Pull sbs into release branch

[pandora-kernel.git] / Documentation / x86_64 / machinecheck

diff --git a/Documentation/x86_64/machinecheck b/Documentation/x86_64/machinecheck
index 068a6d9..a05e58e 100644 (file)
--- a/Documentation/x86_64/machinecheck
+++ b/Documentation/x86_64/machinecheck
@@ -36,7 +36,12 @@ between all CPUs.
 
 check_interval
        How often to poll for corrected machine check errors, in seconds
-       (Note output is hexademical). Default 5 minutes.
+       (Note output is hexademical). Default 5 minutes.  When the poller
+       finds MCEs it triggers an exponential speedup (poll more often) on
+       the polling interval.  When the poller stops finding MCEs, it
+       triggers an exponential backoff (poll less often) on the polling
+       interval. The check_interval variable is both the initial and
+       maximum polling interval.
 
 tolerant
        Tolerance level. When a machine check exception occurs for a non
@@ -44,12 +49,14 @@ tolerant
        Since machine check exceptions can happen any time it is sometimes
        risky for the kernel to kill a process because it defies
        normal kernel locking rules. The tolerance level configures
-       how hard the kernel tries to recover even at some risk of deadlock.
-
-       0: always panic,
-       1: panic if deadlock possible,
-       2: try to avoid panic,
-       3: never panic or exit (for testing only)
+       how hard the kernel tries to recover even at some risk of
+       deadlock.  Higher tolerant values trade potentially better uptime
+       with the risk of a crash or even corruption (for tolerant >= 3).
+
+       0: always panic on uncorrected errors, log corrected errors
+       1: panic or SIGBUS on uncorrected errors, log corrected errors
+       2: SIGBUS or log uncorrected errors, log corrected errors
+       3: never panic or SIGBUS, log all errors (for testing only)
 
        Default: 1