From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug alb_break_llc() decides whether to break LLC preference during active load balance. It does so by testing that every runnable fair task on the source rq prefers its LLC: env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable But the two counters cover different sets. nr_pref_llc_running is updated in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued, so it follows queued tasks. h_nr_runnable is updated in set_delayed()/ clear_delayed() and drops delay-dequeued tasks. So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks, alb_break_llc() returns false, and active balance is free to pull a task off its preferred LLC. Active balance only moves runnable tasks, and this is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB skips the per-task test in can_migrate_task(). The runnable set is the one we want. Fix it on the counter side. A task should be counted in nr_pref_llc_running exactly while it is both queued on its preferred LLC (pref_llc_queued) and runnable (!sched_delayed). Define that membership once in task_pref_llc_runnable(), and adjust the counter only through pref_llc_running_inc()/pref_llc_running_dec() from the four sites that change either input: account_llc_enqueue(), account_llc_dequeue(), set_delayed() and clear_delayed(). Gating every update on the same predicate keeps the delay, wake and dequeue paths from double-counting or underflowing; see the comments at those sites for the ordering. nr_llc_running and sd->llc_counts are not touched and stay on queued semantics. Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC") Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/ Reported-by: Zhan Xusheng Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- Documentation/ABI/testing/sysfs-driver-ccp | 120 +++++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-driver-ccp (limited to 'Documentation/ABI/testing/sysfs-driver-ccp') diff --git a/Documentation/ABI/testing/sysfs-driver-ccp b/Documentation/ABI/testing/sysfs-driver-ccp new file mode 100644 index 000000000..6ec74b9a2 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-ccp @@ -0,0 +1,120 @@ +What: /sys/bus/pci/devices//fused_part +Date: June 2022 +KernelVersion: 5.19 +Contact: mario.limonciello@amd.com +Description: + The /sys/bus/pci/devices//fused_part file reports + whether the CPU or APU has been fused to prevent tampering. + 0: Not fused + 1: Fused + +What: /sys/bus/pci/devices//boot_integrity +Date: April 2026 +KernelVersion: 6.20 +Contact: mario.limonciello@amd.com +Description: + The /sys/bus/pci/devices//boot_integrity reports + whether the AMD CPU or APU is used for a hardware root of trust + during the boot process. + Possible values: + 0: Not hardware root of trust. + 1: Hardware root of trust + + NOTE: Vendors may provide design specific alternative hardware + root of trust implementations. + +What: /sys/bus/pci/devices//debug_lock_on +Date: June 2022 +KernelVersion: 5.19 +Contact: mario.limonciello@amd.com +Description: + The /sys/bus/pci/devices//debug_lock_on reports + whether the AMD CPU or APU has been unlocked for debugging. + Possible values: + 0: Not locked + 1: Locked + +What: /sys/bus/pci/devices//tsme_status +Date: June 2022 +KernelVersion: 5.19 +Contact: mario.limonciello@amd.com +Description: + The /sys/bus/pci/devices//tsme_status file reports + the status of transparent secure memory encryption on AMD systems. + Possible values: + 0: Not active + 1: Active + +What: /sys/bus/pci/devices//anti_rollback_status +Date: June 2022 +KernelVersion: 5.19 +Contact: mario.limonciello@amd.com +Description: + The /sys/bus/pci/devices//anti_rollback_status file reports + whether the PSP is enforcing rollback protection. + Possible values: + 0: Not enforcing + 1: Enforcing + +What: /sys/bus/pci/devices//rpmc_production_enabled +Date: June 2022 +KernelVersion: 5.19 +Contact: mario.limonciello@amd.com +Description: + The /sys/bus/pci/devices//rpmc_production_enabled file reports + whether Replay Protected Monotonic Counter support has been enabled. + Possible values: + 0: Not enabled + 1: Enabled + +What: /sys/bus/pci/devices//rpmc_spirom_available +Date: June 2022 +KernelVersion: 5.19 +Contact: mario.limonciello@amd.com +Description: + The /sys/bus/pci/devices//rpmc_spirom_available file reports + whether an Replay Protected Monotonic Counter supported SPI is installed + on the system. + Possible values: + 0: Not present + 1: Present + +What: /sys/bus/pci/devices//hsp_tpm_available +Date: June 2022 +KernelVersion: 5.19 +Contact: mario.limonciello@amd.com +Description: + The /sys/bus/pci/devices//hsp_tpm_available file reports + whether the HSP TPM has been activated. + Possible values: + 0: Not activated or present + 1: Activated + +What: /sys/bus/pci/devices//rom_armor_enforced +Date: June 2022 +KernelVersion: 5.19 +Contact: mario.limonciello@amd.com +Description: + The /sys/bus/pci/devices//rom_armor_enforced file reports + whether RomArmor SPI protection is enforced. + Possible values: + 0: Not enforced + 1: Enforced + +What: /sys/bus/pci/devices//bootloader_version +Date: June 2023 +KernelVersion: 6.4 +Contact: mario.limonciello@amd.com +Description: + The /sys/bus/pci/devices//bootloader_version + file reports the firmware version of the AMD AGESA + bootloader. + +What: /sys/bus/pci/devices//tee_version +Date: June 2023 +KernelVersion: 6.4 +Contact: mario.limonciello@amd.com +Description: + The /sys/bus/pci/devices//tee_version + file reports the firmware version of the AMD Trusted + Execution Environment (TEE). -- cgit v1.3.1