Add libmemstat(3), a library for use by debugging and monitoring

applications in tracking kernel memory statistics.  It provides an
abstracted interface to uma(9) and malloc(9) statistics, wrapped
around the recently added binary stream sysctls for the allocators.

Using this interface, it is easy to build monitoring tools, query
specific memory types for usage information, etc.  Facilities are
provided for binding caller-provided data to memory types,
incremental updates of memory types, and queries that span multiple
allocators.

Support for additional allocators is (relatively) easy to add.

The API for libmemstat(3) will probably change some over time as
consumers are written, and requirements evolve.  It is written to
avoid encoding ABIs for data structure layout into consuming
applications for this reason.

MFC after:	1 week

1 files changed, 134 insertions, 0 deletions

diff --git a/lib/libmemstat/memstat.h b/lib/libmemstat/memstat.h
new file mode 100644
index 000000000000..847719c83052
--- /dev/null
+++ b/lib/libmemstat/memstat.h
@@ -0,0 +1,134 @@
+/*-
+ * Copyright (c) 2005 Robert N. M. Watson
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _MEMSTAT_H_
+#define	_MEMSTAT_H_
+
+/*
+ * Number of CPU slots in library-internal data structures.  This should be
+ * at least the value of MAXCPU from param.h.
+ */
+#define	MEMSTAT_MAXCPU	16
+
+/*
+ * libmemstat(3) is able to extract memory data from different allocators;
+ * when it does so, it tags which allocator it got the data from so that
+ * consumers can determine which fields are usable, as data returned varies
+ * some.
+ */
+#define	ALLOCATOR_UNKNOWN	0
+#define	ALLOCATOR_MALLOC	1
+#define	ALLOCATOR_UMA		2
+#define	ALLOCATOR_ANY		255
+
+/*
+ * Library maximum type name.  Should be max(set of name maximums over
+ * various allocators).
+ */
+#define	MEMTYPE_MAXNAME		32
+
+/*
+ * Forward declare struct memory_type, which holds per-type properties and
+ * statistics.  This is an opaque type, to be frobbed only from within the
+ * library, in order to avoid building ABI assumptions into the application.
+ * Accessor methods should be used to get and sometimes set the fields from
+ * consumers of the library.
+ */
+struct memory_type;
+
+/*
+ * struct memory_type_list is the head of a list of memory types and
+ * statistics.
+ */
+struct memory_type_list;
+
+/*
+ * Functions for managing memory type and statistics data.
+ */
+struct memory_type_list	*memstat_mtl_alloc(void);
+struct memory_type	*memstat_mtl_first(struct memory_type_list *list);
+struct memory_type	*memstat_mtl_next(struct memory_type *mtp);
+struct memory_type	*memstat_mtl_find(struct memory_type_list *list,
+			    int allocator, const char *name);
+void	memstat_mtl_free(struct memory_type_list *list);
+
+/*
+ * Functions to retrieve data from a live kernel using sysctl.
+ */
+int	memstat_sysctl_all(struct memory_type_list *list, int flags);
+int	memstat_sysctl_malloc(struct memory_type_list *list, int flags);
+int	memstat_sysctl_uma(struct memory_type_list *list, int flags);
+
+/*
+ * Accessor methods for struct memory_type_list.
+ */
+const char	*memstat_get_name(const struct memory_type *mtp);
+int		 memstat_get_allocator(const struct memory_type *mtp);
+uint64_t	 memstat_get_countlimit(const struct memory_type *mtp);
+uint64_t	 memstat_get_byteslimit(const struct memory_type *mtp);
+uint64_t	 memstat_get_sizemask(const struct memory_type *mtp);
+uint64_t	 memstat_get_size(const struct memory_type *mtp);
+uint64_t	 memstat_get_memalloced(const struct memory_type *mtp);
+uint64_t	 memstat_get_memfreed(const struct memory_type *mtp);
+uint64_t	 memstat_get_numallocs(const struct memory_type *mtp);
+uint64_t	 memstat_get_numfrees(const struct memory_type *mtp);
+uint64_t	 memstat_get_bytes(const struct memory_type *mtp);
+uint64_t	 memstat_get_count(const struct memory_type *mtp);
+uint64_t	 memstat_get_free(const struct memory_type *mtp);
+uint64_t	 memstat_get_failures(const struct memory_type *mtp);
+void		*memstat_get_caller_pointer(const struct memory_type *mtp,
+		    int index);
+void		 memstat_set_caller_pointer(struct memory_type *mtp,
+		    int index, void *value);
+uint64_t	 memstat_get_caller_uint64(const struct memory_type *mtp,
+		    int index);
+void		 memstat_set_caller_uint64(struct memory_type *mtp, int index,
+		    uint64_t value);
+uint64_t	 memstat_get_zonefree(const struct memory_type *mtp);
+uint64_t	 memstat_get_percpu_memalloced(const struct memory_type *mtp,
+		    int cpu);
+uint64_t	 memstat_get_percpu_memfreed(const struct memory_type *mtp,
+		    int cpu);
+uint64_t	 memstat_get_percpu_numallocs(const struct memory_type *mtp,
+		    int cpu);
+uint64_t	 memstat_get_percpu_numfrees(const struct memory_type *mtp,
+		    int cpu);
+uint64_t	 memstat_get_percpu_sizemask(const struct memory_type *mtp,
+		    int cpu);
+void		*memstat_get_percpu_caller_pointer(
+		    const struct memory_type *mtp, int cpu, int index);
+void		 memstat_set_percpu_caller_pointer(struct memory_type *mtp,
+		    int cpu, int index, void *value);
+uint64_t	 memstat_get_percpu_caller_uint64(
+		    const struct memory_type *mtp, int cpu, int index);
+void		 memstat_set_percpu_caller_uint64(struct memory_type *mtp,
+		    int cpu, int index, uint64_t value);
+uint64_t	 memstat_get_percpu_free(const struct memory_type *mtp,
+		    int cpu);
+
+#endif /* !_MEMSTAT_H_ */