Hi Hugh, On Sat, 16 Apr 2016 16:41:33 -0700 (PDT) Hugh Dickins <hughd@xxxxxxxxxx> wrote: > > The pmd_fault() method gives the filesystem an opportunity to place > a trans huge pmd entry at *pmd, before any pagetable is exposed (and > an opportunity to split it on COW fault): now use it for huge tmpfs. > > This patch is a little raw: with more time before LSF/MM, I would > probably want to dress it up better - the shmem_mapping() calls look > a bit ugly; it's odd to want FAULT_FLAG_MAY_HUGE and VM_FAULT_HUGE just > for a private conversation between shmem_fault() and shmem_pmd_fault(); > and there might be a better distribution of work between those two, but > prising apart that series of huge tests is not to be done in a hurry. > > Good for now, presents the new way, but might be improved later. > > This patch still leaves the huge tmpfs map_team_by_pmd() allocating a > pagetable while holding page lock, but other filesystems are no longer > doing so; and we've not yet settled whether huge tmpfs should (like anon > THP) or should not (like DAX) participate in deposit/withdraw protocol. > > Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> > --- > I've been testing with this applied on top of mmotm plus 1-4/5, > but I suppose the right place for it is immediately after > huge-tmpfs-map-shmem-by-huge-page-pmd-or-by-page-team-ptes.patch > with a view to perhaps merging it into that in the future. > > mm/huge_memory.c | 4 ++-- > mm/memory.c | 13 +++++++++---- > mm/shmem.c | 33 +++++++++++++++++++++++++++++++++ > 3 files changed, 44 insertions(+), 6 deletions(-) I added this to the end of mmotm in linux-next today. -- Cheers, Stephen Rothwell -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>