lkml.org 
[lkml]   [2015]   [Apr]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[Patch Part2 v5 20/33] x86/irq: Use cached IOAPIC entry instead of reading from hardware
Date
Use cached IOAPIC entry instead of reading data from IOAPIC hardware
registers to improve performance.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Grant Likely <grant.likely@linaro.org>
Link: http://lkml.kernel.org/r/1416901802-24211-30-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/kernel/apic/io_apic.c | 78 +++++++++++-----------------------------
1 file changed, 21 insertions(+), 57 deletions(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 32a8d51975b3..c06f4b531392 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -67,8 +67,13 @@
list_for_each_entry(entry, &head, list)

/*
- * Is the SiS APIC rmw bug present ?
+ * Is the SiS APIC rmw bug present ?
* -1 = don't know, 0 = no, 1 = yes
+ * When doing a read-modify-write operation on IOAPIC registers, older SiS APIC
+ * requires we rewrite the index register again where the read already set up
+ * the index register.
+ * The code to make use of sis_apic_bug has been removed, but we don't want to
+ * loss this knowledge.
*/
int sis_apic_bug = -1;

@@ -293,22 +298,6 @@ static void io_apic_write(unsigned int apic, unsigned int reg,
writel(value, &io_apic->data);
}

-/*
- * Re-write a value: to be used for read-modify-write
- * cycles where the read already set up the index register.
- *
- * Older SiS APIC requires we rewrite the index register
- */
-static void io_apic_modify(unsigned int apic, unsigned int reg,
- unsigned int value)
-{
- struct io_apic __iomem *io_apic = io_apic_base(apic);
-
- if (sis_apic_bug)
- writel(reg, &io_apic->index);
- writel(value, &io_apic->data);
-}
-
union entry_union {
struct { u32 w1, w2; };
struct IO_APIC_route_entry entry;
@@ -445,29 +434,23 @@ static void __init replace_pin_at_irq_node(struct mp_chip_data *data, int node,
add_pin_to_irq_node(data, node, newapic, newpin);
}

-static void __io_apic_modify_irq(struct irq_pin_list *entry,
- int mask_and, int mask_or,
- void (*final)(struct irq_pin_list *entry))
-{
- unsigned int reg, pin;
-
- pin = entry->pin;
- reg = io_apic_read(entry->apic, 0x10 + pin * 2);
- reg &= mask_and;
- reg |= mask_or;
- io_apic_modify(entry->apic, 0x10 + pin * 2, reg);
- if (final)
- final(entry);
-}
-
static void io_apic_modify_irq(struct mp_chip_data *data,
int mask_and, int mask_or,
void (*final)(struct irq_pin_list *entry))
{
+ union entry_union eu;
struct irq_pin_list *entry;

- for_each_irq_pin(entry, data->irq_2_pin)
- __io_apic_modify_irq(entry, mask_and, mask_or, final);
+ eu.entry = data->entry;
+ eu.w1 &= mask_and;
+ eu.w1 |= mask_or;
+ data->entry = eu.entry;
+
+ for_each_irq_pin(entry, data->irq_2_pin) {
+ io_apic_write(entry->apic, 0x10 + 2 * entry->pin, eu.w1);
+ if (final)
+ final(entry);
+ }
}

static void io_apic_sync(struct irq_pin_list *entry)
@@ -1739,28 +1722,6 @@ static unsigned int startup_ioapic_irq(struct irq_data *data)
return was_pending;
}

-static void __target_IO_APIC_irq(unsigned int irq, struct irq_cfg *cfg,
- struct mp_chip_data *data)
-{
- int apic, pin;
- struct irq_pin_list *entry;
- u8 vector = cfg->vector;
- unsigned int dest = SET_APIC_LOGICAL_ID(cfg->dest_apicid);
-
- for_each_irq_pin(entry, data->irq_2_pin) {
- unsigned int reg;
-
- apic = entry->apic;
- pin = entry->pin;
-
- io_apic_write(apic, 0x11 + pin*2, dest);
- reg = io_apic_read(apic, 0x10 + pin*2);
- reg &= ~IO_APIC_REDIR_VECTOR_MASK;
- reg |= vector;
- io_apic_modify(apic, 0x10 + pin*2, reg);
- }
-}
-
atomic_t irq_mis_count;

#ifdef CONFIG_GENERIC_PENDING_IRQ
@@ -1926,6 +1887,7 @@ static int ioapic_set_affinity(struct irq_data *irq_data,
{
struct irq_data *parent = irq_data->parent_data;
struct mp_chip_data *data = irq_data->chip_data;
+ struct irq_pin_list *entry;
struct irq_cfg *cfg;
unsigned long flags;
int ret;
@@ -1936,7 +1898,9 @@ static int ioapic_set_affinity(struct irq_data *irq_data,
cfg = irqd_cfg(irq_data);
data->entry.dest = cfg->dest_apicid;
data->entry.vector = cfg->vector;
- __target_IO_APIC_irq(irq_data->irq, cfg, irq_data->chip_data);
+ for_each_irq_pin(entry, data->irq_2_pin)
+ __ioapic_write_entry(entry->apic, entry->pin,
+ data->entry);
}
raw_spin_unlock_irqrestore(&ioapic_lock, flags);

--
1.7.10.4


\
 
 \ /
  Last update: 2015-04-14 05:01    [W:0.633 / U:1.340 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site