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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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The resctrl architecture specific code may need to create a domain when a CPU
comes online, it also needs to reset the CPUs PQR_ASSOC register. The resctrl
filesystem code needs to update the rdtgroup_default CPU mask when CPUs are
brought online.
Currently, this is all done in one function, resctrl_online_cpu(). It will
need to be split into architecture and filesystem parts before resctrl can be
moved to /fs/.
Pull the rdtgroup_default update work out as a filesystem specific cpu_online
helper. resctrl_online_cpu() is the obvious name for this, which means the
version in core.c needs renaming.
resctrl_online_cpu() is called by the arch code once it has done the work to
add the new CPU to any domains.
In future patches, resctrl_online_cpu() will take the rdtgroup_mutex itself.
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/20240213184438.16675-21-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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resctrl reads rdt_alloc_capable or rdt_mon_capable to determine whether any of
the resources support the corresponding features. resctrl also uses the
static keys that affect the architecture's context-switch code to determine the
same thing.
This forces another architecture to have the same static keys.
As the static key is enabled based on the capable flag, and none of the
filesystem uses of these are in the scheduler path, move the capable flags
behind helpers, and use these in the filesystem code instead of the static key.
After this change, only the architecture code manages and uses the static keys
to ensure __resctrl_sched_in() does not need runtime checks.
This avoids multiple architectures having to define the same static keys.
Cases where the static key implicitly tested if the resctrl filesystem was
mounted all have an explicit check now.
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/20240213184438.16675-20-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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rdt_enable_key is switched when resctrl is mounted. It was also previously used
to prevent a second mount of the filesystem.
Any other architecture that wants to support resctrl has to provide identical
static keys.
Now that there are helpers for enabling and disabling the alloc/mon keys,
resctrl doesn't need to switch this extra key, it can be done by the arch code.
Use the static-key increment and decrement helpers, and change resctrl to
ensure the calls are balanced.
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/20240213184438.16675-19-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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resctrl enables three static keys depending on the features it has enabled.
Another architecture's context switch code may look different, any static keys
that control it should be buried behind helpers.
Move the alloc/mon logic into arch-specific helpers as a preparatory step for
making the rdt_enable_key's status something the arch code decides.
This means other architectures don't have to mirror the static keys.
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/20240213184438.16675-18-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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The rdt_enable_key is switched when resctrl is mounted, and used to prevent
a second mount of the filesystem. It also enables the architecture's context
switch code.
This requires another architecture to have the same set of static keys, as
resctrl depends on them too. The existing users of these static keys are
implicitly also checking if the filesystem is mounted.
Make the resctrl_mounted checks explicit: resctrl can keep track of whether it
has been mounted once. This doesn't need to be combined with whether the arch
code is context switching the CLOSID.
rdt_mon_enable_key is never used just to test that resctrl is mounted, but does
also have this implication. Add a resctrl_mounted to all uses of
rdt_mon_enable_key.
This will allow the static key changing to be moved behind resctrl_arch_ calls.
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/20240213184438.16675-17-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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Depending on the number of monitors available, Arm's MPAM may need to
allocate a monitor prior to reading the counter value. Allocating a
contended resource may involve sleeping.
__check_limbo() and mon_event_count() each make multiple calls to
resctrl_arch_rmid_read(), to avoid extra work on contended systems,
the allocation should be valid for multiple invocations of
resctrl_arch_rmid_read().
The memory or hardware allocated is not specific to a domain.
Add arch hooks for this allocation, which need calling before
resctrl_arch_rmid_read(). The allocated monitor is passed to
resctrl_arch_rmid_read(), then freed again afterwards. The helper
can be called on any CPU, and can sleep.
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/20240213184438.16675-16-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
MPAM's cache occupancy counters can take a little while to settle once the
monitor has been configured. The maximum settling time is described to the
driver via a firmware table. The value could be large enough that it makes
sense to sleep. To avoid exposing this to resctrl, it should be hidden behind
MPAM's resctrl_arch_rmid_read().
resctrl_arch_rmid_read() may be called via IPI meaning it is unable to sleep.
In this case, it should return an error if it needs to sleep. This will only
affect MPAM platforms where the cache occupancy counter isn't available
immediately, nohz_full is in use, and there are no housekeeping CPUs in the
necessary domain.
There are three callers of resctrl_arch_rmid_read(): __mon_event_count() and
__check_limbo() are both called from a non-migrateable context.
mon_event_read() invokes __mon_event_count() using smp_call_on_cpu(), which
adds work to the target CPUs workqueue. rdtgroup_mutex() is held, meaning this
cannot race with the resctrl cpuhp callback. __check_limbo() is invoked via
schedule_delayed_work_on() also adds work to a per-cpu workqueue.
The remaining call is add_rmid_to_limbo() which is called in response to
a user-space syscall that frees an RMID. This opportunistically reads the LLC
occupancy counter on the current domain to see if the RMID is over the dirty
threshold. This has to disable preemption to avoid reading the wrong domain's
value. Disabling preemption here prevents resctrl_arch_rmid_read() from
sleeping.
add_rmid_to_limbo() walks each domain, but only reads the counter on one
domain. If the system has more than one domain, the RMID will always be added
to the limbo list. If the RMIDs usage was not over the threshold, it will be
removed from the list when __check_limbo() runs. Make this the default
behaviour. Free RMIDs are always added to the limbo list for each domain.
The user visible effect of this is that a clean RMID is not available for
re-allocation immediately after 'rmdir()' completes. This behaviour was never
portable as it never happened on a machine with multiple domains.
Removing this path allows resctrl_arch_rmid_read() to sleep if its called with
interrupts unmasked. Document this is the expected behaviour, and add
a might_sleep() annotation to catch changes that won't work on arm64.
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/20240213184438.16675-15-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
Intel is blessed with an abundance of monitors, one per RMID, that can be
read from any CPU in the domain. MPAMs monitors reside in the MMIO MSC,
the number implemented is up to the manufacturer. This means when there are
fewer monitors than needed, they need to be allocated and freed.
MPAM's CSU monitors are used to back the 'llc_occupancy' monitor file. The
CSU counter is allowed to return 'not ready' for a small number of
micro-seconds after programming. To allow one CSU hardware monitor to be
used for multiple control or monitor groups, the CPU accessing the
monitor needs to be able to block when configuring and reading the
counter.
Worse, the domain may be broken up into slices, and the MMIO accesses
for each slice may need performing from different CPUs.
These two details mean MPAMs monitor code needs to be able to sleep, and
IPI another CPU in the domain to read from a resource that has been sliced.
mon_event_read() already invokes mon_event_count() via IPI, which means
this isn't possible. On systems using nohz-full, some CPUs need to be
interrupted to run kernel work as they otherwise stay in user-space
running realtime workloads. Interrupting these CPUs should be avoided,
and scheduling work on them may never complete.
Change mon_event_read() to pick a housekeeping CPU, (one that is not using
nohz_full) and schedule mon_event_count() and wait. If all the CPUs
in a domain are using nohz-full, then an IPI is used as the fallback.
This function is only used in response to a user-space filesystem request
(not the timing sensitive overflow code).
This allows MPAM to hide the slice behaviour from resctrl, and to keep
the monitor-allocation in monitor.c. When the IPI fallback is used on
machines where MPAM needs to make an access on multiple CPUs, the counter
read will always fail.
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: Peter Newman <peternewman@google.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/20240213184438.16675-14-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
The limbo and overflow code picks a CPU to use from the domain's list of online
CPUs. Work is then scheduled on these CPUs to maintain the limbo list and any
counters that may overflow.
cpumask_any() may pick a CPU that is marked nohz_full, which will either
penalise the work that CPU was dedicated to, or delay the processing of limbo
list or counters that may overflow. Perhaps indefinitely. Delaying the overflow
handling will skew the bandwidth values calculated by mba_sc, which expects to
be called once a second.
Add cpumask_any_housekeeping() as a replacement for cpumask_any() that prefers
housekeeping CPUs. This helper will still return a nohz_full CPU if that is the
only option. The CPU to use is re-evaluated each time the limbo/overflow work
runs. This ensures the work will move off a nohz_full CPU once a housekeeping
CPU is available.
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/20240213184438.16675-13-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
When switching tasks, the CLOSID and RMID that the new task should use
are stored in struct task_struct. For x86 the CLOSID known by resctrl,
the value in task_struct, and the value written to the CPU register are
all the same thing.
MPAM's CPU interface has two different PARTIDs - one for data accesses
the other for instruction fetch. Storing resctrl's CLOSID value in
struct task_struct implies the arch code knows whether resctrl is using
CDP.
Move the matching and setting of the struct task_struct properties to
use helpers. This allows arm64 to store the hardware format of the
register, instead of having to convert it each time.
__rdtgroup_move_task()s use of READ_ONCE()/WRITE_ONCE() ensures torn
values aren't seen as another CPU may schedule the task being moved
while the value is being changed. MPAM has an additional corner-case
here as the PMG bits extend the PARTID space.
If the scheduler sees a new-CLOSID but old-RMID, the task will dirty an
RMID that the limbo code is not watching causing an inaccurate count.
x86's RMID are independent values, so the limbo code will still be
watching the old-RMID in this circumstance.
To avoid this, arm64 needs both the CLOSID/RMID WRITE_ONCE()d together.
Both values must be provided together.
Because MPAM's RMID values are not unique, the CLOSID must be provided
when matching the RMID.
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/20240213184438.16675-12-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
MPAM's PMG bits extend its PARTID space, meaning the same PMG value can be used
for different control groups.
This means once a CLOSID is allocated, all its monitoring ids may still be
dirty, and held in limbo.
Instead of allocating the first free CLOSID, on architectures where
CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID is enabled, search
closid_num_dirty_rmid[] to find the cleanest CLOSID.
The CLOSID found is returned to closid_alloc() for the free list
to be updated.
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/20240213184438.16675-11-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
The resctrl CLOSID allocator uses a single 32bit word to track which
CLOSID are free. The setting and clearing of bits is open coded.
Convert the existing open coded bit manipulations of closid_free_map
to use __set_bit() and friends. These don't need to be atomic as this
list is protected by the mutex.
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/20240213184438.16675-10-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
MPAM's PMG bits extend its PARTID space, meaning the same PMG value can be
used for different control groups.
This means once a CLOSID is allocated, all its monitoring ids may still be
dirty, and held in limbo.
Keep track of the number of RMID held in limbo each CLOSID has. This will
allow a future helper to find the 'cleanest' CLOSID when allocating.
The array is only needed when CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID is
defined. This will never be the case on x86.
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/20240213184438.16675-9-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
MPAMs RMID values are not unique unless the CLOSID is considered as well.
alloc_rmid() expects the RMID to be an independent number.
Pass the CLOSID in to alloc_rmid(). Use this to compare indexes when
allocating. If the CLOSID is not relevant to the index, this ends up comparing
the free RMID with itself, and the first free entry will be used. With MPAM the
CLOSID is included in the index, so this becomes a walk of the free RMID
entries, until one that matches the supplied CLOSID is found.
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/20240213184438.16675-8-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
x86 systems identify traffic using the CLOSID and RMID. The CLOSID is
used to lookup the control policy, the RMID is used for monitoring. For
x86 these are independent numbers.
Arm's MPAM has equivalent features PARTID and PMG, where the PARTID is
used to lookup the control policy. The PMG in contrast is a small number
of bits that are used to subdivide PARTID when monitoring. The
cache-occupancy monitors require the PARTID to be specified when
monitoring.
This means MPAM's PMG field is not unique. There are multiple PMG-0, one
per allocated CLOSID/PARTID. If PMG is treated as equivalent to RMID, it
cannot be allocated as an independent number. Bitmaps like rmid_busy_llc
need to be sized by the number of unique entries for this resource.
Treat the combined CLOSID and RMID as an index, and provide architecture
helpers to pack and unpack an index. This makes the MPAM values unique.
The domain's rmid_busy_llc and rmid_ptrs[] are then sized by index, as
are domain mbm_local[] and mbm_total[].
x86 can ignore the CLOSID field when packing and unpacking an index, and
report as many indexes as RMID.
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/20240213184438.16675-7-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
x86's RMID are independent of the CLOSID. An RMID can be allocated,
used and freed without considering the CLOSID.
MPAM's equivalent feature is PMG, which is not an independent number,
it extends the CLOSID/PARTID space. For MPAM, only PMG-bits worth of
'RMID' can be allocated for a single CLOSID.
i.e. if there is 1 bit of PMG space, then each CLOSID can have two
monitor groups.
To allow resctrl to disambiguate RMID values for different CLOSID,
everything in resctrl that keeps an RMID value needs to know the CLOSID
too. This will always be ignored on x86.
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: Xin Hao <xhao@linux.alibaba.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/20240213184438.16675-6-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
RMIDs are allocated for each monitor or control group directory, because
each of these needs its own RMID. For control groups,
rdtgroup_mkdir_ctrl_mon() later goes on to allocate the CLOSID.
MPAM's equivalent of RMID is not an independent number, so can't be
allocated until the CLOSID is known. An RMID allocation for one CLOSID
may fail, whereas another may succeed depending on how many monitor
groups a control group has.
The RMID allocation needs to move to be after the CLOSID has been
allocated.
Move the RMID allocation out of mkdir_rdt_prepare() to occur in its caller,
after the mkdir_rdt_prepare() call. This allows the RMID allocator to
know the CLOSID.
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/20240213184438.16675-5-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
When monitoring is supported, each monitor and control group is allocated an
RMID. For control groups, rdtgroup_mkdir_ctrl_mon() later goes on to allocate
the CLOSID.
MPAM's equivalent of RMID are not an independent number, so can't be allocated
until the CLOSID is known. An RMID allocation for one CLOSID may fail, whereas
another may succeed depending on how many monitor groups a control group has.
The RMID allocation needs to move to be after the CLOSID has been allocated.
Move the RMID allocation and mondata dir creation to a helper.
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: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Link: https://lore.kernel.org/r/20240213184438.16675-4-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
rmid_ptrs[] is allocated from dom_data_init() but never free()d.
While the exit text ends up in the linker script's DISCARD section,
the direction of travel is for resctrl to be/have loadable modules.
Add resctrl_put_mon_l3_config() to cleanup any memory allocated
by rdt_get_mon_l3_config().
There is no reason to backport this to a stable kernel.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Link: https://lore.kernel.org/r/20240213184438.16675-3-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
|
|
The kernel test robot reported the following warning after commit
54e35eb8611c ("x86/resctrl: Read supported bandwidth sources from CPUID").
even though the issue is present even in the original commit
92bd5a139033 ("x86/resctrl: Add interface to write mbm_total_bytes_config")
which added this function. The reported warning is:
$ make C=1 CHECK=scripts/coccicheck arch/x86/kernel/cpu/resctrl/rdtgroup.o
...
arch/x86/kernel/cpu/resctrl/rdtgroup.c:1621:5-8: Unneeded variable: "ret". Return "0" on line 1655
Remove the local variable 'ret'.
[ bp: Massage commit message, make mbm_config_write_domain() void. ]
Fixes: 92bd5a139033 ("x86/resctrl: Add interface to write mbm_total_bytes_config")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202401241810.jbd8Ipa1-lkp@intel.com/
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/202401241810.jbd8Ipa1-lkp@intel.com
|
|
The mba_MBps feedback loop increases throttling when a group is using
more bandwidth than the target set by the user in the schemata file, and
decreases throttling when below target.
To avoid possibly stepping throttling up and down on every poll a flag
"delta_comp" is set whenever throttling is changed to indicate that the
actual change in bandwidth should be recorded on the next poll in
"delta_bw". Throttling is only reduced if the current bandwidth plus
delta_bw is below the user target.
This algorithm works well if the workload has steady bandwidth needs.
But it can go badly wrong if the workload moves to a different phase
just as the throttling level changed. E.g. if the workload becomes
essentially idle right as throttling level is increased, the value
calculated for delta_bw will be more or less the old bandwidth level.
If the workload then resumes, Linux may never reduce throttling because
current bandwidth plus delta_bw is above the target set by the user.
Implement a simpler heuristic by assuming that in the worst case the
currently measured bandwidth is being controlled by the current level of
throttling. Compute how much it may increase if throttling is relaxed to
the next higher level. If that is still below the user target, then it
is ok to reduce the amount of throttling.
Fixes: ba0f26d8529c ("x86/intel_rdt/mba_sc: Prepare for feedback loop")
Reported-by: Xiaochen Shen <xiaochen.shen@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>
Tested-by: Xiaochen Shen <xiaochen.shen@intel.com>
Link: https://lore.kernel.org/r/20240122180807.70518-1-tony.luck@intel.com
|
|
If the BMEC (Bandwidth Monitoring Event Configuration) feature is
supported, the bandwidth events can be configured. The maximum supported
bandwidth bitmask can be read from CPUID:
CPUID_Fn80000020_ECX_x03 [Platform QoS Monitoring Bandwidth Event Configuration]
Bits Description
31:7 Reserved
6:0 Identifies the bandwidth sources that can be tracked.
While at it, move the mask checking to mon_config_write() before
iterating over all the domains. Also, print the valid bitmask when the
user tries to configure invalid event configuration value.
The CPUID details are documented in the Processor Programming Reference
(PPR) Vol 1.1 for AMD Family 19h Model 11h B1 - 55901 Rev 0.25 in the
Link tag.
Fixes: dc2a3e857981 ("x86/resctrl: Add interface to read mbm_total_bytes_config")
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Link: https://lore.kernel.org/r/669896fa512c7451319fa5ca2fdb6f7e015b5635.1705359148.git.babu.moger@amd.com
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The QOS Memory Bandwidth Enforcement Limit is reported by
CPUID_Fn80000020_EAX_x01 and CPUID_Fn80000020_EAX_x02:
Bits Description
31:0 BW_LEN: Size of the QOS Memory Bandwidth Enforcement Limit.
Newer processors can support higher bandwidth limit than the current
hard-coded value. Remove latter and detect using CPUID instead. Also,
update the register variables eax and edx to match the AMD CPUID
definition.
The CPUID details are documented in the Processor Programming Reference
(PPR) Vol 1.1 for AMD Family 19h Model 11h B1 - 55901 Rev 0.25 in the
Link tag below.
Fixes: 4d05bf71f157 ("x86/resctrl: Introduce AMD QOS feature")
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Link: https://lore.kernel.org/r/c26a8ca79d399ed076cf8bf2e9fbc58048808289.1705359148.git.babu.moger@amd.com
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In a "W=1" build gcc throws a warning:
arch/x86/kernel/cpu/resctrl/core.c: In function ‘cache_alloc_hsw_probe’:
arch/x86/kernel/cpu/resctrl/core.c:139:16: warning: variable ‘h’ set but not used
Switch from wrmsr_safe() to wrmsrl_safe(), and from rdmsr() to rdmsrl()
using a single u64 argument for the MSR value instead of the pair of u32
for the high and low halves.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/ZULCd/TGJL9Dmncf@agluck-desk3
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 resource control updates from Borislav Petkov:
- Add support for non-contiguous capacity bitmasks being added to
Intel's CAT implementation
- Other improvements to resctrl code: better configuration,
simplifications, debugging support, fixes
* tag 'x86_cache_for_6.7_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Display RMID of resource group
x86/resctrl: Add support for the files of MON groups only
x86/resctrl: Display CLOSID for resource group
x86/resctrl: Introduce "-o debug" mount option
x86/resctrl: Move default group file creation to mount
x86/resctrl: Unwind properly from rdt_enable_ctx()
x86/resctrl: Rename rftype flags for consistency
x86/resctrl: Simplify rftype flag definitions
x86/resctrl: Add multiple tasks to the resctrl group at once
Documentation/x86: Document resctrl's new sparse_masks
x86/resctrl: Add sparse_masks file in info
x86/resctrl: Enable non-contiguous CBMs in Intel CAT
x86/resctrl: Rename arch_has_sparse_bitmaps
x86/resctrl: Fix remaining kernel-doc warnings
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In x86, hardware uses RMID to identify a monitoring group. When a user
creates a monitor group these details are not visible. These details
can help resctrl debugging.
Add RMID(mon_hw_id) to the monitor groups display in the resctrl interface.
Users can see these details when resctrl is mounted with "-o debug" option.
Add RFTYPE_MON_BASE that complements existing RFTYPE_CTRL_BASE and
represents files belonging to monitoring groups.
Other architectures do not use "RMID". Use the name mon_hw_id to refer
to "RMID" in an effort to keep the naming generic.
For example:
$cat /sys/fs/resctrl/mon_groups/mon_grp1/mon_hw_id
3
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-10-babu.moger@amd.com
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Files unique to monitoring groups have the RFTYPE_MON flag. When a new
monitoring group is created the resctrl files with flags RFTYPE_BASE
(files common to all resource groups) and RFTYPE_MON (files unique to
monitoring groups) are created to support interacting with the new
monitoring group.
A resource group can support both monitoring and control, also termed
a CTRL_MON resource group. CTRL_MON groups should get both monitoring
and control resctrl files but that is not the case. Only the
RFTYPE_BASE and RFTYPE_CTRL files are created for CTRL_MON groups.
Ensure that files with the RFTYPE_MON flag are created for CTRL_MON groups.
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-9-babu.moger@amd.com
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In x86, hardware uses CLOSID to identify a control group. When a user
creates a control group this information is not visible to the user. It
can help resctrl debugging.
Add CLOSID(ctrl_hw_id) to the control groups display in the resctrl
interface. Users can see this detail when resctrl is mounted with the
"-o debug" option.
Other architectures do not use "CLOSID". Use the names ctrl_hw_id to refer
to "CLOSID" in an effort to keep the naming generic.
For example:
$cat /sys/fs/resctrl/ctrl_grp1/ctrl_hw_id
1
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-8-babu.moger@amd.com
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Add "-o debug" option to mount resctrl filesystem in debug mode. When
in debug mode resctrl displays files that have the new RFTYPE_DEBUG flag
to help resctrl debugging.
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-7-babu.moger@amd.com
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The default resource group and its files are created during kernel init
time. Upcoming changes will make some resctrl files optional based on
a mount parameter. If optional files are to be added to the default
group based on the mount option, then each new file needs to be created
separately and call kernfs_activate() again.
Create all files of the default resource group during resctrl mount,
destroyed during unmount, to avoid scattering resctrl file addition
across two separate code flows.
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-6-babu.moger@amd.com
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rdt_enable_ctx() enables the features provided during resctrl mount.
Additions to rdt_enable_ctx() are required to also modify error paths
of rdt_enable_ctx() callers to ensure correct unwinding if errors
are encountered after calling rdt_enable_ctx(). This is error prone.
Introduce rdt_disable_ctx() to refactor the error unwinding of
rdt_enable_ctx() to simplify future additions. This also simplifies
cleanup in rdt_kill_sb().
Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-5-babu.moger@amd.com
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resctrl associates rftype flags with its files so that files can be chosen
based on the resource, whether it is info or base, and if it is control
or monitor type file. These flags use the RF_ as well as RFTYPE_ prefixes.
Change the prefix to RFTYPE_ for all these flags to be consistent.
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-4-babu.moger@amd.com
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The rftype flags are bitmaps used for adding files under the resctrl
filesystem. Some of these bitmap defines have one extra level of
indirection which is not necessary.
Drop the RF_* defines and simplify the macros.
[ bp: Massage commit message. ]
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-3-babu.moger@amd.com
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The resctrl task assignment for monitor or control group needs to be
done one at a time. For example:
$mount -t resctrl resctrl /sys/fs/resctrl/
$mkdir /sys/fs/resctrl/ctrl_grp1
$echo 123 > /sys/fs/resctrl/ctrl_grp1/tasks
$echo 456 > /sys/fs/resctrl/ctrl_grp1/tasks
$echo 789 > /sys/fs/resctrl/ctrl_grp1/tasks
This is not user-friendly when dealing with hundreds of tasks.
Support multiple task assignment in one command with tasks ids separated
by commas. For example:
$echo 123,456,789 > /sys/fs/resctrl/ctrl_grp1/tasks
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-2-babu.moger@amd.com
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Add the interface in resctrl FS to show if sparse cache allocation
bit masks are supported on the platform. Reading the file returns
either a "1" if non-contiguous 1s are supported and "0" otherwise.
The file path is /sys/fs/resctrl/info/{resource}/sparse_masks, where
{resource} can be either "L2" or "L3".
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Peter Newman <peternewman@google.com>
Link: https://lore.kernel.org/r/7300535160beba41fd8aa073749ec1ee29b4621f.1696934091.git.maciej.wieczor-retman@intel.com
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The setting for non-contiguous 1s support in Intel CAT is
hardcoded to false. On these systems, writing non-contiguous
1s into the schemata file will fail before resctrl passes
the value to the hardware.
In Intel CAT CPUID.0x10.1:ECX[3] and CPUID.0x10.2:ECX[3] stopped
being reserved and now carry information about non-contiguous 1s
value support for L3 and L2 cache respectively. The CAT
capacity bitmask (CBM) supports a non-contiguous 1s value if
the bit is set.
The exception are Haswell systems where non-contiguous 1s value
support needs to stay disabled since they can't make use of CPUID
for Cache allocation.
Originally-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Peter Newman <peternewman@google.com>
Link: https://lore.kernel.org/r/1849b487256fe4de40b30f88450cba3d9abc9171.1696934091.git.maciej.wieczor-retman@intel.com
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