[Xen-devel] [PATCH 1/4] xen/p2m: Optimize the get_phys_to_machine function a bit.

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

Running perf tells me that the check for p2m_identity
is done a lot - more than it should.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 arch/x86/xen/p2m.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 64effdc..161bcdc 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -406,7 +406,7 @@ unsigned long get_phys_to_machine(unsigned long pfn)
         * and in p2m_*missing, so returning the INVALID_P2M_ENTRY
         * would be wrong.
         */
-       if (p2m_top[topidx][mididx] == p2m_identity)
+       if (unlikely(p2m_top[topidx][mididx] == p2m_identity))
                return IDENTITY_FRAME(pfn);
 
        return p2m_top[topidx][mididx][idx];
-- 
1.7.7.6


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