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| author | Tejun Heo <tj@kernel.org> | 2024-02-06 01:19:10 +0100 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2024-02-06 01:19:10 +0100 |
| commit | 3bc1e711c26bff01d41ad71145ecb8dcb4412576 (patch) | |
| tree | 9883e58019879774666327e8b69f9dd1fd48ca19 /include | |
| parent | workqueue: Skip __WQ_DESTROYING workqueues when updating global unbound cpumask (diff) | |
| download | linux-3bc1e711c26bff01d41ad71145ecb8dcb4412576.tar.xz linux-3bc1e711c26bff01d41ad71145ecb8dcb4412576.zip | |
workqueue: Don't implicitly make UNBOUND workqueues w/ @max_active==1 ordered
5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered")
automoatically promoted UNBOUND workqueues w/ @max_active==1 to ordered
workqueues because UNBOUND workqueues w/ @max_active==1 used to be the way
to create ordered workqueues and the new NUMA support broke it. These
problems can be subtle and the fact that they can only trigger on NUMA
machines made them even more difficult to debug.
However, overloading the UNBOUND allocation interface this way creates other
issues. It's difficult to tell whether a given workqueue actually needs to
be ordered and users that legitimately want a min concurrency level wq
unexpectedly gets an ordered one instead. With planned UNBOUND workqueue
udpates to improve execution locality and more prevalence of chiplet designs
which can benefit from such improvements, this isn't a state we wanna be in
forever.
There aren't that many UNBOUND w/ @max_active==1 users in the tree and the
preceding patches audited all and converted them to
alloc_ordered_workqueue() as appropriate. This patch removes the implicit
promotion of UNBOUND w/ @max_active==1 workqueues to ordered ones.
v2: v1 patch incorrectly dropped !list_empty(&wq->pwqs) condition in
apply_workqueue_attrs_locked() which spuriously triggers WARNING and
fails workqueue creation. Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202304251050.45a5df1f-oliver.sang@intel.com
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/workqueue.h | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 283d7891b4c4..4ba33cf07f11 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -392,7 +392,6 @@ enum wq_flags { __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */ __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */ __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */ - __WQ_ORDERED_EXPLICIT = 1 << 19, /* internal: alloc_ordered_workqueue() */ /* BH wq only allows the following flags */ __WQ_BH_ALLOWS = WQ_BH | WQ_HIGHPRI, @@ -507,8 +506,7 @@ alloc_workqueue(const char *fmt, unsigned int flags, int max_active, ...); * Pointer to the allocated workqueue on success, %NULL on failure. */ #define alloc_ordered_workqueue(fmt, flags, args...) \ - alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | \ - __WQ_ORDERED_EXPLICIT | (flags), 1, ##args) + alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args) #define create_workqueue(name) \ alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name)) |