As vhost scsi device struct is large, if the device is
created on a busy system, kzalloc() might fail, so this patch does a
fallback to vzalloc().
As vmalloc() adds overhead on data-path, add __GFP_REPEAT
to kzalloc() flags to do this fallback only when really needed.
Reported-by: Dan Aloni <alonid@xxxxxxxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
I put this on my vhost fixes branch, intend to merge for 3.12.
Dan, could you please confirm this works for you?
drivers/vhost/scsi.c | 41 +++++++++++++++++++++++++++--------------
1 file changed, 27 insertions(+), 14 deletions(-)
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 4b79a1f..2c30bb0 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1373,21 +1373,30 @@ static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features)
return 0;
}
+static void vhost_scsi_free(struct vhost_scsi *vs)
+{
+ if (is_vmalloc_addr(vs))
+ vfree(vs);
+ else
+ kfree(vs);
+}
+
static int vhost_scsi_open(struct inode *inode, struct file *f)
{
struct vhost_scsi *vs;
struct vhost_virtqueue **vqs;
- int r, i;
+ int r = -ENOMEM, i;
- vs = kzalloc(sizeof(*vs), GFP_KERNEL);
- if (!vs)
- return -ENOMEM;
+ vs = kzalloc(sizeof(*vs), GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
+ if (!vs) {
+ vs = vzalloc(sizeof(*vs));
+ if (!vs)
+ goto err_vs;
+ }
vqs = kmalloc(VHOST_SCSI_MAX_VQ * sizeof(*vqs), GFP_KERNEL);
- if (!vqs) {
- kfree(vs);
- return -ENOMEM;
- }
+ if (!vqs)
+ goto err_vqs;
vhost_work_init(&vs->vs_completion_work, vhost_scsi_complete_cmd_work);
vhost_work_init(&vs->vs_event_work, tcm_vhost_evt_work);
@@ -1407,14 +1416,18 @@ static int vhost_scsi_open(struct inode *inode, struct file *f)
tcm_vhost_init_inflight(vs, NULL);
- if (r < 0) {
- kfree(vqs);
- kfree(vs);
- return r;
- }
+ if (r < 0)
+ goto err_init;
f->private_data = vs;
return 0;
+
+err_init:
+ kfree(vqs);
+err_vqs:
+ vhost_scsi_free(vs);
+err_vs:
+ return r;
}
static int vhost_scsi_release(struct inode *inode, struct file *f)
@@ -1431,7 +1444,7 @@ static int vhost_scsi_release(struct inode *inode, struct file *f)
/* Jobs can re-queue themselves in evt kick handler. Do extra flush. */
vhost_scsi_flush(vs);
kfree(vs->dev.vqs);
- kfree(vs);
+ vhost_scsi_free(vs);
return 0;
}
--
MST
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