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When parsing a schema configuration value from user-space, resctrl walks
the architectures rdt_resources_all[] array to find a matching struct
rdt_resource.
Once the CDP resources are merged there will be one resource in use
by two schemata. Anything walking rdt_resources_all[] on behalf of a
user-space request should walk the list of struct resctrl_schema
instead.
Change the users of for_each_alloc_enabled_rdt_resource() to walk the
schema instead. Schemata were only created for alloc_enabled resources
so these two lists are currently equivalent.
schemata_list_create() and rdt_kill_sb() are ignored. The first
creates the schema list, and will eventually loop over the resource
indexes using an arch helper to retrieve the resource. rdt_kill_sb()
will eventually make use of an arch 'reset everything' helper.
After the filesystem code is moved, rdtgroup_pseudo_locked_in_hierarchy()
remains part of the x86 specific hooks to support pseudo lock. This
code walks each domain, and still does this after the separate resources
are merged.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lkml.kernel.org/r/20210728170637.25610-7-james.morse@arm.com
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The names of resources are used for the schema name presented to
user-space. The name used is rooted in a structure provided by the
architecture code because the names are different when CDP is enabled.
x86 implements this by swapping between two sets of resource structures
based on their alloc_enabled flag. The type of configuration in-use is
encoded in the name (and cbm_idx_offset).
Once the CDP behaviour is moved into the parts of resctrl that will
move to /fs/, there will be two struct resctrl_schema for one struct
rdt_resource. The schema describes the type of configuration being
applied to the resource. The name of the schema should be generated
by resctrl, base on the type of configuration. To do this struct
resctrl_schema needs to store the type of configuration in use for a
schema.
Create an enum resctrl_conf_type describing the options, and add it to
struct resctrl_schema. The underlying resources are still separate, as
cbm_idx_offset is still in use.
Temporarily label all the entries in rdt_resources_all[] and copy that
value to struct resctrl_schema. Copying the value ensures there is no
mismatch while the filesystem parts of resctrl are modified to use the
schema. Once the resources are merged, the filesystem code can assign
this value based on the schema being created.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lkml.kernel.org/r/20210728170637.25610-6-james.morse@arm.com
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Many of resctrl's per-schema files return a value from struct
rdt_resource, which they take as their 'priv' pointer.
Moving properties that resctrl exposes to user-space into the core 'fs'
code, (e.g. the name of the schema), means some of the functions that
back the filesystem need the schema struct (to where the properties are
moved), but currently take struct rdt_resource. For example, once the
CDP resources are merged, struct rdt_resource no longer reflects all the
properties of the schema.
For the info dirs that represent a control, the information needed
will be accessed via struct resctrl_schema, as this is how the resource
is being used. For the monitors, its still struct rdt_resource as the
monitors aren't described as schema.
This difference means the type of the private pointers varies between
control and monitor info dirs.
Change the 'priv' pointer to point to struct resctrl_schema for
the per-schema files that represent a control. The type can be
determined from the fflags field. If the flags are RF_MON_INFO, its
a struct rdt_resource. If the flags are RF_CTRL_INFO, its a struct
resctrl_schema. No entry in res_common_files[] has both flags.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lkml.kernel.org/r/20210728170637.25610-5-james.morse@arm.com
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Resctrl exposes schemata to user-space, which allow the control values
to be specified for a group of tasks.
User-visible properties of the interface, (such as the schemata names
and how the values are parsed) are rooted in a struct provided by the
architecture code. (struct rdt_hw_resource). Once a second architecture
uses resctrl, this would allow user-visible properties to diverge
between architectures.
These properties should come from the resctrl code that will be common
to all architectures. Resctrl has no per-schema structure, only struct
rdt_{hw_,}resource. Create a struct resctrl_schema to hold the
rdt_resource. Before a second architecture can be supported, this
structure will also need to hold the schema name visible to user-space
and the type of configuration values for resctrl.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lkml.kernel.org/r/20210728170637.25610-4-james.morse@arm.com
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resctrl is the defacto Linux ABI for SoC resource partitioning features.
To support it on another architecture, it needs to be abstracted from
the features provided by Intel RDT and AMD PQoS, and moved to /fs/.
struct rdt_domain contains a mix of architecture private details and
properties of the filesystem interface user-space uses.
Continue by splitting struct rdt_domain, into an architecture private
'hw' struct, which contains the common resctrl structure that would be
used by any architecture. The hardware values in ctrl_val and mbps_val
need to be accessed via helpers to allow another architecture to convert
these into a different format if necessary. After this split, filesystem
code paths touching a 'hw' struct indicates where an abstraction is
needed.
Splitting this structure only moves types around, and should not lead
to any change in behaviour.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lkml.kernel.org/r/20210728170637.25610-3-james.morse@arm.com
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resctrl is the defacto Linux ABI for SoC resource partitioning features.
To support it on another architecture, it needs to be abstracted from
the features provided by Intel RDT and AMD PQoS, and moved to /fs/.
struct rdt_resource contains a mix of architecture private details
and properties of the filesystem interface user-space uses.
Start by splitting struct rdt_resource, into an architecture private
'hw' struct, which contains the common resctrl structure that would be
used by any architecture. The foreach helpers are most commonly used by
the filesystem code, and should return the common resctrl structure.
for_each_rdt_resource() is changed to walk the common structure in its
parent arch private structure.
Move as much of the structure as possible into the common structure
in the core code's header file. The x86 hardware accessors remain
part of the architecture private code, as do num_closid, mon_scale
and mbm_width.
mon_scale and mbm_width are used to detect overflow of the hardware
counters, and convert them from their native size to bytes. Any
cross-architecture abstraction should be in terms of bytes, making
these properties private.
The hardware's num_closid is kept in the private structure to force the
filesystem code to use a helper to access it. MPAM would return a single
value for the system, regardless of the resource. Using the helper
prevents this field from being confused with the version of num_closid
that is being exposed to user-space (added in a later patch).
After this split, filesystem code touching a 'hw' struct indicates
where an abstraction is needed.
Splitting this structure only moves types around, and should not lead
to any change in behaviour.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lkml.kernel.org/r/20210728170637.25610-2-james.morse@arm.com
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Add description of undocumented parameters. Issues detected by
scripts/kernel-doc.
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20210618223206.29539-1-fmdefrancesco@gmail.com
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Add undocumented parameters detected by scripts/kernel-doc.
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20210616181530.4094-1-fmdefrancesco@gmail.com
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const variable must be initconst, not initdata.
Signed-off-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210425211229.3157674-1-ak@linux.intel.com
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This reverts commit cd544fd1dc9293c6702fab6effa63dac1cc67e99.
As discussed in [1] this commit was a no-op because the mapping type was
checked in vma_to_resize before move_vma is ever called. This meant that
vm_ops->mremap() would never be called on such mappings. Furthermore,
we've since expanded support of MREMAP_DONTUNMAP to non-anonymous
mappings, and these special mappings are still protected by the existing
check of !VM_DONTEXPAND and !VM_PFNMAP which will result in a -EINVAL.
1. https://lkml.org/lkml/2020/12/28/2340
Link: https://lkml.kernel.org/r/20210323182520.2712101-2-bgeffon@google.com
Signed-off-by: Brian Geffon <bgeffon@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Alejandro Colomar <alx.manpages@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Michael S . Tsirkin" <mst@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sonny Rao <sonnyrao@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix another ~42 single-word typos in arch/x86/ code comments,
missed a few in the first pass, in particular in .S files.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org
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Fix ~144 single-word typos in arch/x86/ code comments.
Doing this in a single commit should reduce the churn.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org
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A CPU's current task can have its {closid, rmid} fields read locally
while they are being concurrently written to from another CPU.
This can happen anytime __resctrl_sched_in() races with either
__rdtgroup_move_task() or rdt_move_group_tasks().
Prevent load / store tearing for those accesses by giving them the
READ_ONCE() / WRITE_ONCE() treatment.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/9921fda88ad81afb9885b517fbe864a2bc7c35a9.1608243147.git.reinette.chatre@intel.com
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James reported in [1] that there could be two tasks running on the same CPU
with task_struct->on_cpu set. Using task_struct->on_cpu as a test if a task
is running on a CPU may thus match the old task for a CPU while the
scheduler is running and IPI it unnecessarily.
task_curr() is the correct helper to use. While doing so move the #ifdef
check of the CONFIG_SMP symbol to be a C conditional used to determine
if this helper should be used to ensure the code is always checked for
correctness by the compiler.
[1] https://lore.kernel.org/lkml/a782d2f3-d2f6-795f-f4b1-9462205fd581@arm.com
Reported-by: James Morse <james.morse@arm.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/e9e68ce1441a73401e08b641cc3b9a3cf13fe6d4.1608243147.git.reinette.chatre@intel.com
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Mark the function with the __printf attribute to allow the compiler to
more thoroughly typecheck its arguments against a format string with
-Wformat and similar flags.
[ bp: Massage commit message. ]
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20201221160009.3752017-1-trix@redhat.com
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Shakeel Butt reported in [1] that a user can request a task to be moved
to a resource group even if the task is already in the group. It just
wastes time to do the move operation which could be costly to send IPI
to a different CPU.
Add a sanity check to ensure that the move operation only happens when
the task is not already in the resource group.
[1] https://lore.kernel.org/lkml/CALvZod7E9zzHwenzf7objzGKsdBmVwTgEJ0nPgs0LUFU3SN5Pw@mail.gmail.com/
Fixes: e02737d5b826 ("x86/intel_rdt: Add tasks files")
Reported-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/962ede65d8e95be793cb61102cca37f7bb018e66.1608243147.git.reinette.chatre@intel.com
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Currently, when moving a task to a resource group the PQR_ASSOC MSR is
updated with the new closid and rmid in an added task callback. If the
task is running, the work is run as soon as possible. If the task is not
running, the work is executed later in the kernel exit path when the
kernel returns to the task again.
Updating the PQR_ASSOC MSR as soon as possible on the CPU a moved task
is running is the right thing to do. Queueing work for a task that is
not running is unnecessary (the PQR_ASSOC MSR is already updated when
the task is scheduled in) and causing system resource waste with the way
in which it is implemented: Work to update the PQR_ASSOC register is
queued every time the user writes a task id to the "tasks" file, even if
the task already belongs to the resource group.
This could result in multiple pending work items associated with a
single task even if they are all identical and even though only a single
update with most recent values is needed. Specifically, even if a task
is moved between different resource groups while it is sleeping then it
is only the last move that is relevant but yet a work item is queued
during each move.
This unnecessary queueing of work items could result in significant
system resource waste, especially on tasks sleeping for a long time.
For example, as demonstrated by Shakeel Butt in [1] writing the same
task id to the "tasks" file can quickly consume significant memory. The
same problem (wasted system resources) occurs when moving a task between
different resource groups.
As pointed out by Valentin Schneider in [2] there is an additional issue
with the way in which the queueing of work is done in that the task_struct
update is currently done after the work is queued, resulting in a race with
the register update possibly done before the data needed by the update is
available.
To solve these issues, update the PQR_ASSOC MSR in a synchronous way
right after the new closid and rmid are ready during the task movement,
only if the task is running. If a moved task is not running nothing
is done since the PQR_ASSOC MSR will be updated next time the task is
scheduled. This is the same way used to update the register when tasks
are moved as part of resource group removal.
[1] https://lore.kernel.org/lkml/CALvZod7E9zzHwenzf7objzGKsdBmVwTgEJ0nPgs0LUFU3SN5Pw@mail.gmail.com/
[2] https://lore.kernel.org/lkml/20201123022433.17905-1-valentin.schneider@arm.com
[ bp: Massage commit message and drop the two update_task_closid_rmid()
variants. ]
Fixes: e02737d5b826 ("x86/intel_rdt: Add tasks files")
Reported-by: Shakeel Butt <shakeelb@google.com>
Reported-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/17aa2fb38fc12ce7bb710106b3e7c7b45acb9e94.1608243147.git.reinette.chatre@intel.com
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Merge misc updates from Andrew Morton:
- a few random little subsystems
- almost all of the MM patches which are staged ahead of linux-next
material. I'll trickle to post-linux-next work in as the dependents
get merged up.
Subsystems affected by this patch series: kthread, kbuild, ide, ntfs,
ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache,
gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation,
kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc,
uaccess, zram, and cleanups).
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (200 commits)
mm: cleanup kstrto*() usage
mm: fix fall-through warnings for Clang
mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at
mm: shmem: convert shmem_enabled_show to use sysfs_emit_at
mm:backing-dev: use sysfs_emit in macro defining functions
mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening
mm: use sysfs_emit for struct kobject * uses
mm: fix kernel-doc markups
zram: break the strict dependency from lzo
zram: add stat to gather incompressible pages since zram set up
zram: support page writeback
mm/process_vm_access: remove redundant initialization of iov_r
mm/zsmalloc.c: rework the list_add code in insert_zspage()
mm/zswap: move to use crypto_acomp API for hardware acceleration
mm/zswap: fix passing zero to 'PTR_ERR' warning
mm/zswap: make struct kernel_param_ops definitions const
userfaultfd/selftests: hint the test runner on required privilege
userfaultfd/selftests: fix retval check for userfaultfd_open()
userfaultfd/selftests: always dump something in modes
userfaultfd: selftests: make __{s,u}64 format specifiers portable
...
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As kernel expect to see only one of such mappings, any further operations
on the VMA-copy may be unexpected by the kernel. Maybe it's being on the
safe side, but there doesn't seem to be any expected use-case for this, so
restrict it now.
Link: https://lkml.kernel.org/r/20201013013416.390574-4-dima@arista.com
Fixes: commit e346b3813067 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()")
Signed-off-by: Dmitry Safonov <dima@arista.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull x86 cache resource control updates from Borislav Petkov:
- add logic to correct MBM total and local values fixing errata SKX99
and BDF102 (Fenghua Yu)
- cleanups
* tag 'x86_cache_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Clean up unused function parameter in rmdir path
x86/resctrl: Constify kernfs_ops
x86/resctrl: Correct MBM total and local values
Documentation/x86: Rename resctrl_ui.rst and add two errata to the file
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The MBA software controller (mba_sc) is a feedback loop which
periodically reads MBM counters and tries to restrict the bandwidth
below a user-specified value. It tags along the MBM counter overflow
handler to do the updates with 1s interval in mbm_update() and
update_mba_bw().
The purpose of mbm_update() is to periodically read the MBM counters to
make sure that the hardware counter doesn't wrap around more than once
between user samplings. mbm_update() calls __mon_event_count() for local
bandwidth updating when mba_sc is not enabled, but calls mbm_bw_count()
instead when mba_sc is enabled. __mon_event_count() will not be called
for local bandwidth updating in MBM counter overflow handler, but it is
still called when reading MBM local bandwidth counter file
'mbm_local_bytes', the call path is as below:
rdtgroup_mondata_show()
mon_event_read()
mon_event_count()
__mon_event_count()
In __mon_event_count(), m->chunks is updated by delta chunks which is
calculated from previous MSR value (m->prev_msr) and current MSR value.
When mba_sc is enabled, m->chunks is also updated in mbm_update() by
mistake by the delta chunks which is calculated from m->prev_bw_msr
instead of m->prev_msr. But m->chunks is not used in update_mba_bw() in
the mba_sc feedback loop.
When reading MBM local bandwidth counter file, m->chunks was changed
unexpectedly by mbm_bw_count(). As a result, the incorrect local
bandwidth counter which calculated from incorrect m->chunks is shown to
the user.
Fix this by removing incorrect m->chunks updating in mbm_bw_count() in
MBM counter overflow handler, and always calling __mon_event_count() in
mbm_update() to make sure that the hardware local bandwidth counter
doesn't wrap around.
Test steps:
# Run workload with aggressive memory bandwidth (e.g., 10 GB/s)
git clone https://github.com/intel/intel-cmt-cat && cd intel-cmt-cat
&& make
./tools/membw/membw -c 0 -b 10000 --read
# Enable MBA software controller
mount -t resctrl resctrl -o mba_MBps /sys/fs/resctrl
# Create control group c1
mkdir /sys/fs/resctrl/c1
# Set MB throttle to 6 GB/s
echo "MB:0=6000;1=6000" > /sys/fs/resctrl/c1/schemata
# Write PID of the workload to tasks file
echo `pidof membw` > /sys/fs/resctrl/c1/tasks
# Read local bytes counters twice with 1s interval, the calculated
# local bandwidth is not as expected (approaching to 6 GB/s):
local_1=`cat /sys/fs/resctrl/c1/mon_data/mon_L3_00/mbm_local_bytes`
sleep 1
local_2=`cat /sys/fs/resctrl/c1/mon_data/mon_L3_00/mbm_local_bytes`
echo "local b/w (bytes/s):" `expr $local_2 - $local_1`
Before fix:
local b/w (bytes/s): 11076796416
After fix:
local b/w (bytes/s): 5465014272
Fixes: ba0f26d8529c (x86/intel_rdt/mba_sc: Prepare for feedback loop)
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/1607063279-19437-1-git-send-email-xiaochen.shen@intel.com
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Commit
fd8d9db3559a ("x86/resctrl: Remove superfluous kernfs_get() calls to prevent refcount leak")
removed superfluous kernfs_get() calls in rdtgroup_ctrl_remove() and
rdtgroup_rmdir_ctrl(). That change resulted in an unused function
parameter to these two functions.
Clean up the unused function parameter in rdtgroup_ctrl_remove(),
rdtgroup_rmdir_mon() and their callers rdtgroup_rmdir_ctrl() and
rdtgroup_rmdir().
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/1606759618-13181-1-git-send-email-xiaochen.shen@intel.com
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Merge -rc6 tag to pick up dependent changes.
Signed-off-by: Borislav Petkov <bp@suse.de>
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When the AMD QoS feature CDP (code and data prioritization) is enabled
or disabled, the CDP bit in MSR 0000_0C81 is written on one of the CPUs
in an L3 domain (core complex). That is not correct - the CDP bit needs
to be updated on all the logical CPUs in the domain.
This was not spelled out clearly in the spec earlier. The specification
has been updated and the updated document, "AMD64 Technology Platform
Quality of Service Extensions Publication # 56375 Revision: 1.02 Issue
Date: October 2020" is available now. Refer the section: Code and Data
Prioritization.
Fix the issue by adding a new flag arch_has_per_cpu_cfg in rdt_cache
data structure.
The documentation can be obtained at:
https://developer.amd.com/wp-content/resources/56375.pdf
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
[ bp: Massage commit message. ]
Fixes: 4d05bf71f157 ("x86/resctrl: Introduce AMD QOS feature")
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/160675180380.15628.3309402017215002347.stgit@bmoger-ubuntu
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On resource group creation via a mkdir an extra kernfs_node reference is
obtained by kernfs_get() to ensure that the rdtgroup structure remains
accessible for the rdtgroup_kn_unlock() calls where it is removed on
deletion. Currently the extra kernfs_node reference count is only
dropped by kernfs_put() in rdtgroup_kn_unlock() while the rdtgroup
structure is removed in a few other locations that lack the matching
reference drop.
In call paths of rmdir and umount, when a control group is removed,
kernfs_remove() is called to remove the whole kernfs nodes tree of the
control group (including the kernfs nodes trees of all child monitoring
groups), and then rdtgroup structure is freed by kfree(). The rdtgroup
structures of all child monitoring groups under the control group are
freed by kfree() in free_all_child_rdtgrp().
Before calling kfree() to free the rdtgroup structures, the kernfs node
of the control group itself as well as the kernfs nodes of all child
monitoring groups still take the extra references which will never be
dropped to 0 and the kernfs nodes will never be freed. It leads to
reference count leak and kernfs_node_cache memory leak.
For example, reference count leak is observed in these two cases:
(1) mount -t resctrl resctrl /sys/fs/resctrl
mkdir /sys/fs/resctrl/c1
mkdir /sys/fs/resctrl/c1/mon_groups/m1
umount /sys/fs/resctrl
(2) mkdir /sys/fs/resctrl/c1
mkdir /sys/fs/resctrl/c1/mon_groups/m1
rmdir /sys/fs/resctrl/c1
The same reference count leak issue also exists in the error exit paths
of mkdir in mkdir_rdt_prepare() and rdtgroup_mkdir_ctrl_mon().
Fix this issue by following changes to make sure the extra kernfs_node
reference on rdtgroup is dropped before freeing the rdtgroup structure.
(1) Introduce rdtgroup removal helper rdtgroup_remove() to wrap up
kernfs_put() and kfree().
(2) Call rdtgroup_remove() in rdtgroup removal path where the rdtgroup
structure is about to be freed by kfree().
(3) Call rdtgroup_remove() or kernfs_put() as appropriate in the error
exit paths of mkdir where an extra reference is taken by kernfs_get().
Fixes: f3cbeacaa06e ("x86/intel_rdt/cqm: Add rmdir support")
Fixes: e02737d5b826 ("x86/intel_rdt: Add tasks files")
Fixes: 60cf5e101fd4 ("x86/intel_rdt: Add mkdir to resctrl file system")
Reported-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1604085088-31707-1-git-send-email-xiaochen.shen@intel.com
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Willem reported growing of kernfs_node_cache entries in slabtop when
repeatedly creating and removing resctrl subdirectories as well as when
repeatedly mounting and unmounting the resctrl filesystem.
On resource group (control as well as monitoring) creation via a mkdir
an extra kernfs_node reference is obtained to ensure that the rdtgroup
structure remains accessible for the rdtgroup_kn_unlock() calls where it
is removed on deletion. The kernfs_node reference count is dropped by
kernfs_put() in rdtgroup_kn_unlock().
With the above explaining the need for one kernfs_get()/kernfs_put()
pair in resctrl there are more places where a kernfs_node reference is
obtained without a corresponding release. The excessive amount of
reference count on kernfs nodes will never be dropped to 0 and the
kernfs nodes will never be freed in the call paths of rmdir and umount.
It leads to reference count leak and kernfs_node_cache memory leak.
Remove the superfluous kernfs_get() calls and expand the existing
comments surrounding the remaining kernfs_get()/kernfs_put() pair that
remains in use.
Superfluous kernfs_get() calls are removed from two areas:
(1) In call paths of mount and mkdir, when kernfs nodes for "info",
"mon_groups" and "mon_data" directories and sub-directories are
created, the reference count of newly created kernfs node is set to 1.
But after kernfs_create_dir() returns, superfluous kernfs_get() are
called to take an additional reference.
(2) kernfs_get() calls in rmdir call paths.
Fixes: 17eafd076291 ("x86/intel_rdt: Split resource group removal in two")
Fixes: 4af4a88e0c92 ("x86/intel_rdt/cqm: Add mount,umount support")
Fixes: f3cbeacaa06e ("x86/intel_rdt/cqm: Add rmdir support")
Fixes: d89b7379015f ("x86/intel_rdt/cqm: Add mon_data")
Fixes: c7d9aac61311 ("x86/intel_rdt/cqm: Add mkdir support for RDT monitoring")
Fixes: 5dc1d5c6bac2 ("x86/intel_rdt: Simplify info and base file lists")
Fixes: 60cf5e101fd4 ("x86/intel_rdt: Add mkdir to resctrl file system")
Fixes: 4e978d06dedb ("x86/intel_rdt: Add "info" files to resctrl file system")
Reported-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Willem de Bruijn <willemb@google.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1604085053-31639-1-git-send-email-xiaochen.shen@intel.com
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The only usage of the kf_ops field in the rftype struct is to pass
it as argument to __kernfs_create_file(), which accepts a pointer to
const. Make it a pointer to const. This makes it possible to make
rdtgroup_kf_single_ops and kf_mondata_ops const, which allows the
compiler to put them in read-only memory.
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20201110230228.801785-1-rikard.falkeborn@gmail.com
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Intel Memory Bandwidth Monitoring (MBM) counters may report system
memory bandwidth incorrectly on some Intel processors. The errata SKX99
for Skylake server, BDF102 for Broadwell server, and the correction
factor table are documented in Documentation/x86/resctrl.rst.
Intel MBM counters track metrics according to the assigned Resource
Monitor ID (RMID) for that logical core. The IA32_QM_CTR register
(MSR 0xC8E) used to report these metrics, may report incorrect system
bandwidth for certain RMID values.
Due to the errata, system memory bandwidth may not match what is
reported.
To work around the errata, correct MBM total and local readings using a
correction factor table. If rmid > rmid threshold, MBM total and local
values should be multiplied by the correction factor.
[ bp: Mark mbm_cf_table[] __initdata. ]
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20201014004927.1839452-3-fenghua.yu@intel.com
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A previous commit changed the notification mode from true/false to an
int, allowing notify-no, notify-yes, or signal-notify. This was
backwards compatible in the sense that any existing true/false user
would translate to either 0 (on notification sent) or 1, the latter
which mapped to TWA_RESUME. TWA_SIGNAL was assigned a value of 2.
Clean this up properly, and define a proper enum for the notification
mode. Now we have:
- TWA_NONE. This is 0, same as before the original change, meaning no
notification requested.
- TWA_RESUME. This is 1, same as before the original change, meaning
that we use TIF_NOTIFY_RESUME.
- TWA_SIGNAL. This uses TIF_SIGPENDING/JOBCTL_TASK_WORK for the
notification.
Clean up all the callers, switching their 0/1/false/true to using the
appropriate TWA_* mode for notifications.
Fixes: e91b48162332 ("task_work: teach task_work_add() to do signal_wake_up()")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pull x86 cache resource control updates from Borislav Petkov:
- Misc cleanups to the resctrl code in preparation for the ARM side
(James Morse)
- Add support for controlling per-thread memory bandwidth throttling
delay values on hw which supports it (Fenghua Yu)
* tag 'x86_cache_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Enable user to view thread or core throttling mode
x86/resctrl: Enumerate per-thread MBA controls
cacheinfo: Move resctrl's get_cache_id() to the cacheinfo header file
x86/resctrl: Add struct rdt_cache::arch_has_{sparse, empty}_bitmaps
x86/resctrl: Merge AMD/Intel parse_bw() calls
x86/resctrl: Add struct rdt_membw::arch_needs_linear to explain AMD/Intel MBA difference
x86/resctrl: Use is_closid_match() in more places
x86/resctrl: Include pid.h
x86/resctrl: Use container_of() in delayed_work handlers
x86/resctrl: Fix stale comment
x86/resctrl: Remove struct rdt_membw::max_delay
x86/resctrl: Remove unused struct mbm_state::chunks_bw
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Fix spelling mistake "Could't" -> "Couldn't" in user-visible warning
messages.
[ bp: Massage commit message; s/cpu/CPU/g ]
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200810075508.46490-1-colin.king@canonical.com
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Early Intel hardware implementations of Memory Bandwidth Allocation (MBA)
could only control bandwidth at the processor core level. This meant that
when two processes with different bandwidth allocations ran simultaneously
on the same core the hardware had to resolve this difference. It did so by
applying the higher throttling value (lower bandwidth) to both processes.
Newer implementations can apply different throttling values to each
thread on a core.
Introduce a new resctrl file, "thread_throttle_mode", on Intel systems
that shows to the user how throttling values are allocated, per-core or
per-thread.
On systems that support per-core throttling, the file will display "max".
On newer systems that support per-thread throttling, the file will display
"per-thread".
AMD confirmed in [1] that AMD bandwidth allocation is already at thread
level but that the AMD implementation does not use a memory delay
throttle mode. So to avoid confusion the thread throttling mode would be
UNDEFINED on AMD systems and the "thread_throttle_mode" file will not be
visible.
Originally-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/1598296281-127595-3-git-send-email-fenghua.yu@intel.com
Link: [1] https://lore.kernel.org/lkml/18d277fd-6523-319c-d560-66b63ff606b8@amd.com
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resctrl/core.c defines get_cache_id() for use in its cpu-hotplug
callbacks. This gets the id attribute of the cache at the corresponding
level of a CPU.
Later rework means this private function needs to be shared. Move
it to the header file.
The name conflicts with a different definition in intel_cacheinfo.c,
name it get_cpu_cacheinfo_id() to show its relation with
get_cpu_cacheinfo().
Now this is visible on other architectures, check the id attribute
has actually been set.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20200708163929.2783-11-james.morse@arm.com
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Intel CPUs expect the cache bitmap provided by user-space to have on a
single span of 1s, whereas AMD can support bitmaps like 0xf00f. Arm's
MPAM support also allows sparse bitmaps.
Similarly, Intel CPUs check at least one bit set, whereas AMD CPUs are
quite happy with an empty bitmap. Arm's MPAM allows an empty bitmap.
To move resctrl out to /fs/, platform differences like this need to be
explained.
Add two resource properties arch_has_{empty,sparse}_bitmaps. Test these
around the relevant parts of cbm_validate().
Merging the validate calls causes AMD to gain the min_cbm_bits test
needed for Haswell, but as it always sets this value to 1, it will never
match.
[ bp: Massage commit message. ]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20200708163929.2783-10-james.morse@arm.com
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Now after arch_needs_linear has been added, the parse_bw() calls are
almost the same between AMD and Intel.
The difference is '!is_mba_sc()', which is not checked on AMD. This
will always be true on AMD CPUs as mba_sc cannot be enabled as
is_mba_linear() is false.
Removing this duplication means user-space visible behaviour and
error messages are not validated or generated in different places.
Reviewed-by : Babu Moger <babu.moger@amd.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20200708163929.2783-9-james.morse@arm.com
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The configuration values user-space provides to the resctrl filesystem
are ABI. To make this work on another architecture, all the ABI bits
should be moved out of /arch/x86 and under /fs.
To do this, the differences between AMD and Intel CPUs needs to be
explained to resctrl via resource properties, instead of function
pointers that let the arch code accept subtly different values on
different platforms/architectures.
For MBA, Intel CPUs reject configuration attempts for non-linear
resources, whereas AMD ignore this field as its MBA resource is never
linear. To merge the parse/validate functions, this difference needs to
be explained.
Add struct rdt_membw::arch_needs_linear to indicate the arch code needs
the linear property to be true to configure this resource. AMD can set
this and delay_linear to false. Intel can set arch_needs_linear to
true to keep the existing "No support for non-linear MB domains" error
message for affected platforms.
[ bp: convert "we" etc to passive voice. ]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Link: https://lkml.kernel.org/r/20200708163929.2783-8-james.morse@arm.com
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rdtgroup_tasks_assigned() and show_rdt_tasks() loop over threads testing
for a CTRL/MON group match by closid/rmid with the provided rdtgrp.
Further down the file are helpers to do this, move these further up and
make use of them here.
These helpers additionally check for alloc/mon capable. This is harmless
as rdtgroup_mkdir() tests these capable flags before allowing the config
directories to be created.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20200708163929.2783-7-james.morse@arm.com
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mbm_handle_overflow() and cqm_handle_limbo() are both provided with
the domain's work_struct when called, but use get_domain_from_cpu()
to find the domain, along with the appropriate error handling.
container_of() saves some list walking and bitmap testing, use that
instead.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20200708163929.2783-5-james.morse@arm.com
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The comment in rdtgroup_init() refers to the non existent function
rdt_mount(), which has now been renamed rdt_get_tree(). Fix the
comment.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20200708163929.2783-4-james.morse@arm.com
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max_delay is used by x86's __get_mem_config_intel() as a local variable.
Remove it, replacing it with a local variable.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20200708163929.2783-3-james.morse@arm.com
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Nothing reads struct mbm_states's chunks_bw value, its a copy of
chunks. Remove it.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20200708163929.2783-2-james.morse@arm.com
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The callers don't expect *d_cdp to be set to an error pointer, they only
check for NULL. This leads to a static checker warning:
arch/x86/kernel/cpu/resctrl/rdtgroup.c:2648 __init_one_rdt_domain()
warn: 'd_cdp' could be an error pointer
This would not trigger a bug in this specific case because
__init_one_rdt_domain() calls it with a valid domain that would not have
a negative id and thus not trigger the return of the ERR_PTR(). If this
was a negative domain id then the call to rdt_find_domain() in
domain_add_cpu() would have returned the ERR_PTR() much earlier and the
creation of the domain with an invalid id would have been prevented.
Even though a bug is not triggered currently the right and safe thing to
do is to set the pointer to NULL because that is what can be checked for
when the caller is handling the CDP and non-CDP cases.
Fixes: 52eb74339a62 ("x86/resctrl: Fix rdt_find_domain() return value and checks")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Acked-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lkml.kernel.org/r/20200602193611.GA190851@mwanda
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Memory bandwidth is calculated reading the monitoring counter
at two intervals and calculating the delta. It is the software’s
responsibility to read the count often enough to avoid having
the count roll over _twice_ between reads.
The current code hardcodes the bandwidth monitoring counter's width
to 24 bits for AMD. This is due to default base counter width which
is 24. Currently, AMD does not implement the CPUID 0xF.[ECX=1]:EAX
to adjust the counter width. But, the AMD hardware supports much
wider bandwidth counter with the default width of 44 bits.
Kernel reads these monitoring counters every 1 second and adjusts the
counter value for overflow. With 24 bits and scale value of 64 for AMD,
it can only measure up to 1GB/s without overflowing. For the rates
above 1GB/s this will fail to measure the bandwidth.
Fix the issue setting the default width to 44 bits by adjusting the
offset.
AMD future products will implement CPUID 0xF.[ECX=1]:EAX.
[ bp: Let the line stick out and drop {}-brackets around a single
statement. ]
Fixes: 4d05bf71f157 ("x86/resctrl: Introduce AMD QOS feature")
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/159129975546.62538.5656031125604254041.stgit@naples-babu.amd.com
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Convert comments that reference mmap_sem to reference mmap_lock instead.
[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]
Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The original Memory Bandwidth Monitoring (MBM) architectural
definition defines counters of up to 62 bits in the
IA32_QM_CTR MSR while the first-generation MBM implementation
uses statically defined 24 bit counters.
The MBM CPUID enumeration properties have been expanded to include
the MBM counter width, encoded as an offset from 24 bits.
While eight bits are available for the counter width offset IA32_QM_CTR
MSR only supports 62 bit counters. Add a sanity check, with warning
printed when encountered, to ensure counters cannot exceed the 62 bit
limit.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/69d52abd5b14794d3a0f05ba7c755ed1f4c0d5ed.1588715690.git.reinette.chatre@intel.com
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The original Memory Bandwidth Monitoring (MBM) architectural
definition defines counters of up to 62 bits in the
IA32_QM_CTR MSR while the first-generation MBM implementation
uses statically defined 24 bit counters.
Expand the MBM CPUID enumeration properties to include the MBM
counter width. The previously undefined EAX output register contains,
in bits [7:0], the MBM counter width encoded as an offset from
24 bits. Enumerating this property is only specified for Intel
CPUs.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/afa3af2f753f6bc301fb743bc8944e749cb24afa.1588715690.git.reinette.chatre@intel.com
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The original Memory Bandwidth Monitoring (MBM) architectural
definition defines counters of up to 62 bits in the IA32_QM_CTR MSR,
and the first-generation MBM implementation uses 24 bit counters.
Software is required to poll at 1 second or faster to ensure that
data is retrieved before a counter rollover occurs more than once
under worst conditions.
As system bandwidths scale the software requirement is maintained with
the introduction of a per-resource enumerable MBM counter width.
In preparation for supporting hardware with an enumerable MBM counter
width the current globally static MBM counter width is moved to a
per-resource MBM counter width. Currently initialized to 24 always
to result in no functional change.
In essence there is one function, mbm_overflow_count() that needs to
know the counter width to handle rollovers. The static value
used within mbm_overflow_count() will be replaced with a value
discovered from the hardware. Support for learning the MBM counter
width from hardware is added in the change that follows.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/e36743b9800f16ce600f86b89127391f61261f23.1588715690.git.reinette.chatre@intel.com
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Cache and memory bandwidth monitoring are features that are part of
x86 CPU resource control that is supported by the resctrl subsystem.
The monitoring properties are obtained via CPUID from every CPU
and only used within the resctrl subsystem where the properties are
only read from boot_cpu_data.
Obtain the monitoring properties once, placed in boot_cpu_data, via the
->c_bsp_init() helpers of the vendors that support X86_FEATURE_CQM_LLC.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/6d74a6ac3e69f4b7a8b4115835f9455faf0f468d.1588715690.git.reinette.chatre@intel.com
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The function determining a platform's support and properties of cache
occupancy and memory bandwidth monitoring (properties of
X86_FEATURE_CQM_LLC) can be found among the common CPU code. After
the feature's properties is populated in the per-CPU data the resctrl
subsystem is the only consumer (via boot_cpu_data).
Move the function that obtains the CPU information used by resctrl to
the resctrl subsystem and rename it from init_cqm() to
resctrl_cpu_detect(). The function continues to be called from the
common CPU code. This move is done in preparation of the addition of some
vendor specific code.
No functional change.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/38433b99f9d16c8f4ee796f8cc42b871531fa203.1588715690.git.reinette.chatre@intel.com
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asm/resctrl_sched.h is dedicated to the code used for configuration
of the CPU resource control state when a task is scheduled.
Rename resctrl_sched.h to resctrl.h in preparation of additions that
will no longer make this file dedicated to work done during scheduling.
No functional change.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/6914e0ef880b539a82a6d889f9423496d471ad1d.1588715690.git.reinette.chatre@intel.com
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James Morse
Fabio M. De Francesco
Andi Kleen
Brian Geffon
Ingo Molnar
Valentin Schneider
Reinette Chatre
Tom Rix
Fenghua Yu
Linus Torvalds
Dmitry Safonov
Xiaochen Shen
Borislav Petkov
Babu Moger
Rikard Falkeborn
Jens Axboe
Colin Ian King
Dan Carpenter
Michel Lespinasse