irq: move irq_desc according to smp_affinity v5

PATCH In review Yinghai Lu 2 participants 6 messages Dec 6, 2008 – Dec 11, 2008

Subsystems (2)

x86 IRQ

lore

Share & tools

lore

Yinghai Lu

author

2008-12-06 03:01 UTC #0 lore raw

PATCH 5/5 irq: move irq_desc according to smp_affinity v5

impact: new feature move irq_desc with sparseirq

if CONFIG_MOVE_IRQ_DESC is set
make irq_desc to go with affinity aka irq_desc moving etc call move_irq_desc in irq_complete_move()
legacy irq_desc is not moved, because they are allocated via static array

v3: add calling to irq_to_desc after calling ack/eoi instead of passing desc

for logical apic mode, need to add move_desc_in_progress_in_same_domain. otherwise it will not get moved. ==> also could need two phase to get irq_desc moved.

	for example: 0xff is old affinity, and need to set 0xf, and then set to 0xf0.
	[ or we need to change domain definition to cpus on the same node ? ]

LBSuse:~ # cat /proc/irq/22/smp_affinity
00000000,00000000,00000000,000000ff
LBSuse:~ # echo f > /proc/irq/22/smp_affinity
LBSuse:~ # cat /proc/irq/22/smp_affinity
00000000,00000000,00000000,0000000f
LBSuse:~ # tail /var/log/messages
...

Oct 27 12:35:34 LBSuse kernel: klogd 1.4.1, log source = /proc/kmsg started.
Oct 27 12:35:34 LBSuse kernel: eth0: no IPv6 routers present
LBSuse:~ # echo f0 > /proc/irq/22/smp_affinity
LBSuse:~ # tail /var/log/messages
Oct 27 12:35:34 LBSuse kernel: klogd 1.4.1, log source = /proc/kmsg started.
Oct 27 12:35:34 LBSuse kernel: eth0: no IPv6 routers present
Oct 27 12:36:46 LBSuse kernel:   move irq_desc for 22 aka 0x16 to cpu 7 node 1
Oct 27 12:36:46 LBSuse kernel:   alloc kstat_irqs on cpu 7 node 1
Oct 27 12:36:46 LBSuse kernel:   alloc irq_cfg on cpu 7 node 1
Oct 27 12:36:46 LBSuse kernel:   alloc irq_2_pin on cpu 7 node 1

so assume the user space program should update /proc/irq/XX/smp_affinity to 03 or 0f at first on boot or we change irq_default_affinity ?

for physical apic is much simple
on 4 sockets 16 cores system
irq_desc is moving..
when

# echo 10 > /proc/irq/134483967/smp_affinity
# echo 100 > /proc/irq/134483967/smp_affinity
# echo 1000 > /proc/irq/134483967/smp_affinity
got
Nov  9 21:39:51 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 4 node 1
Nov  9 21:39:51 LBSuse kernel:   alloc kstat_irqs on cpu 4 node 1
Nov  9 21:39:51 LBSuse kernel:   alloc irq_cfg on cpu 4 node 1
Nov  9 21:40:05 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 8 node 2
Nov  9 21:40:05 LBSuse kernel:   alloc kstat_irqs on cpu 8 node 2
Nov  9 21:40:05 LBSuse kernel:   alloc irq_cfg on cpu 8 node 2
Nov  9 21:40:18 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 12 node 3
Nov  9 21:40:18 LBSuse kernel:   alloc kstat_irqs on cpu 12 node 3
Nov  9 21:40:18 LBSuse kernel:   alloc irq_cfg on cpu 12 node 3

Signed-off-by Yinghai Lu <[email protected]>

---
 arch/x86/Kconfig          |    9 ++
 arch/x86/kernel/io_apic.c |  143 +++++++++++++++++++++++++++++++++++++++++++++-
 kernel/irq/chip.c         |   30 +++++++++
 kernel/irq/handle.c       |  124 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 301 insertions(+), 5 deletions(-)

arch/x86/Kconfig +9 -0

Index: linux-2.6/arch/x86/Kconfig
===================================================================
@@ -253,6 +253,15 @@ config SPARSE_IRQ
 
 	  If you don't know what to do here, say Y.
 
+config MOVE_IRQ_DESC
+	bool "Move irq desc when changing irq smp_affinity"
+	depends on SPARSE_IRQ && SMP
+	default y
+	help
+	  This enables moving irq_desc to cpu/node that irq will use handled.
+
+	  If you don't know what to do here, say Y.
+
 config X86_FIND_SMP_CONFIG
 	def_bool y
 	depends on X86_MPPARSE || X86_VOYAGER

arch/x86/kernel/io_apic.c +142 -1

177 lines not on this page · raw message

kernel/irq/handle.c +122 -2

156 lines not on this page · raw message

kernel/irq/chip.c +28 -2

Index: linux-2.6/kernel/irq/chip.c
===================================================================
@@ -354,6 +354,10 @@ handle_level_irq(unsigned int irq, struc
 
 	spin_lock(&desc->lock);
 	mask_ack_irq(desc, irq);
+#ifdef CONFIG_MOVE_IRQ_DESC
+	/* get new one */
+	desc = irq_to_desc(irq);
+#endif
 
 	if (unlikely(desc->status & IRQ_INPROGRESS))
 		goto out_unlock;

@@ -431,6 +435,10 @@ handle_fasteoi_irq(unsigned int irq, str
 	desc->status &= ~IRQ_INPROGRESS;
 out:
 	desc->chip->eoi(irq);
+#ifdef CONFIG_MOVE_IRQ_DESC
+	/* get new one */
+	desc = irq_to_desc(irq);
+#endif
 
 	spin_unlock(&desc->lock);
 }

@@ -467,12 +475,20 @@ handle_edge_irq(unsigned int irq, struct
 		    !desc->action)) {
 		desc->status |= (IRQ_PENDING | IRQ_MASKED);
 		mask_ack_irq(desc, irq);
+#ifdef CONFIG_MOVE_IRQ_DESC
+		/* get new one */
+		desc = irq_to_desc(irq);
+#endif
 		goto out_unlock;
 	}
 	kstat_incr_irqs_this_cpu(irq, desc);
 
 	/* Start handling the irq */
 	desc->chip->ack(irq);
+#ifdef CONFIG_MOVE_IRQ_DESC
+	/* get new one */
+	desc = irq_to_desc(irq);
+#endif
 
 	/* Mark the IRQ currently in progress.*/
 	desc->status |= IRQ_INPROGRESS;

@@ -533,8 +549,13 @@ handle_percpu_irq(unsigned int irq, stru
 	if (!noirqdebug)
 		note_interrupt(irq, desc, action_ret);
 
-	if (desc->chip->eoi)
+	if (desc->chip->eoi) {
 		desc->chip->eoi(irq);
+#ifdef CONFIG_MOVE_IRQ_DESC
+		/* get new one */
+		desc = irq_to_desc(irq);
+#endif
+	}
 }
 
 void

@@ -569,8 +590,13 @@ __set_irq_handler(unsigned int irq, irq_
 
 	/* Uninstall? */
 	if (handle == handle_bad_irq) {
-		if (desc->chip != &no_irq_chip)
+		if (desc->chip != &no_irq_chip) {
 			mask_ack_irq(desc, irq);
+#ifdef CONFIG_MOVE_IRQ_DESC
+			/* get new one */
+			desc = irq_to_desc(irq);
+#endif
+		}
 		desc->status |= IRQ_DISABLED;
 		desc->depth = 1;
 	}

Ingo Molnar

2008-12-08 13:42 UTC #1 lore raw

Quoted 44 lines · Yinghai Lu

kernel/irq/chip.c +18 -1

+#ifdef CONFIG_MOVE_IRQ_DESC
+	/* get new one */
+	desc = irq_to_desc(irq);
+#endif
 
 	spin_unlock(&desc->lock);
 }

@@ -467,12 +475,20 @@ handle_edge_irq(unsigned int irq, struct
 		    !desc->action)) {
 		desc->status |= (IRQ_PENDING | IRQ_MASKED);
 		mask_ack_irq(desc, irq);
+#ifdef CONFIG_MOVE_IRQ_DESC
+		/* get new one */
+		desc = irq_to_desc(irq);
+#endif
 		goto out_unlock;
 	}
 	kstat_incr_irqs_this_cpu(irq, desc);
 
 	/* Start handling the irq */
 	desc->chip->ack(irq);
+#ifdef CONFIG_MOVE_IRQ_DESC
+	/* get new one */
+	desc = irq_to_desc(irq);
+#endif
 
 	/* Mark the IRQ currently in progress.*/
 	desc->status |= IRQ_INPROGRESS;

@@ -533,8 +549,13 @@ handle_percpu_irq(unsigned int irq, stru
 	if (!noirqdebug)
 		note_interrupt(irq, desc, action_ret);
 
-	if (desc->chip->eoi)
+	if (desc->chip->eoi) {
 		desc->chip->eoi(irq);
+#ifdef CONFIG_MOVE_IRQ_DESC
+		/* get new one */
+		desc = irq_to_desc(irq);
+#endif
+	}
 }
 
 void

kernel/irq/chip.c __set_irq_handler(unsigned int irq, irq_ · line 598

Quoted 10 lines

kernel/irq/chip.c +5 -1

@@ -569,8 +590,13 @@ __set_irq_handler(unsigned int irq, irq_
 
 	/* Uninstall? */
 	if (handle == handle_bad_irq) {
-		if (desc->chip != &no_irq_chip)
+		if (desc->chip != &no_irq_chip) {
 			mask_ack_irq(desc, irq);
+#ifdef CONFIG_MOVE_IRQ_DESC
+			/* get new one */
+			desc = irq_to_desc(irq);
+#endif

this patch adds a ton of #ifdefs to important .c files, which could all have been avoided by introducing a new method:

	desc = irq_remap_to_desc(irq, desc);

which would do something like:

static struct irq_desc * irq_remap_to_desc(unsigned int irq, struct irq_desc *desc) {

 #ifdef CONFIG_MOVE_IRQ_DESC
	return irq_to_desc(irq);
 #else
	return desc;

#endif
}

right?

Ingo

Yinghai Lu

author

2008-12-08 19:18 UTC #2 lore raw

Quoted 17 lines · Ingo Molnar

kernel/irq/handle.c unsigned int __do_IRQ(unsigned int irq) · line 455
Quoted 6 lines
                      mask_ack_irq(desc, irq);
kernel/irq/handle.c +4 -0
+#ifdef CONFIG_MOVE_IRQ_DESC
+                     /* get new one */
+                     desc = irq_to_desc(irq);
+#endif
this patch adds a ton of #ifdefs to important .c files, which could all have been avoided by introducing a new method:
       desc = irq_remap_to_desc(irq, desc);
which would do something like:
static struct irq_desc * irq_remap_to_desc(unsigned int irq, struct irq_desc *desc) {

Quoted 8 lines

 #ifdef CONFIG_MOVE_IRQ_DESC
       return irq_to_desc(irq);
 #else
       return desc;

#endif
}

right?

yes. will work on it.

Yinghai Lu

author

2008-12-08 22:08 UTC #3 lore raw

PATCH 1/1 irq: move irq_desc according to smp_affinity v6

In reply to Ingo Molnar

impact: new feature move irq_desc with sparseirq

v3: add calling to irq_to_desc after calling ack/eoi instead of passing desc

v6: use irq_remap_to_desc to avoid some #ifdef according to Ingo

for logical apic mode, need to add move_desc_in_progress_in_same_domain. otherwise it will not get moved. ==> also could need two phase to get irq_desc moved.

	for example: 0xff is old affinity, and need to set 0xf, and then set to 0xf0.
	[ or we need to change domain definition to cpus on the same node ? ]

Oct 27 12:35:34 LBSuse kernel: klogd 1.4.1, log source = /proc/kmsg started.
Oct 27 12:35:34 LBSuse kernel: eth0: no IPv6 routers present
LBSuse:~ # echo f0 > /proc/irq/22/smp_affinity
LBSuse:~ # tail /var/log/messages
Oct 27 12:35:34 LBSuse kernel: klogd 1.4.1, log source = /proc/kmsg started.
Oct 27 12:35:34 LBSuse kernel: eth0: no IPv6 routers present
Oct 27 12:36:46 LBSuse kernel:   move irq_desc for 22 aka 0x16 to cpu 7 node 1
Oct 27 12:36:46 LBSuse kernel:   alloc kstat_irqs on cpu 7 node 1
Oct 27 12:36:46 LBSuse kernel:   alloc irq_cfg on cpu 7 node 1
Oct 27 12:36:46 LBSuse kernel:   alloc irq_2_pin on cpu 7 node 1

so assume the user space program should update /proc/irq/XX/smp_affinity to 03 or 0f at first on boot or we change irq_default_affinity ?

for physical apic is much simple
on 4 sockets 16 cores system
irq_desc is moving..
when

# echo 10 > /proc/irq/134483967/smp_affinity
# echo 100 > /proc/irq/134483967/smp_affinity
# echo 1000 > /proc/irq/134483967/smp_affinity
got
Nov  9 21:39:51 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 4 node 1
Nov  9 21:39:51 LBSuse kernel:   alloc kstat_irqs on cpu 4 node 1
Nov  9 21:39:51 LBSuse kernel:   alloc irq_cfg on cpu 4 node 1
Nov  9 21:40:05 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 8 node 2
Nov  9 21:40:05 LBSuse kernel:   alloc kstat_irqs on cpu 8 node 2
Nov  9 21:40:05 LBSuse kernel:   alloc irq_cfg on cpu 8 node 2
Nov  9 21:40:18 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 12 node 3
Nov  9 21:40:18 LBSuse kernel:   alloc kstat_irqs on cpu 12 node 3
Nov  9 21:40:18 LBSuse kernel:   alloc irq_cfg on cpu 12 node 3

Signed-off-by Yinghai Lu <[email protected]>

---
 arch/x86/Kconfig          |    9 ++
 arch/x86/kernel/io_apic.c |  143 +++++++++++++++++++++++++++++++++++++++++++++-
 include/linux/irq.h       |   10 +++
 kernel/irq/chip.c         |   12 +++
 kernel/irq/handle.c       |  119 +++++++++++++++++++++++++++++++++++++-
 5 files changed, 288 insertions(+), 5 deletions(-)

arch/x86/Kconfig +9 -0

Index: linux-2.6/arch/x86/Kconfig
===================================================================
@@ -253,6 +253,15 @@ config SPARSE_IRQ
 
 	  If you don't know what to do here, say Y.
 
+config MOVE_IRQ_DESC
+	bool "Move irq desc when changing irq smp_affinity"
+	depends on SPARSE_IRQ && SMP
+	default y
+	help
+	  This enables moving irq_desc to cpu/node that irq will use handled.
+
+	  If you don't know what to do here, say Y.
+
 config X86_FIND_SMP_CONFIG
 	def_bool y
 	depends on X86_MPPARSE || X86_VOYAGER

arch/x86/kernel/io_apic.c +142 -1

177 lines not on this page · raw message

kernel/irq/handle.c +117 -2

151 lines not on this page · raw message

kernel/irq/chip.c +10 -2

Index: linux-2.6/kernel/irq/chip.c
===================================================================
@@ -354,6 +354,7 @@ handle_level_irq(unsigned int irq, struc
 
 	spin_lock(&desc->lock);
 	mask_ack_irq(desc, irq);
+	desc = irq_remap_to_desc(irq, desc);
 
 	if (unlikely(desc->status & IRQ_INPROGRESS))
 		goto out_unlock;

@@ -431,6 +432,7 @@ handle_fasteoi_irq(unsigned int irq, str
 	desc->status &= ~IRQ_INPROGRESS;
 out:
 	desc->chip->eoi(irq);
+	desc = irq_remap_to_desc(irq, desc);
 
 	spin_unlock(&desc->lock);
 }

@@ -467,12 +469,14 @@ handle_edge_irq(unsigned int irq, struct
 		    !desc->action)) {
 		desc->status |= (IRQ_PENDING | IRQ_MASKED);
 		mask_ack_irq(desc, irq);
+		desc = irq_remap_to_desc(irq, desc);
 		goto out_unlock;
 	}
 	kstat_incr_irqs_this_cpu(irq, desc);
 
 	/* Start handling the irq */
 	desc->chip->ack(irq);
+	desc = irq_remap_to_desc(irq, desc);
 
 	/* Mark the IRQ currently in progress.*/
 	desc->status |= IRQ_INPROGRESS;

@@ -533,8 +537,10 @@ handle_percpu_irq(unsigned int irq, stru
 	if (!noirqdebug)
 		note_interrupt(irq, desc, action_ret);
 
-	if (desc->chip->eoi)
+	if (desc->chip->eoi) {
 		desc->chip->eoi(irq);
+		desc = irq_remap_to_desc(irq, desc);
+	}
 }
 
 void

@@ -569,8 +575,10 @@ __set_irq_handler(unsigned int irq, irq_
 
 	/* Uninstall? */
 	if (handle == handle_bad_irq) {
-		if (desc->chip != &no_irq_chip)
+		if (desc->chip != &no_irq_chip) {
 			mask_ack_irq(desc, irq);
+			desc = irq_remap_to_desc(irq, desc);
+		}
 		desc->status |= IRQ_DISABLED;
 		desc->depth = 1;
 	}

include/linux/irq.h +10 -0

Index: linux-2.6/include/linux/irq.h
===================================================================
@@ -227,6 +227,16 @@ extern struct irq_desc *move_irq_desc(st
 
 #endif
 
+static inline struct irq_desc *
+irq_remap_to_desc(unsigned int irq, struct irq_desc *desc)
+{
+#ifdef CONFIG_MOVE_IRQ_DESC
+	return irq_to_desc(irq);
+#else
+	return desc;
+#endif
+}
+
 /*
  * Migration helpers for obsolete names, they will go away:
  */

Ingo Molnar

2008-12-09 03:42 UTC #4 lore raw

Re: [PATCH] irq: move irq_desc according to smp_affinity v6

Quoted 18 lines · Yinghai Lu

for physical apic is much simple
on 4 sockets 16 cores system
irq_desc is moving..
when

# echo 10 > /proc/irq/134483967/smp_affinity
# echo 100 > /proc/irq/134483967/smp_affinity
# echo 1000 > /proc/irq/134483967/smp_affinity
got
Nov  9 21:39:51 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 4 node 1
Nov  9 21:39:51 LBSuse kernel:   alloc kstat_irqs on cpu 4 node 1
Nov  9 21:39:51 LBSuse kernel:   alloc irq_cfg on cpu 4 node 1
Nov  9 21:40:05 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 8 node 2
Nov  9 21:40:05 LBSuse kernel:   alloc kstat_irqs on cpu 8 node 2
Nov  9 21:40:05 LBSuse kernel:   alloc irq_cfg on cpu 8 node 2
Nov  9 21:40:18 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 12 node 3
Nov  9 21:40:18 LBSuse kernel:   alloc kstat_irqs on cpu 12 node 3
Nov  9 21:40:18 LBSuse kernel:   alloc irq_cfg on cpu 12 node 3

Quoted 1 line

Signed-off-by Yinghai Lu <[email protected]>

Neat feature!

i'm wondering, have you tried to characterise the cost savings of moving the irq desc? It will certainly save three heavy cross-NUMA cachemisses on x86 per rare irq source.

A way to attempt to measure this would be to write some quick debug hack that prints the cycle count of one specific IRQ source, in do_IRQ(), from the entry of do_IRQ() to the exit of do_IRQ(), using rdtscl(). Pick an IRQ that you can trigger arbitrarily, and printk the cycle cost at the end of do_IRQ(). [if irq == your_debug_irq - otherwise you can get a lot of printks and not too good measurements].

plus perhaps add some quick hack that makes the irq_desc/chip_data/kstat_irqs migration dependent on a sysctl, such as 'panic_timeout' (tunable via 'echo 1 > /proc/sys/kernel/panic'). Then you could try to trigger your debug IRQ and the cycle cost printk in two modes:

echo 0 > /proc/sys/kernel/panic

[ migrate the IRQ to another domain and trigger the IRQ - wait for the
cycle printout. Both cache-cold and cache-hot numbers are interesting. ]

echo 1 > /proc/sys/kernel/panic

[ re-migrate the debug IRQ via /proc/irq/*/smp_affinity to make sure
it's NUMA-local, then trigger the debug IRQ and record cache-cold and cache-hot cycle counts. ]

it's hard to measure this reliably, as on x86 the numa factor is usually pretty low, so the local versus remote cachemiss cost is hard to separate.

A few comments about the patch too:

arch/x86/Kconfig config SPARSE_IRQ · line 259

Quoted 4 lines

arch/x86/Kconfig +4 -0

+config MOVE_IRQ_DESC
+	bool "Move irq desc when changing irq smp_affinity"
+	depends on SPARSE_IRQ && SMP
+	default y

new feature - should be default-no.

arch/x86/Kconfig config SPARSE_IRQ · line 263

Quoted 4 lines

arch/x86/Kconfig +4 -0

+	help
+	  This enables moving irq_desc to cpu/node that irq will use handled.
+
+	  If you don't know what to do here, say Y.

Later on i think we should just select this in the NUMA case, instead of complicating the user's selection. It's OK to have it configurable now - should it cause problems.

Quoted 9 lines

arch/x86/Kconfig +1 -0
+
 config X86_FIND_SMP_CONFIG
 	def_bool y
 	depends on X86_MPPARSE || X86_VOYAGER
Index: linux-2.6/arch/x86/kernel/io_apic.c
===================================================================

arch/x86/kernel/io_apic.c struct irq_cfg { · line 146

Quoted 6 lines

arch/x86/kernel/io_apic.c +3 -0

@@ -141,6 +141,9 @@ struct irq_cfg {
 	unsigned move_cleanup_count;
 	u8 vector;
 	u8 move_in_progress : 1;
+#ifdef CONFIG_MOVE_IRQ_DESC
+	u8 move_desc_in_progress_in_same_domain : 1;
+#endif

way too long field name - please rename to move_desc_pending or so.

arch/x86/kernel/io_apic.c void arch_init_chip_data(struct irq_desc · line 233

Quoted 9 lines

arch/x86/kernel/io_apic.c +5 -0

@@ -223,6 +226,122 @@ void arch_init_chip_data(struct irq_desc
 	}
 }
 
+#ifdef CONFIG_MOVE_IRQ_DESC
+
+static void init_copy_irq_2_pin(struct irq_cfg *old_cfg, struct irq_cfg *cfg,
+				 int cpu)
+{

small style nit, it's a tiny bit tidier to break the line the following way:

static void
init_copy_irq_2_pin(struct irq_cfg *old_cfg, struct irq_cfg *cfg, int cpu)

[ as this way we have all the parameters on a single line, and the return
type stands out on a separate line. ]

Quoted 6 lines

arch/x86/kernel/io_apic.c +6 -0

+	struct irq_pin_list *old_entry, *head, *tail, *entry;
+
+	cfg->irq_2_pin = NULL;
+	old_entry = old_cfg->irq_2_pin;
+	if (!old_entry)
+		return;

arch/x86/kernel/io_apic.c void arch_init_chip_data(struct irq_desc · line 249

Quoted 10 lines

arch/x86/kernel/io_apic.c +10 -0

+
+	entry = get_one_free_irq_2_pin(cpu);
+	if (!entry)
+		return;
+
+	entry->apic = old_entry->apic;
+	entry->pin = old_entry->pin;
+	head = entry;
+	tail = entry;
+	old_entry = old_entry->next;

for mass-initialization please try to structure it a bit:

arch/x86/kernel/io_apic.c void arch_init_chip_data(struct irq_desc · line 267

Quoted 6 lines

arch/x86/kernel/io_apic.c +6 -0

+	entry->apic	= old_entry->apic;
+	entry->pin	= old_entry->pin;
+	head		= entry;
+	tail		= entry;
+
+	old_entry	= old_entry->next;

it's much easier to validate such constructs. For example, once vertically aligned, i immediately saw an oddity in it - why is 'old_entry' initialized twice?

arch/x86/kernel/io_apic.c void arch_init_chip_data(struct irq_desc · line 262

Quoted 13 lines

arch/x86/kernel/io_apic.c +13 -0

+
+	while (old_entry) {
+		entry = get_one_free_irq_2_pin(cpu);
+		if (!entry) {
+			entry = head;
+			while (entry) {
+				head = entry->next;
+				kfree(entry);
+				entry = head;
+			}
+			/* still use the old one */
+			return;
+		}

same here:

Quoted 254 lines

arch/x86/kernel/io_apic.c +105 -1

+		entry->apic = old_entry->apic;
+		entry->pin = old_entry->pin;
+		tail->next = entry;
+		tail = entry;
+		old_entry = old_entry->next;
+	}
+
+	tail->next = NULL;
+	cfg->irq_2_pin = head;
+}
+
+static void free_irq_2_pin(struct irq_cfg *old_cfg, struct irq_cfg *cfg)
+{
+	struct irq_pin_list *entry, *next;
+
+	if (old_cfg->irq_2_pin == cfg->irq_2_pin)
+		return;
+
+	entry = old_cfg->irq_2_pin;
+
+	while (entry) {
+		next = entry->next;
+		kfree(entry);
+		entry = next;
+	}
+	old_cfg->irq_2_pin = NULL;
+}
+
+void arch_init_copy_chip_data(struct irq_desc *old_desc,
+				 struct irq_desc *desc, int cpu)
+{
+	struct irq_cfg *cfg;
+	struct irq_cfg *old_cfg;
+
+	cfg = get_one_free_irq_cfg(cpu);
+
+	if (!cfg)
+		return;
+
+	desc->chip_data = cfg;
+
+	old_cfg = old_desc->chip_data;
+
+	memcpy(cfg, old_cfg, sizeof(struct irq_cfg));
+
+	init_copy_irq_2_pin(old_cfg, cfg, cpu);
+}
+
+static void free_irq_cfg(struct irq_cfg *old_cfg)
+{
+	kfree(old_cfg);
+}
+
+void arch_free_chip_data(struct irq_desc *old_desc, struct irq_desc *desc)
+{
+	struct irq_cfg *old_cfg, *cfg;
+
+	old_cfg = old_desc->chip_data;
+	cfg = desc->chip_data;
+
+	if (old_cfg == cfg)
+		return;
+
+	if (old_cfg) {
+		free_irq_2_pin(old_cfg, cfg);
+		free_irq_cfg(old_cfg);
+		old_desc->chip_data = NULL;
+	}
+}
+
+static void set_extra_move_desc(struct irq_desc *desc, cpumask_t mask)
+{
+	struct irq_cfg *cfg = desc->chip_data;
+
+	if (!cfg->move_in_progress) {
+		/* it means that domain is not changed */
+		if (!cpus_intersects(desc->affinity, mask))
+			cfg->move_desc_in_progress_in_same_domain = 1;
+	}
+}
+#endif
+
 #else
 static struct irq_cfg *irq_cfg(unsigned int irq)
 {

@@ -231,9 +350,11 @@ static struct irq_cfg *irq_cfg(unsigned
 
 #endif
 
+#ifndef CONFIG_MOVE_IRQ_DESC
 static inline void set_extra_move_desc(struct irq_desc *desc, cpumask_t mask)
 {
 }
+#endif
 
 struct io_apic {
 	unsigned int index;

@@ -2346,14 +2467,34 @@ static void irq_complete_move(struct irq
 	struct irq_cfg *cfg = desc->chip_data;
 	unsigned vector, me;
 
-	if (likely(!cfg->move_in_progress))
+	if (likely(!cfg->move_in_progress)) {
+#ifdef CONFIG_MOVE_IRQ_DESC
+		if (likely(!cfg->move_desc_in_progress_in_same_domain))
+			return;
+
+		/* domain is not change, but affinity is changed */
+		me = smp_processor_id();
+		if (cpu_isset(me, desc->affinity)) {
+			*descp = desc = move_irq_desc(desc, me);
+			/* get the new one */
+			cfg = desc->chip_data;
+			cfg->move_desc_in_progress_in_same_domain = 0;
+		}
+#endif
 		return;
+	}
 
 	vector = ~get_irq_regs()->orig_ax;
 	me = smp_processor_id();
 	if ((vector == cfg->vector) && cpu_isset(me, cfg->domain)) {
 		cpumask_t cleanup_mask;
 
+#ifdef CONFIG_MOVE_IRQ_DESC
+		*descp = desc = move_irq_desc(desc, me);
+		/* get the new one */
+		cfg = desc->chip_data;
+#endif
+
 		cpus_and(cleanup_mask, cfg->old_domain, cpu_online_map);
 		cfg->move_cleanup_count = cpus_weight(cleanup_mask);
 		send_IPI_mask(cleanup_mask, IRQ_MOVE_CLEANUP_VECTOR);

Index: linux-2.6/kernel/irq/handle.c
===================================================================

kernel/irq/handle.c +99 -0

@@ -90,6 +90,32 @@ static void init_kstat_irqs(struct irq_d
 		desc->kstat_irqs = (unsigned int *)ptr;
 }
 
+#ifdef CONFIG_MOVE_IRQ_DESC
+static void init_copy_kstat_irqs(struct irq_desc *old_desc, struct irq_desc *desc,
+				 int cpu, int nr)
+{
+	unsigned long bytes;
+
+	init_kstat_irqs(desc, cpu, nr);
+
+	if (desc->kstat_irqs != old_desc->kstat_irqs) {
+		/* Compute how many bytes we need per irq and allocate them */
+		bytes = nr * sizeof(unsigned int);
+
+		memcpy(desc->kstat_irqs, old_desc->kstat_irqs, bytes);
+	}
+}
+
+static void free_kstat_irqs(struct irq_desc *old_desc, struct irq_desc *desc)
+{
+	if (old_desc->kstat_irqs == desc->kstat_irqs)
+		return;
+
+	kfree(old_desc->kstat_irqs);
+	old_desc->kstat_irqs = NULL;
+}
+#endif
+
 void __attribute__((weak)) arch_init_chip_data(struct irq_desc *desc, int cpu)
 {
 }

@@ -110,6 +136,23 @@ static void init_one_irq_desc(int irq, s
 	arch_init_chip_data(desc, cpu);
 }
 
+#ifdef CONFIG_MOVE_IRQ_DESC
+static void init_copy_one_irq_desc(int irq, struct irq_desc *old_desc,
+		 struct irq_desc *desc, int cpu)
+{
+	memcpy(desc, old_desc, sizeof(struct irq_desc));
+	desc->cpu = cpu;
+	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
+	init_copy_kstat_irqs(old_desc, desc, cpu, nr_cpu_ids);
+	arch_init_copy_chip_data(old_desc, desc, cpu);
+}
+
+static void free_one_irq_desc(struct irq_desc *old_desc, struct irq_desc *desc)
+{
+	free_kstat_irqs(old_desc, desc);
+	arch_free_chip_data(old_desc, desc);
+}
+#endif
 /*
  * Protect the sparse_irqs:
  */

@@ -203,6 +246,73 @@ out_unlock:
 	return desc;
 }
 
+#ifdef CONFIG_MOVE_IRQ_DESC
+static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
+						int cpu)
+{
+	struct irq_desc *desc;
+	unsigned int irq;
+	unsigned long flags;
+	int node;
+
+	irq = old_desc->irq;
+
+	spin_lock_irqsave(&sparse_irq_lock, flags);
+
+	/* We have to check it to avoid races with another CPU */
+	desc = irq_desc_ptrs[irq];
+
+	if (desc && old_desc != desc)
+			goto out_unlock;
+
+	node = cpu_to_node(cpu);
+	desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
+	printk(KERN_DEBUG "  move irq_desc for %d to cpu %d node %d\n",
+		 irq, cpu, node);
+	if (!desc) {
+		printk(KERN_ERR "can not get new irq_desc for moving\n");
+		/* still use old one */
+		desc = old_desc;
+		goto out_unlock;
+	}
+	init_copy_one_irq_desc(irq, old_desc, desc, cpu);
+
+	irq_desc_ptrs[irq] = desc;
+
+	/* free the old one */
+	free_one_irq_desc(old_desc, desc);
+	kfree(old_desc);
+
+out_unlock:
+	spin_unlock_irqrestore(&sparse_irq_lock, flags);
+
+	return desc;
+}
+
+struct irq_desc *move_irq_desc(struct irq_desc *desc, int cpu)
+{
+	int old_cpu;
+	int node, old_node;
+
+	/* those all static, do move them */
+	if (desc->irq < NR_IRQS_LEGACY)
+		return desc;
+
+	old_cpu = desc->cpu;
+	printk(KERN_DEBUG "try to move irq_desc from cpu %d to %d\n", old_cpu, cpu);
+	if (old_cpu != cpu) {
+		node = cpu_to_node(cpu);

kernel/irq/handle.c out_unlock: · line 314

Quoted 10 lines

kernel/irq/handle.c +10 -0

+		old_node = cpu_to_node(old_cpu);
+		if (old_node != node)
+			desc = __real_move_irq_desc(desc, cpu);
+		else
+			desc->cpu = cpu;
+	}
+
+	return desc;
+}
+#endif

Still a bit too much of #ifdeffery for my taste in kernel/irq/*.c, we tend to have higher maintenance costs in files that have a lot of #ifdefs.

Wouldnt it look neater if you introduced a new kernel/irq/numa_migrate.c function that would provide these methods, with the prototypes being #ifdef-ed to inlines in the !CONFIG_MOVE_IRQ_DESC case in kernel/irq/internals.h?

i'd also suggest to rename the config option to the more descriptive:
CONFIG_NUMA_MIGRATE_IRQ_DESC name.

kernel/irq/handle.c unsigned int __do_IRQ(unsigned int irq) · line 454

Quoted 9 lines

kernel/irq/handle.c +4 -1

 		/*
 		 * No locking required for CPU-local interrupts:
 		 */
-		if (desc->chip->ack)
+		if (desc->chip->ack) {
 			desc->chip->ack(irq);
+			/* get new one */
+			desc = irq_remap_to_desc(irq, desc);
+		}

thanks for fixing this - it looks much nicer now!

Ingo

Yinghai Lu

author

2008-12-11 08:16 UTC #5 lore raw

PATCH 1/1 irq: move irq_desc according to smp_affinity v7

impact: new feature move irq_desc with sparseirq

if CONFIG_NUMA_MIGRATE_IRQ_DESC is set
make irq_desc to go with affinity aka irq_desc moving etc call move_irq_desc in irq_complete_move()
legacy irq_desc is not moved, because they are allocated via static array

v3: add calling to irq_to_desc after calling ack/eoi instead of passing desc

v6: use irq_remap_to_desc to avoid some #ifdef according to Ingo

for logical apic mode, need to add move_desc_in_progress_in_same_domain. otherwise it will not get moved. ==> also could need two phase to get irq_desc moved.

	for example: 0xff is old affinity, and need to set 0xf, and then set to 0xf0.
	[ or we need to change domain definition to cpus on the same node ? ]

Oct 27 12:35:34 LBSuse kernel: klogd 1.4.1, log source = /proc/kmsg started.
Oct 27 12:35:34 LBSuse kernel: eth0: no IPv6 routers present
LBSuse:~ # echo f0 > /proc/irq/22/smp_affinity
LBSuse:~ # tail /var/log/messages
Oct 27 12:35:34 LBSuse kernel: klogd 1.4.1, log source = /proc/kmsg started.
Oct 27 12:35:34 LBSuse kernel: eth0: no IPv6 routers present
Oct 27 12:36:46 LBSuse kernel:   move irq_desc for 22 aka 0x16 to cpu 7 node 1
Oct 27 12:36:46 LBSuse kernel:   alloc kstat_irqs on cpu 7 node 1
Oct 27 12:36:46 LBSuse kernel:   alloc irq_cfg on cpu 7 node 1
Oct 27 12:36:46 LBSuse kernel:   alloc irq_2_pin on cpu 7 node 1

so assume the user space program should update /proc/irq/XX/smp_affinity to 03 or 0f at first on boot or we change irq_default_affinity ?

for physical apic is much simple
on 4 sockets 16 cores system
irq_desc is moving..
when

# echo 10 > /proc/irq/134483967/smp_affinity
# echo 100 > /proc/irq/134483967/smp_affinity
# echo 1000 > /proc/irq/134483967/smp_affinity
got
Nov  9 21:39:51 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 4 node 1
Nov  9 21:39:51 LBSuse kernel:   alloc kstat_irqs on cpu 4 node 1
Nov  9 21:39:51 LBSuse kernel:   alloc irq_cfg on cpu 4 node 1
Nov  9 21:40:05 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 8 node 2
Nov  9 21:40:05 LBSuse kernel:   alloc kstat_irqs on cpu 8 node 2
Nov  9 21:40:05 LBSuse kernel:   alloc irq_cfg on cpu 8 node 2
Nov  9 21:40:18 LBSuse kernel:   move irq_desc for 134483967 aka 0x8040fff to cpu 12 node 3
Nov  9 21:40:18 LBSuse kernel:   alloc kstat_irqs on cpu 12 node 3
Nov  9 21:40:18 LBSuse kernel:   alloc irq_cfg on cpu 12 node 3

Signed-off-by Yinghai Lu <[email protected]>

---
 arch/x86/Kconfig          |    9 ++
 arch/x86/kernel/io_apic.c |  142 +++++++++++++++++++++++++++++++++++++++++++++-
 include/linux/irq.h       |   10 +++
 kernel/irq/Makefile       |    1 
 kernel/irq/chip.c         |   12 +++
 kernel/irq/handle.c       |   15 +++-
 kernel/irq/internals.h    |    5 +
 kernel/irq/numa_migrate.c |  125 ++++++++++++++++++++++++++++++++++++++++
 8 files changed, 311 insertions(+), 8 deletions(-)

arch/x86/Kconfig +9 -0

Index: linux-2.6/arch/x86/Kconfig
===================================================================
@@ -253,6 +253,15 @@ config SPARSE_IRQ
 
 	  If you don't know what to do here, say Y.
 
+config NUMA_MIGRATE_IRQ_DESC
+	bool "Move irq desc when changing irq smp_affinity"
+	depends on SPARSE_IRQ && SMP
+	default n
+	help
+	  This enables moving irq_desc to cpu/node that irq will use handled.
+
+	  If you don't know what to do here, say N.
+
 config X86_FIND_SMP_CONFIG
 	def_bool y
 	depends on X86_MPPARSE || X86_VOYAGER

arch/x86/kernel/io_apic.c +141 -1

176 lines not on this page · raw message

kernel/irq/handle.c +10 -5

Index: linux-2.6/kernel/irq/handle.c
===================================================================
@@ -23,7 +23,7 @@
 /*
  * lockdep: we want to handle all irq_desc locks as a single lock-class:
  */
-static struct lock_class_key irq_desc_lock_class;
+struct lock_class_key irq_desc_lock_class;
 
 /**
  * handle_bad_irq - handle spurious and unhandled irqs

@@ -73,7 +73,7 @@ static struct irq_desc irq_desc_init = {
 #endif
 };
 
-static void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
+void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
 {
 	unsigned long bytes;
 	char *ptr;

@@ -113,7 +113,7 @@ static void init_one_irq_desc(int irq, s
 /*
  * Protect the sparse_irqs:
  */
-static DEFINE_SPINLOCK(sparse_irq_lock);
+DEFINE_SPINLOCK(sparse_irq_lock);
 
 struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;

@@ -337,8 +337,11 @@ unsigned int __do_IRQ(unsigned int irq)
 		/*
 		 * No locking required for CPU-local interrupts:
 		 */
-		if (desc->chip->ack)
+		if (desc->chip->ack) {
 			desc->chip->ack(irq);
+			/* get new one */
+			desc = irq_remap_to_desc(irq, desc);
+		}
 		if (likely(!(desc->status & IRQ_DISABLED))) {
 			action_ret = handle_IRQ_event(irq, desc->action);
 			if (!noirqdebug)

@@ -349,8 +352,10 @@ unsigned int __do_IRQ(unsigned int irq)
 	}
 
 	spin_lock(&desc->lock);
-	if (desc->chip->ack)
+	if (desc->chip->ack) {
 		desc->chip->ack(irq);
+		desc = irq_remap_to_desc(irq, desc);
+	}
 	/*
 	 * REPLAY is when Linux resends an IRQ that was dropped earlier
 	 * WAITING is used by probe to mark irqs that are being tested

kernel/irq/chip.c +10 -2

Index: linux-2.6/kernel/irq/chip.c
===================================================================
@@ -354,6 +354,7 @@ handle_level_irq(unsigned int irq, struc
 
 	spin_lock(&desc->lock);
 	mask_ack_irq(desc, irq);
+	desc = irq_remap_to_desc(irq, desc);
 
 	if (unlikely(desc->status & IRQ_INPROGRESS))
 		goto out_unlock;

@@ -431,6 +432,7 @@ handle_fasteoi_irq(unsigned int irq, str
 	desc->status &= ~IRQ_INPROGRESS;
 out:
 	desc->chip->eoi(irq);
+	desc = irq_remap_to_desc(irq, desc);
 
 	spin_unlock(&desc->lock);
 }

@@ -467,12 +469,14 @@ handle_edge_irq(unsigned int irq, struct
 		    !desc->action)) {
 		desc->status |= (IRQ_PENDING | IRQ_MASKED);
 		mask_ack_irq(desc, irq);
+		desc = irq_remap_to_desc(irq, desc);
 		goto out_unlock;
 	}
 	kstat_incr_irqs_this_cpu(irq, desc);
 
 	/* Start handling the irq */
 	desc->chip->ack(irq);
+	desc = irq_remap_to_desc(irq, desc);
 
 	/* Mark the IRQ currently in progress.*/
 	desc->status |= IRQ_INPROGRESS;

@@ -533,8 +537,10 @@ handle_percpu_irq(unsigned int irq, stru
 	if (!noirqdebug)
 		note_interrupt(irq, desc, action_ret);
 
-	if (desc->chip->eoi)
+	if (desc->chip->eoi) {
 		desc->chip->eoi(irq);
+		desc = irq_remap_to_desc(irq, desc);
+	}
 }
 
 void

@@ -569,8 +575,10 @@ __set_irq_handler(unsigned int irq, irq_
 
 	/* Uninstall? */
 	if (handle == handle_bad_irq) {
-		if (desc->chip != &no_irq_chip)
+		if (desc->chip != &no_irq_chip) {
 			mask_ack_irq(desc, irq);
+			desc = irq_remap_to_desc(irq, desc);
+		}
 		desc->status |= IRQ_DISABLED;
 		desc->depth = 1;
 	}

include/linux/irq.h +10 -0

Index: linux-2.6/include/linux/irq.h
===================================================================
@@ -227,6 +227,16 @@ extern struct irq_desc *move_irq_desc(st
 
 #endif
 
+static inline struct irq_desc *
+irq_remap_to_desc(unsigned int irq, struct irq_desc *desc)
+{
+#ifdef CONFIG_NUMA_MIGRATE_IRQ_DESC
+	return irq_to_desc(irq);
+#else
+	return desc;
+#endif
+}
+
 /*
  * Migration helpers for obsolete names, they will go away:
  */

kernel/irq/numa_migrate.c new file +127 -0

127 lines not on this page · raw message

kernel/irq/Makefile +1 -0

Index: linux-2.6/kernel/irq/Makefile
===================================================================
@@ -3,3 +3,4 @@ obj-y := handle.o manage.o spurious.o re
 obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o
 obj-$(CONFIG_PROC_FS) += proc.o
 obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o
+obj-$(CONFIG_NUMA_MIGRATE_IRQ_DESC) += numa_migrate.o

kernel/irq/internals.h +5 -0

Index: linux-2.6/kernel/irq/internals.h
===================================================================
@@ -13,6 +13,11 @@ extern void compat_irq_chip_set_default_
 extern int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 		unsigned long flags);
 
+extern struct lock_class_key irq_desc_lock_class;
+extern void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr);
+extern spinlock_t sparse_irq_lock;
+extern struct irq_desc *irq_desc_ptrs[NR_IRQS];
+
 #ifdef CONFIG_PROC_FS
 extern void register_irq_proc(unsigned int irq, struct irq_desc *desc);
 extern void register_handler_proc(unsigned int irq, struct irqaction *action);