup_mutex as part of a cpuhp
callback, cpus_read_lock() must always be taken first.
rdtgroup_schemata_write() already does this.
Most of the filesystem code's domain list walkers are currently protected by
the rdtgroup_mutex taken in rdtgroup_kn_lock_live(). The exceptions are
rdt_bit_usage_show() and the mon_config helpers which take the lock directly.
Make the domain list protected by RCU. An architecture-specific lock prevents
concurrent writers. rdt_bit_usage_show() could walk the domain list using RCU,
but to keep all the filesystem operations the same, this is changed to call
cpus_read_lock(). The mon_config helpers send multiple IPIs, take the
cpus_read_lock() in these cases.
The other filesystem list walkers need to be able to sleep. Add
cpus_read_lock() to rdtgroup_kn_lock_live() so that the cpuhp callbacks can't
be invoked when file system operations are occurring.
Add lockdep_assert_cpus_held() in the cases where the rdtgroup_kn_lock_live()
call isn't obvious.
Resctrl's domain online/offline calls now need to take the rdtgroup_mutex
themselves.
[ bp: Fold in a build fix: https://lore.kernel.org/r/87zfvwieli.ffs@tglx ]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Link: https://lore.kernel.org/r/20240213184438.16675-25-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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When a CPU is taken offline the resctrl filesystem code needs to check if it
was the CPU nominated to perform the periodic overflow and limbo work. If so,
another CPU needs to be chosen to do this work.
This is currently done in core.c, mixed in with the code that removes the CPU
from the domain's mask, and potentially free()s the domain.
Move the migration of the overflow and limbo helpers into the filesystem code,
into resctrl_offline_cpu(). As resctrl_offline_cpu() runs before the
architecture code has removed the CPU from the domain mask, the callers need to
be told which CPU is being removed, to avoid picking it as the new CPU. This
uses the exclude_cpu feature previously added.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Link: https://lore.kernel.org/r/20240213184438.16675-24-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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The resctrl architecture specific code may need to free a domain when a CPU
goes offline, it also needs to reset the CPUs PQR_ASSOC register. Amongst
other things, the resctrl filesystem code needs to clear this CPU from the
cpu_mask of any control and monitor groups.
Currently, this is all done in core.c and called from resctrl_offline_cpu(),
making the split between architecture and filesystem code unclear.
Move the filesystem work to remove the CPU from the control and monitor groups
into a filesystem helper called resctrl_offline_cpu(), and rename the one in
core.c resctrl_arch_offline_cpu().
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Link: https://lore.kernel.org/r/20240213184438.16675-23-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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When a CPU is taken offline resctrl may need to move the overflow or limbo
handlers to run on a different CPU.
Once the offline callbacks have been split, cqm_setup_limbo_handler() will be
called while the CPU that is going offline is still present in the CPU mask.
Pass the CPU to exclude to cqm_setup_limbo_handler() and
mbm_setup_overflow_handler(). These functions can use a variant of
cpumask_any_but() when selecting the CPU. -1 is used to indicate no CPUs need
excluding.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Link: https://lore.kernel.org/r/20240213184438.16675-22-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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