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 --- .../devicetree/bindings/dpll/dpll-device.yaml | 76 ++++++++++++ .../devicetree/bindings/dpll/dpll-pin.yaml | 58 +++++++++ .../bindings/dpll/microchip,zl30731.yaml | 138 +++++++++++++++++++++ 3 files changed, 272 insertions(+) create mode 100644 Documentation/devicetree/bindings/dpll/dpll-device.yaml create mode 100644 Documentation/devicetree/bindings/dpll/dpll-pin.yaml create mode 100644 Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml (limited to 'Documentation/devicetree/bindings/dpll') diff --git a/Documentation/devicetree/bindings/dpll/dpll-device.yaml b/Documentation/devicetree/bindings/dpll/dpll-device.yaml new file mode 100644 index 000000000..fb8d7a9a3 --- /dev/null +++ b/Documentation/devicetree/bindings/dpll/dpll-device.yaml @@ -0,0 +1,76 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/dpll/dpll-device.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Digital Phase-Locked Loop (DPLL) Device + +maintainers: + - Ivan Vecera + +description: + Digital Phase-Locked Loop (DPLL) device is used for precise clock + synchronization in networking and telecom hardware. The device can + have one or more channels (DPLLs) and one or more physical input and + output pins. Each DPLL channel can either produce pulse-per-clock signal + or drive ethernet equipment clock. The type of each channel can be + indicated by dpll-types property. + +properties: + $nodename: + pattern: "^dpll(@.*)?$" + + "#address-cells": + const: 0 + + "#size-cells": + const: 0 + + dpll-types: + description: List of DPLL channel types, one per DPLL instance. + $ref: /schemas/types.yaml#/definitions/non-unique-string-array + items: + enum: [pps, eec] + + input-pins: + type: object + description: DPLL input pins + unevaluatedProperties: false + + properties: + "#address-cells": + const: 1 + "#size-cells": + const: 0 + + patternProperties: + "^pin@[0-9a-f]+$": + $ref: /schemas/dpll/dpll-pin.yaml + unevaluatedProperties: false + + required: + - "#address-cells" + - "#size-cells" + + output-pins: + type: object + description: DPLL output pins + unevaluatedProperties: false + + properties: + "#address-cells": + const: 1 + "#size-cells": + const: 0 + + patternProperties: + "^pin@[0-9]+$": + $ref: /schemas/dpll/dpll-pin.yaml + unevaluatedProperties: false + + required: + - "#address-cells" + - "#size-cells" + +additionalProperties: true diff --git a/Documentation/devicetree/bindings/dpll/dpll-pin.yaml b/Documentation/devicetree/bindings/dpll/dpll-pin.yaml new file mode 100644 index 000000000..1287a472f --- /dev/null +++ b/Documentation/devicetree/bindings/dpll/dpll-pin.yaml @@ -0,0 +1,58 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/dpll/dpll-pin.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: DPLL Pin + +maintainers: + - Ivan Vecera + +description: | + The DPLL pin is either a physical input or output pin that is provided + by a DPLL( Digital Phase-Locked Loop) device. The pin is identified by + its physical order number that is stored in reg property and can have + an additional set of properties like supported (allowed) frequencies, + label, type and may support embedded sync. + + Note that the pin in this context has nothing to do with pinctrl. + +properties: + reg: + description: Hardware index of the DPLL pin. + maxItems: 1 + + connection-type: + description: Connection type of the pin + $ref: /schemas/types.yaml#/definitions/string + enum: [ext, gnss, int, mux, synce] + + esync-control: + description: Indicates whether the pin supports embedded sync functionality. + type: boolean + + label: + description: String exposed as the pin board label + $ref: /schemas/types.yaml#/definitions/string + + ref-sync-sources: + description: | + List of phandles to input pins that can serve as the sync source + in a Reference-Sync pair with this pin acting as the clock source. + A Ref-Sync pair consists of a clock reference and a low-frequency + sync signal. The DPLL locks to the clock reference but + phase-aligns to the sync reference. + Only valid for input pins. Each referenced pin must be a + different input pin on the same device. + $ref: /schemas/types.yaml#/definitions/phandle-array + items: + maxItems: 1 + + supported-frequencies-hz: + description: List of supported frequencies for this pin, expressed in Hz. + +required: + - reg + +additionalProperties: false diff --git a/Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml b/Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml new file mode 100644 index 000000000..17983e6c3 --- /dev/null +++ b/Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml @@ -0,0 +1,138 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/dpll/microchip,zl30731.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Microchip Azurite DPLL device + +maintainers: + - Ivan Vecera + +description: + Microchip Azurite DPLL (ZL3073x) is a family of DPLL devices that + provides up to 5 independent DPLL channels, up to 10 differential or + single-ended inputs and 10 differential or 20 single-ended outputs. + These devices support both I2C and SPI interfaces. + The ZL3064x line card timing ICs share the ZL3073x register map + and are described with a fallback to the register equivalent ZL3073x + part. + +properties: + compatible: + oneOf: + - enum: + - microchip,zl30731 + - microchip,zl30732 + - microchip,zl30733 + - microchip,zl30734 + - microchip,zl30735 + - items: + - const: microchip,zl30643 + - const: microchip,zl30733 + + reg: + maxItems: 1 + +required: + - compatible + - reg + +allOf: + - $ref: /schemas/dpll/dpll-device.yaml# + - $ref: /schemas/spi/spi-peripheral-props.yaml# + +unevaluatedProperties: false + +examples: + - | + i2c { + #address-cells = <1>; + #size-cells = <0>; + + dpll@70 { + compatible = "microchip,zl30732"; + reg = <0x70>; + dpll-types = "pps", "eec"; + + input-pins { + #address-cells = <1>; + #size-cells = <0>; + + sync0: pin@0 { /* REF0P - 1 PPS sync source */ + reg = <0>; + connection-type = "ext"; + label = "SMA1"; + supported-frequencies-hz = /bits/ 64 <1>; + }; + + pin@1 { /* REF0N - clock source, can pair with sync0 */ + reg = <1>; + connection-type = "ext"; + label = "SMA2"; + supported-frequencies-hz = /bits/ 64 <10000 10000000>; + ref-sync-sources = <&sync0>; + }; + }; + + output-pins { + #address-cells = <1>; + #size-cells = <0>; + + pin@3 { /* OUT1N */ + reg = <3>; + connection-type = "gnss"; + esync-control; + label = "Output 1"; + supported-frequencies-hz = /bits/ 64 <1 10000>; + }; + }; + }; + }; + - | + spi { + #address-cells = <1>; + #size-cells = <0>; + + dpll@70 { + compatible = "microchip,zl30731"; + reg = <0x70>; + spi-max-frequency = <12500000>; + + dpll-types = "pps"; + + input-pins { + #address-cells = <1>; + #size-cells = <0>; + + sync1: pin@0 { /* REF0P - 1 PPS sync source */ + reg = <0>; + connection-type = "gnss"; + label = "GNSS_1PPS_IN"; + supported-frequencies-hz = /bits/ 64 <1>; + }; + + pin@1 { /* REF0N - clock source */ + reg = <1>; + connection-type = "gnss"; + label = "GNSS_10M_IN"; + supported-frequencies-hz = /bits/ 64 <10000000>; + ref-sync-sources = <&sync1>; + }; + }; + + output-pins { + #address-cells = <1>; + #size-cells = <0>; + + pin@3 { /* OUT1N */ + reg = <3>; + connection-type = "gnss"; + esync-control; + label = "Output 1"; + supported-frequencies-hz = /bits/ 64 <1 10000>; + }; + }; + }; + }; +... -- cgit v1.3.1