[dm-devel] [PATCH] vmalloc: introduce vmap_pfn for persistent memory
Mikulas Patocka
mpatocka at redhat.com
Wed Nov 8 15:21:38 UTC 2017
On Wed, 8 Nov 2017, Christoph Hellwig wrote:
> On Wed, Nov 08, 2017 at 07:33:09AM -0500, Mikulas Patocka wrote:
> > We could use the function clwb() (or arch-independent wrapper dax_flush())
> > - that uses the clflushopt instruction on Broadwell or clwb on Skylake -
> > but it is very slow, write performance on Broadwell is only 350MB/s.
> >
> > So in practice I use the movnti instruction that bypasses cache. The
> > write-combining buffer is flushed with sfence.
>
> And what do you do for an architecture with virtuall indexed caches?
Persistent memory is not supported on such architectures - it is only
supported on x86-64 and arm64.
Mikulas
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