x86: arch_probe_nr_irqs
Impact: save RAM with large NR_CPUS, get smaller nr_irqs
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Mike Travis <travis@sgi.com>
diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
index 602361a..a16a2ab 100644
--- a/arch/x86/include/asm/irq_vectors.h
+++ b/arch/x86/include/asm/irq_vectors.h
@@ -115,14 +115,11 @@
# endif
#else
-/* defined as a macro so nr_irqs = max_nr_irqs(nr_cpu_ids) can be used */
-# define max_nr_irqs(nr_cpus) \
- ((8 * nr_cpus) > (32 * MAX_IO_APICS) ? \
+# define NR_IRQS \
+ ((8 * NR_CPUS) > (32 * MAX_IO_APICS) ? \
(NR_VECTORS + (8 * NR_CPUS)) : \
(NR_VECTORS + (32 * MAX_IO_APICS))) \
-# define NR_IRQS max_nr_irqs(NR_CPUS)
-
#endif
#elif defined(CONFIG_X86_VOYAGER)
diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c
index ae806380..1579869 100644
--- a/arch/x86/kernel/io_apic.c
+++ b/arch/x86/kernel/io_apic.c
@@ -3850,6 +3850,22 @@
nr_irqs_gsi = nr;
}
+#ifdef CONFIG_SPARSE_IRQ
+int __init arch_probe_nr_irqs(void)
+{
+ int nr;
+
+ nr = ((8 * nr_cpu_ids) > (32 * nr_ioapics) ?
+ (NR_VECTORS + (8 * nr_cpu_ids)) :
+ (NR_VECTORS + (32 * nr_ioapics)));
+
+ if (nr < nr_irqs && nr > nr_irqs_gsi)
+ nr_irqs = nr;
+
+ return 0;
+}
+#endif
+
/* --------------------------------------------------------------------------
ACPI-based IOAPIC Configuration
-------------------------------------------------------------------------- */