Messages in this thread | | | Date | Sat, 18 Oct 2014 13:22:07 -0400 | From | Matthew Wilcox <> | Subject | Re: [PATCH v11 04/21] mm: Allow page fault handlers to perform the COW |
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On Fri, Oct 17, 2014 at 03:35:01PM +0000, Mathieu Desnoyers wrote: > > > The page fault handler being very much performance sensitive, I'm > > > wondering if it would not be better to move cow_page near the end of > > > struct vm_fault, so that the "page" field can stay on the first > > > cache line. > > Although it's pretty much always true that recent architectures L2 cache > lines are 64 bytes, I was more thinking about L1 cache lines, which are, > at least on moderately old Intel Pentium HW, 32 bytes in size (AFAIK > Pentium II and III). > > It remains to be seen whether we care about performance that much on this > kind of HW though.
Oh, I just remembered ... this data structure is on the stack, so if it's not cache-hot, something has gone horribly wrong.
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