Re: CVS commit: src/sys/uvm

[Masao Uebayashi <uebayasi%tombi.co.jp@localhost>]

>> Log Message:
>> uvm_fault_internal: Skip another long code segment (lower "neighbor" fault)
>> by a goto.
>>
>>
>> To generate a diff of this commit:
>> cvs rdiff -u -r1.133 -r1.134 src/sys/uvm/uvm_fault.c
>
> Isn't this what the compiler would make anyways,
> and making the code harder to read?
> There's a reason modern programming doesn't advocate "goto"s...

I used goto there because it had the if-indented block a) was long, b) had
an important sequence of code, and c) had a very similar code fragment in
the same file.  So the intent was to make the block into a function, reduce
unnecessary differences, then kill code duplication.  (The current code is
not in a good shape yet.)

In general, goto is useful in kernel, especially where you need to meet
conditions at some exit point (free memory, exit mutex, etc.).  Such a code
should be coded very carefully, and done so in UVM.

Masao

-- 
Masao Uebayashi / Tombi Inc. / Tel: +81-90-9141-4635