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[Xen-devel] [PATCH]: Fix xentrace buffer allocation

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Subject: [Xen-devel] [PATCH]: Fix xentrace buffer allocation
From: Andre Przywara <andre.przywara@xxxxxxx>
Date: Mon, 16 Aug 2010 13:23:01 +0200
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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during experiments with xentrace we found that the t_info buffer allocation does not match the constants describing the buffer size. Attached patch fixes this, so changes of the buffer size only requires a single line change in the future. Thanks to Uwe for reporting this.


Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>

Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 448-3567-12
diff -r 774dfc178c39 xen/common/trace.c
--- a/xen/common/trace.c        Thu Aug 12 17:06:21 2010 +0100
+++ b/xen/common/trace.c        Mon Aug 16 13:22:47 2010 +0200
@@ -321,9 +321,9 @@
     /* Calculate offset in u32 of first mfn */
-    /* t_info size fixed at 2 pages for now.  That should be big enough / 
small enough
-     * until it's worth making it dynamic. */
-    t_info = alloc_xenheap_pages(1, 0);
+    /* t_info size is fixed for now. Currently this works great, so there
+     * seems to be no need to make it dynamic. */
+    t_info = alloc_xenheap_pages(get_order_from_pages(T_INFO_PAGES), 0);
     if ( t_info == NULL )
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