Re: [Xen-devel] [RFC] KEXEC: allocate crash note buffers at boot time v3

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 01.12.11 at 16:02, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
> On 01/12/11 12:56, Jan Beulich wrote:
>>>>> On 01.12.11 at 13:29, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
>>> +static spinlock_t crash_notes_lock = SPIN_LOCK_UNLOCKED;
>> Please use DEFINE_SPINLOCK() here.
>>
>>> +    register_keyhandler('C', &crashdump_trigger_keyhandler);
>>> +
>>> +    /* If no crash area, no need to allocate space for notes. */
>>> +    if ( 0 == kexec_crash_area.size )
>>> +        return 0;
>> Wouldn't it make sense to switch the order of these?
>>
>>> +    crash_notes = xmalloc_bytes(nr_cpu_ids * sizeof(void*));
>> Please use xmalloc_array() here.
>>
>>> +    if ( !crash_notes[nr] && 0 != kexec_init_cpu_notes(nr) )
>> The first check is pointless - the function will return zero if the
>> allocation was already done.
> 
> I forgot to say in my previous email.  Short circuit evaluation should
> prevent the kexec_init_cpu_notes() function call actually being made.

What would that buy you? Performance is not an issue on this code
path.

Jan


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