USAGE: Update debugfs prerequisites section

Signed-off-by: SeongJae Park <sj38.park@gmail.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/USAGE.md b/USAGE.md
index 301b99e3..6a34abf0 100644
--- a/USAGE.md
+++ b/USAGE.md
@@ -39,8 +39,9 @@ Kernel
 ------
 
 You should first ensure your system is running on a kernel built with at least
-``CONFIG_DAMON``, ``CONFIG_DAMON_VADDR``, ``CONFIG_DAMON_PADDR``,
-``CONFIG_DAMON_SYSFS``, and ``CONFIG_DAMON_DBGFS``.
+``CONFIG_DAMON``, ``CONFIG_DAMON_VADDR``, ``CONFIG_DAMON_PADDR``, and
+``CONFIG_DAMON_SYSFS``.  Depending on the kernel version, you may need to
+enable ``CONFIG_DAMON_DBGFS`` instead of ``CONFIG_DAMON_SYSFS``.
 
 Sysfs or Debugfs
 ----------------