8c407e05a9
This test stresses the race between of madvise(DONTNEED), a page fault
and a parallel huge page mmap, which should fail due to lack of
available page available for mapping.
This test case must run on a system with one and only one huge page
available.
# echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
During setup, the test allocates the only available page, and starts
three threads:
- thread 1:
* madvise(MADV_DONTNEED) on the allocated huge page
- thread 2:
* Write to the allocated huge page
- thread 3:
* Tries to allocated (steal) an extra huge page (which is not
available)
thread 3 should never succeed in the allocation, since the only huge
page was never unmapped, and should be reserved.
Touching the old page after thread3 allocation will raise a SIGBUS.
Link: https://lkml.kernel.org/r/20240105155419.1939484-2-leitao@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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.