kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-10-26 19:14:18 +00:00
Code Issues Releases Packages Activity
No description
1,336,155 commits 117 branches 5,805 tags 5.9 GiB
  • C 96.8%
  • Assembly 0.9%
  • Rust 0.7%
  • Shell 0.6%
  • Python 0.5%
  • Other 0.3%
Find a file
Ge Yang 67bab13307 mm/hugetlb: wait for hugetlb folios to be freed 
Since the introduction of commit c77c0a8ac4 ("mm/hugetlb: defer freeing
of huge pages if in non-task context"), which supports deferring the
freeing of hugetlb pages, the allocation of contiguous memory through
cma_alloc() may fail probabilistically.

In the CMA allocation process, if it is found that the CMA area is
occupied by in-use hugetlb folios, these in-use hugetlb folios need to be
migrated to another location.  When there are no available hugetlb folios
in the free hugetlb pool during the migration of in-use hugetlb folios,
new folios are allocated from the buddy system.  A temporary state is set
on the newly allocated folio.  Upon completion of the hugetlb folio
migration, the temporary state is transferred from the new folios to the
old folios.  Normally, when the old folios with the temporary state are
freed, it is directly released back to the buddy system.  However, due to
the deferred freeing of hugetlb pages, the PageBuddy() check fails,
ultimately leading to the failure of cma_alloc().

Here is a simplified call trace illustrating the process:
cma_alloc()
    ->__alloc_contig_migrate_range() // Migrate in-use hugetlb folios
        ->unmap_and_move_huge_page()
            ->folio_putback_hugetlb() // Free old folios
    ->test_pages_isolated()
        ->__test_page_isolated_in_pageblock()
             ->PageBuddy(page) // Check if the page is in buddy

To resolve this issue, we have implemented a function named
wait_for_freed_hugetlb_folios().  This function ensures that the hugetlb
folios are properly released back to the buddy system after their
migration is completed.  By invoking wait_for_freed_hugetlb_folios()
before calling PageBuddy(), we ensure that PageBuddy() will succeed.

Link: https://lkml.kernel.org/r/1739936804-18199-1-git-send-email-yangge1116@126.com
Fixes: c77c0a8ac4 ("mm/hugetlb: defer freeing of huge pages if in non-task context")
Signed-off-by: Ge Yang <yangge1116@126.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
History 2025-03-05 21:36:14 -08:00
arch arm: pgtable: fix NULL pointer dereference issue 2025-03-05 21:36:12 -08:00
block block-6.14-20250214 2025-02-14 11:40:59 -08:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
Documentation MAINTAINERS: update Nick's contact info 2025-02-17 22:40:04 -08:00
drivers Driver core api addition for 6.14-rc3 2025-02-16 12:54:42 -08:00
fs procfs: fix a locking bug in a vmcore_add_device_dump() error path 2025-02-17 22:40:00 -08:00
include mm/hugetlb: wait for hugetlb folios to be freed 2025-03-05 21:36:14 -08:00
init Kbuild updates for v6.14 2025-01-31 12:07:07 -08:00
io_uring io_uring-6.14-20250214 2025-02-14 11:30:53 -08:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel - Remove an unused config item GENERIC_PENDING_IRQ_CHIPFLAGS 2025-02-16 10:55:17 -08:00
lib Documentation: fix doc link to fault-injection.rst 2025-03-05 21:36:13 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/hugetlb: wait for hugetlb folios to be freed 2025-03-05 21:36:14 -08:00
net Including fixes from netfilter, wireless and bluetooth. 2025-02-13 12:17:04 -08:00
rust Driver core api addition for 6.14-rc3 2025-02-16 12:54:42 -08:00
samples Driver core api addition for 6.14-rc3 2025-02-16 12:54:42 -08:00
scripts modpost: Fix a few typos in a comment 2025-02-16 03:10:58 +09:00
security Redo of pathname patternization and fix spelling errors. 2025-02-11 10:19:36 -08:00
sound sound fixes for 6.14-rc1 2025-01-31 09:17:02 -08:00
tools selftests/damon/damos_quota_goal: handle minimum quota that cannot be further reduced 2025-03-05 21:36:12 -08:00
usr kbuild: Drop support for include/asm-<arch> in headers_check.pl 2024-12-21 11:43:17 +09:00
virt KVM: remove kvm_arch_post_init_vm 2025-02-04 11:27:45 -05:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-01-10 00:17:25 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: use host dylib naming convention to support macOS 2025-01-10 01:01:24 +01:00
.mailmap mailmap: update Nick's entry 2025-02-17 22:40:03 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Pavel to kernel.org address 2025-02-07 09:12:33 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: update Nick's contact info 2025-02-17 22:40:04 -08:00
Makefile Linux 6.14-rc3 2025-02-16 14:02:44 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

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.