On Thu, Mar 11, 2021 at 07:57:12PM -0500, Zi Yan wrote: > From: Zi Yan <ziy@xxxxxxxxxx> > > We do not have a direct user interface of splitting the compound page > backing a THP But we do. You expand it. > and there is no need unless we want to expose the THP > implementation details to users. Make <debugfs>/split_huge_pages accept > a new command to do that. > > By writing "<pid>,<vaddr_start>,<vaddr_end>" to > <debugfs>/split_huge_pages, THPs within the given virtual address range > from the process with the given pid are split. It is used to test > split_huge_page function. In addition, a selftest program is added to > tools/testing/selftests/vm to utilize the interface by splitting > PMD THPs and PTE-mapped THPs. > Okay, makes sense. But it doesn't cover non-mapped THPs. tmpfs may have file backed by THP that mapped nowhere. Do we want to cover this case too? Maybe have PID:<pid>,<vaddr_start>,<vaddr_end> and FILE:<path>,<off_start>,<off_end> ? -- Kirill A. Shutemov
