[tip:x86/mce2] x86, mce: Add mce=nopoll option to disable timer polling
From: Hidetoshi Seto
Date: Sat Mar 28 2009 - 17:32:18 EST
Commit-ID: f5b3ca6efb64aa3ab5fa32f0fc9cc0f6cfedee95
Gitweb: http://git.kernel.org/tip/f5b3ca6efb64aa3ab5fa32f0fc9cc0f6cfedee95
Author: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
AuthorDate: Thu, 26 Mar 2009 17:39:39 +0900
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Sat, 28 Mar 2009 13:13:01 +0100
x86, mce: Add mce=nopoll option to disable timer polling
Impact: add new boot option
This patch adds "mce=nopoll" option to disable timer polling
for corrected errors from boot. Unlike "mce=off", it doesn't
prevent handling for uncorrected errors.
It is useful if:
- You don't have any interests in corrected errors. You may
use option mce_threshold=0 to disable cmci too.
- You'd like to care banks only which cmci are supported.
- You have an application such as hardware monitor that
checks error banks, and that can conflict with OS's polling.
- Your system have an intelligent BIOS which can provide
enough health information, so reports from OS is redundant.
Once booted, we can disable polling by setting check_interval
to 0, but there are no mention about the fact.
Some additional comments are help for this.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
LKML-Reference: <49CB3F4B.8070406@xxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
Documentation/x86/x86_64/boot-options.txt | 2 ++
arch/x86/kernel/cpu/mcheck/mce_64.c | 10 ++++++++--
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt
index 34c1304..5d55158 100644
--- a/Documentation/x86/x86_64/boot-options.txt
+++ b/Documentation/x86/x86_64/boot-options.txt
@@ -13,6 +13,8 @@ Machine check
in a reboot. On Intel systems it is enabled by default.
mce=nobootlog
Disable boot machine check logging.
+ mce=nopoll
+ Disable timer polling for corrected errors
mce=tolerancelevel (number)
0: always panic on uncorrected errors, log corrected errors
1: panic or SIGBUS on uncorrected errors, log corrected errors
diff --git a/arch/x86/kernel/cpu/mcheck/mce_64.c b/arch/x86/kernel/cpu/mcheck/mce_64.c
index 9bf52bd..fe21883 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_64.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_64.c
@@ -449,6 +449,8 @@ void mce_log_therm_throt_event(__u64 status)
* Periodic polling timer for "silent" machine check errors. If the
* poller finds an MCE, poll 2x faster. When the poller finds no more
* errors, poll 2x slower (up to check_interval seconds).
+ *
+ * If check_interval is 0, polling is disabled.
*/
static int check_interval = 5 * 60; /* 5 minutes */
@@ -633,11 +635,12 @@ static void mce_init_timer(void)
{
struct timer_list *t = &__get_cpu_var(mce_timer);
+ /* Disable polling if check_interval is 0 */
+ if (!check_interval)
+ return;
/* data race harmless because everyone sets to the same value */
if (!next_interval)
next_interval = check_interval * HZ;
- if (!next_interval)
- return;
setup_timer(t, mcheck_timer, smp_processor_id());
t->expires = round_jiffies(jiffies + next_interval);
add_timer(t);
@@ -845,11 +848,14 @@ __setup("nomce", mcheck_disable);
* mce=TOLERANCELEVEL (number, see above)
* mce=bootlog Log MCEs from before booting. Disabled by default on AMD.
* mce=nobootlog Don't log MCEs from before booting.
+ * mce=nopoll Disable timer polling for corrected errors
*/
static int __init mcheck_enable(char *str)
{
if (!strcmp(str, "off"))
mce_dont_init = 1;
+ else if (!strcmp(str, "nopoll"))
+ check_interval = 0;
else if (!strcmp(str, "bootlog") || !strcmp(str, "nobootlog"))
mce_bootlog = (str[0] == 'b');
else if (isdigit(str[0]))
--
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