[PATCH v2 3/3] irqchip/gic-v3-its: Limit memreserve cpuhp state lifetime

From: Valentin Schneider
Date: Wed Oct 27 2021 - 11:15:25 EST


The new memreserve cpuhp callback only needs to survive up until a point
where every CPU in the system has booted once. Beyond that, it becomes a
no-op and can be put in the bin.

Signed-off-by: Valentin Schneider <valentin.schneider@xxxxxxx>
---
drivers/irqchip/irq-gic-v3-its.c | 16 ++++++++++++++++
include/linux/irqchip/arm-gic-v3.h | 1 +
2 files changed, 17 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index f860733d3e4e..ee83eb377d7e 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -5203,6 +5203,15 @@ int its_cpu_init(void)
return 0;
}

+static void rdist_memreserve_cpuhp_cleanup_workfn(struct work_struct *work)
+{
+ cpuhp_remove_state_nocalls(gic_rdists->cpuhp_memreserve_state);
+ gic_rdists->cpuhp_memreserve_state = CPUHP_INVALID;
+}
+
+static DECLARE_WORK(rdist_memreserve_cpuhp_cleanup_work,
+ rdist_memreserve_cpuhp_cleanup_workfn);
+
static int its_cpu_memreserve_lpi(unsigned int cpu)
{
struct page *pend_page;
@@ -5231,6 +5240,10 @@ static int its_cpu_memreserve_lpi(unsigned int cpu)
}

out:
+ /* Last CPU being brought up gets to issue the cleanup */
+ if (cpumask_equal(&cpus_booted_once_mask, cpu_possible_mask))
+ schedule_work(&rdist_memreserve_cpuhp_cleanup_work);
+
gic_data_rdist()->flags |= RD_LOCAL_MEMRESERVE_DONE;
return ret;
}
@@ -5425,6 +5438,7 @@ int __init its_lpi_memreserve_init(void)
if (!efi_enabled(EFI_CONFIG_TABLES))
return 0;

+ gic_rdists->cpuhp_memreserve_state = CPUHP_INVALID;
state = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
"irqchip/arm/gicv3/memreserve:online",
its_cpu_memreserve_lpi,
@@ -5432,6 +5446,8 @@ int __init its_lpi_memreserve_init(void)
if (state < 0)
return state;

+ gic_rdists->cpuhp_memreserve_state = state;
+
return 0;
}

diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index 51b85506ae90..12d91f0dedf9 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -624,6 +624,7 @@ struct rdists {
u64 flags;
u32 gicd_typer;
u32 gicd_typer2;
+ int cpuhp_memreserve_state;
bool has_vlpis;
bool has_rvpeid;
bool has_direct_lpi;
--
2.25.1