@@ -471,7 +471,7 @@ void vhost_dev_cleanup(struct vhost_dev *dev, bool locked)
fput(dev->log_file);
dev->log_file = NULL;
/* No one will access memory at this point */
- kfree(dev->memory);
+ kvfree(dev->memory);
dev->memory = NULL;
WARN_ON(!list_empty(&dev->work_list));
if (dev->worker) {
@@ -601,6 +601,18 @@ static int vhost_memory_reg_sort_cmp(const void *p1, const void *p2)
return 0;
}
+static void *vhost_kvzalloc(unsigned long size)
+{
+ void *n = kzalloc(size, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
+
+ if (!n) {
+ n = vzalloc(size);
+ if (!n)
+ return ERR_PTR(-ENOMEM);
+ }
+ return n;
+}
+
static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
{
struct vhost_memory mem, *newmem, *oldmem;
@@ -613,21 +625,21 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
return -EOPNOTSUPP;
if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS)
return -E2BIG;
- newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL);
+ newmem = vhost_kvzalloc(size + mem.nregions * sizeof(*m->regions));
if (!newmem)
return -ENOMEM;
memcpy(newmem, &mem, size);
if (copy_from_user(newmem->regions, m->regions,
mem.nregions * sizeof *m->regions)) {
- kfree(newmem);
+ kvfree(newmem);
return -EFAULT;
}
sort(newmem->regions, newmem->nregions, sizeof(*newmem->regions),
vhost_memory_reg_sort_cmp, NULL);
if (!memory_access_ok(d, newmem, 0)) {
- kfree(newmem);
+ kvfree(newmem);
return -EFAULT;
}
oldmem = d->memory;
@@ -639,7 +651,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
d->vqs[i]->memory = newmem;
mutex_unlock(&d->vqs[i]->mutex);
}
- kfree(oldmem);
+ kvfree(oldmem);
return 0;
}
with large number of memory regions we could end up with high order allocations and kmalloc could fail if host is under memory pressure. Considering that memory regions array is used on hot path try harder to allocate using kmalloc and if it fails resort to vmalloc. It's still better than just failing vhost_set_memory() and causing guest crash due to it when a new memory hotplugged to guest. I'll still look at QEMU side solution to reduce amount of memory regions it feeds to vhost to make things even better, but it doesn't hurt for kernel to behave smarter and don't crash older QEMU's which could use large amount of memory regions. Signed-off-by: Igor Mammedov <imammedo@redhat.com> --- drivers/vhost/vhost.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-)