Hi Michal, On 03/26/19 at 03:31pm, Michal Hocko wrote: > > > > OK, I am fine to drop it. Or only put the section existence checking > > > > earlier to avoid unnecessary usemap/memmap allocation? > > > > > > DO you have any data on how often that happens? Should basically never > > > happening, right? > > > > Oh, you think about it in this aspect. Yes, it rarely happens. > > Always allocating firstly can increase efficiency. Then I will just drop > > it. > > OK, let me try once more. Doing a check early is something that makes > sense in general. Another question is whether the check is needed at > all. So rather than fiddling with its placement I would go whether it is > actually failing at all. I suspect it doesn't because the memory hotplug > is currently enforced to be section aligned. There are people who would > like to allow subsection or section unaligned aware hotplug and then > this would be much more relevant but without any solid justification > such a patch is not really helpful because it might cause code conflicts > with other work or obscure the git blame tracking by an additional hop. > > In short, if you want to optimize something then make sure you describe > what you are optimizing how it helps. I must be dizzy last night when thinking and replying mails, I thought about it a while, got a point you may mean. Now when I check mail and rethink about it, that reply may make misunderstanding. It doesn't actually makes sense to optimize, just a little code block moving. I now agree with you that it doesn't optimize anything and may impact people's code change. Sorry about that. Thanks Baoquan
