Re: linux-next: build warnings after merge of the mm tree

Jiaqi Yan
2024-07-02T04:33:35Z

On Mon, Jul 1, 2024 at 9:15 PM Jiaqi Yan <jiaqiyan@google.com> wrote:
>
> On Mon, Jul 1, 2024 at 8:15 PM Andrew Morton <akpm@linux-foundation.org> wrote:
> >
> > On Mon, 1 Jul 2024 18:49:12 +1000 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
> >
> > > Hi all,
> > >
> > > After merging the mm tree, today's linux-next build (htmldocs) produced
> > > these warnings:
> > >
> > > Documentation/admin-guide/sysctl/vm.rst:278: ERROR: Unexpected indentation.
> > > Documentation/admin-guide/sysctl/vm.rst:279: WARNING: Block quote ends without a blank line; unexpected unindent.
> > >
> > > Introduced by commit
> > >
> > > 2cba7831f62c ("docs: mm: add enable_soft_offline sysctl")
> >
> > Well that's annoying.
> >
> > @@ -267,6 +268,37 @@ used::
> > These are informational only. They do not mean that anything is wrong
> > with your system. To disable them, echo 4 (bit 2) into drop_caches.
> >
> > +enable_soft_offline
> > +===================
> > +Correctable memory errors are very common on servers. Soft-offline is kernel's
> > +solution for memory pages having (excessive) corrected memory errors.
> > +
> > +For different types of page, soft-offline has different behaviors / costs.
> > +- For a raw error page, soft-offline migrates the in-use page's content to
> > + a new raw page.
> > +- For a page that is part of a transparent hugepage, soft-offline splits the
> > + transparent hugepage into raw pages, then migrates only the raw error page.
> > + As a result, user is transparently backed by 1 less hugepage, impacting
> > + memory access performance.
> > +- For a page that is part of a HugeTLB hugepage, soft-offline first migrates
> > + the entire HugeTLB hugepage, during which a free hugepage will be consumed
> > + as migration target. Then the original hugepage is dissolved into raw
> > + pages without compensation, reducing the capacity of the HugeTLB pool by 1.
> > +
> > + ...
> >
> > This seems a reasonable thing to do so there's probably some way in
> > which to do it, but a bit of grepping failed to turn up examples in
> > existing .rst files. Can someone please suggest?
>
> It seems I need to add some blank lines according to [1], especially
> to add a blank line above the first list item:
>
> diff --git a/Documentation/admin-guide/sysctl/vm.rst
> b/Documentation/admin-guide/sysctl/vm.rst
> index 75e22137d849..74b4c0f65213 100644
> --- a/Documentation/admin-guide/sysctl/vm.rst
> +++ b/Documentation/admin-guide/sysctl/vm.rst
> @@ -274,12 +274,15 @@ Correctable memory errors are very common on
> servers. Soft-offline is kernel's
> solution for memory pages having (excessive) corrected memory errors.
>
> For different types of page, soft-offline has different behaviors / costs.
> +
> - For a raw error page, soft-offline migrates the in-use page's content to
> a new raw page.
> +
> - For a page that is part of a transparent hugepage, soft-offline splits the
> transparent hugepage into raw pages, then migrates only the raw error page.
> As a result, user is transparently backed by 1 less hugepage, impacting
> memory access performance.
> +
> - For a page that is part of a HugeTLB hugepage, soft-offline first migrates
> the entire HugeTLB hugepage, during which a free hugepage will be consumed
> as migration target. Then the original hugepage is dissolved into raw
>
> But I am having trouble testing the build, so wasn't able to validate
> the change above:
>
> Documentation$ make
> /tools/net/ynl/ynl-gen-rst.py -o
> /Documentation/networking/netlink_spec/index.rst -x
> make: /tools/net/ynl/ynl-gen-rst.py: No such file or directory
> make: *** [Makefile:113:
> /Documentation/networking/netlink_spec/index.rst] Error 127

I tried another way: make htmldocs at repo's root directory. Although
I wasn't able to finish the make process,

- without the blank lines:

Documentation/admin-guide/sysctl/vm.rst:278: ERROR: Unexpected indentation.
Documentation/admin-guide/sysctl/vm.rst:279: WARNING: Block quote
ends without a blank line; unexpected unindent.

- with the blank lines added, the ERROR and WARNING in vm/rst are gone.

Andrew and Stephen, what is the best way to post the fix for this?
Should I send out a v8 of the patch with the blank lines added? or a
standalone commit for this fix?

>
> [1] https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#bullet-lists