kernel/linux.git/fs/resctrl/internal.h, branch v6.18.21

fs/resctrl: Introduce the interface to switch between monitor modes

2025-09-15T10:49:18+00:00

Resctrl subsystem can support two monitoring modes, "mbm_event" or "default". In mbm_event mode, monitoring event can only accumulate data while it is backed by a hardware counter. In "default" mode, resctrl assumes there is a hardware counter for each event within every CTRL_MON and MON group. Introduce mbm_assign_mode resctrl file to switch between mbm_event and default modes. Example: To list the MBM monitor modes supported: $ cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode [mbm_event] default To enable the "mbm_event" counter assignment mode: $ echo "mbm_event" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode To enable the "default" monitoring mode: $ echo "default" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode Reset MBM event counters automatically as part of changing the mode. Clear both architectural and non-architectural event states to prevent overflow conditions during the next event read. Clear assignable counter configuration on all the domains. Also, enable auto assignment when switching to "mbm_event" mode. Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com

fs/resctrl: Introduce the interface to modify assignments in a group

2025-09-15T10:47:17+00:00

Enable the mbm_l3_assignments resctrl file to be used to modify counter assignments of CTRL_MON and MON groups when the "mbm_event" counter assignment mode is enabled. Process the assignment modifications in the following format: :=;= Event: A valid MBM event in the /sys/fs/resctrl/info/L3_MON/event_configs directory. Domain ID: A valid domain ID. When writing, '*' applies the changes to all domains. Assignment states: _ : Unassign a counter. e : Assign a counter exclusively. Examples: $ cd /sys/fs/resctrl $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=e;1=e mbm_local_bytes:0=e;1=e To unassign the counter associated with the mbm_total_bytes event on domain 0: $ echo "mbm_total_bytes:0=_" > mbm_L3_assignments $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=_;1=e mbm_local_bytes:0=e;1=e To unassign the counter associated with the mbm_total_bytes event on all the domains: $ echo "mbm_total_bytes:*=_" > mbm_L3_assignments $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=_;1=_ mbm_local_bytes:0=e;1=e Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com

fs/resctrl: Introduce mbm_L3_assignments to list assignments in a group

2025-09-15T10:45:34+00:00

Introduce the mbm_L3_assignments resctrl file associated with CTRL_MON and MON resource groups to display the counter assignment states of the resource group when "mbm_event" counter assignment mode is enabled. Display the list in the following format: :=;= Event: A valid MBM event listed in /sys/fs/resctrl/info/L3_MON/event_configs directory. Domain ID: A valid domain ID. The assignment state can be one of the following: _ : No counter assigned. e : Counter assigned exclusively. Example: To list the assignment states for the default group $ cd /sys/fs/resctrl $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=e;1=e mbm_local_bytes:0=e;1=e Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com

fs/resctrl: Introduce mbm_assign_on_mkdir to enable assignments on mkdir

2025-09-15T10:42:02+00:00

The "mbm_event" counter assignment mode allows users to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. Introduce a user-configurable option that determines if a counter will automatically be assigned to an RMID, event pair when its associated monitor group is created via mkdir. Accessible when "mbm_event" counter assignment mode is enabled. Suggested-by: Peter Newman Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com

fs/resctrl: Provide interface to update the event configurations

2025-09-15T10:40:38+00:00

When "mbm_event" counter assignment mode is enabled, users can modify the event configuration by writing to the 'event_filter' resctrl file. The event configurations for mbm_event mode are located in /sys/fs/resctrl/info/L3_MON/event_configs/. Update the assignments of all CTRL_MON and MON resource groups when the event configuration is modified. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory $ echo "local_reads,local_non_temporal_writes" > info/L3_MON/event_configs/mbm_total_bytes/event_filter $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,local_non_temporal_writes Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com

fs/resctrl: Add event configuration directory under info/L3_MON/

2025-09-15T10:39:38+00:00

The "mbm_event" counter assignment mode allows the user to assign a hardware counter to an RMID, event pair and monitor the bandwidth as long as it is assigned. The user can specify the memory transaction(s) for the counter to track. When this mode is supported, the /sys/fs/resctrl/info/L3_MON/event_configs directory contains a sub-directory for each MBM event that can be assigned to a counter. The MBM event sub-directory contains a file named "event_filter" that is used to view and modify which memory transactions the MBM event is configured with. Create /sys/fs/resctrl/info/L3_MON/event_configs directory on resctrl mount and pre-populate it with directories for the two existing MBM events: mbm_total_bytes and mbm_local_bytes. Create the "event_filter" file within each MBM event directory with the needed *show() that displays the memory transactions with which the MBM event is configured. Example: $ mount -t resctrl resctrl /sys/fs/resctrl $ cd /sys/fs/resctrl/ $ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter local_reads,remote_reads,local_non_temporal_writes, remote_non_temporal_writes,local_reads_slow_memory, remote_reads_slow_memory,dirty_victim_writes_all $ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter local_reads,local_non_temporal_writes,local_reads_slow_memory Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com

fs/resctrl: Support counter read/reset with mbm_event assignment mode

2025-09-15T10:38:58+00:00

When "mbm_event" counter assignment mode is enabled, the architecture requires a counter ID to read the event data. Introduce an is_mbm_cntr field in struct rmid_read to indicate whether counter assignment mode is in use. Update the logic to call resctrl_arch_cntr_read() and resctrl_arch_reset_cntr() when the assignment mode is active. Report 'Unassigned' in case the user attempts to read an event without assigning a hardware counter. Suggested-by: Reinette Chatre Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com

fs/resctrl: Add the functionality to unassign MBM events

2025-09-15T10:22:24+00:00

The "mbm_event" counter assignment mode offers "num_mbm_cntrs" number of counters that can be assigned to RMID, event pairs and monitor bandwidth usage as long as it is assigned. If all the counters are in use, the kernel logs the error message "Failed to allocate counter for in domain " in /sys/fs/resctrl/info/last_cmd_status when a new assignment is requested. To make space for a new assignment, users must unassign an already assigned counter and retry the assignment again. Add the functionality to unassign and free the counters in the domain. Also, add the helper rdtgroup_unassign_cntrs() to unassign counters in the group. Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com

fs/resctrl: Add the functionality to assign MBM events

2025-09-15T10:21:24+00:00

When supported, "mbm_event" counter assignment mode offers "num_mbm_cntrs" number of counters that can be assigned to RMID, event pairs and monitor bandwidth usage as long as it is assigned. Add the functionality to allocate and assign a counter to an RMID, event pair in the domain. Also, add the helper rdtgroup_assign_cntrs() to assign counters in the group. Log the error message "Failed to allocate counter for in domain " in /sys/fs/resctrl/info/last_cmd_status if all the counters are in use. Exit on the first failure when assigning counters across all the domains. Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com

fs/resctrl: Introduce event configuration field in struct mon_evt

2025-09-15T10:18:31+00:00

When supported, mbm_event counter assignment mode allows the user to configure events to track specific types of memory transactions. Introduce an evt_cfg field in struct mon_evt to define the type of memory transactions tracked by a monitoring event. Also add a helper function to get the evt_cfg value. Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com