|
|
|
|
|
|
|
|
|
|
xen-devel
[Xen-devel] [PATCH 01 of 12] xenpaging: correct dropping of pages to avo
# HG changeset patch
# User Olaf Hering <olaf@xxxxxxxxx>
# Date 1307437209 -7200
# Node ID 6b8446bf4e5fbfa93169ec2509364c0fde74beca
# Parent c231a26a29327aa3c737170e04c738289be2d309
xenpaging: correct dropping of pages to avoid full ring buffer
Doing a one-way channel from Xen to xenpaging is not possible with the
current ring buffer implementation. xenpaging uses the mem_event ring
buffer, which expects request/response pairs to make progress. The
previous patch, which tried to establish a one-way communication from
Xen to xenpaging, stalled the guest once the buffer was filled up with
requests. Correct page-dropping by taking the slow path and let
p2m_mem_paging_resume() consume the response from xenpaging. This makes
room for yet another request/response pair and avoids hanging guests.
Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
diff -r c231a26a2932 -r 6b8446bf4e5f tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c Mon Jun 06 09:56:08 2011 +0100
+++ b/tools/xenpaging/xenpaging.c Tue Jun 07 11:00:09 2011 +0200
@@ -653,19 +653,19 @@ int main(int argc, char *argv[])
ERROR("Error populating page");
goto out;
}
+ }
- /* Prepare the response */
- rsp.gfn = req.gfn;
- rsp.p2mt = req.p2mt;
- rsp.vcpu_id = req.vcpu_id;
- rsp.flags = req.flags;
+ /* Prepare the response */
+ rsp.gfn = req.gfn;
+ rsp.p2mt = req.p2mt;
+ rsp.vcpu_id = req.vcpu_id;
+ rsp.flags = req.flags;
- rc = xenpaging_resume_page(paging, &rsp, 1);
- if ( rc != 0 )
- {
- ERROR("Error resuming page");
- goto out;
- }
+ rc = xenpaging_resume_page(paging, &rsp, 1);
+ if ( rc != 0 )
+ {
+ ERROR("Error resuming page");
+ goto out;
}
/* Evict a new page to replace the one we just paged in */
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
|
|