[Xen-devel] [PATCH] xenpaging: use poll timeout if no paging target exists

[Olaf Hering <olaf@xxxxxxxxx>]

# HG changeset patch
# User Olaf Hering <olaf@xxxxxxxxx>
# Date 1346142745 -7200
# Node ID b088e473c7fb1a47b9578693c1750cd27767cc25
# Parent  03ef29089830b119b6efd87db8ab5c38b7428938
xenpaging: use poll timeout if no paging target exists

Currently xenpaging will use 100% cpu time if a paging target is not yet
set via xenstore. The reason is that ->use_poll_timeout is initialized
to zero. Another case is when the paging target is set to zero. In this
case ->use_poll_timeout will not be set to 1.

Fix the first case by initializing use_poll_timeout to 1 in
xenpaging_init. The second case is fixed by setting use_poll_timeout in
case the target is zero and there are no more pages left to resume.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>

diff -r 03ef29089830 -r b088e473c7fb tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c
+++ b/tools/xenpaging/xenpaging.c
@@ -482,6 +482,9 @@ static struct xenpaging *xenpaging_init(
         goto err;
     }
 
+    /* Use a poll timeout until xenpaging got a target from xenstore */
+    paging->use_poll_timeout = 1;
+
     return paging;
 
  err:
@@ -1019,6 +1022,8 @@ int main(int argc, char *argv[])
         {
             if ( paging->num_paged_out )
                 resume_pages(paging, paging->num_paged_out);
+            else
+                paging->use_poll_timeout = 1;
         }
         /* Evict more pages if target not reached */
         else if ( tot_pages > paging->target_tot_pages )

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