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| author | Tejun Heo <tj@kernel.org> | 2012-08-08 20:38:42 +0400 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2012-08-14 03:27:55 +0400 |
| commit | 1265057fa02c7bed3b6d9ddc8a2048065a370364 (patch) | |
| tree | b10e631ca6157103fcc71188e972b06e18c3570f /include/linux/workqueue.h | |
| parent | 41f63c5359d14ca995172b8f6eaffd93f60fec54 (diff) | |
| download | linux-1265057fa02c7bed3b6d9ddc8a2048065a370364.tar.xz | |
workqueue: fix CPU binding of flush_delayed_work[_sync]()
delayed_work encodes the workqueue to use and the last CPU in
delayed_work->work.data while it's on timer. The target CPU is
implicitly recorded as the CPU the timer is queued on and
delayed_work_timer_fn() queues delayed_work->work to the CPU it is
running on.
Unfortunately, this leaves flush_delayed_work[_sync]() no way to find
out which CPU the delayed_work was queued for when they try to
re-queue after killing the timer. Currently, it chooses the local CPU
flush is running on. This can unexpectedly move a delayed_work queued
on a specific CPU to another CPU and lead to subtle errors.
There isn't much point in trying to save several bytes in struct
delayed_work, which is already close to a hundred bytes on 64bit with
all debug options turned off. This patch adds delayed_work->cpu to
remember the CPU it's queued for.
Note that if the timer is migrated during CPU down, the work item
could be queued to the downed global_cwq after this change. As a
detached global_cwq behaves like an unbound one, this doesn't change
much for the delayed_work.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/workqueue.h')
| -rw-r--r-- | include/linux/workqueue.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 20000305a8a6..b14d5d59af7c 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -102,6 +102,7 @@ struct work_struct { struct delayed_work { struct work_struct work; struct timer_list timer; + int cpu; }; static inline struct delayed_work *to_delayed_work(struct work_struct *work) |