[Xen-devel] [PATCH 2/5] xen: events: Make last processed event channel a per-cpu variable.

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxxxxx>
Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
[ijc: forward ported from linux-2.6.18-xen.hg 325:b2768401db94]
---
 drivers/xen/events.c |   13 ++++++-------
 1 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 75cc6f5..1fc3192 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1026,6 +1026,8 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 }
 
 static DEFINE_PER_CPU(unsigned, xed_nesting_count);
+static DEFINE_PER_CPU(unsigned int, last_word_idx) = { BITS_PER_LONG - 1 };
+static DEFINE_PER_CPU(unsigned int, last_bit_idx) = { BITS_PER_LONG - 1 };
 
 /*
  * Mask out the i least significant bits of w
@@ -1043,8 +1045,6 @@ static DEFINE_PER_CPU(unsigned, xed_nesting_count);
  */
 static void __xen_evtchn_do_upcall(void)
 {
-       static unsigned int last_word_idx = BITS_PER_LONG - 1;
-       static unsigned int last_bit_idx = BITS_PER_LONG - 1;
        int word_idx, bit_idx;
        int cpu = get_cpu();
        struct shared_info *s = HYPERVISOR_shared_info;
@@ -1065,8 +1065,8 @@ static void __xen_evtchn_do_upcall(void)
 #endif
                pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
 
-               word_idx = last_word_idx;
-               bit_idx = last_bit_idx;
+               word_idx = __this_cpu_read(last_word_idx);
+               bit_idx = __this_cpu_read(last_bit_idx);
 
                while (pending_words != 0) {
                        unsigned long pending_bits;
@@ -1121,9 +1121,8 @@ static void __xen_evtchn_do_upcall(void)
                                 * If this is the final port processed, we'll
                                 * pick up here+1 next time.
                                 */
-                               last_word_idx = word_idx;
-                               last_bit_idx = bit_idx;
-
+                               __this_cpu_write(last_word_idx, word_idx);
+                               __this_cpu_write(last_bit_idx, bit_idx);
                        } while (bit_idx != BITS_PER_LONG - 1);
 
                        pending_bits = active_evtchns(cpu, s, word_idx);
-- 
1.5.6.5


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