Thread (115 messages) 115 messages, 11 authors, 2013-03-05

Re: [PATCH V2] lglock: add read-preference local-global rwlock

From: Michel Lespinasse <hidden>
Date: 2013-03-05 01:37:14
Also in: linux-arch, linux-arm-kernel, linux-pm, lkml, netdev

On Sun, Mar 3, 2013 at 9:40 AM, Oleg Nesterov [off-list ref] wrote:
quoted
However, I still think that FALLBACK_BASE only adds the unnecessary
complications. But even if I am right this is subjective of course, please
feel free to ignore.
Would it help if I sent out that version (without FALLBACK_BASE) as a
formal proposal ?
Hmm. But then I do not understand the lglock annotations. Obviously,
rwlock_acquire_read() in lg_local_lock() can't even detect the simplest
deadlock, say, lg_local_lock(LOCK) + lg_local_lock(LOCK). Not to mention
spin_lock(X) + lg_local_lock(Y) vs lg_local_lock(Y) + spin_lock(X).

OK, I understand that it is not easy to make these annotations correct...
I am going to send out a proposal to fix the existing lglock
annotations and detect the two cases you noticed. It's actually not
that hard :)

-- 
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.
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