From: Matt Mackall <[EMAIL PROTECTED]> Date: Tue, 13 Mar 2007 16:14:35 -0500
> Well you -could- do this: > > - reuse a long in struct page as a used map that divides the page up > into 32 or 64 segments > - every time you set a PTE, set the corresponding bit in the mask > - when we zap, only visit the regions set in the mask > > Thus, you avoid visiting most of a PMD page in the sparse case, > assuming PTEs aren't evenly spread across the PMD. > > This might not even be too horrible as the appropriate struct page > should be in cache with the appropriate bits of the mm already locked, > etc. Yes, I've even had that idea before. You can even hide it behind pmd_none() et al., the generic VM doesn't even have to know that the page table macros are doing this optimization. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
