[Xen-devel] [PATCH v3 07/10] xen/nodemask: Drop nodes_{setall, clear}() and improve the initialisers

[Andrew Cooper <andrew.cooper3@citrix.com>]

There is no need to use runtime variable-length clearing when MAX_NUMNODES is
known to the compiler.  Drop these functions and use the initialisers instead.

numa_initmem_init() opencodes nodemask_of_node(), but its implemention is
still poor, so replace it with NODEMASK_OF() which is calculated at compile
time, and without the use of a locked set_bit() operation.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wl@xen.org>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien.grall@arm.com>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>

v3:
 * New
---
 xen/arch/x86/dom0_build.c  |  2 +-
 xen/arch/x86/numa.c        |  3 +-
 xen/common/domain.c        |  4 +--
 xen/include/xen/nodemask.h | 85 +++++++++++++++++-----------------------------
 4 files changed, 35 insertions(+), 59 deletions(-)

diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index c69570920c..06500c87c6 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -231,7 +231,7 @@ unsigned int __init dom0_max_vcpus(void)
 
     if ( pv_shim )
     {
-        nodes_setall(dom0_nodes);
+        dom0_nodes = NODEMASK_ALL;
 
         /*
          * When booting in shim mode APs are not started until the guest brings
diff --git a/xen/arch/x86/numa.c b/xen/arch/x86/numa.c
index 7e1f563012..7473f83b7b 100644
--- a/xen/arch/x86/numa.c
+++ b/xen/arch/x86/numa.c
@@ -269,8 +269,7 @@ void __init numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn)
     /* setup dummy node covering all memory */
     memnode_shift = BITS_PER_LONG - 1;
     memnodemap = _memnodemap;
-    nodes_clear(node_online_map);
-    node_set_online(0);
+    node_online_map = NODEMASK_OF(0);
     for ( i = 0; i < nr_cpu_ids; i++ )
         numa_set_node(i, 0);
     cpumask_copy(&node_to_cpumask[0], cpumask_of(0));
diff --git a/xen/common/domain.c b/xen/common/domain.c
index e8e850796e..11565a64b3 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -384,7 +384,7 @@ struct domain *domain_create(domid_t domid,
     INIT_PAGE_LIST_HEAD(&d->xenpage_list);
 
     spin_lock_init(&d->node_affinity_lock);
-    d->node_affinity = NODE_MASK_ALL;
+    d->node_affinity = NODEMASK_ALL;
     d->auto_node_affinity = 1;
 
     spin_lock_init(&d->shutdown_lock);
@@ -615,7 +615,7 @@ void domain_update_node_affinity(struct domain *d)
         dom_affinity = cpumask_empty(dom_cpumask_soft) ?
                            dom_cpumask : dom_cpumask_soft;
 
-        nodes_clear(d->node_affinity);
+        d->node_affinity = NODEMASK_NONE;
         for_each_cpu ( cpu, dom_affinity )
             node_set(cpu_to_node(cpu), d->node_affinity);
     }
diff --git a/xen/include/xen/nodemask.h b/xen/include/xen/nodemask.h
index 1dd6c7458e..9933fec5c4 100644
--- a/xen/include/xen/nodemask.h
+++ b/xen/include/xen/nodemask.h
@@ -12,8 +12,6 @@
  *
  * void node_set(node, mask)		turn on bit 'node' in mask
  * void node_clear(node, mask)		turn off bit 'node' in mask
- * void nodes_setall(mask)		set all bits
- * void nodes_clear(mask)		clear all bits
  * bool nodemask_test(node, mask)	true iff bit 'node' set in mask
  * int node_test_and_set(node, mask)	test and set bit 'node' in mask
  *
@@ -36,9 +34,9 @@
  * int cycle_node(node, mask)		Next node cycling from 'node', or
  *					MAX_NUMNODES
  *
- * nodemask_t nodemask_of_node(node)	Return nodemask with bit 'node' set
- * NODE_MASK_ALL			Initializer - all bits set
- * NODE_MASK_NONE			Initializer - no bits set
+ * nodemask_t NODEMASK_OF(node)		Initializer - bit 'node' set
+ * NODEMASK_ALL				Initializer - all bits set
+ * NODEMASK_NONE			Initializer - no bits set
  * unsigned long *nodemask_bits(mask)	Array of unsigned long's in mask
  *
  * for_each_node_mask(node, mask)	for-loop node over mask
@@ -67,7 +65,34 @@ typedef struct { DECLARE_BITMAP(bits, MAX_NUMNODES); } nodemask_t;
 
 #define nodemask_bits(src) ((src)->bits)
 
-extern nodemask_t _unused_nodemask_arg_;
+#define NODEMASK_LAST_WORD BITMAP_LAST_WORD_MASK(MAX_NUMNODES)
+
+#define NODEMASK_NONE                                                   \
+((nodemask_t) {{                                                        \
+        [0 ... BITS_TO_LONGS(MAX_NUMNODES) - 1] = 0                     \
+}})
+
+#if MAX_NUMNODES <= BITS_PER_LONG
+
+#define NODEMASK_ALL      ((nodemask_t) {{ NODEMASK_LAST_WORD }})
+#define NODEMASK_OF(node) ((nodemask_t) {{ 1UL << (node) }})
+
+#else /* MAX_NUMNODES > BITS_PER_LONG */
+
+#define NODEMASK_ALL                                                    \
+((nodemask_t) {{                                                        \
+        [0 ... BITS_TO_LONGS(MAX_NUMNODES) - 2] = ~0UL,                 \
+        [BITS_TO_LONGS(MAX_NUMNODES) - 1] = NODEMASK_LAST_WORD          \
+}})
+
+#define NODEMASK_OF(node)                                               \
+({                                                                      \
+    nodemask_t m = NODES_NONE;                                          \
+    m.bits[(node) / BITS_PER_LONG] = 1UL << ((node) % BITS_PER_LONG);   \
+    m;                                                                  \
+})
+
+#endif /* MAX_NUMNODES */
 
 #define node_set(node, dst) __node_set((node), &(dst))
 static inline void __node_set(int node, volatile nodemask_t *dstp)
@@ -81,18 +106,6 @@ static inline void __node_clear(int node, volatile nodemask_t *dstp)
 	clear_bit(node, dstp->bits);
 }
 
-#define nodes_setall(dst) __nodes_setall(&(dst), MAX_NUMNODES)
-static inline void __nodes_setall(nodemask_t *dstp, int nbits)
-{
-	bitmap_fill(dstp->bits, nbits);
-}
-
-#define nodes_clear(dst) __nodes_clear(&(dst), MAX_NUMNODES)
-static inline void __nodes_clear(nodemask_t *dstp, int nbits)
-{
-	bitmap_zero(dstp->bits, nbits);
-}
-
 static inline bool nodemask_test(unsigned int node, const nodemask_t *dst)
 {
     return test_bit(node, dst->bits);
@@ -213,18 +226,6 @@ static inline int __last_node(const nodemask_t *srcp, int nbits)
 	return pnode;
 }
 
-#define nodemask_of_node(node)						\
-({									\
-	typeof(_unused_nodemask_arg_) m;				\
-	if (sizeof(m) == sizeof(unsigned long)) {			\
-		m.bits[0] = 1UL<<(node);				\
-	} else {							\
-		nodes_clear(m);						\
-		node_set((node), m);					\
-	}								\
-	m;								\
-})
-
 #define cycle_node(n, src) __cycle_node((n), &(src), MAX_NUMNODES)
 static inline int __cycle_node(int n, const nodemask_t *maskp, int nbits)
 {
@@ -235,30 +236,6 @@ static inline int __cycle_node(int n, const nodemask_t *maskp, int nbits)
     return nxt;
 }
 
-#define NODE_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(MAX_NUMNODES)
-
-#if MAX_NUMNODES <= BITS_PER_LONG
-
-#define NODE_MASK_ALL							\
-((nodemask_t) { {							\
-	[BITS_TO_LONGS(MAX_NUMNODES)-1] = NODE_MASK_LAST_WORD		\
-} })
-
-#else
-
-#define NODE_MASK_ALL							\
-((nodemask_t) { {							\
-	[0 ... BITS_TO_LONGS(MAX_NUMNODES)-2] = ~0UL,			\
-	[BITS_TO_LONGS(MAX_NUMNODES)-1] = NODE_MASK_LAST_WORD		\
-} })
-
-#endif
-
-#define NODE_MASK_NONE							\
-((nodemask_t) { {							\
-	[0 ... BITS_TO_LONGS(MAX_NUMNODES)-1] =  0UL			\
-} })
-
 #if MAX_NUMNODES > 1
 #define for_each_node_mask(node, mask)			\
 	for ((node) = first_node(mask);			\
-- 
2.11.0


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