Messages in this thread | | | Subject | Re: [RFC PATCH 1/2] ipc: introduce obtaining a lockless ipc object | From | Mike Galbraith <> | Date | Sun, 03 Mar 2013 06:53:10 +0100 |
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On Sat, 2013-03-02 at 21:18 -0500, Rik van Riel wrote: > On 03/01/2013 11:32 PM, Michel Lespinasse wrote: > > > I think it may be nicer to take the rcu read lock at the call site > > rather than in ipc_obtain_object(), to make the rcu read lock/unlock > > sites pair up more nicely. Either that or make an inline > > ipc_release_object function that pairs up with ipc_obtain_object() and > > just does an rcu_read_unlock(). > > I started on a patch series to untangle the IPC locking, so > it will be a little more readable, and easier to maintain. > > It is a slower approach than Davidlohr's, as in, it will take > a little longer to put a patch series together, but I hope it > will be easier to debug... > > I hope to post a first iteration of the series by the middle > of next week.
Goody, I'll be watching out for it. I have a big box rt user who uses semaphores in their very tight constraint application. While they're using them carefully, I saw a trace where contention cost vs jitter budget was a bit too high for comfort, and semctl/semop collision.
-Mike
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