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authorIngo Molnar <mingo@elte.hu>2009-08-11 14:19:09 +0200
committerIngo Molnar <mingo@elte.hu>2009-08-11 14:19:09 +0200
commit89034bc2c7b839702c00a704e79d112737f98be0 (patch)
treee65b1f3d4c751baa840efc81bc4734f089379eb3 /include/linux/nodemask.h
parentfb82ad719831db58e9baa4c67015aae3fe27e7e3 (diff)
parent85dfd81dc57e8183a277ddd7a56aa65c96f3f487 (diff)
Merge branch 'linus' into tracing/core
Conflicts: kernel/trace/trace_events_filter.c We use the tracing/core version. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/nodemask.h')
-rw-r--r--include/linux/nodemask.h28
1 files changed, 28 insertions, 0 deletions
diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index 829b94b156f..b359c4a9ec9 100644
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -82,6 +82,12 @@
* to generate slightly worse code. So use a simple one-line #define
* for node_isset(), instead of wrapping an inline inside a macro, the
* way we do the other calls.
+ *
+ * NODEMASK_SCRATCH
+ * When doing above logical AND, OR, XOR, Remap operations the callers tend to
+ * need temporary nodemask_t's on the stack. But if NODES_SHIFT is large,
+ * nodemask_t's consume too much stack space. NODEMASK_SCRATCH is a helper
+ * for such situations. See below and CPUMASK_ALLOC also.
*/
#include <linux/kernel.h>
@@ -473,4 +479,26 @@ static inline int num_node_state(enum node_states state)
#define for_each_node(node) for_each_node_state(node, N_POSSIBLE)
#define for_each_online_node(node) for_each_node_state(node, N_ONLINE)
+/*
+ * For nodemask scrach area.(See CPUMASK_ALLOC() in cpumask.h)
+ */
+
+#if NODES_SHIFT > 8 /* nodemask_t > 64 bytes */
+#define NODEMASK_ALLOC(x, m) struct x *m = kmalloc(sizeof(*m), GFP_KERNEL)
+#define NODEMASK_FREE(m) kfree(m)
+#else
+#define NODEMASK_ALLOC(x, m) struct x _m, *m = &_m
+#define NODEMASK_FREE(m)
+#endif
+
+/* A example struture for using NODEMASK_ALLOC, used in mempolicy. */
+struct nodemask_scratch {
+ nodemask_t mask1;
+ nodemask_t mask2;
+};
+
+#define NODEMASK_SCRATCH(x) NODEMASK_ALLOC(nodemask_scratch, x)
+#define NODEMASK_SCRATCH_FREE(x) NODEMASK_FREE(x)
+
+
#endif /* __LINUX_NODEMASK_H */