Messages in this thread | | | Date | Thu, 26 Apr 2018 14:24:06 +0100 | From | Stefan Hajnoczi <> | Subject | Re: [RFC v2] qemu: Add virtio pmem device |
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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
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