[PATCH v2 sched_ext/for-7.2] sched_ext: Documentation: clarify arena-backed doubly-linked lists in scx_qmap

[PATCH v2 sched_ext/for-7.2] sched_ext: Documentation: clarify arena-backed doubly-linked lists in scx_qmap

[Cheng-Yang Chou]

Update scx_qmap description to reflect arena-backed doubly-linked
lists with per-queue bpf_res_spin_lock.

Also update scx_qmap.bpf.c to reflect switch from PIDs to TIDs.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
---
Changes in v2:
- Clarify scx_qmap uses arena-backed doubly-linked lists with per-queue
  bpf_res_spin_lock. (Tejun Heo)
- Update scx_qmap.bpf.c comment to TID-based queueing.
- Link to v1:
  https://lore.kernel.org/r/20260418120058.1555036-1-yphbchou0911@gmail.com/

 Documentation/scheduler/sched-ext.rst | 2 +-
 tools/sched_ext/README.md             | 6 +++---
 tools/sched_ext/scx_qmap.bpf.c        | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/Documentation/scheduler/sched-ext.rst b/Documentation/scheduler/sched-ext.rst
index 03d595d178ea..aa030fc1a59a 100644
--- a/Documentation/scheduler/sched-ext.rst
+++ b/Documentation/scheduler/sched-ext.rst
@@ -503,7 +503,7 @@ Where to Look
     custom DSQ.
 
   * ``scx_qmap[.bpf].c``: A multi-level FIFO scheduler supporting five
-    levels of priority implemented with ``BPF_MAP_TYPE_QUEUE``.
+    levels of priority implemented with arena-backed doubly-linked lists.
 
   * ``scx_central[.bpf].c``: A central FIFO scheduler where all scheduling
     decisions are made on one CPU, demonstrating ``LOCAL_ON`` dispatching,
diff --git a/tools/sched_ext/README.md b/tools/sched_ext/README.md
index 6e282bce453c..0ee5a3d997e5 100644
--- a/tools/sched_ext/README.md
+++ b/tools/sched_ext/README.md
@@ -168,9 +168,9 @@ well on single-socket systems with a unified L3 cache.
 
 Another simple, yet slightly more complex scheduler that provides an example of
 a basic weighted FIFO queuing policy. It also provides examples of some common
-useful BPF features, such as sleepable per-task storage allocation in the
-`ops.prep_enable()` callback, and using the `BPF_MAP_TYPE_QUEUE` map type to
-enqueue tasks. It also illustrates how core-sched support could be implemented.
+useful BPF features, such as arena-backed doubly-linked lists threaded through
+per-task context and `bpf_res_spin_lock` for per-queue synchronization. It also
+illustrates how core-sched support could be implemented.
 
 ## scx_central
 
diff --git a/tools/sched_ext/scx_qmap.bpf.c b/tools/sched_ext/scx_qmap.bpf.c
index 2f4c45f6544d..a73a2dcbaeb7 100644
--- a/tools/sched_ext/scx_qmap.bpf.c
+++ b/tools/sched_ext/scx_qmap.bpf.c
@@ -10,7 +10,7 @@
  *
  * This scheduler demonstrates:
  *
- * - BPF-side queueing using PIDs.
+ * - BPF-side queueing using TIDs.
  * - BPF arena for scheduler state.
  * - Core-sched support.
  *
-- 
2.48.1

Re: [PATCH v2 sched_ext/for-7.2] sched_ext: Documentation: clarify arena-backed doubly-linked lists in scx_qmap

[Tejun Heo]

Hello,

Applied to sched_ext/for-7.2.

Thanks.
--
tejun