iommu/iova: Separate atomic variables to improve performance

In struct iova_domain, there are three atomic variables, the former two
are about TLB flush counters which use atomic_add operation, anoter is
used to flush timer that use cmpxhg operation.
These variables are in the same cache line, so it will cause some
performance loss under the condition that many cores call queue_iova
function, Let's isolate the two type atomic variables to different
cache line to reduce cache line conflict.

Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Jinyu Qi <jinyuqi@huawei.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/include/linux/iova.h b/include/linux/iova.h
index 0b93bf96693ef6f3ea8b6a30315a24fe548443c6..28a5128405f82dd04e03caff3188d90f31eed71c 100644 (file)
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -76,6 +76,14 @@ struct iova_domain {
        unsigned long   start_pfn;      /* Lower limit for this domain */
        unsigned long   dma_32bit_pfn;
        unsigned long   max32_alloc_size; /* Size of last failed allocation */
+       struct iova_fq __percpu *fq;    /* Flush Queue */
+
+       atomic64_t      fq_flush_start_cnt;     /* Number of TLB flushes that
+                                                  have been started */
+
+       atomic64_t      fq_flush_finish_cnt;    /* Number of TLB flushes that
+                                                  have been finished */
+
        struct iova     anchor;         /* rbtree lookup anchor */
        struct iova_rcache rcaches[IOVA_RANGE_CACHE_MAX_SIZE];  /* IOVA range caches */
 
@@ -85,14 +93,6 @@ struct iova_domain {
        iova_entry_dtor entry_dtor;     /* IOMMU driver specific destructor for
                                           iova entry */
 
-       struct iova_fq __percpu *fq;    /* Flush Queue */
-
-       atomic64_t      fq_flush_start_cnt;     /* Number of TLB flushes that
-                                                  have been started */
-
-       atomic64_t      fq_flush_finish_cnt;    /* Number of TLB flushes that
-                                                  have been finished */
-
        struct timer_list fq_timer;             /* Timer to regularily empty the
                                                   flush-queues */
        atomic_t fq_timer_on;                   /* 1 when timer is active, 0