diff options
| author |   Jan Beulich <JBeulich@suse.com> | 2012-06-11 09:52:27 +0000 |
|---|---|---|
| committer |   Michael Roth <mdroth@linux.vnet.ibm.com> | 2012-06-25 09:00:42 -0500 |
| commit | c9c2479289fd1faf4a1a40db54cc255fbf03af21 (patch) | |
| tree | 29b1756f47558ba263f6bf9750d6b5b9359af301 | |
| parent | 4c45bf61d315316b5932051551c16b17cf9b3d85 (diff) | |
qemu/xendisk: set maximum number of grants to be used
Legacy (non-pvops) gntdev drivers may require this to be done when the
number of grants intended to be used simultaneously exceeds a certain
driver specific default limit.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
(cherry picked from commit 64c27e5b1fdb6d94bdc0bda3b1869d7383a35c65)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
| -rw-r--r-- | hw/xen_disk.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/hw/xen_disk.c b/hw/xen_disk.c index 07594bc0c..de7e8a4a5 100644 --- a/hw/xen_disk.c +++ b/hw/xen_disk.c @@ -537,6 +537,15 @@ static void blk_bh(void *opaque) blk_handle_requests(blkdev); } +/* + * We need to account for the grant allocations requiring contiguous + * chunks; the worst case number would be + * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, + * but in order to keep things simple just use + * 2 * max_req * max_seg. + */ +#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg)) + static void blk_alloc(struct XenDevice *xendev) { struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); @@ -548,6 +557,11 @@ static void blk_alloc(struct XenDevice *xendev) if (xen_mode != XEN_EMULATE) { batch_maps = 1; } + if (xc_gnttab_set_max_grants(xendev->gnttabdev, + MAX_GRANTS(max_requests, BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) { + xen_be_printf(xendev, 0, "xc_gnttab_set_max_grants failed: %s\n", + strerror(errno)); + } } static int blk_init(struct XenDevice *xendev) |