Messages in this thread | | | Date | Sat, 2 Mar 2013 18:01:45 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH] lglock: add read-preference local-global rwlock |
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On 03/02, Lai Jiangshan wrote: > > On 02/03/13 02:28, Oleg Nesterov wrote: > > Lai, I didn't read this discussion except the code posted by Michel. > > I'll try to read this patch carefully later, but I'd like to ask > > a couple of questions. > > > > This version looks more complex than Michel's, why? Just curious, I > > am trying to understand what I missed. See > > http://marc.info/?l=linux-kernel&m=136196350213593 > > Michel changed my old draft version a little, his version is good enough for me.
Yes, I see. But imho Michel suggested the valuable cleanup, the code becomes even more simple with the same perfomance.
Your v2 looks almost correct to me, but I still think it makes sense to incorporate the simplification from Michel.
> My new version tries to add a little better nestable support with only > adding single __this_cpu_op() in _read_[un]lock().
How? Afaics with or without FALLBACK_BASE you need _reed + _inc/dec in _read_lock/unlock.
Oleg.
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