lkml.org 
[lkml]   [2018]   [Apr]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC v2] qemu: Add virtio pmem device
On Wed, Apr 25, 2018 at 04:54:15PM +0530, Pankaj Gupta wrote:
> +static void virtio_pmem_flush(VirtIODevice *vdev, VirtQueue *vq)
> +{
> + VirtQueueElement *elem;
> + VirtIOPMEM *pmem = VIRTIO_PMEM(vdev);
> + HostMemoryBackend *backend = MEMORY_BACKEND(pmem->memdev);
> + int fd = memory_region_get_fd(&backend->mr);
> +
> + elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
> + if (!elem) {
> + return;
> + }
> + /* flush raw backing image */
> + fsync(fd);

fsync(2) is a blocking syscall. This can hang QEMU for an unbounded
amount of time.

Please do the fsync from a thread pool. See block/file-posix.c's
aio_worker() for an example.

> +static void virtio_pmem_get_config(VirtIODevice *vdev, uint8_t *config)
> +{
> + VirtIOPMEM *pmem = VIRTIO_PMEM(vdev);
> + struct virtio_pmem_config *pmemcfg = (struct virtio_pmem_config *) config;
> +
> + pmemcfg->start = pmem->start;
> + pmemcfg->size = pmem->size;

Endianness. Please use virtio_st*_p() instead.

> +#define VIRTIO_PMEM_PLUG 0

What is this?
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2018-04-26 15:45    [W:0.195 / U:0.180 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site