diff options
Diffstat (limited to 'Documentation/fault-injection/fault-injection.txt')
| -rw-r--r-- | Documentation/fault-injection/fault-injection.txt | 70 |
1 files changed, 35 insertions, 35 deletions
diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt index 6d6e5ac5ea92..b7ca560b9340 100644 --- a/Documentation/fault-injection/fault-injection.txt +++ b/Documentation/fault-injection/fault-injection.txt @@ -17,7 +17,7 @@ o fail_page_alloc o fail_make_request - injects disk IO errors on permitted devices by + injects disk IO errors on devices permitted by setting /sys/block/<device>/make-it-fail or /sys/block/<device>/<partition>/make-it-fail. (generic_make_request()) @@ -29,16 +29,16 @@ o debugfs entries fault-inject-debugfs kernel module provides some debugfs entries for runtime configuration of fault-injection capabilities. -- /debug/*/probability: +- /debug/fail*/probability: likelihood of failure injection, in percent. Format: <percent> - Note that one-failure-per-handred is a very high error rate - for some testcases. Please set probably=100 and configure - /debug/*/interval for such testcases. + Note that one-failure-per-hundred is a very high error rate + for some testcases. Consider setting probability=100 and configure + /debug/fail*/interval for such testcases. -- /debug/*/interval: +- /debug/fail*/interval: specifies the interval between failures, for calls to should_fail() that pass all the other tests. @@ -46,37 +46,36 @@ configuration of fault-injection capabilities. Note that if you enable this, by setting interval>1, you will probably want to set probability=100. -- /debug/*/times: +- /debug/fail*/times: specifies how many times failures may happen at most. A value of -1 means "no limit". -- /debug/*/space: +- /debug/fail*/space: specifies an initial resource "budget", decremented by "size" on each call to should_fail(,size). Failure injection is suppressed until "space" reaches zero. -- /debug/*/verbose +- /debug/fail*/verbose Format: { 0 | 1 | 2 } - specifies the verbosity of the messages when failure is injected. - We default to 0 (no extra messages), setting it to '1' will - print only to tell failure happened, '2' will print call trace too - - it is useful to debug the problems revealed by fault injection - capabilities. + specifies the verbosity of the messages when failure is + injected. '0' means no messages; '1' will print only a single + log line per failure; '2' will print a call trace too -- useful + to debug the problems revealed by fault injection. -- /debug/*/task-filter: +- /debug/fail*/task-filter: - Format: { 0 | 1 } - A value of '0' disables filtering by process (default). + Format: { 'Y' | 'N' } + A value of 'N' disables filtering by process (default). Any positive value limits failures to only processes indicated by /proc/<pid>/make-it-fail==1. -- /debug/*/require-start: -- /debug/*/require-end: -- /debug/*/reject-start: -- /debug/*/reject-end: +- /debug/fail*/require-start: +- /debug/fail*/require-end: +- /debug/fail*/reject-start: +- /debug/fail*/reject-end: specifies the range of virtual addresses tested during stacktrace walking. Failure is injected only if some caller @@ -85,22 +84,23 @@ configuration of fault-injection capabilities. Default required range is [0,ULONG_MAX) (whole of virtual address space). Default rejected range is [0,0). -- /debug/*/stacktrace-depth: +- /debug/fail*/stacktrace-depth: specifies the maximum stacktrace depth walked during search - for a caller within [address-start,address-end). + for a caller within [require-start,require-end) OR + [reject-start,reject-end). - /debug/fail_page_alloc/ignore-gfp-highmem: - Format: { 0 | 1 } - default is 0, setting it to '1' won't inject failures into + Format: { 'Y' | 'N' } + default is 'N', setting it to 'Y' won't inject failures into highmem/user allocations. - /debug/failslab/ignore-gfp-wait: - /debug/fail_page_alloc/ignore-gfp-wait: - Format: { 0 | 1 } - default is 0, setting it to '1' will inject failures + Format: { 'Y' | 'N' } + default is 'N', setting it to 'Y' will inject failures only into non-sleep allocations (GFP_ATOMIC allocations). o Boot option @@ -124,22 +124,22 @@ o define the fault attributes Please see the definition of struct fault_attr in fault-inject.h for details. -o provide the way to configure fault attributes +o provide a way to configure fault attributes - boot option If you need to enable the fault injection capability from boot time, you can - provide boot option to configure it. There is a helper function for it. + provide boot option to configure it. There is a helper function for it: - setup_fault_attr(attr, str); + setup_fault_attr(attr, str); - debugfs entries failslab, fail_page_alloc, and fail_make_request use this way. - There is a helper function for it. + Helper functions: - init_fault_attr_entries(entries, attr, name); - void cleanup_fault_attr_entries(entries); + init_fault_attr_entries(entries, attr, name); + void cleanup_fault_attr_entries(entries); - module parameters @@ -149,9 +149,9 @@ o provide the way to configure fault attributes o add a hook to insert failures - should_fail() returns 1 when failures should happen. + Upon should_fail() returning true, client code should inject a failure. - should_fail(attr,size); + should_fail(attr, size); Application Examples -------------------- |