Auke Kok <auke-jan.h.kok@xxxxxxxxx> writes:[snip]
Hi,
I've established a regression in the MSI vector/irq allocation routine for both
i386 and x86_64. Our test labs repeatedly modprobe/rmmod the e1000 driver for
serveral minutes which allocates msi vectors and frees them. These tests have
been running fine until 2.6.19.
I mostly suspect commit 7bd007e480672c99d8656c7b7b12ef0549432c37 at the
moment. Perhaps Eric Biederman can help?
Does this patch fix it for you? It looks like i386 vector allocate
did not have logic to look through the set of vectors more than once.
The code in this patch is a simplified version of what we have-
on x86_64.
Eric
diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index 2424cc9..6a3875f 100644
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -1227,26 +1227,32 @@ static u8 irq_vector[NR_IRQ_VECTORS] __read_mostly = { FIRST_DEVICE_VECTOR , 0 }
static int __assign_irq_vector(int irq)
{
- static int current_vector = FIRST_DEVICE_VECTOR, offset = 0;
- int vector;
+ static int current_vector = FIRST_DEVICE_VECTOR, current_offset = 0;
+ int vector, offset, i;
BUG_ON((unsigned)irq >= NR_IRQ_VECTORS);
if (irq_vector[irq] > 0)
return irq_vector[irq];
- current_vector += 8;
- if (current_vector == SYSCALL_VECTOR)
- current_vector += 8;
-
- if (current_vector >= FIRST_SYSTEM_VECTOR) {
- offset++;
- if (!(offset % 8))
- return -ENOSPC;
- current_vector = FIRST_DEVICE_VECTOR + offset;
- }
-
vector = current_vector;
+ offset = current_offset;
+next:
+ vector += 8;
+ if (vector >= FIRST_SYSTEM_VECTOR) {
+ offset = (offset + 1) % 8;
+ vector = FIRST_DEVICE_VECTOR + offset;
+ }
+ if (vector == current_vector)
+ return -ENOSPC;
+ if (vector == SYSCALL_VECTOR)
+ goto next;
+ for (i = 0; i < NR_IRQ_VECTORS; i++)
+ if (irq_vector[i] == vector)
+ goto next;
+
+ current_vector = vector;
+ current_offset = offset;
irq_vector[irq] = vector;
return vector;