On Thu, Apr 26, 2007 at 09:42:50AM -0500, Milton Miller wrote:
> Yes. The whole point of
> >-static int get_irq_server(unsigned int virq)
> >+static int get_irq_server(unsigned int virq, unsigned int
> >strict_check)
> was to factor out the common code in this function.
>
> I wasn't trying to change the prototype of xics_set_affinity.
>
> Looking at the code a bit, I think part of the confusion is that newmask
> is horribly misnamed. Please rename it to server or irqserver.
> Obtain its value by calling get_irq_server. If the server returned
> is -1 (in strict mode), don't call rtas (just return like today).
> I guess a printk could be in order since the function is void, and
> only root can request the change.
Milton,
How about this patch?
It is observed that in some PPC970 based machines, When the kernel is
booted with maxcpus=1, interrupts were distributed to offline cpus
also. So a condition is included to check whether the cpu online
map and cpu present map are equal or not. If they are equal
default_distrib_server is used as the interrupt server otherwise
default_server(ie boot cpu) is used as the interrupt server.
In addition to this, if an interrupt is assigned to a specific cpu (ie
smp affinity) and if that cpu is not online, the earlier code used to
return the default_distrib_server as interrupt server. This patch
introduces an additional paramter to the get_irq function ie
strict_check, based on this parameter, if the cpu is not online either
default_distrib_server or -1 is returned.
Cc: Milton Miller <miltonm at bga.com>,
Michael Ellerman <michael at ellerman.id.au>
Signed-off-by: Mohan Kumar M <mohan at in.ibm.com>
---
arch/powerpc/platforms/pseries/xics.c | 63 +++++++++++++++++++++-------------
1 file changed, 39 insertions(+), 24 deletions(-)
Index: linux-2.6.21.1/arch/powerpc/platforms/pseries/xics.c
===================================================================
--- linux-2.6.21.1.orig/arch/powerpc/platforms/pseries/xics.c
+++ linux-2.6.21.1/arch/powerpc/platforms/pseries/xics.c
@@ -156,9 +156,9 @@ static inline void lpar_qirr_info(int n_
#ifdef CONFIG_SMP
-static int get_irq_server(unsigned int virq)
+static int get_irq_server(unsigned int virq, unsigned int strict_check)
{
- unsigned int server;
+ int server;
/* For the moment only implement delivery to all cpus or one cpu */
cpumask_t cpumask = irq_desc[virq].affinity;
cpumask_t tmp = CPU_MASK_NONE;
@@ -166,22 +166,28 @@ static int get_irq_server(unsigned int v
if (!distribute_irqs)
return default_server;
- if (cpus_equal(cpumask, CPU_MASK_ALL)) {
- server = default_distrib_server;
- } else {
+ if (!cpus_equal(cpumask, CPU_MASK_ALL)) {
cpus_and(tmp, cpu_online_map, cpumask);
- if (cpus_empty(tmp))
- server = default_distrib_server;
+ server = first_cpu(tmp);
+
+ if (server < NR_CPUS)
+ return get_hard_smp_processor_id(server);
+ else {
+ if (strict_check)
+ return -1;
+ else
+ return default_distrib_server;
+ }
+ } else {
+ if (cpus_equal(cpu_online_map, cpu_present_map))
+ return default_distrib_server;
else
- server = get_hard_smp_processor_id(first_cpu(tmp));
+ return default_server;
}
-
- return server;
-
}
#else
-static int get_irq_server(unsigned int virq)
+static int get_irq_server(unsigned int virq, unsigned int strict_check)
{
return default_server;
}
@@ -192,7 +198,7 @@ static void xics_unmask_irq(unsigned int
{
unsigned int irq;
int call_status;
- unsigned int server;
+ int server;
pr_debug("xics: unmask virq %d\n", virq);
@@ -201,7 +207,7 @@ static void xics_unmask_irq(unsigned int
if (irq == XICS_IPI || irq == XICS_IRQ_SPURIOUS)
return;
- server = get_irq_server(virq);
+ server = get_irq_server(virq, 0);
call_status = rtas_call(ibm_set_xive, 3, 1, NULL, irq, server,
DEFAULT_PRIORITY);
@@ -398,8 +404,7 @@ static void xics_set_affinity(unsigned i
unsigned int irq;
int status;
int xics_status[2];
- unsigned long newmask;
- cpumask_t tmp = CPU_MASK_NONE;
+ int irq_server;
irq = (unsigned int)irq_map[virq].hwirq;
if (irq == XICS_IPI || irq == XICS_IRQ_SPURIOUS)
@@ -413,18 +418,28 @@ static void xics_set_affinity(unsigned i
return;
}
- /* For the moment only implement delivery to all cpus or one cpu */
- if (cpus_equal(cpumask, CPU_MASK_ALL)) {
- newmask = default_distrib_server;
- } else {
- cpus_and(tmp, cpu_online_map, cpumask);
- if (cpus_empty(tmp))
+ /* Get current irq_server for the given irq */
+ irq_server = get_irq_server(irq, 1);
+ if (irq_server == -1) {
+ printk(KERN_ERR "xics_set_affinity: Invalid cpumask\n");
+ return;
+ }
+
+ /* For the moment only implement delivery to all cpus or one cpu.
+ * Compare the irq_server with the new cpumask. If the irq_server
+ * is specified in cpumask, do the required rtas_call, otherwise
+ * return by printing an error message
+ */
+ if (!cpus_equal(cpumask, CPU_MASK_ALL)) {
+ if (!cpu_isset(irq_server, cpumask)) {
+ printk(KERN_ERR "xics_set_affinity: Invalid "
+ "cpumask\n");
return;
- newmask = get_hard_smp_processor_id(first_cpu(tmp));
+ }
}
status = rtas_call(ibm_set_xive, 3, 1, NULL,
- irq, newmask, xics_status[1]);
+ irq, irq_server, xics_status[1]);
if (status) {
printk(KERN_ERR "xics_set_affinity: irq=%u ibm,set-xive "
