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c0531714d6
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Naoya Horiguchi c0531714d6 mm/hugetlb: check gigantic_page_runtime_supported() in return_unused_surplus_pages() 
Patch series "mm, hwpoison: enable 1GB hugepage support", v7.


This patch (of 8):

I found a weird state of 1GB hugepage pool, caused by the following
procedure:

  - run a process reserving all free 1GB hugepages,
  - shrink free 1GB hugepage pool to zero (i.e. writing 0 to
    /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages), then
  - kill the reserving process.

, then all the hugepages are free *and* surplus at the same time.

  $ cat /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
  3
  $ cat /sys/kernel/mm/hugepages/hugepages-1048576kB/free_hugepages
  3
  $ cat /sys/kernel/mm/hugepages/hugepages-1048576kB/resv_hugepages
  0
  $ cat /sys/kernel/mm/hugepages/hugepages-1048576kB/surplus_hugepages
  3

This state is resolved by reserving and allocating the pages then freeing
them again, so this seems not to result in serious problem.  But it's a
little surprising (shrinking pool suddenly fails).

This behavior is caused by hstate_is_gigantic() check in
return_unused_surplus_pages().  This was introduced so long ago in 2008 by
commit aa888a7497 ("hugetlb: support larger than MAX_ORDER"), and at
that time the gigantic pages were not supposed to be allocated/freed at
run-time.  Now kernel can support runtime allocation/free, so let's check
gigantic_page_runtime_supported() together.

Link: https://lkml.kernel.org/r/20220714042420.1847125-1-naoya.horiguchi@linux.dev
Link: https://lkml.kernel.org/r/20220714042420.1847125-2-naoya.horiguchi@linux.dev
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-08-08 18:06:43 -07:00
arch mm: hugetlb_vmemmap: delete hugetlb_optimize_vmemmap_enabled() 2022-08-08 18:06:42 -07:00
block for-5.20/block-2022-08-04 2022-08-04 20:00:14 -07:00
certs certs: make system keyring depend on x509 parser 2022-07-24 12:53:55 -07:00
crypto tpmdd updates for Linux v5.20 2022-08-06 09:43:02 -07:00
Documentation mm: hugetlb_vmemmap: move code comments to vmemmap_dedup.rst 2022-08-08 18:06:43 -07:00
drivers LED updates for 5.20: new driver for bcm63138, is31fl319x updates, 2022-08-08 11:36:21 -07:00
fs mm: hugetlb_vmemmap: introduce the name HVO 2022-08-08 18:06:42 -07:00
include mm: hugetlb_vmemmap: move code comments to vmemmap_dedup.rst 2022-08-08 18:06:43 -07:00
init Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
io_uring iov_iter work, part 1 - isolated cleanups and optimizations. 2022-08-03 13:50:22 -07:00
ipc Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
kernel Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
lib Bitmap patches for v6.0-rc1 2022-08-07 17:52:35 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/hugetlb: check gigantic_page_runtime_supported() in return_unused_surplus_pages() 2022-08-08 18:06:43 -07:00
net 9p-for-5.20 2022-08-06 14:48:54 -07:00
samples Tracing updates for 5.20 / 6.0 2022-08-05 09:41:12 -07:00
scripts Coccinelle semantic patch changes 2022-08-08 09:42:04 -07:00
security linux-kselftest-kunit-5.20-rc1 2022-08-02 19:34:45 -07:00
sound sound updates for 6.0-rc1 2022-08-06 10:19:51 -07:00
tools Bitmap patches for v6.0-rc1 2022-08-07 17:52:35 -07:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt Merge remote-tracking branch 'kvm/next' into kvm-next-5.20 2022-08-01 03:21:00 -04:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS drm for 5.20/6.0 2022-08-03 19:52:08 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS TTY / Serial driver changes for 6.0-rc1 2022-08-08 11:31:40 -07:00
Makefile linux-kselftest-next-5.20-rc1 2022-08-02 19:44:56 -07:00
README

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 Restructured Text 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.