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SubjectRe: [RFC] Reimplementation of linux dynamic percpu memory allocator
Ravikiran G Thirumalai wrote:

>Hmmm..I knew from some experiments earlier that access to per cpu versions
>of memory was slow with the slab based implementation -- which this patch
>addresses, but I didn't know allocs themselves were slow...
>Creation of a disk should not be a fast path no?
>
>
No, not fast path. But it can happen a few thousand times. The slab
implementation failed due to heavy internal fragmentation. If your code
runs fine with a few thousand users, then there shouldn't be a problem.

>>>
>>>
>>That means no large pte entries for the per-cpu allocations, right?
>>I think that's a bad idea for non-numa systems. What about a fallback to
>>simple getfreepages() for non-numa systems?
>>
>>
>
>Can we have large pte entries with PAGE_SIZEd pages?
>
>
>
For non-NUMA systems, I would use get_free_pages() to allocate a
multi-page area instead of map_vm_area(). Typically, get_free_pages() is
backed by large pte memory and map_vm_area() by normal virtual memory.

--
Manfred
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