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Message-ID: <20140911124437.GB18490@dhcp-27-160.brq.redhat.com>
Date: Thu, 11 Sep 2014 14:44:37 +0200
From: Alexander Gordeev <agordeev@...hat.com>
To: Tejun Heo <tj@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-ide@...r.kernel.org
Subject: [PATCH v2] AHCI: Optimize interrupt processing
Split interrupt service routine into hardware context handler and
threaded context handler. That allows to protect ports with individual
locks rather than with a single host-wide lock, which results in better
parallelism.
Cc: linux-ide@...r.kernel.org
Signed-off-by: Alexander Gordeev <agordeev@...hat.com>
---
drivers/ata/acard-ahci.c | 3 +-
drivers/ata/ahci.c | 100 ++++++++++++++++++++++++++---------------
drivers/ata/ahci.h | 8 ++--
drivers/ata/libahci.c | 74 +++++++++++++++++-------------
drivers/ata/libahci_platform.c | 3 +-
5 files changed, 115 insertions(+), 73 deletions(-)
diff --git a/drivers/ata/acard-ahci.c b/drivers/ata/acard-ahci.c
index 25d0ac3..c962886 100644
--- a/drivers/ata/acard-ahci.c
+++ b/drivers/ata/acard-ahci.c
@@ -498,8 +498,7 @@ static int acard_ahci_init_one(struct pci_dev *pdev, const struct pci_device_id
acard_ahci_pci_print_info(host);
pci_set_master(pdev);
- return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
- &acard_ahci_sht);
+ return ahci_host_activate(host, pdev->irq, &acard_ahci_sht);
}
module_pci_driver(acard_ahci_pci_driver);
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index a29f801..52decdc 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1211,6 +1211,9 @@ static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
goto single_msi;
}
+ if (nvec > 1)
+ hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
+
return nvec;
single_msi:
@@ -1223,32 +1226,11 @@ intx:
return 0;
}
-/**
- * ahci_host_activate - start AHCI host, request IRQs and register it
- * @host: target ATA host
- * @irq: base IRQ number to request
- * @n_msis: number of MSIs allocated for this host
- * @irq_handler: irq_handler used when requesting IRQs
- * @irq_flags: irq_flags used when requesting IRQs
- *
- * Similar to ata_host_activate, but requests IRQs according to AHCI-1.1
- * when multiple MSIs were allocated. That is one MSI per port, starting
- * from @irq.
- *
- * LOCKING:
- * Inherited from calling layer (may sleep).
- *
- * RETURNS:
- * 0 on success, -errno otherwise.
- */
-int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis)
+static int ahci_host_activate_multi_irqs(struct ata_host *host, int irq,
+ struct scsi_host_template *sht)
{
int i, rc;
- /* Sharing Last Message among several ports is not supported */
- if (n_msis < host->n_ports)
- return -EINVAL;
-
rc = ata_host_start(host);
if (rc)
return rc;
@@ -1263,8 +1245,8 @@ int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis)
}
rc = devm_request_threaded_irq(host->dev, irq + i,
- ahci_hw_interrupt,
- ahci_thread_fn, IRQF_SHARED,
+ ahci_multi_irqs_intr,
+ ahci_port_thread_fn, IRQF_SHARED,
pp->irq_desc, host->ports[i]);
if (rc)
goto out_free_irqs;
@@ -1273,7 +1255,7 @@ int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis)
for (i = 0; i < host->n_ports; i++)
ata_port_desc(host->ports[i], "irq %d", irq + i);
- rc = ata_host_register(host, &ahci_sht);
+ rc = ata_host_register(host, sht);
if (rc)
goto out_free_all_irqs;
@@ -1288,6 +1270,60 @@ out_free_irqs:
return rc;
}
+static int ahci_host_activate_single_irq(struct ata_host *host, int irq,
+ struct scsi_host_template *sht)
+{
+ int i, rc;
+
+ rc = ata_host_start(host);
+ if (rc)
+ return rc;
+
+ rc = devm_request_threaded_irq(host->dev, irq, ahci_single_irq_intr,
+ ahci_thread_fn, IRQF_SHARED,
+ dev_driver_string(host->dev), host);
+ if (rc)
+ return rc;
+
+ for (i = 0; i < host->n_ports; i++)
+ ata_port_desc(host->ports[i], "irq %d", irq);
+
+ rc = ata_host_register(host, sht);
+ if (rc)
+ devm_free_irq(host->dev, irq, host);
+
+ return rc;
+
+}
+
+/**
+ * ahci_host_activate - start AHCI host, request IRQs and register it
+ * @host: target ATA host
+ * @irq: base IRQ number to request
+ * @sht: scsi_host_template to use when registering the host
+ *
+ * Similar to ata_host_activate, but requests IRQs according to AHCI-1.1
+ * when multiple MSIs were allocated. That is one MSI per port, starting
+ * from @irq.
+ *
+ * LOCKING:
+ * Inherited from calling layer (may sleep).
+ *
+ * RETURNS:
+ * 0 on success, -errno otherwise.
+ */
+int ahci_host_activate(struct ata_host *host, int irq,
+ struct scsi_host_template *sht)
+{
+ struct ahci_host_priv *hpriv = host->private_data;
+
+ if (hpriv->flags & AHCI_HFLAG_MULTI_MSI)
+ return ahci_host_activate_multi_irqs(host, irq, sht);
+ else
+ return ahci_host_activate_single_irq(host, irq, sht);
+}
+EXPORT_SYMBOL_GPL(ahci_host_activate);
+
static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
{
unsigned int board_id = ent->driver_data;
@@ -1296,7 +1332,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
struct device *dev = &pdev->dev;
struct ahci_host_priv *hpriv;
struct ata_host *host;
- int n_ports, n_msis, i, rc;
+ int n_ports, i, rc;
int ahci_pci_bar = AHCI_PCI_BAR_STANDARD;
VPRINTK("ENTER\n");
@@ -1437,9 +1473,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
*/
n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));
- n_msis = ahci_init_interrupts(pdev, n_ports, hpriv);
- if (n_msis > 1)
- hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
+ ahci_init_interrupts(pdev, n_ports, hpriv);
host = ata_host_alloc_pinfo(&pdev->dev, ppi, n_ports);
if (!host)
@@ -1491,11 +1525,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
pci_set_master(pdev);
- if (hpriv->flags & AHCI_HFLAG_MULTI_MSI)
- return ahci_host_activate(host, pdev->irq, n_msis);
-
- return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
- &ahci_sht);
+ return ahci_host_activate(host, pdev->irq, &ahci_sht);
}
module_pci_driver(ahci_pci_driver);
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 59ae0ee..c12f590 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -388,11 +388,13 @@ int ahci_port_resume(struct ata_port *ap);
void ahci_set_em_messages(struct ahci_host_priv *hpriv,
struct ata_port_info *pi);
int ahci_reset_em(struct ata_host *host);
-irqreturn_t ahci_interrupt(int irq, void *dev_instance);
-irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance);
+irqreturn_t ahci_single_irq_intr(int irq, void *dev_instance);
+irqreturn_t ahci_multi_irqs_intr(int irq, void *dev_instance);
irqreturn_t ahci_thread_fn(int irq, void *dev_instance);
+irqreturn_t ahci_port_thread_fn(int irq, void *dev_instance);
void ahci_print_info(struct ata_host *host, const char *scc_s);
-int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis);
+int ahci_host_activate(struct ata_host *host, int irq,
+ struct scsi_host_template *sht);
void ahci_error_handler(struct ata_port *ap);
static inline void __iomem *__ahci_port_base(struct ata_host *host,
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index b784e9d..169c272 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1693,9 +1693,9 @@ static void ahci_error_intr(struct ata_port *ap, u32 irq_stat)
ata_port_abort(ap);
}
-static void ahci_handle_port_interrupt(struct ata_port *ap,
- void __iomem *port_mmio, u32 status)
+static void ahci_handle_port_interrupt(struct ata_port *ap, u32 status)
{
+ void __iomem *port_mmio = ahci_port_base(ap);
struct ata_eh_info *ehi = &ap->link.eh_info;
struct ahci_port_priv *pp = ap->private_data;
struct ahci_host_priv *hpriv = ap->host->private_data;
@@ -1778,22 +1778,10 @@ static void ahci_handle_port_interrupt(struct ata_port *ap,
}
}
-static void ahci_port_intr(struct ata_port *ap)
-{
- void __iomem *port_mmio = ahci_port_base(ap);
- u32 status;
-
- status = readl(port_mmio + PORT_IRQ_STAT);
- writel(status, port_mmio + PORT_IRQ_STAT);
-
- ahci_handle_port_interrupt(ap, port_mmio, status);
-}
-
-irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
+irqreturn_t ahci_port_thread_fn(int irq, void *dev_instance)
{
struct ata_port *ap = dev_instance;
struct ahci_port_priv *pp = ap->private_data;
- void __iomem *port_mmio = ahci_port_base(ap);
unsigned long flags;
u32 status;
@@ -1804,14 +1792,43 @@ irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
spin_unlock_irqrestore(&ap->host->lock, flags);
spin_lock_bh(ap->lock);
- ahci_handle_port_interrupt(ap, port_mmio, status);
+ ahci_handle_port_interrupt(ap, status);
spin_unlock_bh(ap->lock);
return IRQ_HANDLED;
}
+EXPORT_SYMBOL_GPL(ahci_port_thread_fn);
+
+irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
+{
+ struct ata_host *host = dev_instance;
+ struct ahci_host_priv *hpriv = host->private_data;
+ u32 irq_masked = hpriv->port_map;
+ unsigned int i;
+
+ for (i = 0; i < host->n_ports; i++) {
+ struct ata_port *ap;
+
+ if (!(irq_masked & (1 << i)))
+ continue;
+
+ ap = host->ports[i];
+ if (ap) {
+ ahci_port_thread_fn(irq, ap);
+ VPRINTK("port %u\n", i);
+ } else {
+ VPRINTK("port %u (no irq)\n", i);
+ if (ata_ratelimit())
+ dev_warn(host->dev,
+ "interrupt on disabled port %u\n", i);
+ }
+ }
+
+ return IRQ_HANDLED;
+}
EXPORT_SYMBOL_GPL(ahci_thread_fn);
-static void ahci_hw_port_interrupt(struct ata_port *ap)
+static void ahci_update_intr_status(struct ata_port *ap)
{
void __iomem *port_mmio = ahci_port_base(ap);
struct ahci_port_priv *pp = ap->private_data;
@@ -1823,7 +1840,7 @@ static void ahci_hw_port_interrupt(struct ata_port *ap)
pp->intr_status |= status;
}
-irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
+irqreturn_t ahci_multi_irqs_intr(int irq, void *dev_instance)
{
struct ata_port *ap_this = dev_instance;
struct ahci_port_priv *pp = ap_this->private_data;
@@ -1859,7 +1876,7 @@ irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
ap = host->ports[i];
if (ap) {
- ahci_hw_port_interrupt(ap);
+ ahci_update_intr_status(ap);
VPRINTK("port %u\n", i);
} else {
VPRINTK("port %u (no irq)\n", i);
@@ -1877,9 +1894,9 @@ irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
return IRQ_WAKE_THREAD;
}
-EXPORT_SYMBOL_GPL(ahci_hw_interrupt);
+EXPORT_SYMBOL_GPL(ahci_multi_irqs_intr);
-irqreturn_t ahci_interrupt(int irq, void *dev_instance)
+irqreturn_t ahci_single_irq_intr(int irq, void *dev_instance)
{
struct ata_host *host = dev_instance;
struct ahci_host_priv *hpriv;
@@ -1909,7 +1926,7 @@ irqreturn_t ahci_interrupt(int irq, void *dev_instance)
ap = host->ports[i];
if (ap) {
- ahci_port_intr(ap);
+ ahci_update_intr_status(ap);
VPRINTK("port %u\n", i);
} else {
VPRINTK("port %u (no irq)\n", i);
@@ -1936,9 +1953,9 @@ irqreturn_t ahci_interrupt(int irq, void *dev_instance)
VPRINTK("EXIT\n");
- return IRQ_RETVAL(handled);
+ return handled ? IRQ_WAKE_THREAD : IRQ_NONE;
}
-EXPORT_SYMBOL_GPL(ahci_interrupt);
+EXPORT_SYMBOL_GPL(ahci_single_irq_intr);
unsigned int ahci_qc_issue(struct ata_queued_cmd *qc)
{
@@ -2349,13 +2366,8 @@ static int ahci_port_start(struct ata_port *ap)
*/
pp->intr_mask = DEF_PORT_IRQ;
- /*
- * Switch to per-port locking in case each port has its own MSI vector.
- */
- if ((hpriv->flags & AHCI_HFLAG_MULTI_MSI)) {
- spin_lock_init(&pp->lock);
- ap->lock = &pp->lock;
- }
+ spin_lock_init(&pp->lock);
+ ap->lock = &pp->lock;
ap->private_data = pp;
diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c
index 5b92c29..a085224 100644
--- a/drivers/ata/libahci_platform.c
+++ b/drivers/ata/libahci_platform.c
@@ -495,8 +495,7 @@ int ahci_platform_init_host(struct platform_device *pdev,
ahci_init_controller(host);
ahci_print_info(host, "platform");
- return ata_host_activate(host, irq, ahci_interrupt, IRQF_SHARED,
- &ahci_platform_sht);
+ return ahci_host_activate(host, irq, &ahci_platform_sht);
}
EXPORT_SYMBOL_GPL(ahci_platform_init_host);
--
1.9.3
--
Regards,
Alexander Gordeev
agordeev@...hat.com
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