From 28bfb8763bf72cea49497dadfe9342d6a1e9ad85 Mon Sep 17 00:00:00 2001
From: Michal Berger <michal.berger@intel.com>
Date: Tue, 11 Oct 2022 09:27:39 +0200
Subject: [PATCH] scripts/setup: Don't overwrite already allocated number of
 hugepages

Don't touch existing hp allocations when they already meet the NRHUGE
requirement. Introduce new environment switch, SHRINK_HUGE, to
override that new behavior.

Signed-off-by: Michal Berger <michal.berger@intel.com>
Change-Id: I0cd124b98c3deb7c21b4fbd57529d0995978c2e5
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/14912
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
---
 scripts/setup.sh        | 10 ++++++++++
 test/setup/hugepages.sh | 17 +++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/scripts/setup.sh b/scripts/setup.sh
index 2eba58113..8412e9568 100755
--- a/scripts/setup.sh
+++ b/scripts/setup.sh
@@ -57,6 +57,9 @@ function usage() {
 	echo "                  2048 pages for node0, 512 for node1 and default NRHUGE for node2."
 	echo "HUGEPGSZ          Size of the hugepages to use in kB. If not set, kernel's default"
 	echo "                  setting is used."
+	echo "SHRINK_HUGE       If set to 'yes', hugepages allocation won't be skipped in case"
+	echo "                  number of requested hugepages is lower from what's already"
+	echo "                  allocated. Doesn't apply when HUGE_EVEN_ALLOC is in use."
 	echo "CLEAR_HUGE        If set to 'yes', the attempt to remove hugepages from all nodes will"
 	echo "                  be made prior to allocation".
 	echo "PCI_ALLOWED"
@@ -467,6 +470,13 @@ check_hugepages_alloc() {
 	local hp_int=$1
 	local allocated_hugepages
 
+	allocated_hugepages=$(< "$hp_int")
+
+	if ((NRHUGE <= allocated_hugepages)) && [[ $SHRINK_HUGE != yes ]]; then
+		echo "INFO: Requested $NRHUGE hugepages but $allocated_hugepages already allocated ${2:+on node$2}"
+		return 0
+	fi
+
 	echo $((NRHUGE < 0 ? 0 : NRHUGE)) > "$hp_int"
 
 	allocated_hugepages=$(< "$hp_int")
diff --git a/test/setup/hugepages.sh b/test/setup/hugepages.sh
index d66216bb5..0411c6bdb 100755
--- a/test/setup/hugepages.sh
+++ b/test/setup/hugepages.sh
@@ -186,6 +186,22 @@ custom_alloc() {
 	nr_hugepages=$_nr_hugepages verify_nr_hugepages
 }
 
+no_shrink_alloc() {
+	# Defalut HUGEMEM (2G) alloc on node0
+	# attempt to shrink by half: 2G should remain
+
+	get_test_nr_hugepages $((2048 * 1024)) 0
+
+	# Verify the default first
+	setup
+	verify_nr_hugepages
+
+	# Now attempt to shrink the hp number
+	CLEAR_HUGE=no NRHUGE=$((nr_hugepages / 2)) setup
+	# 2G should remain
+	verify_nr_hugepages
+}
+
 get_nodes
 clear_hp
 
@@ -194,5 +210,6 @@ run_test "per_node_2G_alloc" per_node_2G_alloc
 run_test "even_2G_alloc" even_2G_alloc
 run_test "odd_alloc" odd_alloc
 run_test "custom_alloc" custom_alloc
+run_test "no_shrink_alloc" no_shrink_alloc
 
 clear_hp