Messages in this thread | | | Date | Tue, 29 May 2012 18:51:57 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 7/7] uprobes: kill uprobes_srcu/uprobe_srcu_id |
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On Wed, May 30, 2012 at 01:04:47AM +0200, Peter Zijlstra wrote: > On Tue, 2012-05-29 at 21:30 +0200, Oleg Nesterov wrote: > > Kill the no longer needed uprobes_srcu/uprobe_srcu_id code. > > > > It doesn't really work anyway. synchronize_srcu() can only synchronize > > with the code "inside" the srcu_read_lock/srcu_read_unlock section, > > while uprobe_pre_sstep_notifier() does srcu_read_lock() _after_ we > > already hit the breakpoint. > > > > I guess this probably works "in practice". synchronize_srcu() is slow > > and it implies synchronize_sched(), and the probed task enters the non- > > preemptible section at the start of exception handler. Still this is not > > right at least in theory, and task->uprobe_srcu_id blows task_struct. > > This kills the only user of srcu_read_{,un}lock_raw(), so I guess we > could also make: > > 9ceae0e2 > 101db7b4 > 0c53dd8b > > go away..
If it is still unused in a few months, I will get rid of them.
Thanx, Paul
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