On 06/24/19 at 03:23pm, Kirill A. Shutemov wrote: > On Mon, Jun 24, 2019 at 06:07:42PM +0800, Baoquan He wrote: > > On 06/21/19 at 01:54pm, Kirill A. Shutemov wrote: > > > > The code block as below is to zero p4d entries which are not coverred by > > > > the current memory range, and if haven't been mapped already. It's > > > > clearred away in this patch, could you also mention it in log, and tell > > > > why it doesn't matter now? > > > > > > > > If it doesn't matter, should we clear away the simillar code in > > > > phys_pud_init/phys_pmd_init/phys_pte_init? Maybe a prep patch to do the > > > > clean up? > > > > > > It only matters for the levels that contains page table entries that can > > > point to pages, not page tables. There's no p4d or pgd huge pages on x86. > > > Otherwise we only leak page tables without any benefit. > > > > Ah, I checked git history, didn't find why it's added. I just Have a > > superficial knowledge of the clearing, but in a low-efficiency way. > > > > > > > > We might have this on all leveles under p?d_large() condition and don't > > > touch page tables at all. > > > > I see. > > > > > > > > BTW, it all becomes rather risky for this late in the release cycle. Maybe > > > we should revert the original patch and try again later with more > > > comprehansive solution? > > > > It's not added in one time. I am fine with your current change, would be > > much better if mention it in log, and also add code comment above the > > clearing code. Surely reverting and trying later with more comprehensive > > solution is also good to me, this need a little more effort. > > I've decided to keep the block for now. We can remove it later, once the > fixis in. > I'll post it soon
That's great, can make those codes more understandable with clear commit log and code comment.
