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xen: issue warning message when out of grant maptrack entries

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When a driver domain (e.g. dom0) is running out of maptrack entries it
can't map any more foreign domain pages. Instead of silently stalling
the affected domUs issue a rate limited warning in this case in order
to make it easier to detect that situation.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This commit is contained in:
Juergen Gross 2018-09-19 15:42:33 +02:00 committed by Boris Ostrovsky
parent 70513d5875
commit d59f532480
1 changed files with 21 additions and 6 deletions
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27
drivers/xen/grant-table.c
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@ -1040,18 +1040,33 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
return ret; return ret;
for (i = 0; i < count; i++) { for (i = 0; i < count; i++) {
/* Retry eagain maps */ switch (map_ops[i].status) {
if (map_ops[i].status == GNTST_eagain) case GNTST_okay:
gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i, {
&map_ops[i].status, __func__);
if (map_ops[i].status == GNTST_okay) {
struct xen_page_foreign *foreign; struct xen_page_foreign *foreign;
SetPageForeign(pages[i]); SetPageForeign(pages[i]);
foreign = xen_page_foreign(pages[i]); foreign = xen_page_foreign(pages[i]);
foreign->domid = map_ops[i].dom; foreign->domid = map_ops[i].dom;
foreign->gref = map_ops[i].ref; foreign->gref = map_ops[i].ref;
break;
}
case GNTST_no_device_space:
pr_warn_ratelimited("maptrack limit reached, can't map all guest pages\n");
break;
case GNTST_eagain:
/* Retry eagain maps */
gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref,
map_ops + i,
&map_ops[i].status, __func__);
/* Test status in next loop iteration. */
i--;
break;
default:
break;
} }
} }