+ selftests-mm-alloc-hugepages-in-va_high_addr_switch-test.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: selftests/mm: alloc hugepages in va_high_addr_switch test
has been added to the -mm mm-new branch.  Its filename is
     selftests-mm-alloc-hugepages-in-va_high_addr_switch-test.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-alloc-hugepages-in-va_high_addr_switch-test.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
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fixup patches in mm-new.

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------------------------------------------------------
From: Chunyu Hu <chuhu@redhat.com>
Subject: selftests/mm: alloc hugepages in va_high_addr_switch test
Date: Mon, 8 Sep 2025 20:47:38 +0800

Alloc hugepages in the test internally, so we don't fully rely on the
run_vmtests.sh.  If run_vmtests.sh does that great, free hugepages is
enough for being used to run the test, leave it as it is, otherwise setup
the hugepages in the test.

Save the original nr_hugepages value and restore it after test finish, so
leave a stable test envronment.

Link: https://lkml.kernel.org/r/20250908124740.2946005-3-chuhu@redhat.com
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/mm/va_high_addr_switch.sh |   37 ++++++++++++
 1 file changed, 37 insertions(+)

--- a/tools/testing/selftests/mm/va_high_addr_switch.sh~selftests-mm-alloc-hugepages-in-va_high_addr_switch-test
+++ a/tools/testing/selftests/mm/va_high_addr_switch.sh
@@ -9,6 +9,7 @@
 
 # Kselftest framework requirement - SKIP code is 4.
 ksft_skip=4
+orig_nr_hugepages=0
 
 skip()
 {
@@ -76,5 +77,41 @@ check_test_requirements()
 	esac
 }
 
+save_nr_hugepages()
+{
+	orig_nr_hugepages=$(cat /proc/sys/vm/nr_hugepages)
+}
+
+restore_nr_hugepages()
+{
+	echo "$orig_nr_hugepages" > /proc/sys/vm/nr_hugepages
+}
+
+setup_nr_hugepages()
+{
+	local needpgs=$1
+	while read -r name size unit; do
+		if [ "$name" = "HugePages_Free:" ]; then
+			freepgs="$size"
+			break
+		fi
+	done < /proc/meminfo
+	if [ "$freepgs" -ge "$needpgs" ]; then
+		return
+	fi
+	local hpgs=$((orig_nr_hugepages + needpgs))
+	echo $hpgs > /proc/sys/vm/nr_hugepages
+
+	local nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages)
+	if [ "$nr_hugepgs" != "$hpgs" ]; then
+		restore_nr_hugepages
+		skip "$0: no enough hugepages for testing"
+	fi
+}
+
 check_test_requirements
+save_nr_hugepages
+# 4 keep_mapped pages, and one for tmp usage
+setup_nr_hugepages 5
 ./va_high_addr_switch --run-hugetlb
+restore_nr_hugepages
_

Patches currently in -mm which might be from chuhu@redhat.com are

selftests-mm-fix-hugepages-cleanup-too-early.patch
selftests-mm-alloc-hugepages-in-va_high_addr_switch-test.patch
selftests-mm-fix-va_high_addr_switchsh-failure-on-x86_64.patch