On 04/16/18 19:02, Huang, Ying wrote: > From: Huang Ying <[email protected]> > > A huge PMD need to be split when zap a part of the PMD mapping etc. > If the PMD mapping is a swap mapping, we need to split it too. This > patch implemented the support for this. This is similar as splitting > the PMD page mapping, except we need to decrease the PMD swap mapping > count for the huge swap cluster too. If the PMD swap mapping count > becomes 0, the huge swap cluster will be split. > > Notice: is_huge_zero_pmd() and pmd_page() doesn't work well with swap > PMD, so pmd_present() check is called before them.
FWIW, I would prefer to see that comment in the source code, not just in the commit description. > > Signed-off-by: "Huang, Ying" <[email protected]> > Cc: "Kirill A. Shutemov" <[email protected]> > Cc: Andrea Arcangeli <[email protected]> > Cc: Michal Hocko <[email protected]> > Cc: Johannes Weiner <[email protected]> > Cc: Shaohua Li <[email protected]> > Cc: Hugh Dickins <[email protected]> > Cc: Minchan Kim <[email protected]> > Cc: Rik van Riel <[email protected]> > Cc: Dave Hansen <[email protected]> > Cc: Naoya Horiguchi <[email protected]> > Cc: Zi Yan <[email protected]> > --- > include/linux/swap.h | 6 +++++ > mm/huge_memory.c | 54 ++++++++++++++++++++++++++++++++++++++++---- > mm/swapfile.c | 28 +++++++++++++++++++++++ > 3 files changed, 83 insertions(+), 5 deletions(-) -- ~Randy
