[tip: irq/msi] genirq/matrix: Dynamic bitmap allocation

tip-bot2 for Björn Töpel
2024-02-23T09:43:59Z

The following commit has been merged into the irq/msi branch of tip:

Commit-ID: 5b98d210ac1e4eb35abfbd940df50dec10ae81e1
Gitweb: https://git.kernel.org/tip/5b98d210ac1e4eb35abfbd940df50dec10ae81e1
Author: Björn Töpel <bjorn@rivosinc.com>
AuthorDate: Thu, 22 Feb 2024 15:09:58 +05:30
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Fri, 23 Feb 2024 10:18:44 +01:00

genirq/matrix: Dynamic bitmap allocation

A future user of the matrix allocator, does 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>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240222094006.1030709-11-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 b02c3cd..edebf10 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 75d0ae4..8f222d1 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;
}