archive mirror
 help / color / mirror / Atom feed
From: Dan Williams <>
Cc:, "Balbir Singh" <>,
	"Logan Gunthorpe" <>,
	"Christoph Hellwig" <>,
	"Jérôme Glisse" <>,
	"Michal Hocko" <>,
	"Jérôme Glisse" <>,,
Subject: [PATCH v7 0/7] mm: Merge hmm into devm_memremap_pages, mark GPL-only
Date: Fri, 12 Oct 2018 10:47:37 -0700	[thread overview]
Message-ID: <> (raw)

Changes since v6 [1]:
* Rebase on next-20181008 and fixup conflicts with the xarray conversion
  and hotplug optimizations
* It has soaked on a 0day visible branch for a few days without any



Hi Andrew,

Jérôme has reviewed the cleanups, thanks Jérôme. We still disagree on
the EXPORT_SYMBOL_GPL status of the core HMM implementation, but Logan,
Christoph and I continue to support marking all devm_memremap_pages()
derivatives EXPORT_SYMBOL_GPL.

HMM has been upstream for over a year, with no in-tree users it is clear
it was designed first and foremost for out of tree drivers. It takes
advantage of a facility Christoph and I spearheaded to support
persistent memory. It continues to see expanding use cases with no clear
end date when it will stop attracting features / revisions. It is not
suitable to export devm_memremap_pages() as a stable 3rd party driver

devm_memremap_pages() is a facility that can create struct page entries
for any arbitrary range and give out-of-tree drivers the ability to
subvert core aspects of page management. It, and anything derived from
it (e.g. hmm, pcip2p, etc...), is a deep integration point into the core
kernel, and an EXPORT_SYMBOL_GPL() interface. 

Commit 31c5bda3a656 "mm: fix exports that inadvertently make put_page()
EXPORT_SYMBOL_GPL" was merged ahead of this series to relieve some of
the pressure from innocent consumers of put_page(), but now we need this
series to address *producers* of device pages.

More details and justification in the changelogs. The 0day
infrastructure has reported success across 152 configs and this survives
the libnvdimm unit test suite. Aside from the controversial bits the
diffstat is compelling at:

	7 files changed, 126 insertions(+), 323 deletions(-)

Note that the series has some minor collisions with Alex's recent series
to improve devm_memremap_pages() scalability [2]. So, whichever you take
first the other will need a minor rebase.


Dan Williams (7):
      mm, devm_memremap_pages: Mark devm_memremap_pages() EXPORT_SYMBOL_GPL
      mm, devm_memremap_pages: Kill mapping "System RAM" support
      mm, devm_memremap_pages: Fix shutdown handling
      mm, devm_memremap_pages: Add MEMORY_DEVICE_PRIVATE support
      mm, hmm: Use devm semantics for hmm_devmem_{add,remove}
      mm, hmm: Replace hmm_devmem_pages_create() with devm_memremap_pages()
      mm, hmm: Mark hmm_devmem_{add,add_resource} EXPORT_SYMBOL_GPL

 drivers/dax/pmem.c                |   14 --
 drivers/nvdimm/pmem.c             |   13 +-
 include/linux/hmm.h               |    4 
 include/linux/memremap.h          |    2 
 kernel/memremap.c                 |   94 +++++++----
 mm/hmm.c                          |  305 +++++--------------------------------
 tools/testing/nvdimm/test/iomap.c |   17 ++
 7 files changed, 126 insertions(+), 323 deletions(-)

             reply	other threads:[~2018-10-12 17:59 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-12 17:47 Dan Williams [this message]
2018-10-12 17:47 ` [PATCH v7 1/7] mm, devm_memremap_pages: Mark devm_memremap_pages() EXPORT_SYMBOL_GPL Dan Williams
2018-10-12 17:49 [PATCH v7 0/7] mm: Merge hmm into devm_memremap_pages, mark GPL-only Dan Williams
2018-10-12 18:14 ` Jerome Glisse

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \ \
    --subject='Re: [PATCH v7 0/7] mm: Merge hmm into devm_memremap_pages, mark GPL-only' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).