selftests/mm: skip the hugetlb-madvise tests on unmet hugepage requirements

Now that run_vmtests.sh does not guarantee that the correct hugepage count
is available, skip the hugetlb-madvise test if the requirements are not
met rather than failing.

Link: https://lkml.kernel.org/r/20240306223714.320681-4-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: export get_free_hugepages()

Patch series "New selftest for mm", v2.

This is a simple test case that reproduces an mm problem[1], where a page
fault races with madvise(), and it is not trivial to reproduce and debug.

This test-case aims to avoid such race problems from happening again,
impacting workloads that leverages external allocators, such as tcmalloc,
jemalloc, etc.

[1] https://lore.kernel.org/all/20231001005659.2185316-1-riel@surriel.com/#r


This patch (of 2):

get_free_hugepages() is helpful for other hugepage tests. Export it to
the common file (vm_util.c) to be reused.

Link: https://lkml.kernel.org/r/20231005163922.87568-1-leitao@debian.org
Link: https://lkml.kernel.org/r/20231005163922.87568-2-leitao@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: fix unused variable warnings in hugetlb-madvise.c, migration.c

Dummy variables are required in order to make these two (similar)
routines work, so in both cases, declare the variables as volatile in
order to avoid the clang compiler warning.

Furthermore, in order to ensure that each test actually does what is
intended, add an asm volatile invocation (thanks to David Hildenbrand
for the suggestion), with a clarifying comment so that it survives
future maintenance.

Link: https://lkml.kernel.org/r/20230606071637.267103-3-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: merge default_huge_page_size() into one

There're already 3 same definitions of the three functions. Move it into
vm_util.[ch].

Link: https://lkml.kernel.org/r/20230412164223.328134-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/vm: rename selftests/vm to selftests/mm

Rename selftets/vm to selftests/mm for being more consistent with the
code, documentation, and tools directories, and won't be confused with
virtual machines.

[sj@kernel.org: convert missing vm->mm changes]
Link: https://lkml.kernel.org/r/20230107230643.252273-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20230103180754.129637-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>