diff options
author | Oleg Nesterov <oleg@tv-sign.ru> | 2007-05-09 02:34:09 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-09 12:30:52 -0700 |
commit | 3af24433efac62f451bfdb1cf1edb7181fb73645 (patch) | |
tree | 330353b50a88615ef6e99440e8412667ae0a855e /scripts/patch-kernel | |
parent | 36aa9dfc39bf473780439f5629c30f59d677e793 (diff) |
workqueue: don't migrate pending works from the dead CPU
Currently CPU_DEAD uses kthread_stop() to stop cwq->thread and then
transfers cwq->worklist to another CPU. However, it is very unlikely that
worker_thread() will notice kthread_should_stop() before flushing
cwq->worklist. It is only possible if worker_thread() was preempted after
run_workqueue(cwq), a new work_struct was added, and CPU_DEAD happened
before cwq->thread has a chance to run.
This means that take_over_work() mostly adds unneeded complications. Note
also that kthread_stop() is not good per se, wake_up_process() may confuse
work->func() if it sleeps waiting for some event.
Remove take_over_work() and migrate_sequence complications. CPU_DEAD sets
the cwq->should_stop flag (introduced by this patch) and waits for
cwq->thread to flush cwq->worklist and exit. Because the dead CPU is not
on cpu_online_map, no more works can be added to that cwq.
cpu_populated_map was introduced to optimize for_each_possible_cpu(), it is
not strictly needed, and it is more a documentation in fact.
Saves 418 bytes.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: Gautham shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'scripts/patch-kernel')
0 files changed, 0 insertions, 0 deletions