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SubjectRe: [PATCH] vhost/scsi: use vmalloc for order-10 allocation
Hello.

On 09/17/2013 11:21 AM, Michael S. Tsirkin wrote:

> 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@stratoscale.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---

> 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);

Indent with the tabs ISO spaces, please.

> +}
> +
> 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);

Indent here with a tab, please.

> + if (!vs) {
> + vs = vzalloc(sizeof(*vs));
> + if (!vs)
> + goto err_vs;
> + }

WBR, Sergei



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