Messages in this thread | | | Subject | Re: [PATCH 6/6] mm/page_alloc: Introduce vm.percpu_pagelist_high_fraction | From | Dave Hansen <> | Date | Fri, 21 May 2021 15:57:20 -0700 |
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On 5/21/21 3:28 AM, Mel Gorman wrote: > This introduces a new sysctl vm.percpu_pagelist_high_fraction. It is > similar to the old vm.percpu_pagelist_fraction except it only adjusts > pcp->high to potentially reduce zone->lock contention while preserving > allocation latency when PCP lists have to be refilled.
Look at me... Five patches later and I already forgot what the old one did and why it stinks. I wonder if you might do a wee bit of compare and contrast. Something like:
The old vm.percpu_pagelist_fraction increased both the batch and high limits for the per-cpu page allocator. Its worst feature was that it led to absurdly large batch sizes that incurred nasty worst-case allocation latency.
This new sysctl in comparison...
Anyway, the approach looks sound to me. The batch size isn't important now, especially given the auto-scaling in patch 4.
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
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