>>> Also there are some scenarios where __page_to_pfn is not that simple a >>> call with us having to get the node ID so we can find the pgdat structure >>> to perform the calculation. I'm not sure the compiler would be ble to >>> figure out that the result is the same for both calls, so it is better to >>> make it explicit. >> >> Only in case of CONFIG_SPARSEMEM we have to go via the section - but I >> doubt this is really worth optimizing here. >> >> But yeah, I'm fine with this change, only "IMHO >> get_pageblock_migratetype() would be nicer" :) > > Aren't most distros running with CONFIG_SPARSEMEM enabled? If that is the > case why not optimize for it? Because I tend to dislike micro-optimizations without performance numbers for code that is not on a hot path. But I mean in this case, as you said, you need the pfn either way, so it's completely fine with. I do wonder, however, if you should just pass in the migratetype from the caller. That would be even faster ;) -- Thanks, David / dhildenb
