hw/virtio/vhost.c | 14 ++++++++++++++ include/hw/virtio/vhost.h | 2 ++ 2 files changed, 16 insertions(+)
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
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 >
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