Merge from projects/counters:

  Pad struct pcpu so that its size is denominator of PAGE_SIZE. This
is done to reduce memory waste in UMA_PCPU_ZONE zones.

Sponsored by:	Nginx, Inc.

1 files changed, 16 insertions, 0 deletions

diff --git a/sys/sys/pcpu.h b/sys/sys/pcpu.h
index e860385..c73cc53 100644
--- a/sys/sys/pcpu.h
+++ b/sys/sys/pcpu.h
@@ -180,6 +180,14 @@ struct pcpu {
 	PCPU_MD_FIELDS;
 } __aligned(CACHE_LINE_SIZE);
 
+#ifdef CTASSERT
+/*
+ * To minimize memory waste in per-cpu UMA zones, size of struct pcpu
+ * should be denominator of PAGE_SIZE.
+ */
+CTASSERT((PAGE_SIZE / sizeof(struct pcpu)) * sizeof(struct pcpu) == PAGE_SIZE);
+#endif
+
 #ifdef _KERNEL
 
 STAILQ_HEAD(cpuhead, pcpu);
@@ -194,6 +202,14 @@ extern struct pcpu *cpuid_to_pcpu[];
 #endif
 #define	curvidata	PCPU_GET(vidata)
 
+/* Accessor to elements allocated via UMA_ZONE_PCPU zone. */
+static inline void *
+zpcpu_get(void *base)
+{
+
+	return ((char *)(base) + sizeof(struct pcpu) * curcpu);
+}
+
 /*
  * Machine dependent callouts.  cpu_pcpu_init() is responsible for
  * initializing machine dependent fields of struct pcpu, and