| Message ID | 20220823053820.35499-1-fengli@smartx.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vhost: reduce the set_mem_table call frenquency | expand |
Sorry, looks like I use the old qemu code, master has fix this issue. Just ignore this patch. > 2022年8月23日 下午1:38，Li Feng <fengli@smartx.com> 写道： > > If the vhost memory layout doesn't change, don't need to call the vhost > backend. > The set_mem_table is time consuming when sending to vhost-user backend. > > On aarch64, the edk2 uefi firmware will write the pflash which will > trigger the vhost_commit hundreds of times. > > Signed-off-by: Li Feng <fengli@smartx.com> > --- > hw/virtio/vhost.c | 14 ++++++++++++++ > include/hw/virtio/vhost.h | 2 ++ > 2 files changed, 16 insertions(+) > > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c > index f758f177bb..848d2f20d6 100644 > --- a/hw/virtio/vhost.c > +++ b/hw/virtio/vhost.c > @@ -523,6 +523,11 @@ static void vhost_commit(MemoryListener *listener) > /* Rebuild the regions list from the new sections list */ > regions_size = offsetof(struct vhost_memory, regions) + > dev->n_mem_sections * sizeof dev->mem->regions[0]; > + if (dev->mem && dev->started) { > + g_free(dev->old_mem); > + dev->old_mem = dev->mem; > + dev->mem = NULL; > + } > dev->mem = g_realloc(dev->mem, regions_size); > dev->mem->nregions = dev->n_mem_sections; > used_memslots = dev->mem->nregions; > @@ -542,6 +547,12 @@ static void vhost_commit(MemoryListener *listener) > goto out; > } > > + if (dev->old_mem && dev->regions_size == regions_size && > + memcmp(dev->mem, dev->old_mem, dev->regions_size) == 0) { > + goto out; > + } > + > + dev->regions_size = regions_size; > for (i = 0; i < dev->mem->nregions; i++) { > if (vhost_verify_ring_mappings(dev, > (void *)(uintptr_t)dev->mem->regions[i].userspace_addr, > @@ -1445,6 +1456,8 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque, > hdev->mem = g_malloc0(offsetof(struct vhost_memory, regions)); > hdev->n_mem_sections = 0; > hdev->mem_sections = NULL; > + hdev->old_mem = NULL; > + hdev->regions_size = 0; > hdev->log = NULL; > hdev->log_size = 0; > hdev->log_enabled = false; > @@ -1491,6 +1504,7 @@ void vhost_dev_cleanup(struct vhost_dev *hdev) > } > g_free(hdev->mem); > g_free(hdev->mem_sections); > + g_free(hdev->old_mem); > if (hdev->vhost_ops) { > hdev->vhost_ops->vhost_backend_cleanup(hdev); > } > diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h > index a346f23d13..b1d7287099 100644 > --- a/include/hw/virtio/vhost.h > +++ b/include/hw/virtio/vhost.h > @@ -73,6 +73,8 @@ struct vhost_dev { > MemoryListener memory_listener; > MemoryListener iommu_listener; > struct vhost_memory *mem; > + struct vhost_memory *old_mem; > + int regions_size; > int n_mem_sections; > MemoryRegionSection *mem_sections; > int n_tmp_sections; > -- > 2.37.2 >
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index f758f177bb..848d2f20d6 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -523,6 +523,11 @@ static void vhost_commit(MemoryListener *listener) /* Rebuild the regions list from the new sections list */ regions_size = offsetof(struct vhost_memory, regions) + dev->n_mem_sections * sizeof dev->mem->regions[0]; + if (dev->mem && dev->started) { + g_free(dev->old_mem); + dev->old_mem = dev->mem; + dev->mem = NULL; + } dev->mem = g_realloc(dev->mem, regions_size); dev->mem->nregions = dev->n_mem_sections; used_memslots = dev->mem->nregions; @@ -542,6 +547,12 @@ static void vhost_commit(MemoryListener *listener) goto out; } + if (dev->old_mem && dev->regions_size == regions_size && + memcmp(dev->mem, dev->old_mem, dev->regions_size) == 0) { + goto out; + } + + dev->regions_size = regions_size; for (i = 0; i < dev->mem->nregions; i++) { if (vhost_verify_ring_mappings(dev, (void *)(uintptr_t)dev->mem->regions[i].userspace_addr, @@ -1445,6 +1456,8 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque, hdev->mem = g_malloc0(offsetof(struct vhost_memory, regions)); hdev->n_mem_sections = 0; hdev->mem_sections = NULL; + hdev->old_mem = NULL; + hdev->regions_size = 0; hdev->log = NULL; hdev->log_size = 0; hdev->log_enabled = false; @@ -1491,6 +1504,7 @@ void vhost_dev_cleanup(struct vhost_dev *hdev) } g_free(hdev->mem); g_free(hdev->mem_sections); + g_free(hdev->old_mem); if (hdev->vhost_ops) { hdev->vhost_ops->vhost_backend_cleanup(hdev); } diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h index a346f23d13..b1d7287099 100644 --- a/include/hw/virtio/vhost.h +++ b/include/hw/virtio/vhost.h @@ -73,6 +73,8 @@ struct vhost_dev { MemoryListener memory_listener; MemoryListener iommu_listener; struct vhost_memory *mem; + struct vhost_memory *old_mem; + int regions_size; int n_mem_sections; MemoryRegionSection *mem_sections; int n_tmp_sections;
If the vhost memory layout doesn't change, don't need to call the vhost backend. The set_mem_table is time consuming when sending to vhost-user backend. On aarch64, the edk2 uefi firmware will write the pflash which will trigger the vhost_commit hundreds of times. Signed-off-by: Li Feng <fengli@smartx.com> --- hw/virtio/vhost.c | 14 ++++++++++++++ include/hw/virtio/vhost.h | 2 ++ 2 files changed, 16 insertions(+)