Re: [PATCH] Documentation/x86: Update split lock documentation

From: Fenghua Yu
Date: Wed Mar 15 2023 - 19:13:32 EST


Hi, Tony,

On 3/15/23 15:57, Tony Luck wrote:
commit b041b525dab9 ("x86/split_lock: Make life miserable for split
lockers") added a delay and serialization of cplit locks. Commit
s/cplit/split/

727209376f49 ("x86/split_lock: Add sysctl to control the misery mode")
provided a sysctl to turn off the misery.

Update the split lock documentation to describe the current state of
the code.

Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
---
Documentation/x86/buslock.rst | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/Documentation/x86/buslock.rst b/Documentation/x86/buslock.rst
index 7c051e714943..31ec0ef78086 100644
--- a/Documentation/x86/buslock.rst
+++ b/Documentation/x86/buslock.rst
@@ -53,8 +53,14 @@ parameter "split_lock_detect". Here is a summary of different options:
|off |Do nothing |Do nothing |
+------------------+----------------------------+-----------------------+
|warn |Kernel OOPs |Warn once per task and |
-|(default) |Warn once per task and |and continues to run. |
-| |disable future checking | |
+|(default) |Warn once per task, add a |and continues to run. |
+| |delay, add synchronization | |
+| |to prevent more than one | |
+| |core from executing a | |
+| |split lock in parallel. | |
+| |sysctl split_lock_mitigate | |
+| |can be used to avoid the | |
+| |delay and synchronization | |
| |When both features are | |
| |supported, warn in #AC | |
+------------------+----------------------------+-----------------------+

Other than the typo, looks good to me.

Thanks.

-Fenghua