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From: Stefan Hajnoczi <stefanha@gmail.com>
To: Pankaj Gupta <pagupta@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	qemu-devel@nongnu.org, linux-nvdimm@ml01.01.org,
	linux-mm@kvack.org, jack@suse.cz, stefanha@redhat.com,
	dan.j.williams@intel.com, riel@surriel.com,
	haozhong.zhang@intel.com, nilal@redhat.com, kwolf@redhat.com,
	pbonzini@redhat.com, ross.zwisler@intel.com, david@redhat.com,
	xiaoguangrong.eric@gmail.com, hch@infradead.org,
	marcel@redhat.com, mst@redhat.com, niteshnarayanlal@hotmail.com,
	imammedo@redhat.com, lcapitulino@redhat.com
Subject: Re: [RFC v2 2/2] pmem: device flush over VIRTIO
Date: Thu, 26 Apr 2018 14:15:17 +0100	[thread overview]
Message-ID: <20180426131517.GB30991@stefanha-x1.localdomain> (raw)
In-Reply-To: <20180425112415.12327-3-pagupta@redhat.com>

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On Wed, Apr 25, 2018 at 04:54:14PM +0530, Pankaj Gupta wrote:
> This patch adds functionality to perform 
> flush from guest to hosy over VIRTIO 
> when 'ND_REGION_VIRTIO'flag is set on 
> nd_negion. Flag is set by 'virtio-pmem'
> driver.
> 
> Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
> ---
>  drivers/nvdimm/region_devs.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
> index a612be6..6c6454e 100644
> --- a/drivers/nvdimm/region_devs.c
> +++ b/drivers/nvdimm/region_devs.c
> @@ -20,6 +20,7 @@
>  #include <linux/nd.h>
>  #include "nd-core.h"
>  #include "nd.h"
> +#include <linux/virtio_pmem.h>
>  
>  /*
>   * For readq() and writeq() on 32-bit builds, the hi-lo, lo-hi order is
> @@ -1074,6 +1075,12 @@ void nvdimm_flush(struct nd_region *nd_region)
>  	struct nd_region_data *ndrd = dev_get_drvdata(&nd_region->dev);
>  	int i, idx;
>  
> +       /* call PV device flush */
> +	if (test_bit(ND_REGION_VIRTIO, &nd_region->flags)) {
> +		virtio_pmem_flush(&nd_region->dev);
> +		return;
> +	}

How does libnvdimm know when flush has completed?

Callers expect the flush to be finished when nvdimm_flush() returns but
the virtio driver has only queued the request, it hasn't waited for
completion!

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  parent reply	other threads:[~2018-04-26 13:15 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-25 11:24 [RFC v2 0/2] kvm "fake DAX" device flushing Pankaj Gupta
2018-04-25 11:24 ` [RFC v2 1/2] virtio: add pmem driver Pankaj Gupta
2018-04-25 14:21   ` Dan Williams
2018-04-25 14:43     ` Dan Williams
2018-04-26 12:27       ` Jeff Moyer
2018-04-26 17:15         ` [Qemu-devel] " Pankaj Gupta
2018-04-26 17:24           ` Jeff Moyer
2018-04-25 14:52   ` Michael S. Tsirkin
2018-04-25 15:11     ` [Qemu-devel] " Pankaj Gupta
2018-04-26 13:12   ` Stefan Hajnoczi
2018-04-26 15:44     ` Pankaj Gupta
2018-04-27 13:31       ` Stefan Hajnoczi
2018-04-28 10:48         ` Pankaj Gupta
2018-04-25 11:24 ` [RFC v2 2/2] pmem: device flush over VIRTIO Pankaj Gupta
2018-04-25 14:23   ` Dan Williams
2018-04-25 14:47     ` Pankaj Gupta
2018-04-26 13:15   ` Stefan Hajnoczi [this message]
2018-04-26 16:40     ` Pankaj Gupta
2018-04-26 16:57       ` Dan Williams
2018-04-26 17:13         ` Pankaj Gupta
2018-04-25 11:24 ` [RFC v2] qemu: Add virtio pmem device Pankaj Gupta
2018-04-25 11:35   ` [Qemu-devel] " no-reply
2018-04-25 11:58     ` Pankaj Gupta
2018-04-25 14:23       ` Eric Blake
2018-04-25 14:51         ` Pankaj Gupta
2018-04-25 11:46   ` no-reply
2018-04-25 14:25   ` Eric Blake
2018-04-25 14:55     ` Pankaj Gupta
2018-04-26 13:24   ` Stefan Hajnoczi
2018-04-26 16:43     ` [Qemu-devel] " Pankaj Gupta
2018-06-01 12:24 ` [Qemu-devel] [RFC v2 0/2] kvm "fake DAX" device flushing Igor Mammedov
2018-06-04  5:56   ` Pankaj Gupta
2018-06-04  9:55   ` David Hildenbrand

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