[PATCH -v3 1/2] x86: use vector_desc instead of vector_irq

From: Yinghai Lu
Date: Tue Feb 23 2010 - 01:41:31 EST


Eric pointed out that radix tree version of irq_to_desc will magnify delay on
the path of handle_irq.

use vector_desc to reduce the calling of irq_to_desc.

next step: need to change all ack, mask, umask, eoi for all irq_chip to take irq_desc

-v2: irq should be unsigned in 32bit handle_irq according to Eric
also reset vector_desc for lguest in setup_irq
-v3: keep irq in x+execute_on_irq_stack() ...

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Acked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>

---
arch/x86/include/asm/desc.h | 2 -
arch/x86/include/asm/hw_irq.h | 10 ++---
arch/x86/include/asm/irq.h | 3 +
arch/x86/kernel/apic/io_apic.c | 75 ++++++++++++++++++++---------------------
arch/x86/kernel/irq.c | 15 +++-----
arch/x86/kernel/irq_32.c | 10 ++---
arch/x86/kernel/irq_64.c | 7 +--
arch/x86/kernel/irqinit.c | 8 +---
arch/x86/kernel/smpboot.c | 2 -
arch/x86/kernel/vmiclock_32.c | 2 -
arch/x86/lguest/boot.c | 7 +++
11 files changed, 71 insertions(+), 70 deletions(-)

Index: linux-2.6/arch/x86/include/asm/desc.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/desc.h
+++ linux-2.6/arch/x86/include/asm/desc.h
@@ -334,7 +334,7 @@ static inline void set_intr_gate(unsigne
}

extern int first_system_vector;
-/* used_vectors is BITMAP for irq is not managed by percpu vector_irq */
+/* used_vectors is BITMAP for irq is not managed by percpu vector_desc */
extern unsigned long used_vectors[];

static inline void alloc_system_vector(int vector)
Index: linux-2.6/arch/x86/include/asm/hw_irq.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/hw_irq.h
+++ linux-2.6/arch/x86/include/asm/hw_irq.h
@@ -99,7 +99,7 @@ struct irq_cfg {
};

extern struct irq_cfg *irq_cfg(unsigned int);
-extern int assign_irq_vector(int, struct irq_cfg *, const struct cpumask *);
+extern int assign_irq_vector(struct irq_desc *, struct irq_cfg *, const struct cpumask *);
extern void send_cleanup_vector(struct irq_cfg *);

struct irq_desc;
@@ -138,17 +138,17 @@ extern asmlinkage void smp_invalidate_in

extern void (*__initconst interrupt[NR_VECTORS-FIRST_EXTERNAL_VECTOR])(void);

-typedef int vector_irq_t[NR_VECTORS];
-DECLARE_PER_CPU(vector_irq_t, vector_irq);
+typedef struct irq_desc *vector_desc_t[NR_VECTORS];
+DECLARE_PER_CPU(vector_desc_t, vector_desc);

#ifdef CONFIG_X86_IO_APIC
extern void lock_vector_lock(void);
extern void unlock_vector_lock(void);
-extern void __setup_vector_irq(int cpu);
+extern void __setup_vector_desc(int cpu);
#else
static inline void lock_vector_lock(void) {}
static inline void unlock_vector_lock(void) {}
-static inline void __setup_vector_irq(int cpu) {}
+static inline void __setup_vector_desc(int cpu) {}
#endif

#endif /* !ASSEMBLY_ */
Index: linux-2.6/arch/x86/include/asm/irq.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/irq.h
+++ linux-2.6/arch/x86/include/asm/irq.h
@@ -39,7 +39,8 @@ extern void irq_force_complete_move(int)

extern void (*x86_platform_ipi_callback)(void);
extern void native_init_IRQ(void);
-extern bool handle_irq(unsigned irq, struct pt_regs *regs);
+struct irq_desc;
+extern bool handle_irq(struct irq_desc *desc, struct pt_regs *regs);

extern unsigned int do_IRQ(struct pt_regs *regs);

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
@@ -1142,7 +1142,7 @@ void unlock_vector_lock(void)
}

static int
-__assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask)
+__assign_irq_vector(struct irq_desc *desc, struct irq_cfg *cfg, const struct cpumask *mask)
{
/*
* NOTE! The local APIC isn't very good at handling
@@ -1201,7 +1201,7 @@ next:
goto next;

for_each_cpu_and(new_cpu, tmp_mask, cpu_online_mask)
- if (per_cpu(vector_irq, new_cpu)[vector] != -1)
+ if (per_cpu(vector_desc, new_cpu)[vector] != NULL)
goto next;
/* Found one! */
current_vector = vector;
@@ -1211,7 +1211,7 @@ next:
cpumask_copy(cfg->old_domain, cfg->domain);
}
for_each_cpu_and(new_cpu, tmp_mask, cpu_online_mask)
- per_cpu(vector_irq, new_cpu)[vector] = irq;
+ per_cpu(vector_desc, new_cpu)[vector] = desc;
cfg->vector = vector;
cpumask_copy(cfg->domain, tmp_mask);
err = 0;
@@ -1221,18 +1221,18 @@ next:
return err;
}

-int assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask)
+int assign_irq_vector(struct irq_desc *desc, struct irq_cfg *cfg, const struct cpumask *mask)
{
int err;
unsigned long flags;

raw_spin_lock_irqsave(&vector_lock, flags);
- err = __assign_irq_vector(irq, cfg, mask);
+ err = __assign_irq_vector(desc, cfg, mask);
raw_spin_unlock_irqrestore(&vector_lock, flags);
return err;
}

-static void __clear_irq_vector(int irq, struct irq_cfg *cfg)
+static void __clear_irq_vector(struct irq_desc *desc, struct irq_cfg *cfg)
{
int cpu, vector;

@@ -1240,7 +1240,7 @@ static void __clear_irq_vector(int irq,

vector = cfg->vector;
for_each_cpu_and(cpu, cfg->domain, cpu_online_mask)
- per_cpu(vector_irq, cpu)[vector] = -1;
+ per_cpu(vector_desc, cpu)[vector] = NULL;

cfg->vector = 0;
cpumask_clear(cfg->domain);
@@ -1250,18 +1250,18 @@ static void __clear_irq_vector(int irq,
for_each_cpu_and(cpu, cfg->old_domain, cpu_online_mask) {
for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS;
vector++) {
- if (per_cpu(vector_irq, cpu)[vector] != irq)
+ if (per_cpu(vector_desc, cpu)[vector] != desc)
continue;
- per_cpu(vector_irq, cpu)[vector] = -1;
+ per_cpu(vector_desc, cpu)[vector] = NULL;
break;
}
}
cfg->move_in_progress = 0;
}

-void __setup_vector_irq(int cpu)
+void __setup_vector_desc(int cpu)
{
- /* Initialize vector_irq on a new cpu */
+ /* Initialize vector_desc on a new cpu */
int irq, vector;
struct irq_cfg *cfg;
struct irq_desc *desc;
@@ -1278,17 +1278,17 @@ void __setup_vector_irq(int cpu)
if (!cpumask_test_cpu(cpu, cfg->domain))
continue;
vector = cfg->vector;
- per_cpu(vector_irq, cpu)[vector] = irq;
+ per_cpu(vector_desc, cpu)[vector] = desc;
}
/* Mark the free vectors */
for (vector = 0; vector < NR_VECTORS; ++vector) {
- irq = per_cpu(vector_irq, cpu)[vector];
- if (irq < 0)
+ desc = per_cpu(vector_desc, cpu)[vector];
+ if (!desc)
continue;

- cfg = irq_cfg(irq);
+ cfg = desc->chip_data;
if (!cpumask_test_cpu(cpu, cfg->domain))
- per_cpu(vector_irq, cpu)[vector] = -1;
+ per_cpu(vector_desc, cpu)[vector] = NULL;
}
raw_spin_unlock(&vector_lock);
}
@@ -1448,7 +1448,7 @@ static void setup_IO_APIC_irq(int apic_i
if (irq < nr_legacy_irqs && cpumask_test_cpu(0, cfg->domain))
apic->vector_allocation_domain(0, cfg->domain);

- if (assign_irq_vector(irq, cfg, apic->target_cpus()))
+ if (assign_irq_vector(desc, cfg, apic->target_cpus()))
return;

dest = apic->cpu_mask_to_apicid_and(cfg->domain, apic->target_cpus());
@@ -1464,7 +1464,7 @@ static void setup_IO_APIC_irq(int apic_i
dest, trigger, polarity, cfg->vector, pin)) {
printk("Failed to setup ioapic entry for ioapic %d, pin %d\n",
mp_ioapics[apic_id].apicid, pin);
- __clear_irq_vector(irq, cfg);
+ __clear_irq_vector(desc, cfg);
return;
}

@@ -2340,14 +2340,12 @@ set_desc_affinity(struct irq_desc *desc,
unsigned int *dest_id)
{
struct irq_cfg *cfg;
- unsigned int irq;

if (!cpumask_intersects(mask, cpu_online_mask))
return -1;

- irq = desc->irq;
cfg = desc->chip_data;
- if (assign_irq_vector(irq, cfg, mask))
+ if (assign_irq_vector(desc, cfg, mask))
return -1;

cpumask_copy(desc->affinity, mask);
@@ -2420,7 +2418,7 @@ migrate_ioapic_irq_desc(struct irq_desc
return ret;

cfg = desc->chip_data;
- if (assign_irq_vector(irq, cfg, mask))
+ if (assign_irq_vector(desc, cfg, mask))
return ret;

dest = apic->cpu_mask_to_apicid_and(cfg->domain, mask);
@@ -2474,20 +2472,15 @@ asmlinkage void smp_irq_move_cleanup_int

me = smp_processor_id();
for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
- unsigned int irq;
unsigned int irr;
struct irq_desc *desc;
struct irq_cfg *cfg;
- irq = __get_cpu_var(vector_irq)[vector];
-
- if (irq == -1)
- continue;
+ desc = __get_cpu_var(vector_desc)[vector];

- desc = irq_to_desc(irq);
if (!desc)
continue;

- cfg = irq_cfg(irq);
+ cfg = desc->chip_data;
raw_spin_lock(&desc->lock);

/*
@@ -2512,7 +2505,7 @@ asmlinkage void smp_irq_move_cleanup_int
apic->send_IPI_self(IRQ_MOVE_CLEANUP_VECTOR);
goto unlock;
}
- __get_cpu_var(vector_irq)[vector] = -1;
+ __get_cpu_var(vector_desc)[vector] = NULL;
unlock:
raw_spin_unlock(&desc->lock);
}
@@ -2949,7 +2942,7 @@ static inline void __init check_timer(vo
* get/set the timer IRQ vector:
*/
disable_8259A_irq(0);
- assign_irq_vector(0, cfg, apic->target_cpus());
+ assign_irq_vector(desc, cfg, apic->target_cpus());

/*
* As IRQ0 is to be enabled in the 8259A, the virtual
@@ -3285,7 +3278,7 @@ unsigned int create_irq_nr(unsigned int
desc_new = move_irq_desc(desc_new, node);
cfg_new = desc_new->chip_data;

- if (__assign_irq_vector(new, cfg_new, apic->target_cpus()) == 0)
+ if (__assign_irq_vector(desc_new, cfg_new, apic->target_cpus()) == 0)
irq = new;
break;
}
@@ -3315,12 +3308,16 @@ int create_irq(void)
void destroy_irq(unsigned int irq)
{
unsigned long flags;
+ struct irq_desc *desc;
+ struct irq_cfg *cfg;

dynamic_irq_cleanup_keep_chip_data(irq);

free_irte(irq);
raw_spin_lock_irqsave(&vector_lock, flags);
- __clear_irq_vector(irq, get_irq_chip_data(irq));
+ desc = irq_to_desc(irq);
+ cfg = desc->chip_data;
+ __clear_irq_vector(desc, cfg);
raw_spin_unlock_irqrestore(&vector_lock, flags);
}

@@ -3331,6 +3328,7 @@ void destroy_irq(unsigned int irq)
static int msi_compose_msg(struct pci_dev *pdev, unsigned int irq,
struct msi_msg *msg, u8 hpet_id)
{
+ struct irq_desc *desc;
struct irq_cfg *cfg;
int err;
unsigned dest;
@@ -3338,8 +3336,9 @@ static int msi_compose_msg(struct pci_de
if (disable_apic)
return -ENXIO;

- cfg = irq_cfg(irq);
- err = assign_irq_vector(irq, cfg, apic->target_cpus());
+ desc = irq_to_desc(irq);
+ cfg = desc->chip_data;
+ err = assign_irq_vector(desc, cfg, apic->target_cpus());
if (err)
return err;

@@ -3812,14 +3811,16 @@ static struct irq_chip ht_irq_chip = {

int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
{
+ struct irq_desc *desc;
struct irq_cfg *cfg;
int err;

if (disable_apic)
return -ENXIO;

- cfg = irq_cfg(irq);
- err = assign_irq_vector(irq, cfg, apic->target_cpus());
+ desc = irq_to_desc(irq);
+ cfg = desc->chip_data;
+ err = assign_irq_vector(desc, cfg, apic->target_cpus());
if (!err) {
struct ht_irq_msg msg;
unsigned dest;
Index: linux-2.6/arch/x86/kernel/irq.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/irq.c
+++ linux-2.6/arch/x86/kernel/irq.c
@@ -229,19 +229,19 @@ unsigned int __irq_entry do_IRQ(struct p

/* high bit used in ret_from_ code */
unsigned vector = ~regs->orig_ax;
- unsigned irq;
+ struct irq_desc *desc;

exit_idle();
irq_enter();

- irq = __get_cpu_var(vector_irq)[vector];
+ desc = __get_cpu_var(vector_desc)[vector];

- if (!handle_irq(irq, regs)) {
+ if (!handle_irq(desc, regs)) {
ack_APIC_irq();

if (printk_ratelimit())
- pr_emerg("%s: %d.%d No irq handler for vector (irq %d)\n",
- __func__, smp_processor_id(), vector, irq);
+ pr_emerg("%s: %d.%d No irq handler for vector\n",
+ __func__, smp_processor_id(), vector);
}

irq_exit();
@@ -348,14 +348,13 @@ void fixup_irqs(void)
for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
unsigned int irr;

- if (__get_cpu_var(vector_irq)[vector] < 0)
+ if (__get_cpu_var(vector_desc)[vector] == NULL)
continue;

irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
if (irr & (1 << (vector % 32))) {
- irq = __get_cpu_var(vector_irq)[vector];
+ desc = __get_cpu_var(vector_desc)[vector];

- desc = irq_to_desc(irq);
raw_spin_lock(&desc->lock);
if (desc->chip->retrigger)
desc->chip->retrigger(irq);
Index: linux-2.6/arch/x86/kernel/irq_32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/irq_32.c
+++ linux-2.6/arch/x86/kernel/irq_32.c
@@ -76,7 +76,7 @@ static void call_on_stack(void *func, vo
}

static inline int
-execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq)
+execute_on_irq_stack(int overflow, struct irq_desc *desc, unsigned int irq)
{
union irq_ctx *curctx, *irqctx;
u32 *isp, arg1, arg2;
@@ -189,20 +189,20 @@ asmlinkage void do_softirq(void)

#else
static inline int
-execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq) { return 0; }
+execute_on_irq_stack(int overflow, struct irq_desc *desc, unsigned int irq) { return 0; }
#endif

-bool handle_irq(unsigned irq, struct pt_regs *regs)
+bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
{
- struct irq_desc *desc;
int overflow;
+ unsigned int irq;

overflow = check_stack_overflow();

- desc = irq_to_desc(irq);
if (unlikely(!desc))
return false;

+ irq = desc->irq;
if (!execute_on_irq_stack(overflow, desc, irq)) {
if (unlikely(overflow))
print_stack_overflow();
Index: linux-2.6/arch/x86/kernel/irq_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/irq_64.c
+++ linux-2.6/arch/x86/kernel/irq_64.c
@@ -48,17 +48,14 @@ static inline void stack_overflow_check(
#endif
}

-bool handle_irq(unsigned irq, struct pt_regs *regs)
+bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
{
- struct irq_desc *desc;
-
stack_overflow_check(regs);

- desc = irq_to_desc(irq);
if (unlikely(!desc))
return false;

- generic_handle_irq_desc(irq, desc);
+ generic_handle_irq_desc(desc->irq, desc);
return true;
}

Index: linux-2.6/arch/x86/kernel/irqinit.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/irqinit.c
+++ linux-2.6/arch/x86/kernel/irqinit.c
@@ -83,16 +83,14 @@ static struct irqaction irq2 = {
.name = "cascade",
};

-DEFINE_PER_CPU(vector_irq_t, vector_irq) = {
- [0 ... NR_VECTORS - 1] = -1,
-};
+DEFINE_PER_CPU(vector_desc_t, vector_desc);

int vector_used_by_percpu_irq(unsigned int vector)
{
int cpu;

for_each_online_cpu(cpu) {
- if (per_cpu(vector_irq, cpu)[vector] != -1)
+ if (per_cpu(vector_desc, cpu)[vector] != NULL)
return 1;
}

@@ -139,7 +137,7 @@ void __init init_IRQ(void)
* irq's migrate etc.
*/
for (i = 0; i < nr_legacy_irqs; i++)
- per_cpu(vector_irq, 0)[IRQ0_VECTOR + i] = i;
+ per_cpu(vector_desc, 0)[IRQ0_VECTOR + i] = irq_to_desc(i);

x86_init.irqs.intr_init();
}
Index: linux-2.6/arch/x86/kernel/smpboot.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/smpboot.c
+++ linux-2.6/arch/x86/kernel/smpboot.c
@@ -245,7 +245,7 @@ static void __cpuinit smp_callin(void)
/*
* Need to setup vector mappings before we enable interrupts.
*/
- __setup_vector_irq(smp_processor_id());
+ __setup_vector_desc(smp_processor_id());
/*
* Get our bogomips.
*
Index: linux-2.6/arch/x86/kernel/vmiclock_32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/vmiclock_32.c
+++ linux-2.6/arch/x86/kernel/vmiclock_32.c
@@ -236,7 +236,7 @@ void __init vmi_time_init(void)
vmi_time_init_clockevent();
setup_irq(0, &vmi_clock_action);
for_each_possible_cpu(cpu)
- per_cpu(vector_irq, cpu)[vmi_get_timer_vector()] = 0;
+ per_cpu(vector_desc, cpu)[vmi_get_timer_vector()] = irq_to_desc(0);
}

#ifdef CONFIG_X86_LOCAL_APIC
Index: linux-2.6/arch/x86/lguest/boot.c
===================================================================
--- linux-2.6.orig/arch/x86/lguest/boot.c
+++ linux-2.6/arch/x86/lguest/boot.c
@@ -819,7 +819,7 @@ static void __init lguest_init_IRQ(void)

for (i = FIRST_EXTERNAL_VECTOR; i < NR_VECTORS; i++) {
/* Some systems map "vectors" to interrupts weirdly. Not us! */
- __get_cpu_var(vector_irq)[i] = i - FIRST_EXTERNAL_VECTOR;
+ __get_cpu_var(vector_desc)[i] = irq_to_desc(i - FIRST_EXTERNAL_VECTOR);
if (i != SYSCALL_VECTOR)
set_intr_gate(i, interrupt[i - FIRST_EXTERNAL_VECTOR]);
}
@@ -842,6 +842,11 @@ static void __init lguest_init_IRQ(void)
void lguest_setup_irq(unsigned int irq)
{
irq_to_desc_alloc_node(irq, 0);
+ /*
+ * for sparseirq, we could get new desc other than legacy irq,
+ * so set vector_desc again for that irq
+ */
+ __get_cpu_var(vector_desc)[irq + FIRST_EXTERNAL_VECTOR] = irq_to_desc(irq);
set_irq_chip_and_handler_name(irq, &lguest_irq_controller,
handle_level_irq, "level");
}
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