From: Robert Hancock <hancockr@shaw.ca>
To: linux-kernel <linux-kernel@vger.kernel.org>,
linux-ide@vger.kernel.org, Jeff Garzik <jeff@garzik.org>,
Andrew Morton <akpm@osdl.org>
Subject: [PATCH 4/5] sata_nv: Use notifier for completion checks
Date: Mon, 19 Feb 2007 19:03:08 -0600 [thread overview]
Message-ID: <45DA48CC.3090704@shaw.ca> (raw)
The hardware provides us a notifier register that indicates what command
tags have completed. Use this to determine which CPBs to check, rather
than blindly checking all active CPBs. This should provide a minor
performance win, since if the controller has touched some of these
incomplete CPBs, accessing them will likely result in a cache miss.
Signed-off-by: Robert Hancock <hancockr@shaw.ca>
--- linux-2.6.20-git6edit/drivers/ata/sata_nv.c 2007-02-15 22:36:02.000000000 -0600
+++ linux-2.6.20-git6edit/drivers/ata/sata_nv.c.delayandfixes 2007-02-19 17:00:14.000000000 -0600
@@ -853,22 +854,14 @@ static irqreturn_t nv_adma_interrupt(int
if (status & (NV_ADMA_STAT_DONE |
NV_ADMA_STAT_CPBERR)) {
+ u32 check_commands = notifier | notifier_error;
+ int pos, error = 0;
/** Check CPBs for completed commands */
-
- if (ata_tag_valid(ap->active_tag)) {
- /* Non-NCQ command */
- nv_adma_check_cpb(ap, ap->active_tag,
- notifier_error & (1 << ap->active_tag));
- } else {
- int pos, error = 0;
- u32 active = ap->sactive;
-
- while ((pos = ffs(active)) && !error) {
- pos--;
- error = nv_adma_check_cpb(ap, pos,
- notifier_error & (1 << pos) );
- active &= ~(1 << pos );
- }
+ while ((pos = ffs(check_commands)) && !error) {
+ pos--;
+ error = nv_adma_check_cpb(ap, pos,
+ notifier_error & (1 << pos) );
+ check_commands &= ~(1 << pos );
}
}
}
reply other threads:[~2007-02-20 1:06 UTC|newest]
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