Messages in this thread | | | Subject | Re: Subject: [PATCH 1/2] x86: get back 15 vectors | From | (Eric W. Biederman) | Date | Mon, 04 Jan 2010 08:18:45 -0800 |
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Yinghai Lu <yinghai@kernel.org> writes:
This patch is wrong.
> between FIRST_EXTERNAL_VECTOR (0x20) and FIRST_DEVICE_VECTOR (0x41) > > for 0x20 and 0x2f, we are safe be used_vectors will prevent it to use used one.
We can not use any of 0x20 - 0x2f for ioapic irqs. We need the entire priority level to ensure that the irq move cleanup ipi is of a lower priority.
> also try to reuse 0x30 to 0x3f after smp_affinity for irq[0,15] is changed to other cpu.
There may be a point with 0x30 to 0x3f as I recall when those irqs come through a legacy pic we need to reserve those vectors on all cpus.
Eric
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> --- > arch/x86/kernel/apic/io_apic.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > Index: linux-2.6/arch/x86/kernel/apic/io_apic.c > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/apic/io_apic.c > +++ linux-2.6/arch/x86/kernel/apic/io_apic.c > @@ -1162,7 +1162,8 @@ __assign_irq_vector(int irq, struct irq_ > * Also, we've got to be careful not to trash gate > * 0x80, because int 0x80 is hm, kind of importantish. ;) > */ > - static int current_vector = FIRST_DEVICE_VECTOR, current_offset = 0; > + static int current_vector = FIRST_EXTERNAL_VECTOR + 1; > + static int current_offset = 0; > unsigned int old_vector; > int cpu, err; > cpumask_var_t tmp_mask; > @@ -1198,7 +1199,7 @@ next: > if (vector >= first_system_vector) { > /* If out of vectors on large boxen, must share them. */ > offset = (offset + 1) % 8; > - vector = FIRST_DEVICE_VECTOR + offset; > + vector = FIRST_EXTERNAL_VECTOR + 1 + offset; > } > if (unlikely(current_vector == vector)) > continue;
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