[PATCH v14 10/18] genirq/matrix: Dynamic bitmap allocation

Anup Patel
2024-02-22T09:41:38Z

From: Björn Töpel <bjorn@rivosinc.com>

Some (future) users of the irq matrix allocator, do not know the size
of the matrix bitmaps at compile time.

To avoid wasting memory on unnecessary large bitmaps, size the bitmap
at matrix allocation time.

Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
arch/x86/include/asm/hw_irq.h | 2 --
kernel/irq/matrix.c | 28 +++++++++++++++++-----------
2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index b02c3cd3c0f6..edebf1020e04 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -16,8 +16,6 @@

#include <asm/irq_vectors.h>

-#define IRQ_MATRIX_BITS NR_VECTORS
-
#ifndef __ASSEMBLY__

#include <linux/percpu.h>
diff --git a/kernel/irq/matrix.c b/kernel/irq/matrix.c
index 75d0ae490e29..8f222d1cccec 100644
--- a/kernel/irq/matrix.c
+++ b/kernel/irq/matrix.c
@@ -8,8 +8,6 @@
#include <linux/cpu.h>
#include <linux/irq.h>

-#define IRQ_MATRIX_SIZE (BITS_TO_LONGS(IRQ_MATRIX_BITS))
-
struct cpumap {
unsigned int available;
unsigned int allocated;
@@ -17,8 +15,8 @@ struct cpumap {
unsigned int managed_allocated;
bool initialized;
bool online;
- unsigned long alloc_map[IRQ_MATRIX_SIZE];
- unsigned long managed_map[IRQ_MATRIX_SIZE];
+ unsigned long *managed_map;
+ unsigned long alloc_map[];
};

struct irq_matrix {
@@ -32,8 +30,8 @@ struct irq_matrix {
unsigned int total_allocated;
unsigned int online_maps;
struct cpumap __percpu *maps;
- unsigned long scratch_map[IRQ_MATRIX_SIZE];
- unsigned long system_map[IRQ_MATRIX_SIZE];
+ unsigned long *system_map;
+ unsigned long scratch_map[];
};

#define CREATE_TRACE_POINTS
@@ -50,24 +48,32 @@ __init struct irq_matrix *irq_alloc_matrix(unsigned int matrix_bits,
unsigned int alloc_start,
unsigned int alloc_end)
{
+ unsigned int cpu, matrix_size = BITS_TO_LONGS(matrix_bits);
struct irq_matrix *m;

- if (matrix_bits > IRQ_MATRIX_BITS)
- return NULL;
-
- m = kzalloc(sizeof(*m), GFP_KERNEL);
+ m = kzalloc(struct_size(m, scratch_map, matrix_size * 2), GFP_KERNEL);
if (!m)
return NULL;

+ m->system_map = &m->scratch_map[matrix_size];
+
m->matrix_bits = matrix_bits;
m->alloc_start = alloc_start;
m->alloc_end = alloc_end;
m->alloc_size = alloc_end - alloc_start;
- m->maps = alloc_percpu(*m->maps);
+ m->maps = __alloc_percpu(struct_size(m->maps, alloc_map, matrix_size * 2),
+ __alignof__(*m->maps));
if (!m->maps) {
kfree(m);
return NULL;
}
+
+ for_each_possible_cpu(cpu) {
+ struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
+
+ cm->managed_map = &cm->alloc_map[matrix_size];
+ }
+
return m;
}

--
2.34.1