kdump-lib: Skip adding reserved memory for small-memory machine

This increased "crashkernel=" raises the risk of OOM conditions in the
production kernel, particularly on small-memory machines that typically
lack such hardware features (Mellanox network cards, SMMU, SME). So we
skip that case.

Signed-off-by: Pingfan Liu <[email protected]>

Author: Pingfan Liu

kdump-lib.sh

@@ -1027,7 +1027,7 @@ kdump_get_arch_recommend_crashkernel()
 	_arch=$(uname -m)
 
 	if [[ $_arch == "x86_64" ]] || [[ $_arch == "s390x" ]]; then
-		_ck_cmdline="2G-64G:256M,64G-:512M"
+		_ck_cmdline="2G-4G:256M,4G-64G:256M,64G-:512M"
 		is_sme_or_sev_active && ((_delta += 64))
 	elif [[ $_arch == "aarch64" ]]; then
 		local _running_kernel
@@ -1062,7 +1062,7 @@ kdump_get_arch_recommend_crashkernel()
 		fi
 	fi
 
-	echo -n "$(_crashkernel_add "$_ck_cmdline" "${_delta}M")"
+	echo -n "$(_crashkernel_add "$_ck_cmdline" "${_delta}M" 1)"
 }
 
 # return recommended size based on current system RAM size