Messages in this thread Patch in this message |  | | From | Amir Goldstein <> | Date | Mon, 15 Jun 2020 13:05:08 +0300 | Subject | Re: [PATCH v4 1/2] hugetlb: use f_mode & FMODE_HUGETLBFS to identify hugetlbfs files |
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On Mon, Jun 15, 2020 at 10:53 AM Miklos Szeredi <miklos@szeredi.hu> wrote: > > On Sat, Jun 13, 2020 at 9:12 PM Mike Kravetz <mike.kravetz@oracle.com> wrote: > > > > On 6/12/20 11:53 PM, Amir Goldstein wrote: > > > As a hugetlbfs developer, I do not know of a use case for interoperability > > with overlayfs. So yes, I am not too interested in making them work well > > together. However, if there was an actual use case I would be more than > > happy to consider doing the work. Just hate to put effort into fixing up > > two 'special' filesystems for functionality that may not be used. > > > > I can't speak for overlayfs developers. > > As I said, I only know of tmpfs being upper layer as a valid use case. > Does that work with hugepages? How would I go about testing that?
Simple, after enabling CONFIG_HUGETLBFS:
diff --git a/mount_union.py b/mount_union.py index fae8899..4070c70 100644 --- a/mount_union.py +++ b/mount_union.py @@ -15,7 +15,7 @@ def mount_union(ctx): snapshot_mntroot = cfg.snapshot_mntroot() if cfg.should_mount_upper(): system("mount " + upper_mntroot + " 2>/dev/null" - " || mount -t tmpfs upper_layer " + upper_mntroot) + " || mount -t hugetlbfs upper_layer " + upper_mntroot) layer_mntroot = upper_mntroot + "/" + ctx.curr_layer() upperdir = layer_mntroot + "/u" workdir = layer_mntroot + "/w" It fails colossally, because hugetlbfs, does not have write_iter(). It is only meant as an interface to create named maps of huge pages. So I don't really see the use case for using it as upper.
Thanks, Amir.
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