Messages in this thread | | | Date | Fri, 13 Dec 2019 19:47:59 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 4/5] locking/lockdep: Reuse free chain_hlocks entries |
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On Fri, Dec 13, 2019 at 01:35:05PM -0500, Waiman Long wrote: > On 12/13/19 1:12 PM, Peter Zijlstra wrote: > >> In this way, the wasted space will be k bytes where k is the number of > >> 1-entry chains. I don't think merging adjacent blocks will be that > >> useful at this point. We can always add this capability later on if it > >> is found to be useful. > > I'm thinking 1 entry isn't much of a chain. My brain is completely fried > > atm, but are we really storing single entry 'chains' ? It seems to me we > > could skip that. > > > Indeed, the current code can produce a 1-entry chain. I also thought > that a chain had to be at least 2 entries. I got tripped up assuming > that. It could be a bug somewhere that allow a 1-entry chain to happen, > but I am not focusing on that right now.
If we need the minimum 2 entry granularity, it might make sense to spend a little time on that. If we can get away with single entry markers, then maybe write a comment so we'll not forget about it.
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