Messages in this thread | | | Subject | Re: [RFC][PATCH 2/5] [PATCH 2/5] proc: introduce /proc/PID/idle_bitmap | From | Dave Hansen <> | Date | Thu, 6 Sep 2018 07:12:39 -0700 |
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On 09/01/2018 04:28 AM, Fengguang Wu wrote: > To walk 1TB memory of 4k active pages, it costs 2s vs 15s system > time to scan the per-task/global idle bitmaps.
To me, that says this interface simply won't work on large systems. 2s and 15s are both simply unacceptably long.
> OTOH, the per-task idle bitmap is not suitable in some situations: > > - not accurate for shared pages > - don't work with non-mapped file pages > - don't perform well for sparse page tables (pointed out by Huang Ying)
OK, so we have a new ABI that doesn't work on large systems, consumes lots of time and resources to query and isn't suitable in quite a few situations.
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