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| author | Dave Young <hidave.darkstar@gmail.com> | 2009-09-22 16:43:33 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-23 07:39:28 -0700 |
| commit | af91322ef3f29ae4114e736e2a72e28b4d619cf9 (patch) | |
| tree | debba08531c7dd78b90b5d8f2c03f6bf7c9e7877 /kernel/sysctl.c | |
| parent | 3a3b6ed2235f2f619889dd6096e24b6d93bf3339 (diff) | |
| download | lwn-af91322ef3f29ae4114e736e2a72e28b4d619cf9.tar.gz lwn-af91322ef3f29ae4114e736e2a72e28b4d619cf9.zip | |
printk: add printk_delay to make messages readable for some scenarios
When syslog is not possible, at the same time there's no serial/net
console available, it will be hard to read the printk messages. For
example oops/panic/warning messages in shutdown phase.
Add a printk delay feature, we can make each printk message delay some
milliseconds.
Setting the delay by proc/sysctl interface: /proc/sys/kernel/printk_delay
The value range from 0 - 10000, default value is 0
[akpm@linux-foundation.org: fix a few things]
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/sysctl.c')
| -rw-r--r-- | kernel/sysctl.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 6ba49c7cb128..0dfaa47d7cb6 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -106,6 +106,9 @@ static int __maybe_unused one = 1; static int __maybe_unused two = 2; static unsigned long one_ul = 1; static int one_hundred = 100; +#ifdef CONFIG_PRINTK +static int ten_thousand = 10000; +#endif /* this is needed for the proc_doulongvec_minmax of vm_dirty_bytes */ static unsigned long dirty_bytes_min = 2 * PAGE_SIZE; @@ -722,6 +725,17 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = &proc_dointvec, }, + { + .ctl_name = CTL_UNNUMBERED, + .procname = "printk_delay", + .data = &printk_delay_msec, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .strategy = &sysctl_intvec, + .extra1 = &zero, + .extra2 = &ten_thousand, + }, #endif { .ctl_name = KERN_NGROUPS_MAX, |