* [PATCH] powerpc: Reduce footprint of irq_stat
@ 2010-01-12 10:56 Anton Blanchard
2010-01-12 10:58 ` [PATCH] powerpc: Reduce footprint of xics_ipi_struct Anton Blanchard
2010-02-01 5:21 ` [PATCH] powerpc: Reduce footprint of irq_stat Benjamin Herrenschmidt
0 siblings, 2 replies; 6+ messages in thread
From: Anton Blanchard @ 2010-01-12 10:56 UTC (permalink / raw)
To: benh; +Cc: linuxppc-dev
PowerPC is currently using asm-generic/hardirq.h which statically allocates an
NR_CPUS irq_stat array. Switch to an arch specific implementation which uses
per cpu data:
On a kernel with NR_CPUS=1024, this saves quite a lot of memory:
text data bss dec hex filename
8767938 2944132 1636796 13348866 cbb002 vmlinux.baseline
8767779 2944260 1505724 13217763 c9afe3 vmlinux.irq_cpustat
A saving of around 128kB.
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: linux-cpumask/arch/powerpc/include/asm/hardirq.h
===================================================================
--- linux-cpumask.orig/arch/powerpc/include/asm/hardirq.h 2010-01-06 16:24:31.220084536 +1100
+++ linux-cpumask/arch/powerpc/include/asm/hardirq.h 2010-01-06 17:45:25.219563704 +1100
@@ -1 +1,22 @@
-#include <asm-generic/hardirq.h>
+#ifndef _ASM_POWERPC_HARDIRQ_H
+#define _ASM_POWERPC_HARDIRQ_H
+
+#include <linux/threads.h>
+#include <linux/irq.h>
+
+typedef struct {
+ unsigned int __softirq_pending;
+} ____cacheline_aligned irq_cpustat_t;
+
+DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+
+#define __ARCH_IRQ_STAT
+
+#define local_softirq_pending() __get_cpu_var(irq_stat).__softirq_pending
+
+static inline void ack_bad_irq(unsigned int irq)
+{
+ printk(KERN_CRIT "unexpected IRQ trap at vector %02x\n", irq);
+}
+
+#endif /* _ASM_POWERPC_HARDIRQ_H */
Index: linux-cpumask/arch/powerpc/kernel/irq.c
===================================================================
--- linux-cpumask.orig/arch/powerpc/kernel/irq.c 2010-01-06 16:29:31.370083802 +1100
+++ linux-cpumask/arch/powerpc/kernel/irq.c 2010-01-06 16:48:04.210086075 +1100
@@ -73,6 +73,9 @@
#define CREATE_TRACE_POINTS
#include <asm/trace.h>
+DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+EXPORT_PER_CPU_SYMBOL(irq_stat);
+
int __irq_offset_value;
static int ppc_spurious_interrupts;
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] powerpc: Reduce footprint of xics_ipi_struct
2010-01-12 10:56 [PATCH] powerpc: Reduce footprint of irq_stat Anton Blanchard
@ 2010-01-12 10:58 ` Anton Blanchard
2010-02-01 5:18 ` Benjamin Herrenschmidt
2010-02-01 5:21 ` [PATCH] powerpc: Reduce footprint of irq_stat Benjamin Herrenschmidt
1 sibling, 1 reply; 6+ messages in thread
From: Anton Blanchard @ 2010-01-12 10:58 UTC (permalink / raw)
To: benh; +Cc: linuxppc-dev
Right now we allocate a cacheline sized NR_CPUS array for xics IPI
communication. Since irq_stat is now PowerPC specific and using
DECLARE_PER_CPU_SHARED_ALIGNED (which should mean remote writes to
this should not conflict with other per cpu data), we can put it in there.
On a kernel with NR_CPUS=1024, this saves quite a lot of memory:
text data bss dec hex filename
8767779 2944260 1505724 13217763 c9afe3 vmlinux.irq_cpustat
8767555 2813444 1505724 13086723 c7b003 vmlinux.xics
A saving of around 128kB.
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: linux-cpumask/arch/powerpc/include/asm/hardirq.h
===================================================================
--- linux-cpumask.orig/arch/powerpc/include/asm/hardirq.h 2010-01-12 12:36:47.174226189 +1100
+++ linux-cpumask/arch/powerpc/include/asm/hardirq.h 2010-01-12 12:36:47.432976459 +1100
@@ -6,6 +6,9 @@
typedef struct {
unsigned int __softirq_pending;
+#if defined(CONFIG_XICS) && defined(CONFIG_SMP)
+ unsigned long xics_ipi;
+#endif
} ____cacheline_aligned irq_cpustat_t;
DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
Index: linux-cpumask/arch/powerpc/platforms/pseries/xics.c
===================================================================
--- linux-cpumask.orig/arch/powerpc/platforms/pseries/xics.c 2010-01-12 12:36:46.905477650 +1100
+++ linux-cpumask/arch/powerpc/platforms/pseries/xics.c 2010-01-12 12:40:54.782975198 +1100
@@ -514,15 +514,12 @@ static void __init xics_init_host(void)
/*
* XICS only has a single IPI, so encode the messages per CPU
*/
-struct xics_ipi_struct {
- unsigned long value;
- } ____cacheline_aligned;
-
-static struct xics_ipi_struct xics_ipi_message[NR_CPUS] __cacheline_aligned;
static inline void smp_xics_do_message(int cpu, int msg)
{
- set_bit(msg, &xics_ipi_message[cpu].value);
+ unsigned long *tgt = &(per_cpu(irq_stat, cpu).xics_ipi);
+
+ set_bit(msg, tgt);
mb();
if (firmware_has_feature(FW_FEATURE_LPAR))
lpar_qirr_info(cpu, IPI_PRIORITY);
@@ -548,25 +545,23 @@ void smp_xics_message_pass(int target, i
static irqreturn_t xics_ipi_dispatch(int cpu)
{
+ unsigned long *tgt = &(per_cpu(irq_stat, cpu).xics_ipi);
+
WARN_ON(cpu_is_offline(cpu));
mb(); /* order mmio clearing qirr */
- while (xics_ipi_message[cpu].value) {
- if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION,
- &xics_ipi_message[cpu].value)) {
+ while (*tgt) {
+ if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION, tgt)) {
smp_message_recv(PPC_MSG_CALL_FUNCTION);
}
- if (test_and_clear_bit(PPC_MSG_RESCHEDULE,
- &xics_ipi_message[cpu].value)) {
+ if (test_and_clear_bit(PPC_MSG_RESCHEDULE, tgt)) {
smp_message_recv(PPC_MSG_RESCHEDULE);
}
- if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE,
- &xics_ipi_message[cpu].value)) {
+ if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE, tgt)) {
smp_message_recv(PPC_MSG_CALL_FUNC_SINGLE);
}
#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
- if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK,
- &xics_ipi_message[cpu].value)) {
+ if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK, tgt)) {
smp_message_recv(PPC_MSG_DEBUGGER_BREAK);
}
#endif
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] powerpc: Reduce footprint of xics_ipi_struct
2010-01-12 10:58 ` [PATCH] powerpc: Reduce footprint of xics_ipi_struct Anton Blanchard
@ 2010-02-01 5:18 ` Benjamin Herrenschmidt
2010-02-01 6:26 ` Anton Blanchard
0 siblings, 1 reply; 6+ messages in thread
From: Benjamin Herrenschmidt @ 2010-02-01 5:18 UTC (permalink / raw)
To: Anton Blanchard; +Cc: linuxppc-dev
On Tue, 2010-01-12 at 21:58 +1100, Anton Blanchard wrote:
> Index: linux-cpumask/arch/powerpc/include/asm/hardirq.h
> ===================================================================
> --- linux-cpumask.orig/arch/powerpc/include/asm/hardirq.h 2010-01-12 12:36:47.174226189 +1100
> +++ linux-cpumask/arch/powerpc/include/asm/hardirq.h 2010-01-12 12:36:47.432976459 +1100
> @@ -6,6 +6,9 @@
>
> typedef struct {
> unsigned int __softirq_pending;
> +#if defined(CONFIG_XICS) && defined(CONFIG_SMP)
> + unsigned long xics_ipi;
> +#endif
> } ____cacheline_aligned irq_cpustat_t;
This is still a gross abuse of irq_cpustat_t ... Can't we do
a separate DECLARE_PER_CPU_SHARED_ALIGNED(unsigned long, xics_ipi)
inside xics.c instead ?
Cheers,
Ben.
> DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
> Index: linux-cpumask/arch/powerpc/platforms/pseries/xics.c
> ===================================================================
> --- linux-cpumask.orig/arch/powerpc/platforms/pseries/xics.c 2010-01-12 12:36:46.905477650 +1100
> +++ linux-cpumask/arch/powerpc/platforms/pseries/xics.c 2010-01-12 12:40:54.782975198 +1100
> @@ -514,15 +514,12 @@ static void __init xics_init_host(void)
> /*
> * XICS only has a single IPI, so encode the messages per CPU
> */
> -struct xics_ipi_struct {
> - unsigned long value;
> - } ____cacheline_aligned;
> -
> -static struct xics_ipi_struct xics_ipi_message[NR_CPUS] __cacheline_aligned;
>
> static inline void smp_xics_do_message(int cpu, int msg)
> {
> - set_bit(msg, &xics_ipi_message[cpu].value);
> + unsigned long *tgt = &(per_cpu(irq_stat, cpu).xics_ipi);
> +
> + set_bit(msg, tgt);
> mb();
> if (firmware_has_feature(FW_FEATURE_LPAR))
> lpar_qirr_info(cpu, IPI_PRIORITY);
> @@ -548,25 +545,23 @@ void smp_xics_message_pass(int target, i
>
> static irqreturn_t xics_ipi_dispatch(int cpu)
> {
> + unsigned long *tgt = &(per_cpu(irq_stat, cpu).xics_ipi);
> +
> WARN_ON(cpu_is_offline(cpu));
>
> mb(); /* order mmio clearing qirr */
> - while (xics_ipi_message[cpu].value) {
> - if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION,
> - &xics_ipi_message[cpu].value)) {
> + while (*tgt) {
> + if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION, tgt)) {
> smp_message_recv(PPC_MSG_CALL_FUNCTION);
> }
> - if (test_and_clear_bit(PPC_MSG_RESCHEDULE,
> - &xics_ipi_message[cpu].value)) {
> + if (test_and_clear_bit(PPC_MSG_RESCHEDULE, tgt)) {
> smp_message_recv(PPC_MSG_RESCHEDULE);
> }
> - if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE,
> - &xics_ipi_message[cpu].value)) {
> + if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE, tgt)) {
> smp_message_recv(PPC_MSG_CALL_FUNC_SINGLE);
> }
> #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
> - if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK,
> - &xics_ipi_message[cpu].value)) {
> + if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK, tgt)) {
> smp_message_recv(PPC_MSG_DEBUGGER_BREAK);
> }
> #endif
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] powerpc: Reduce footprint of irq_stat
2010-01-12 10:56 [PATCH] powerpc: Reduce footprint of irq_stat Anton Blanchard
2010-01-12 10:58 ` [PATCH] powerpc: Reduce footprint of xics_ipi_struct Anton Blanchard
@ 2010-02-01 5:21 ` Benjamin Herrenschmidt
2010-02-01 5:44 ` Anton Blanchard
1 sibling, 1 reply; 6+ messages in thread
From: Benjamin Herrenschmidt @ 2010-02-01 5:21 UTC (permalink / raw)
To: Anton Blanchard; +Cc: linuxppc-dev
> +typedef struct {
> + unsigned int __softirq_pending;
> +} ____cacheline_aligned irq_cpustat_t;
> +
> +DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
> +
> +#define __ARCH_IRQ_STAT
> +
> +#define local_softirq_pending() __get_cpu_var(irq_stat).__softirq_pending
> +
> +static inline void ack_bad_irq(unsigned int irq)
> +{
> + printk(KERN_CRIT "unexpected IRQ trap at vector %02x\n", irq);
> +}
Looks like some unrelated gunk slipped into this patch :-)
Cheers,
Ben.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] powerpc: Reduce footprint of irq_stat
2010-02-01 5:21 ` [PATCH] powerpc: Reduce footprint of irq_stat Benjamin Herrenschmidt
@ 2010-02-01 5:44 ` Anton Blanchard
0 siblings, 0 replies; 6+ messages in thread
From: Anton Blanchard @ 2010-02-01 5:44 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: linuxppc-dev
Hi,
> > +static inline void ack_bad_irq(unsigned int irq)
> > +{
> > + printk(KERN_CRIT "unexpected IRQ trap at vector %02x\n", irq);
> > +}
>
> Looks like some unrelated gunk slipped into this patch :-)
We need that to link :)
kernel/irq/handle.c: In function ‘handle_bad_irq’:
kernel/irq/handle.c:43: error: implicit declaration of function ‘ack_bad_irq’
It's basically a copy of the fallback handler in the asm-generic hardirq.h
I'm happy to change it print "IRQ on fire" :)
Anton
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] powerpc: Reduce footprint of xics_ipi_struct
2010-02-01 5:18 ` Benjamin Herrenschmidt
@ 2010-02-01 6:26 ` Anton Blanchard
0 siblings, 0 replies; 6+ messages in thread
From: Anton Blanchard @ 2010-02-01 6:26 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: linuxppc-dev
Hi,
> > +#if defined(CONFIG_XICS) && defined(CONFIG_SMP)
> > + unsigned long xics_ipi;
> > +#endif
> > } ____cacheline_aligned irq_cpustat_t;
>
> This is still a gross abuse of irq_cpustat_t ... Can't we do
> a separate DECLARE_PER_CPU_SHARED_ALIGNED(unsigned long, xics_ipi)
> inside xics.c instead ?
Yeah it was a bit tasteless :) Respinning...
Anton
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2010-02-01 6:26 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2010-01-12 10:56 [PATCH] powerpc: Reduce footprint of irq_stat Anton Blanchard
2010-01-12 10:58 ` [PATCH] powerpc: Reduce footprint of xics_ipi_struct Anton Blanchard
2010-02-01 5:18 ` Benjamin Herrenschmidt
2010-02-01 6:26 ` Anton Blanchard
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2010-02-01 5:44 ` Anton Blanchard
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