Messages in this thread | | | Date | Mon, 25 Jul 2016 13:41:32 -0400 | From | Tejun Heo <> | Subject | Re: [PATCH v4 0/5] vfs: Use dlock list for SB's s_inodes list |
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Hello, Christoph.
On Mon, Jul 25, 2016 at 08:48:25AM -0500, Christoph Lameter wrote: > On Fri, 22 Jul 2016, Waiman Long wrote: > > > - Add a new patch to make the percpu head structure cacheline aligned > > to prevent cacheline contention from disrupting the performance > > of nearby percpu variables. > > It would be better not to use the percpu allocation etc for this. > Given the frequency of off node data access I would say that the data > structure does not qualify as per cpu data. You have per cpu data items > yes but this is not used as per cpu data.
I don't get it. What's the harm of using percpu memory here? Other percpu data structures have remote access too. They're to a lower degree but I don't see a clear demarcation line and making addtions per-cpu seems to have significant benefits here. If there's a better way of splitting the list and locking, sure, let's try that but short of that I don't see anything wrong with doing this per-cpu.
Thanks.
-- tejun
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