[PATCH v5 2/3] workqueue: doc: Add a note saturating the system_wq is not permitted

[Chen Ridong]

From: Chen Ridong <chenridong@xxxxxxxxxx>

If something is expected to generate large number of concurrent works,
it should utilize its own dedicated workqueue rather than system wq.
Because this may saturate system_wq and potentially block other's works.
eg, cgroup release work. Let's document this as a note.

Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx>
---
 Documentation/core-api/workqueue.rst | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/core-api/workqueue.rst b/Documentation/core-api/workqueue.rst
index 16f861c9791e..9de622188f2f 100644
--- a/Documentation/core-api/workqueue.rst
+++ b/Documentation/core-api/workqueue.rst
@@ -357,6 +357,11 @@ Guidelines
   difference in execution characteristics between using a dedicated wq
   and a system wq.
 
+  Note: If something is expected to generate a large number of concurrent
+  works, it should utilize its own dedicated workqueue rather than
+  system wq. Because this may saturate system_wq and potentially lead
+  to deadlock.
+
 * Unless work items are expected to consume a huge amount of CPU
   cycles, using a bound wq is usually beneficial due to the increased
   level of locality in wq operations and work item execution.
-- 
2.34.1