diff options
author | Oleg Nesterov <oleg@tv-sign.ru> | 2007-04-26 15:45:32 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2007-04-26 15:45:32 -0700 |
commit | 071b638689464c6b39407025eedd810d5b5e6f5d (patch) | |
tree | 702b28d1a7acdd7ea904cd442c4491a24b93c059 /Documentation/sysrq.txt | |
parent | 566ec03448052c096dc3982fbe573522dc0ba479 (diff) |
[WORKQUEUE]: cancel_delayed_work: use del_timer() instead of del_timer_sync()
del_timer_sync() buys nothing for cancel_delayed_work(), but it is less
efficient since it locks the timer unconditionally, and may wait for the
completion of the delayed_work_timer_fn().
cancel_delayed_work() == 0 means:
before this patch:
work->func may still be running or queued
after this patch:
work->func may still be running or queued, or
delayed_work_timer_fn->__queue_work() in progress.
The latter doesn't differ from the caller's POV,
delayed_work_timer_fn() is called with _PENDING
bit set.
cancel_delayed_work() == 1 with this patch adds a new possibility:
delayed_work->work was cancelled, but delayed_work_timer_fn
is still running (this is only possible for the re-arming
works on single-threaded workqueue).
In this case the timer was re-started by work->func(), nobody
else can do this. This in turn means that delayed_work_timer_fn
has already passed __queue_work() (and wont't touch delayed_work)
because nobody else can queue delayed_work->work.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/sysrq.txt')
0 files changed, 0 insertions, 0 deletions