lkml.org 
[lkml]   [2018]   [Sep]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] xen: issue warning message when out of grant maptrack entries
From
Date
On 19/09/18 15:29, Boris Ostrovsky wrote:
> On 9/18/18 1:17 PM, Juergen Gross wrote:
>> On 18/09/18 19:03, Boris Ostrovsky wrote:
>>> On 9/18/18 5:32 AM, Juergen Gross wrote:
>>>> 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>
>>>> ---
>>>> drivers/xen/grant-table.c | 25 +++++++++++++++++++------
>>>> 1 file changed, 19 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
>>>> index 7bafa703a992..09f6ff8c1957 100644
>>>> --- a/drivers/xen/grant-table.c
>>>> +++ b/drivers/xen/grant-table.c
>>>> @@ -1040,18 +1040,31 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
>>>> return ret;
>>>>
>>>> for (i = 0; i < count; i++) {
>>>> - /* Retry eagain maps */
>>>> - if (map_ops[i].status == GNTST_eagain)
>>>> - gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
>>>> - &map_ops[i].status, __func__);
>>>> -
>>>> - if (map_ops[i].status == GNTST_okay) {
>>>> + switch (map_ops[i].status) {
>>>> + case GNTST_okay:
>>>> + {
>>>> struct xen_page_foreign *foreign;
>>>>
>>>> SetPageForeign(pages[i]);
>>>> foreign = xen_page_foreign(pages[i]);
>>>> foreign->domid = map_ops[i].dom;
>>>> 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__);
>>>> + break;
>>>> +
>>>> + default:
>>>> + break;
>>>> }
>>>> }
>
>
> After having a second look at this (and at the risk of embarrassing
> myself again with this patch) --- aren't we supposed to test status
> after gnttab_retry_eagain_gop() call, and then actually set foreign
> properties?

Right. Thanks for catching that!

V2 coming soon...


Juergen

\
 
 \ /
  Last update: 2018-09-19 15:35    [W:0.160 / U:1.372 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site