| Message ID | 1412887900-21631-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 594521b..eff358e 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -455,7 +455,7 @@ __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active, alloc_workqueue("%s", WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, \ 1, (name)) #define create_singlethread_workqueue(name) \ - alloc_workqueue("%s", WQ_UNBOUND | WQ_MEM_RECLAIM, 1, (name)) + alloc_ordered_workqueue("%s", WQ_MEM_RECLAIM, name) extern void destroy_workqueue(struct workqueue_struct *wq);
This is a note to let you know that I have just added a patch titled workqueue: apply __WQ_ORDERED to create_singlethread_workqueue() to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue This patch is scheduled to be released in version 3.13.11.9. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.13.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From c89a14f3f8244e0f9c7d81158aeae97e65f90b19 Mon Sep 17 00:00:00 2001 From: Tejun Heo <tj@kernel.org> Date: Sat, 13 Sep 2014 04:14:30 +0900 Subject: workqueue: apply __WQ_ORDERED to create_singlethread_workqueue() commit e09c2c295468476a239d13324ce9042ec4de05eb upstream. create_singlethread_workqueue() is a compat interface for single threaded workqueue which maps to ordered workqueue w/ rescuer in the current implementation. create_singlethread_workqueue() currently implemented by invoking alloc_workqueue() w/ appropriate parameters. 8719dceae2f9 ("workqueue: reject adjusting max_active or applying attrs to ordered workqueues") introduced __WQ_ORDERED to protect ordered workqueues against dynamic attribute changes which can break ordering guarantees but forgot to apply it to create_singlethread_workqueue(). This in itself is okay as nobody currently uses dynamic attribute change on workqueues created with create_singlethread_workqueue(). However, 4c16bd327c ("workqueue: implement NUMA affinity for unbound workqueues") broke singlethreaded guarantee for ordered workqueues through allocating a separate pool_workqueue on each NUMA node by default. A later change 8a2b75384444 ("workqueue: fix ordered workqueues in NUMA setups") fixed it by allocating only one global pool_workqueue if __WQ_ORDERED is set. Combined, the __WQ_ORDERED omission in create_singlethread_workqueue() became critical breaking its single threadedness and ordering guarantee. Let's make create_singlethread_workqueue() wrap alloc_ordered_workqueue() instead so that it inherits __WQ_ORDERED and can implicitly track future ordered_workqueue changes. v2: I missed that __WQ_ORDERED now protects against pwq splitting across NUMA nodes and incorrectly described the patch as a nice-to-have fix to protect against future dynamic attribute usages. Oleg pointed out that this is actually a critical breakage due to 8a2b75384444 ("workqueue: fix ordered workqueues in NUMA setups"). Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Mike Anderson <mike.anderson@us.ibm.com> Cc: Oleg Nesterov <onestero@redhat.com> Cc: Gustavo Luiz Duarte <gduarte@redhat.com> Cc: Tomas Henzl <thenzl@redhat.com> Fixes: 4c16bd327c ("workqueue: implement NUMA affinity for unbound workqueues") Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- include/linux/workqueue.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 1.9.1