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 --- arch/powerpc/sysdev/ge/Makefile | 2 + arch/powerpc/sysdev/ge/ge_pic.c | 254 ++++++++++++++++++++++++++++++++++++++++ arch/powerpc/sysdev/ge/ge_pic.h | 9 ++ 3 files changed, 265 insertions(+) create mode 100644 arch/powerpc/sysdev/ge/Makefile create mode 100644 arch/powerpc/sysdev/ge/ge_pic.c create mode 100644 arch/powerpc/sysdev/ge/ge_pic.h (limited to 'arch/powerpc/sysdev/ge') diff --git a/arch/powerpc/sysdev/ge/Makefile b/arch/powerpc/sysdev/ge/Makefile new file mode 100644 index 000000000..a63fdb379 --- /dev/null +++ b/arch/powerpc/sysdev/ge/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_GE_FPGA) += ge_pic.o diff --git a/arch/powerpc/sysdev/ge/ge_pic.c b/arch/powerpc/sysdev/ge/ge_pic.c new file mode 100644 index 000000000..0bc3f0b36 --- /dev/null +++ b/arch/powerpc/sysdev/ge/ge_pic.c @@ -0,0 +1,254 @@ +/* + * Interrupt handling for GE FPGA based PIC + * + * Author: Martyn Welch + * + * 2008 (c) GE Intelligent Platforms Embedded Systems, Inc. + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +#include "ge_pic.h" + +#define DEBUG +#undef DEBUG + +#ifdef DEBUG +#define DBG(fmt...) do { printk(KERN_DEBUG "gef_pic: " fmt); } while (0) +#else +#define DBG(fmt...) do { } while (0) +#endif + +#define GEF_PIC_NUM_IRQS 32 + +/* Interrupt Controller Interface Registers */ +#define GEF_PIC_INTR_STATUS 0x0000 + +#define GEF_PIC_INTR_MASK(cpu) (0x0010 + (0x4 * cpu)) +#define GEF_PIC_CPU0_INTR_MASK GEF_PIC_INTR_MASK(0) +#define GEF_PIC_CPU1_INTR_MASK GEF_PIC_INTR_MASK(1) + +#define GEF_PIC_MCP_MASK(cpu) (0x0018 + (0x4 * cpu)) +#define GEF_PIC_CPU0_MCP_MASK GEF_PIC_MCP_MASK(0) +#define GEF_PIC_CPU1_MCP_MASK GEF_PIC_MCP_MASK(1) + + +static DEFINE_RAW_SPINLOCK(gef_pic_lock); + +static void __iomem *gef_pic_irq_reg_base; +static struct irq_domain *gef_pic_irq_host; +static int gef_pic_cascade_irq; + +/* + * Interrupt Controller Handling + * + * The interrupt controller handles interrupts for most on board interrupts, + * apart from PCI interrupts. For example on SBC610: + * + * 17:31 RO Reserved + * 16 RO PCI Express Doorbell 3 Status + * 15 RO PCI Express Doorbell 2 Status + * 14 RO PCI Express Doorbell 1 Status + * 13 RO PCI Express Doorbell 0 Status + * 12 RO Real Time Clock Interrupt Status + * 11 RO Temperature Interrupt Status + * 10 RO Temperature Critical Interrupt Status + * 9 RO Ethernet PHY1 Interrupt Status + * 8 RO Ethernet PHY3 Interrupt Status + * 7 RO PEX8548 Interrupt Status + * 6 RO Reserved + * 5 RO Watchdog 0 Interrupt Status + * 4 RO Watchdog 1 Interrupt Status + * 3 RO AXIS Message FIFO A Interrupt Status + * 2 RO AXIS Message FIFO B Interrupt Status + * 1 RO AXIS Message FIFO C Interrupt Status + * 0 RO AXIS Message FIFO D Interrupt Status + * + * Interrupts can be forwarded to one of two output lines. Nothing + * clever is done, so if the masks are incorrectly set, a single input + * interrupt could generate interrupts on both output lines! + * + * The dual lines are there to allow the chained interrupts to be easily + * passed into two different cores. We currently do not use this functionality + * in this driver. + * + * Controller can also be configured to generate Machine checks (MCP), again on + * two lines, to be attached to two different cores. It is suggested that these + * should be masked out. + */ + +static void gef_pic_cascade(struct irq_desc *desc) +{ + struct irq_chip *chip = irq_desc_get_chip(desc); + unsigned int cascade_irq; + + /* + * See if we actually have an interrupt, call generic handling code if + * we do. + */ + cascade_irq = gef_pic_get_irq(); + + if (cascade_irq) + generic_handle_irq(cascade_irq); + + chip->irq_eoi(&desc->irq_data); +} + +static void gef_pic_mask(struct irq_data *d) +{ + unsigned long flags; + unsigned int hwirq = irqd_to_hwirq(d); + u32 mask; + + raw_spin_lock_irqsave(&gef_pic_lock, flags); + mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0)); + mask &= ~(1 << hwirq); + out_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0), mask); + raw_spin_unlock_irqrestore(&gef_pic_lock, flags); +} + +static void gef_pic_mask_ack(struct irq_data *d) +{ + /* Don't think we actually have to do anything to ack an interrupt, + * we just need to clear down the devices interrupt and it will go away + */ + gef_pic_mask(d); +} + +static void gef_pic_unmask(struct irq_data *d) +{ + unsigned long flags; + unsigned int hwirq = irqd_to_hwirq(d); + u32 mask; + + raw_spin_lock_irqsave(&gef_pic_lock, flags); + mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0)); + mask |= (1 << hwirq); + out_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0), mask); + raw_spin_unlock_irqrestore(&gef_pic_lock, flags); +} + +static struct irq_chip gef_pic_chip = { + .name = "gefp", + .irq_mask = gef_pic_mask, + .irq_mask_ack = gef_pic_mask_ack, + .irq_unmask = gef_pic_unmask, +}; + + +/* When an interrupt is being configured, this call allows some flexibility + * in deciding which irq_chip structure is used + */ +static int gef_pic_host_map(struct irq_domain *h, unsigned int virq, + irq_hw_number_t hwirq) +{ + /* All interrupts are LEVEL sensitive */ + irq_set_status_flags(virq, IRQ_LEVEL); + irq_set_chip_and_handler(virq, &gef_pic_chip, handle_level_irq); + + return 0; +} + +static int gef_pic_host_xlate(struct irq_domain *h, struct device_node *ct, + const u32 *intspec, unsigned int intsize, + irq_hw_number_t *out_hwirq, unsigned int *out_flags) +{ + + *out_hwirq = intspec[0]; + if (intsize > 1) + *out_flags = intspec[1]; + else + *out_flags = IRQ_TYPE_LEVEL_HIGH; + + return 0; +} + +static const struct irq_domain_ops gef_pic_host_ops = { + .map = gef_pic_host_map, + .xlate = gef_pic_host_xlate, +}; + + +/* + * Initialisation of PIC, this should be called in BSP + */ +void __init gef_pic_init(struct device_node *np) +{ + unsigned long flags; + + /* Map the devices registers into memory */ + gef_pic_irq_reg_base = of_iomap(np, 0); + + raw_spin_lock_irqsave(&gef_pic_lock, flags); + + /* Initialise everything as masked. */ + out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU0_INTR_MASK, 0); + out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU1_INTR_MASK, 0); + + out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU0_MCP_MASK, 0); + out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU1_MCP_MASK, 0); + + raw_spin_unlock_irqrestore(&gef_pic_lock, flags); + + /* Map controller */ + gef_pic_cascade_irq = irq_of_parse_and_map(np, 0); + if (!gef_pic_cascade_irq) { + printk(KERN_ERR "SBC610: failed to map cascade interrupt"); + return; + } + + /* Setup an irq_domain structure */ + gef_pic_irq_host = irq_domain_create_linear(of_fwnode_handle(np), + GEF_PIC_NUM_IRQS, + &gef_pic_host_ops, NULL); + if (gef_pic_irq_host == NULL) + return; + + /* Chain with parent controller */ + irq_set_chained_handler(gef_pic_cascade_irq, gef_pic_cascade); +} + +/* + * This is called when we receive an interrupt with apparently comes from this + * chip - check, returning the highest interrupt generated or return 0. + */ +unsigned int gef_pic_get_irq(void) +{ + u32 cause, mask, active; + unsigned int virq = 0; + int hwirq; + + cause = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_STATUS); + + mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0)); + + active = cause & mask; + + if (active) { + for (hwirq = GEF_PIC_NUM_IRQS - 1; hwirq > -1; hwirq--) { + if (active & (0x1 << hwirq)) + break; + } + virq = irq_find_mapping(gef_pic_irq_host, + (irq_hw_number_t)hwirq); + } + + return virq; +} + diff --git a/arch/powerpc/sysdev/ge/ge_pic.h b/arch/powerpc/sysdev/ge/ge_pic.h new file mode 100644 index 000000000..923dedba3 --- /dev/null +++ b/arch/powerpc/sysdev/ge/ge_pic.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __GEF_PIC_H__ +#define __GEF_PIC_H__ + +unsigned int gef_pic_get_irq(void); +void gef_pic_init(struct device_node *); + +#endif /* __GEF_PIC_H__ */ + -- cgit v1.3.1