[PATCH] x86/mce: Restore rate limit on MCE logged message

[Rik van Riel <riel@surriel.com>]

FCommit ea324444ece9f moved the "Machine check events logged"
print from mce_notify_irq() into mce_log() and dropped its
two-per-minute rate limit as a side effect.

A particularly unhappy system can spew out around 100 million
of those "Machine check events logged" messages every hour,
without that rate limit. A large fleet may have several unhappy
systems, leaving the netcons infrastructure somewhat flustered.

Reinstate the rate limit we had before.

Fixes: ea324444ece9f ("x86/mce: Restore MCA polling interval halving")
Cc: stable@vger.kernel.org
Signed-off-by: Rik van Riel <riel@surriel.com>
---
 arch/x86/kernel/cpu/mce/core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 50b1614968be..06f858faf2b1 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -150,8 +150,12 @@ EXPORT_PER_CPU_SYMBOL_GPL(injectm);
 
 void mce_log(struct mce_hw_err *err)
 {
+	/* Not more than two messages every minute */
+	static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);
+
 	if (mce_gen_pool_add(err)) {
-		pr_info(HW_ERR "Machine check events logged\n");
+		if (__ratelimit(&ratelimit))
+			pr_info(HW_ERR "Machine check events logged\n");
 		irq_work_queue(&mce_irq_work);
 	}
 }
-- 
2.56.0