On Fri, Apr 04, 2025 at 11:02:46AM +0100, Luis Chamberlain wrote: > On Fri, Apr 04, 2025 at 06:31:16PM +0200, Pankaj Raghav (Samsung) wrote: > > On Fri, Apr 04, 2025 at 08:32:15AM -0700, Luis Chamberlain wrote: > > > On Fri, Apr 04, 2025 at 04:06:57PM +0200, Pankaj Raghav (Samsung) wrote: > > > > From: Pankaj Raghav <p.raghav@xxxxxxxxxxx> > > > > > > > > THP support for non-tmpfs filesystem has been around for some time now. > > > > Update the admin guide to reflect it. > > > > > > > > While we are at it, move FilePmdMapped to previous paragraph for clarity, > > > > and clarify ShmemPmdMapped & ShmemHugePage. > > > > > > > > Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx> > > > > Acked-by: David Hildenbrand <david@xxxxxxxxxx> > > > > --- > > > > > > > > Changes since v2: > > > > - Address comment from Bagas Sanjaya > > > > - Squash commits and Ack from David > > > > > > > > Documentation/admin-guide/mm/transhuge.rst | 22 +++++++++++++++------- > > > > 1 file changed, 15 insertions(+), 7 deletions(-) > > > > > > > > diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst > > > > index dff8d5985f0f..f8aae64e38d0 100644 > > > > --- a/Documentation/admin-guide/mm/transhuge.rst > > > > +++ b/Documentation/admin-guide/mm/transhuge.rst > > > > @@ -12,8 +12,8 @@ using huge pages for the backing of virtual memory with huge pages > > > > that supports the automatic promotion and demotion of page sizes and > > > > without the shortcomings of hugetlbfs. > > > > > > > > -Currently THP only works for anonymous memory mappings and tmpfs/shmem. > > > > -But in the future it can expand to other filesystems. > > > > +Currently, THP only works for anonymous memory mappings, tmpfs/shmem and > > > > +filesystems that support large folios. > > > > > > That seems to allude that THP can be supported on filesystems > > > that suppor large folios. I don't think we want to call that THP > > > > But we do allocate a THP in the page cache if we support large folios. > > > > See [1] where THP was supported through page cache. From what I > > understand, THP support was added first to the page cache and then large > > folios (orders in between) support came later. > > I see, yes Do we want to clarify this further? According to this thread [1], large folios currently depends on CONFIG_TRANSPARENT_HUGEPAGE, but that will be removed eventually. https://lore.kernel.org/all/ZPINmXyTgy2wqLqr@xxxxxxxxxxxxxxxxxxxx/ I agree this needs to be clarified. THP for anonymous memory and tmpfs/shmem is not the same for filesystems that support large folios.
