Messages in this thread Patch in this message | | | From | Mike Waychison <> | Subject | [PATCH] x86: Add an option to disable decoding of MCE | Date | Mon, 10 Jan 2011 15:03:17 -0800 |
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This patch applies to v2.6.37.
Updated with documentation of the new option. ---
On our systems, we do not want to have any "decoders" called on machine check events. These decoders can easily spam our logs and cause space problems on machines that have a lot of correctable error events. We _do_ however want to get the messages delivered via /dev/mcelog for userland processing.
Introduce an interface "dont_decode" that allows us to skip the decoders. We always call the decoders by default.
Google-Bug-Id: 3289142 Signed-off-by: Mike Waychison <mikew@google.com> --- Documentation/x86/x86_64/boot-options.txt | 5 +++++ Documentation/x86/x86_64/machinecheck | 6 ++++++ arch/x86/kernel/cpu/mcheck/mce.c | 24 ++++++++++++++++++------ 3 files changed, 29 insertions(+), 6 deletions(-)
diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt index 7fbbaf8..dd7145a 100644 --- a/Documentation/x86/x86_64/boot-options.txt +++ b/Documentation/x86/x86_64/boot-options.txt @@ -22,6 +22,11 @@ Machine check as corrected are silently cleared by OS. This option will be useful if you have no interest in any of corrected errors. + mce=dont_decode + Disable in-kernel decoding of errors. Setting this boot + option will cause EDAC to be skipped (if enabled) and no + messages to be printed into the logs. Events will still + be available via /dev/mcelog however. mce=ignore_ce Disable features for corrected errors, e.g. polling timer and CMCI. All events reported as corrected are not cleared diff --git a/Documentation/x86/x86_64/machinecheck b/Documentation/x86/x86_64/machinecheck index b1fb302..7ef7003 100644 --- a/Documentation/x86/x86_64/machinecheck +++ b/Documentation/x86/x86_64/machinecheck @@ -65,6 +65,12 @@ tolerant Note this only makes a difference if the CPU allows recovery from a machine check exception. Current x86 CPUs generally do not. +dont_decode + Disable in-kernel decoding of any errors. Setting this boot + option will cause EDAC to be skipped (if enabled) and no + messages to be printed into the logs. Events will still be + available via /dev/mcelog however. + trigger Program to run when a machine check event is detected. This is an alternative to running mcelog regularly from cron diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 7a35b72..3c30057 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -82,6 +82,7 @@ static int mce_bootlog __read_mostly = -1; static int monarch_timeout __read_mostly = -1; static int mce_panic_timeout __read_mostly; static int mce_dont_log_ce __read_mostly; +static int mce_dont_decode __read_mostly; int mce_cmci_disabled __read_mostly; int mce_ignore_ce __read_mostly; int mce_ser __read_mostly; @@ -209,6 +210,17 @@ void mce_log(struct mce *mce) set_bit(0, &mce_need_notify); } +static void call_decoders(struct mce *m) +{ + if (mce_dont_decode) + return; + /* + * Print out human-readable details about the MCE error, + * (if the CPU has an implementation for that) + */ + atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m); +} + static void print_mce(struct mce *m) { pr_emerg(HW_ERR "CPU %d: Machine Check Exception: %Lx Bank %d: %016Lx\n", @@ -234,11 +246,7 @@ static void print_mce(struct mce *m) pr_emerg(HW_ERR "PROCESSOR %u:%x TIME %llu SOCKET %u APIC %x\n", m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid); - /* - * Print out human-readable details about the MCE error, - * (if the CPU has an implementation for that) - */ - atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m); + call_decoders(m); } #define PANIC_TIMEOUT 5 /* 5 seconds */ @@ -588,7 +596,7 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b) */ if (!(flags & MCP_DONTLOG) && !mce_dont_log_ce) { mce_log(&m); - atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, &m); + call_decoders(&m); add_taint(TAINT_MACHINE_CHECK); } @@ -1700,6 +1708,8 @@ static int __init mcheck_enable(char *str) mce_cmci_disabled = 1; else if (!strcmp(str, "dont_log_ce")) mce_dont_log_ce = 1; + else if (!strcmp(str, "dont_decode")) + mce_dont_decode = 1; else if (!strcmp(str, "ignore_ce")) mce_ignore_ce = 1; else if (!strcmp(str, "bootlog") || !strcmp(str, "nobootlog")) @@ -1926,6 +1936,7 @@ static SYSDEV_ATTR(trigger, 0644, show_trigger, set_trigger); static SYSDEV_INT_ATTR(tolerant, 0644, tolerant); static SYSDEV_INT_ATTR(monarch_timeout, 0644, monarch_timeout); static SYSDEV_INT_ATTR(dont_log_ce, 0644, mce_dont_log_ce); +static SYSDEV_INT_ATTR(dont_decode, 0644, mce_dont_decode); static struct sysdev_ext_attribute attr_check_interval = { _SYSDEV_ATTR(check_interval, 0644, sysdev_show_int, @@ -1949,6 +1960,7 @@ static struct sysdev_attribute *mce_attrs[] = { &attr_trigger, &attr_monarch_timeout.attr, &attr_dont_log_ce.attr, + &attr_dont_decode.attr, &attr_ignore_ce.attr, &attr_cmci_disabled.attr, NULL -- 1.7.3.1
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