On Thu, May 2, 2024 at 12:08 AM SeongJae Park <sj@xxxxxxxxxx> wrote: > > Hi Lance, > > On Wed, 1 May 2024 12:26:57 +0800 Lance Yang <ioworker0@xxxxxxxxx> wrote: > > > Hi all, > > > > This series adds support for reclaiming PMD-mapped THP marked as lazyfree > > without needing to first split the large folio via split_huge_pmd_address(). > > > > When the user no longer requires the pages, they would use madvise(MADV_FREE) > > to mark the pages as lazy free. Subsequently, they typically would not re-write > > to that memory again. > > > > During memory reclaim, if we detect that the large folio and its PMD are both > > still marked as clean and there are no unexpected references(such as GUP), so we > > can just discard the memory lazily, improving the efficiency of memory > > reclamation in this case. > > > > Performance Testing > > =================== > > > > On an Intel i5 CPU, reclaiming 1GiB of lazyfree THPs using > > mem_cgroup_force_empty() results in the following runtimes in seconds > > (shorter is better): > > > > -------------------------------------------- > > | Old | New | Change | > > -------------------------------------------- > > | 0.683426 | 0.049197 | -92.80% | > > -------------------------------------------- > > > > --- > > > > Changes since v3 [3] > > ==================== > > - mm/rmap: integrate PMD-mapped folio splitting into pagewalk loop > > - Resolve compilation errors by handling the case where > > CONFIG_PGTABLE_HAS_HUGE_LEAVES is undefined (thanks to SeongJae Park) > > I confirmed that the issue I reported before is disappeared with this version > of the patchset. For the fix, > > Tested-by: SeongJae Park <sj@xxxxxxxxxx> Hey SJ, Thanks for taking time to confirm! I appreciate your feedback! Thanks, Lance > > > Thanks, > SJ > > [...]
