From 0ee281e1e4e12f8c09b99f80a2482a55cd7d6bca Mon Sep 17 00:00:00 2001 From: Leo Yan Date: Mon, 19 Oct 2020 08:36:13 +0800 Subject: [PATCH] perf mem2node: Improve warning if detected no memory nodes Some archs (e.g. x86 and Arm64) don't enable the configuration CONFIG_MEMORY_HOTPLUG by default, if this configuration is not enabled when build the kernel image, the SysFS for memory nodes will be missed. This results in perf tool has no chance to catpure the memory nodes information, when perf tool reports the result and detects no memory nodes, it outputs "assertion failed at util/mem2node.c:99". The output log doesn't give out reason for the failure and users have no clue for how to fix it. This patch changes to use explicit way for warning: it tells user that detected no memory nodes and suggests to enable CONFIG_MEMORY_HOTPLUG for kernel building. Signed-off-by: Leo Yan Acked-by: Jiri Olsa Link: https://lore.kernel.org/r/20201019003613.8399-1-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/mem2node.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/mem2node.c b/tools/perf/util/mem2node.c index c84f584..03a7d7b 100644 --- a/tools/perf/util/mem2node.c +++ b/tools/perf/util/mem2node.c @@ -96,7 +96,8 @@ int mem2node__init(struct mem2node *map, struct perf_env *env) /* Cut unused entries, due to merging. */ tmp_entries = realloc(entries, sizeof(*entries) * j); - if (tmp_entries || WARN_ON_ONCE(j == 0)) + if (tmp_entries || + WARN_ONCE(j == 0, "No memory nodes, is CONFIG_MEMORY_HOTPLUG enabled?\n")) entries = tmp_entries; for (i = 0; i < j; i++) { -- 2.7.4