On 04/16/18 19:02, Huang, Ying wrote: > From: Huang Ying <ying.huang@xxxxxxxxx> > > 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" <ying.huang@xxxxxxxxx> > Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> > Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxx> > Cc: Johannes Weiner <hannes@xxxxxxxxxxx> > Cc: Shaohua Li <shli@xxxxxxxxxx> > Cc: Hugh Dickins <hughd@xxxxxxxxxx> > Cc: Minchan Kim <minchan@xxxxxxxxxx> > Cc: Rik van Riel <riel@xxxxxxxxxx> > Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> > Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> > Cc: Zi Yan <zi.yan@xxxxxxxxxxxxxx> > --- > include/linux/swap.h | 6 +++++ > mm/huge_memory.c | 54 ++++++++++++++++++++++++++++++++++++++++---- > mm/swapfile.c | 28 +++++++++++++++++++++++ > 3 files changed, 83 insertions(+), 5 deletions(-) -- ~Randy
