Pavel Machek 写道:
Hi!For SysRq, we just can get hot key list from Documentation/sysrq.txt , but in the most of cases, the user can't access it by hand on using SysRq to debug, so it is better for SysRq to provide an online help for the users. SysRq has already provided a similiar help before this patch, but it is not so definite that the user doesn't know what happened and how to do on pressing an undefined hot key. In addition, that funtion has a big loop with another big loop embedded which is very inefficient, it is intended to skip some hot key help info for such a function as "Changing Loglevel", just print a help info for this, that is very unnecessary. In fact, the key '0' - '8' have different results the user should know. This patch add this online help function, it'll print thw whole hot key list and corresponding function descriptions, it can print the new defined hot key without any changed needed. The output is the below on pressing an undefined hot key: SysRq : <6>this hot key isn't defined. SysRq Help Information: Hot Key Function Description =========== ==================== ALT+SysRq+0 Changing Loglevel to this value ALT+SysRq+1 Changing Loglevel to this value ALT+SysRq+2 Changing Loglevel to this value ALT+SysRq+3 Changing Loglevel to this value ALT+SysRq+4 Changing Loglevel to this value ALT+SysRq+5 Changing Loglevel to this value ALT+SysRq+6 Changing Loglevel to this value ALT+SysRq+7 Changing Loglevel to this value ALT+SysRq+8 Changing Loglevel to this value ALT+SysRq+9 Changing Loglevel to this value ALT+SysRq+a Not defined ALT+SysRq+b Resetting ALT+SysRq+c Trigger a crashdump ALT+SysRq+d Not defined ALT+SysRq+e Terminate All Tasks ALT+SysRq+f Manual OOM execution ALT+SysRq+g Not defined ALT+SysRq+h Not defined ALT+SysRq+i Kill All Tasks ALT+SysRq+j Not defined ALT+SysRq+k SAK ALT+SysRq+l Not defined ALT+SysRq+m Show Memory ALT+SysRq+n Nice All RT Tasks ALT+SysRq+o Power Off ALT+SysRq+p Show Regs ALT+SysRq+q Show Pending Timers ALT+SysRq+r Keyboard mode set to XLATE ALT+SysRq+s Emergency Sync ALT+SysRq+t Show State ALT+SysRq+u Emergency Remount R/O ALT+SysRq+v Not defined ALT+SysRq+w Show Blocked State ALT+SysRq+x Not defined ALT+SysRq+y Not defined ALT+SysRq+z Not definedThis will scroll out of users view on small terminals. Plus it is untrue. On sparc, it is stop+x, not sysrq+x.
You're right, it it better to remove ALT+SysRq
This char array is just for output, thees are jsut the keys sysrq has defined, in the current design of sysrq, to add a new key is not easy unless you use an existed but unused key,+/* + * Hot key table SysRq supports + */ +static char __read_mostly sysrq_hot_key_table[36] = { + '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', + 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', + 'u', 'v', 'w', 'x', 'y', 'z' +};Plus this is practically guaranteed to get out of sync with reality. If you did this to make sysrq printing faster... then that is very bad optimization. Pavel
so this has no problem.SysRq is just for debugging or emergent handling, so this array is impossible to result in
any bad effects, it is just for convenience. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
- References:
- Prev by Date: Re: [RT] seqlocks: use of PICK_FUNCTION breaks kernel compile when CONFIG_GENERIC_TIME is NOT set
- Next by Date: Re: [PATCH 4/5] ibmebus: Move to of_device and of_platform_driver, match eHCA and eHEA drivers
- Previous by thread: Re: [PATCH 2.6.23] SysRq: print hotkey info while pressing undef key
- Next by thread: r8169 & TX offload
- Index(es):
 |