Merge tag 'wq-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

Pull workqueue updates from Tejun Heo:

 - New default WQ_AFFN_CACHE_SHARD affinity scope subdivides LLCs into
   smaller shards to improve scalability on machines with many CPUs per
   LLC

 - Misc:
    - system_dfl_long_wq for long unbound works
    - devm_alloc_workqueue() for device-managed allocation
    - sysfs exposure for ordered workqueues and the EFI workqueue
    - removal of HK_TYPE_WQ from wq_unbound_cpumask
    - various small fixes

* tag 'wq-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (21 commits)
  workqueue: validate cpumask_first() result in llc_populate_cpu_shard_id()
  workqueue: use NR_STD_WORKER_POOLS instead of hardcoded value
  workqueue: avoid unguarded 64-bit division
  docs: workqueue: document WQ_AFFN_CACHE_SHARD affinity scope
  workqueue: add test_workqueue benchmark module
  tools/workqueue: add CACHE_SHARD support to wq_dump.py
  workqueue: set WQ_AFFN_CACHE_SHARD as the default affinity scope
  workqueue: add WQ_AFFN_CACHE_SHARD affinity scope
  workqueue: fix typo in WQ_AFFN_SMT comment
  workqueue: Remove HK_TYPE_WQ from affecting wq_unbound_cpumask
  workqueue: unlink pwqs from wq->pwqs list in alloc_and_link_pwqs() error path
  workqueue: Remove NULL wq WARN in __queue_delayed_work()
  workqueue: fix parse_affn_scope() prefix matching bug
  workqueue: devres: Add device-managed allocate workqueue
  workqueue: Add system_dfl_long_wq for long unbound works
  tools/workqueue/wq_dump.py: add NODE prefix to all node columns
  tools/workqueue/wq_dump.py: fix column alignment in node_nr/max_active section
  tools/workqueue/wq_dump.py: remove backslash separator from node_nr/max_active header
  efi: Allow to expose the workqueue via sysfs
  workqueue: Allow to expose ordered workqueues via sysfs
  ...

3 files changed, 16 insertions, 5 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index f2ce1f4975c1..b9a2c649e411 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -8543,7 +8543,8 @@ Kernel parameters
         workqueue.default_affinity_scope=
 			Select the default affinity scope to use for unbound
 			workqueues. Can be one of "cpu", "smt", "cache",
-			"numa" and "system". Default is "cache". For more
+			"cache_shard", "numa" and "system". Default is
+			"cache_shard". For more
 			information, see the Affinity Scopes section in
 			Documentation/core-api/workqueue.rst.
 
diff --git a/Documentation/core-api/workqueue.rst b/Documentation/core-api/workqueue.rst
index 165ca73e8351..411e1b28b8de 100644
--- a/Documentation/core-api/workqueue.rst
+++ b/Documentation/core-api/workqueue.rst
@@ -378,9 +378,9 @@ Affinity Scopes
 
 An unbound workqueue groups CPUs according to its affinity scope to improve
 cache locality. For example, if a workqueue is using the default affinity
-scope of "cache", it will group CPUs according to last level cache
-boundaries. A work item queued on the workqueue will be assigned to a worker
-on one of the CPUs which share the last level cache with the issuing CPU.
+scope of "cache_shard", it will group CPUs into sub-LLC shards. A work item
+queued on the workqueue will be assigned to a worker on one of the CPUs
+within the same shard as the issuing CPU.
 Once started, the worker may or may not be allowed to move outside the scope
 depending on the ``affinity_strict`` setting of the scope.
 
@@ -402,7 +402,13 @@ Workqueue currently supports the following affinity scopes.
 ``cache``
   CPUs are grouped according to cache boundaries. Which specific cache
   boundary is used is determined by the arch code. L3 is used in a lot of
-  cases. This is the default affinity scope.
+  cases.
+
+``cache_shard``
+  CPUs are grouped into sub-LLC shards of at most ``wq_cache_shard_size``
+  cores (default 8, tunable via the ``workqueue.cache_shard_size`` boot
+  parameter). Shards are always split on core (SMT group) boundaries.
+  This is the default affinity scope.
 
 ``numa``
   CPUs are grouped according to NUMA boundaries.
diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index 7d2b897d66fa..017fb155a5bc 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -464,3 +464,7 @@ SPI
 
 WATCHDOG
   devm_watchdog_register_device()
+
+WORKQUEUE
+  devm_alloc_workqueue()
+  devm_alloc_ordered_workqueue()