From: Christoph Lameter <cl@linux-foundation.org>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, David Miller <davem@davemloft.net>,
Ingo Molnar <mingo@elte.hu>
Subject: [Patch vs. percpu-next] Use this_cpu_xx in nmi handling
Date: Wed, 7 Oct 2009 19:04:29 -0400 (EDT) [thread overview]
Message-ID: <alpine.DEB.1.10.0910071856400.3379@gentwo.org> (raw)
From: Christoph Lameter <cl@linux-foundation.org>
Subject: Use this_cpu_xx in nmi handling
this_cpu_inc/dec reduces the number of instructions needed.
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
---
arch/sparc/kernel/nmi.c | 8 ++++----
arch/x86/kernel/apic/nmi.c | 8 ++++----
2 files changed, 8 insertions(+), 8 deletions(-)
Index: linux-2.6/arch/sparc/kernel/nmi.c
===================================================================
--- linux-2.6.orig/arch/sparc/kernel/nmi.c 2009-10-07 16:58:11.000000000 -0500
+++ linux-2.6/arch/sparc/kernel/nmi.c 2009-10-07 17:12:35.000000000 -0500
@@ -47,7 +47,7 @@ static DEFINE_PER_CPU(short, wd_enabled)
static int endflag __initdata;
static DEFINE_PER_CPU(unsigned int, last_irq_sum);
-static DEFINE_PER_CPU(local_t, alert_counter);
+static DEFINE_PER_CPU(long, alert_counter);
static DEFINE_PER_CPU(int, nmi_touch);
void touch_nmi_watchdog(void)
@@ -112,13 +112,13 @@ notrace __kprobes void perfctr_irq(int i
touched = 1;
}
if (!touched && __get_cpu_var(last_irq_sum) == sum) {
- local_inc(&__get_cpu_var(alert_counter));
- if (local_read(&__get_cpu_var(alert_counter)) == 30 * nmi_hz)
+ __this_cpu_inc(per_cpu_var(alert_counter));
+ if (__this_cpu_read(per_cpu_var(alert_counter)) == 30 * nmi_hz)
die_nmi("BUG: NMI Watchdog detected LOCKUP",
regs, panic_on_timeout);
} else {
__get_cpu_var(last_irq_sum) = sum;
- local_set(&__get_cpu_var(alert_counter), 0);
+ __this_cpu_write(per_cpu_var(alert_counter), 0);
}
if (__get_cpu_var(wd_enabled)) {
write_pic(picl_value(nmi_hz));
Index: linux-2.6/arch/x86/kernel/apic/nmi.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apic/nmi.c 2009-10-07 16:56:39.000000000 -0500
+++ linux-2.6/arch/x86/kernel/apic/nmi.c 2009-10-07 16:58:02.000000000 -0500
@@ -360,7 +360,7 @@ void stop_apic_nmi_watchdog(void *unused
*/
static DEFINE_PER_CPU(unsigned, last_irq_sum);
-static DEFINE_PER_CPU(local_t, alert_counter);
+static DEFINE_PER_CPU(long, alert_counter);
static DEFINE_PER_CPU(int, nmi_touch);
void touch_nmi_watchdog(void)
@@ -437,8 +437,8 @@ nmi_watchdog_tick(struct pt_regs *regs,
* Ayiee, looks like this CPU is stuck ...
* wait a few IRQs (5 seconds) before doing the oops ...
*/
- local_inc(&__get_cpu_var(alert_counter));
- if (local_read(&__get_cpu_var(alert_counter)) == 5 * nmi_hz)
+ __this_cpu_inc(per_cpu_var(alert_counter));
+ if (__this_cpu_read(per_cpu_var(alert_counter)) == 5 * nmi_hz)
/*
* die_nmi will return ONLY if NOTIFY_STOP happens..
*/
@@ -446,7 +446,7 @@ nmi_watchdog_tick(struct pt_regs *regs,
regs, panic_on_timeout);
} else {
__get_cpu_var(last_irq_sum) = sum;
- local_set(&__get_cpu_var(alert_counter), 0);
+ __this_cpu_write(per_cpu_var(alert_counter), 0);
}
/* see if the nmi watchdog went off */
next reply other threads:[~2009-10-07 23:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-07 23:04 Christoph Lameter [this message]
2009-10-12 10:52 ` Tejun Heo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.DEB.1.10.0910071856400.3379@gentwo.org \
--to=cl@linux-foundation.org \
--cc=davem@davemloft.net \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®