linux.git/arch/x86/kernel/cpu/resctrl, branch v5.10 Linux kernel source tree x86/resctrl: Fix incorrect local bandwidth when mba_sc is enabled 2020-12-10T16:52:37+00:00 Xiaochen Shen xiaochen.shen@intel.com 2020-12-04T06:27:59+00:00 06c5fe9b12dde1b62821f302f177c972bb1c81f9 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 
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
x86/resctrl: Fix AMD L3 QOS CDP enable/disable 2020-12-01T16:53:31+00:00 Babu Moger babu.moger@amd.com 2020-11-30T15:57:20+00:00 fae3a13d2a3d49a89391889808428cf1e72afbd7 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 
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
x86/resctrl: Add necessary kernfs_put() calls to prevent refcount leak 2020-11-24T11:13:37+00:00 Xiaochen Shen xiaochen.shen@intel.com 2020-10-30T19:11:28+00:00 758999246965eeb8b253d47e72f7bfe508804b16 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 
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
x86/resctrl: Remove superfluous kernfs_get() calls to prevent refcount leak 2020-11-24T11:03:04+00:00 Xiaochen Shen xiaochen.shen@intel.com 2020-10-30T19:10:53+00:00 fd8d9db3559a29fd737bcdb7c4fcbe1940caae34 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 
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
task_work: cleanup notification modes 2020-10-17T21:05:30+00:00 Jens Axboe axboe@kernel.dk 2020-10-16T15:02:26+00:00 91989c707884ecc7cd537281ab1a4b8fb7219da3 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> 
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>
Merge tag 'x86_cache_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-10-12T17:53:32+00:00 Linus Torvalds torvalds@linux-foundation.org 2020-10-12T17:53:32+00:00 64743e652cea9d6df4264caaa1d7f95273024afb 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 
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
x86/resctrl: Fix spelling in user-visible warning messages 2020-09-04T23:24:17+00:00 Colin Ian King colin.king@canonical.com 2020-08-10T07:55:08+00:00 93921baa3f6ff77e57d7e772165aa7bd709b5387 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 
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
x86/resctrl: Enable user to view thread or core throttling mode 2020-08-26T15:53:22+00:00 Fenghua Yu fenghua.yu@intel.com 2020-08-24T19:11:21+00:00 29b6bd41ee24f69a85666b9f68d500b382d408fd 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 
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
cacheinfo: Move resctrl's get_cache_id() to the cacheinfo header file 2020-08-19T09:04:23+00:00 James Morse james.morse@arm.com 2020-07-08T16:39:29+00:00 709c4362725abb5fa1e36fd94893a9b0d049df82 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 
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
x86/resctrl: Add struct rdt_cache::arch_has_{sparse, empty}_bitmaps 2020-08-19T08:41:40+00:00 James Morse james.morse@arm.com 2020-07-08T16:39:28+00:00 316e7f901f5aedb415c72d1eedd7de0846238dd0 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 
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