Re: [PATCH] introduce for_each_populated_zone() macro
From: KOSAKI Motohiro
Date: Tue Feb 10 2009 - 09:13:24 EST
Hi
>> +#define for_each_populated_zone(zone) \
>> + for (zone = (first_online_pgdat())->node_zones; \
>> + zone; \
>> + zone = next_zone(zone)) \
>> + if (!populated_zone(zone)) \
>> + ; /* do nothing */ \
>> + else
>> +
>> +
>> +
>> +
>
> There is tabs vs whitespace damage in there.
??
I'm look at it again. but I don't found whitespace damage.
> Multiple empty lines are introduced for no apparent reason.
Will fix. thanks.
> It's not clear why you did not use if (populated_zone(zone))
> instead of an if/else.
Good question.
if we make following macro,
#define for_each_populated_zone(zone) \
for (zone = (first_online_pgdat())->node_zones; \
zone; \
zone = next_zone(zone)) \
if (populated_zone(zone))
and, writing following caller code.
if (always_true_assumption)
for_each_populated_zone(){
/* some code */
}
else
panic();
expand to
if (always_true_assumption)
for()
if (populated_zone() {
/* some code */
}
else
panic();
then, memoryless node cause panic().
>
> Otherwise, I did not spot anything out of the ordinary. Nice cleanup.
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