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Date: Thu, 31 May 2018 15:28:56 +0100
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Message-ID: <20180531142856.GA2936@work-vm>
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Subject: Re: [Qemu-devel] [PATCH V5 0/9] nvdimm: guarantee persistence of
 QEMU writes to persistent memory
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: junyan.he@gmx.com, qemu-devel@nongnu.org, Haozhong Zhang <haozhong.zhang@intel.com>, xiaoguangrong.eric@gmail.com, crosthwaite.peter@gmail.com, mst@redhat.com, ehabkost@redhat.com, quintela@redhat.com, Junyan He <junyan.he@intel.com>, stefanha@redhat.com, pbonzini@redhat.com, imammedo@redhat.com, rth@twiddle.net

* Stefan Hajnoczi (stefanha@gmail.com) wrote:
> David Gilbert previously suggested a memory access interface.  I guess
> it would look something like this:
> 
>   typedef struct {
>       void (*memset)(void *s, int c, size_t n);
>       void (*memcpy)(void *dest, const void *src, size_t n);
>   } MemoryOperations;
> 
> That way code doesn't need if (pmem) A else B.  It can just do
> mem_ops->foo().  Have you looked into this idea?

Yep, it really needs to be less invasive in the migration code;
I think a set of ops like that would make it much less painful.

> Also, there was a discussion about leaving the code unchanged but adding
> an nvdimm_flush() call at the very end of migration.  I think someone
> benchmarked it but can't find the email.  Please post a link or
> summarize the results, because that approach would be much less
> invasive.  Thanks!

Dave

> Stefan


--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK