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authorTejun Heo <htejun@gmail.com>2008-05-20 02:17:52 +0900
committerJeff Garzik <jgarzik@redhat.com>2008-07-14 15:59:32 -0400
commit0a2c0f56159999e20015241d3b8fa89b1ab14309 (patch)
tree2c516452d3b3f85e9a4092b6092160e123d5f5d4
parent341c2c958ec7bdd9f54733a8b0b432fe76842a82 (diff)
downloadop-kernel-dev-0a2c0f56159999e20015241d3b8fa89b1ab14309.zip
op-kernel-dev-0a2c0f56159999e20015241d3b8fa89b1ab14309.tar.gz
libata: improve EH retry delay handling
EH retries were delayed by 5 seconds to ensure that resets don't occur back-to-back. However, this 5 second delay is superflous or excessive in many cases. For example, after IDENTIFY times out, there's no reason to wait five more seconds before retrying. This patch adds ehc->last_reset timestamp and record the timestamp for the last reset trial or success and uses it to space resets by ATA_EH_RESET_COOL_DOWN which is 5 secs and removes unconditional 5 sec sleeps. As this change makes inter-try waits often shorter and they're redundant in nature, this patch also removes the "retrying..." messages. While at it, convert explicit rounding up division to DIV_ROUND_UP(). This change speeds up EH in many cases w/o sacrificing robustness. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
-rw-r--r--drivers/ata/libata-eh.c38
-rw-r--r--drivers/ata/libata-pmp.c10
-rw-r--r--include/linux/libata.h2
3 files changed, 22 insertions, 28 deletions
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 08dd07f..5b5ae63 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -67,6 +67,9 @@ enum {
ATA_ECAT_DUBIOUS_UNK_DEV = 7,
ATA_ECAT_NR = 8,
+ /* always put at least this amount of time between resets */
+ ATA_EH_RESET_COOL_DOWN = 5000,
+
/* Waiting in ->prereset can never be reliable. It's
* sometimes nice to wait there but it can't be depended upon;
* otherwise, we wouldn't be resetting. Just give it enough
@@ -485,6 +488,9 @@ void ata_scsi_error(struct Scsi_Host *host)
if (ata_ncq_enabled(dev))
ehc->saved_ncq_enabled |= 1 << devno;
}
+
+ /* set last reset timestamp to some time in the past */
+ ehc->last_reset = jiffies - 60 * HZ;
}
ap->pflags |= ATA_PFLAG_EH_IN_PROGRESS;
@@ -2088,11 +2094,17 @@ int ata_eh_reset(struct ata_link *link, int classify,
/*
* Prepare to reset
*/
+ now = jiffies;
+ deadline = ata_deadline(ehc->last_reset, ATA_EH_RESET_COOL_DOWN);
+ if (time_before(now, deadline))
+ schedule_timeout_uninterruptible(deadline - now);
+
spin_lock_irqsave(ap->lock, flags);
ap->pflags |= ATA_PFLAG_RESETTING;
spin_unlock_irqrestore(ap->lock, flags);
ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
+ ehc->last_reset = jiffies;
ata_link_for_each_dev(dev, link) {
/* If we issue an SRST then an ATA drive (not ATAPI)
@@ -2158,6 +2170,7 @@ int ata_eh_reset(struct ata_link *link, int classify,
/*
* Perform reset
*/
+ ehc->last_reset = jiffies;
if (ata_is_host_link(link))
ata_eh_freeze_port(ap);
@@ -2278,6 +2291,7 @@ int ata_eh_reset(struct ata_link *link, int classify,
/* reset successful, schedule revalidation */
ata_eh_done(link, NULL, ATA_EH_RESET);
+ ehc->last_reset = jiffies;
ehc->i.action |= ATA_EH_REVALIDATE;
rc = 0;
@@ -2304,9 +2318,9 @@ int ata_eh_reset(struct ata_link *link, int classify,
if (time_before(now, deadline)) {
unsigned long delta = deadline - now;
- ata_link_printk(link, KERN_WARNING, "reset failed "
- "(errno=%d), retrying in %u secs\n",
- rc, (jiffies_to_msecs(delta) + 999) / 1000);
+ ata_link_printk(link, KERN_WARNING,
+ "reset failed (errno=%d), retrying in %u secs\n",
+ rc, DIV_ROUND_UP(jiffies_to_msecs(delta), 1000));
while (delta)
delta = schedule_timeout_uninterruptible(delta);
@@ -2623,7 +2637,7 @@ int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
{
struct ata_link *link;
struct ata_device *dev;
- int nr_failed_devs, nr_disabled_devs;
+ int nr_failed_devs;
int rc;
unsigned long flags;
@@ -2666,7 +2680,6 @@ int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
retry:
rc = 0;
nr_failed_devs = 0;
- nr_disabled_devs = 0;
/* if UNLOADING, finish immediately */
if (ap->pflags & ATA_PFLAG_UNLOADING)
@@ -2733,8 +2746,7 @@ int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
dev_fail:
nr_failed_devs++;
- if (ata_eh_handle_dev_fail(dev, rc))
- nr_disabled_devs++;
+ ata_eh_handle_dev_fail(dev, rc);
if (ap->pflags & ATA_PFLAG_FROZEN) {
/* PMP reset requires working host port.
@@ -2746,18 +2758,8 @@ dev_fail:
}
}
- if (nr_failed_devs) {
- if (nr_failed_devs != nr_disabled_devs) {
- ata_port_printk(ap, KERN_WARNING, "failed to recover "
- "some devices, retrying in 5 secs\n");
- ssleep(5);
- } else {
- /* no device left to recover, repeat fast */
- msleep(500);
- }
-
+ if (nr_failed_devs)
goto retry;
- }
out:
if (rc && r_failed_link)
diff --git a/drivers/ata/libata-pmp.c b/drivers/ata/libata-pmp.c
index 63691d7..b65db30 100644
--- a/drivers/ata/libata-pmp.c
+++ b/drivers/ata/libata-pmp.c
@@ -727,19 +727,12 @@ static int sata_pmp_eh_recover_pmp(struct ata_port *ap,
}
if (tries) {
- int sleep = ehc->i.flags & ATA_EHI_DID_RESET;
-
/* consecutive revalidation failures? speed down */
if (reval_failed)
sata_down_spd_limit(link);
else
reval_failed = 1;
- ata_dev_printk(dev, KERN_WARNING,
- "retrying reset%s\n",
- sleep ? " in 5 secs" : "");
- if (sleep)
- ssleep(5);
ehc->i.action |= ATA_EH_RESET;
goto retry;
} else {
@@ -991,10 +984,7 @@ static int sata_pmp_eh_recover(struct ata_port *ap)
goto retry;
if (--pmp_tries) {
- ata_port_printk(ap, KERN_WARNING,
- "failed to recover PMP, retrying in 5 secs\n");
pmp_ehc->i.action |= ATA_EH_RESET;
- ssleep(5);
goto retry;
}
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 94110b6..9058c2a 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -602,6 +602,8 @@ struct ata_eh_context {
unsigned int did_probe_mask;
unsigned int saved_ncq_enabled;
u8 saved_xfer_mode[ATA_MAX_DEVICES];
+ /* timestamp for the last reset attempt or success */
+ unsigned long last_reset;
};
struct ata_acpi_drive
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