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Peter Xu 1b16761802 mm/gup: handle huge pud for follow_pud_mask()
Teach follow_pud_mask() to be able to handle normal PUD pages like
hugetlb.

Rename follow_devmap_pud() to follow_huge_pud() so that it can process
either huge devmap or hugetlb.  Move it out of TRANSPARENT_HUGEPAGE_PUD
and and huge_memory.c (which relies on CONFIG_THP).  Switch to pud_leaf()
to detect both cases in the slow gup.

In the new follow_huge_pud(), taking care of possible CoR for hugetlb if
necessary.  touch_pud() needs to be moved out of huge_memory.c to be
accessable from gup.c even if !THP.

Since at it, optimize the non-present check by adding a pud_present()
early check before taking the pgtable lock, failing the follow_page()
early if PUD is not present: that is required by both devmap or hugetlb. 
Use pud_huge() to also cover the pud_devmap() case.

One more trivial thing to mention is, introduce "pud_t pud" in the code
paths along the way, so the code doesn't dereference *pudp multiple time. 
Not only because that looks less straightforward, but also because if the
dereference really happened, it's not clear whether there can be race to
see different *pudp values when it's being modified at the same time.

Setting ctx->page_mask properly for a PUD entry.  As a side effect, this
patch should also be able to optimize devmap GUP on PUD to be able to jump
over the whole PUD range, but not yet verified.  Hugetlb already can do so
prior to this patch.

Link: https://lkml.kernel.org/r/20240327152332.950956-11-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Mike Rapoport (IBM)" <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25 20:56:22 -07:00
arch mm/arch: provide pud_pfn() fallback 2024-04-25 20:56:21 -07:00
block block-6.9-20240412 2024-04-12 10:22:33 -07:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto This push fixes a regression that broke iwd as well as a divide by 2024-03-25 10:48:23 -07:00
Documentation remove references to page->flags in documentation 2024-04-25 20:56:15 -07:00
drivers virt: acrn: stop using follow_pfn 2024-04-25 20:56:12 -07:00
fs dax: use huge_zero_folio 2024-04-25 20:56:20 -07:00
include mm/gup: handle huge pud for follow_pud_mask() 2024-04-25 20:56:22 -07:00
init mm: introduce slabobj_ext to support slab object extensions 2024-04-25 20:55:51 -07:00
io_uring io_uring/net: restore msg_control on sendzc retry 2024-04-08 21:48:41 -06:00
ipc sysctl changes for v6.9-rc1 2024-03-18 14:59:13 -07:00
kernel mm: rename mm_put_huge_zero_page to mm_put_huge_zero_folio 2024-04-25 20:56:20 -07:00
lib mm/filemap: optimize filemap folio adding 2024-04-25 20:56:09 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/gup: handle huge pud for follow_pud_mask() 2024-04-25 20:56:22 -07:00
net mm: change inlined allocation helpers to account at the call site 2024-04-25 20:55:59 -07:00
rust rust: add a rust helper for krealloc() 2024-04-25 20:55:55 -07:00
samples Tracing updates for 6.9: 2024-03-18 15:11:44 -07:00
scripts lib: add allocation tagging support for memory allocation profiling 2024-04-25 20:55:52 -07:00
security security: Place security_path_post_mknod() where the original IMA call was 2024-04-03 10:21:32 -07:00
sound fix missing vmalloc.h includes 2024-04-25 20:55:49 -07:00
tools proc: rewrite stable_page_flags() 2024-04-25 20:56:15 -07:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt KVM Xen and pfncache changes for 6.9: 2024-03-11 10:42:55 -04:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: create a list of all built DTB files 2024-02-19 18:20:39 +09:00
.mailmap MAINTAINERS: update Naoya Horiguchi's email address 2024-04-16 15:39:51 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS MAINTAINERS: Drop Gustavo Pimentel as PCI DWC Maintainer 2024-03-27 13:41:02 -05:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS MAINTAINERS: add entries for code tagging and memory allocation profiling 2024-04-25 20:55:58 -07:00
Makefile Linux 6.9-rc4 2024-04-14 13:38:39 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.