53 lines
2.1 KiB
Diff
53 lines
2.1 KiB
Diff
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xenpaging: correct dropping pages to avoid full ring buffer
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Doing a one-way channel from Xen to xenpaging is not possible with the
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current ring buffer implementation. xenpaging uses the mem_event ring
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buffer, which expects request/response pairs to make progress. The
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previous patch, which tried to establish a one-way communication from
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Xen to xenpaging, stalled the guest once the buffer was filled up with
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requests. Correct page-dropping by taking the slow path and let
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p2m_mem_paging_resume() consume the response from xenpaging. This makes
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room for yet another request/response pair and avoids hanging guests.
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Signed-off-by: Olaf Hering <olaf@aepfle.de>
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---
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tools/xenpaging/xenpaging.c | 22 +++++++++++-----------
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1 file changed, 11 insertions(+), 11 deletions(-)
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Index: xen-4.1.1-testing/tools/xenpaging/xenpaging.c
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===================================================================
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--- xen-4.1.1-testing.orig/tools/xenpaging/xenpaging.c
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+++ xen-4.1.1-testing/tools/xenpaging/xenpaging.c
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@@ -653,19 +653,19 @@ int main(int argc, char *argv[])
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ERROR("Error populating page");
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goto out;
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}
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+ }
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- /* Prepare the response */
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- rsp.gfn = req.gfn;
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- rsp.p2mt = req.p2mt;
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- rsp.vcpu_id = req.vcpu_id;
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- rsp.flags = req.flags;
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+ /* Prepare the response */
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+ rsp.gfn = req.gfn;
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+ rsp.p2mt = req.p2mt;
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+ rsp.vcpu_id = req.vcpu_id;
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+ rsp.flags = req.flags;
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- rc = xenpaging_resume_page(paging, &rsp, 1);
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- if ( rc != 0 )
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- {
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- ERROR("Error resuming page");
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- goto out;
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- }
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+ rc = xenpaging_resume_page(paging, &rsp, 1);
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+ if ( rc != 0 )
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+ {
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+ ERROR("Error resuming page");
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+ goto out;
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}
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/* Evict a new page to replace the one we just paged in */
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