[Xen-devel] [PATCH v1] x86/dom0: use MEMF_no_scrub for Dom0 RAM allocation

[Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>]

Now that idle scrub is the default option, all memory is marked as dirty
and alloc_domheap_pages() will do eager scrubbing by default. This can
lead to longer Dom0 construction and potentially to a watchdog timeout,
especially on older H/W (e.g. Harpertown).

Pass MEMF_no_scrub to optimise this process since there is little point
in scrubbing memory for Dom0 RAM.

Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
---
CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/hvm/dom0_build.c | 2 +-
 xen/arch/x86/pv/dom0_build.c  | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/hvm/dom0_build.c b/xen/arch/x86/hvm/dom0_build.c
index 3e29cd30b8..12c20a4b66 100644
--- a/xen/arch/x86/hvm/dom0_build.c
+++ b/xen/arch/x86/hvm/dom0_build.c
@@ -101,7 +101,7 @@ static int __init pvh_populate_memory_range(struct domain 
*d,
         unsigned int range_order = get_order_from_pages(nr_pages + 1);
 
         order = min(range_order ? range_order - 1 : 0, order);
-        page = alloc_domheap_pages(d, order, dom0_memflags);
+        page = alloc_domheap_pages(d, order, dom0_memflags | MEMF_no_scrub);
         if ( page == NULL )
         {
             if ( order == 0 && dom0_memflags )
diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index dc3c1e1202..f50a36c1f3 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -239,7 +239,8 @@ static struct page_info * __init alloc_chunk(struct domain 
*d,
         order = last_order;
     else if ( max_pages & (max_pages - 1) )
         --order;
-    while ( (page = alloc_domheap_pages(d, order, dom0_memflags)) == NULL )
+    while ( (page = alloc_domheap_pages(d, order, dom0_memflags |
+                                                  MEMF_no_scrub)) == NULL )
         if ( order-- == 0 )
             break;
     if ( page )
@@ -265,7 +266,7 @@ static struct page_info * __init alloc_chunk(struct domain 
*d,
 
         if ( d->tot_pages + (1 << order) > d->max_pages )
             continue;
-        pg2 = alloc_domheap_pages(d, order, MEMF_exact_node);
+        pg2 = alloc_domheap_pages(d, order, MEMF_exact_node | MEMF_no_scrub);
         if ( pg2 > page )
         {
             free_domheap_pages(page, free_order);
-- 
2.17.1


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