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authorMichael S. Tsirkin <mst@redhat.com>2013-01-23 21:46:47 +0100
committerMichael S. Tsirkin <mst@redhat.com>2014-06-09 16:21:05 +0300
commit23cc5a991c7a9fb7e6d6550e65cee4f4173111c5 (patch)
treef064aee3320d1491255bc68d8ae3989e00499e0b /drivers/vhost
parent1860e379875dfe7271c649058aeddffe5afd9d0d (diff)
vhost-net: extend device allocation to vmalloc
Michael Mueller provided a patch to reduce the size of vhost-net structure as some allocations could fail under memory pressure/fragmentation. We are still left with high order allocations though. This patch is handling the problem at the core level, allowing vhost structures to use vmalloc() if kmalloc() failed. As vmalloc() adds overhead on a critical network path, add __GFP_REPEAT to kzalloc() flags to do this fallback only when really needed. People are still looking at cleaner ways to handle the problem at the API level, probably passing in multiple iovecs. This hack seems consistent with approaches taken since then by drivers/vhost/scsi.c and net/core/dev.c Based on patch by Romain Francoise. Cc: Michael Mueller <mimu@linux.vnet.ibm.com> Signed-off-by: Romain Francoise <romain@orebokech.com> Acked-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/vhost')
-rw-r--r--drivers/vhost/net.c23
1 files changed, 18 insertions, 5 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index be414d2b2b22..e489161d0feb 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -17,6 +17,7 @@
#include <linux/workqueue.h>
#include <linux/file.h>
#include <linux/slab.h>
+#include <linux/vmalloc.h>
#include <linux/net.h>
#include <linux/if_packet.h>
@@ -699,18 +700,30 @@ static void handle_rx_net(struct vhost_work *work)
handle_rx(net);
}
+static void vhost_net_free(void *addr)
+{
+ if (is_vmalloc_addr(addr))
+ vfree(addr);
+ else
+ kfree(addr);
+}
+
static int vhost_net_open(struct inode *inode, struct file *f)
{
- struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL);
+ struct vhost_net *n;
struct vhost_dev *dev;
struct vhost_virtqueue **vqs;
int i;
- if (!n)
- return -ENOMEM;
+ n = kmalloc(sizeof *n, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
+ if (!n) {
+ n = vmalloc(sizeof *n);
+ if (!n)
+ return -ENOMEM;
+ }
vqs = kmalloc(VHOST_NET_VQ_MAX * sizeof(*vqs), GFP_KERNEL);
if (!vqs) {
- kfree(n);
+ vhost_net_free(n);
return -ENOMEM;
}
@@ -827,7 +840,7 @@ static int vhost_net_release(struct inode *inode, struct file *f)
* since jobs can re-queue themselves. */
vhost_net_flush(n);
kfree(n->dev.vqs);
- kfree(n);
+ vhost_net_free(n);
return 0;
}