freebsd-dev/lib/libmemstat/memstat_internal.h
Robert Watson 345628080d Introduce more formal error handling for libmemstat(3):
- Define a set of libmemstat(3) error constants, which are used by all
  libmemstat(3) methods except for memstat_mtl_alloc(), which allocates
  a memory type list and may return ENOMEM via errno.

- Define a per-memory_type_list current error value, which is set when a
  call associated with a memory list fails.  This requires wrapping a
  structure around the queue(9) list head data structure, but this change
  is not visible to libmemstat(3) consumers due to using access methods.

- Add a new accessor method, memstat_mtl_geterror() to retrieve the error
  number.

- Consistently set the error number in a number of failure modes where
  previously some combination of setting errno and printf'ing error
  descriptions was used.  libmemstat(3) will now no longer print to stdio
  under any circumstances.  Returns of NULL/-1 for errors remain the
  same.

This avoids use of stdio, misuse of error numbers, and should make it
easier to program a libmemstat(3) consumer able to print useful error
messages.  Currently, no error-to-string function is provided, as I'm
unsure how to address internationalization concerns.

MFC after:	1 day
2005-07-24 01:28:54 +00:00

124 lines
4.6 KiB
C

/*-
* 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_INTERNAL_H_
#define _MEMSTAT_INTERNAL_H_
/*
* memstat maintains its own internal notion of statistics on each memory
* type, common across UMA and kernel malloc. Some fields are straight from
* the allocator statistics, others are derived when extracted from the
* kernel. A struct memory_type will describe each type supported by an
* allocator. memory_type structures can be chained into lists.
*/
struct memory_type {
/*
* Static properties of type.
*/
int mt_allocator; /* malloc(9), uma(9), etc. */
char mt_name[MEMTYPE_MAXNAME]; /* name of memory type. */
/*
* (Relatively) static zone settings, that don't uniquely identify
* the zone, but also don't change much.
*/
uint64_t mt_countlimit; /* 0, or maximum allocations. */
uint64_t mt_byteslimit; /* 0, or maximum bytes. */
uint64_t mt_sizemask; /* malloc: allocated size bitmask. */
uint64_t mt_size; /* uma: size of objects. */
/*
* Zone or type information that includes all caches and any central
* zone state. Depending on the allocator, this may be synthesized
* from several sources, or directly measured.
*/
uint64_t mt_memalloced; /* Bytes allocated over life time. */
uint64_t mt_memfreed; /* Bytes freed over life time. */
uint64_t mt_numallocs; /* Allocations over life time. */
uint64_t mt_numfrees; /* Frees over life time. */
uint64_t mt_bytes; /* Bytes currently allocated. */
uint64_t mt_count; /* Number of current allocations. */
uint64_t mt_free; /* Number of cached free items. */
uint64_t mt_failures; /* Number of allocation failures. */
/*
* Caller-owned memory.
*/
void *mt_caller_pointer[MEMSTAT_MAXCALLER]; /* Pointers. */
uint64_t mt_caller_uint64[MEMSTAT_MAXCALLER]; /* Integers. */
/*
* For allocators making use of per-CPU caches, we also provide raw
* statistics from the central allocator and each per-CPU cache,
* which (combined) sometimes make up the above general statistics.
*
* First, central zone/type state, all numbers excluding any items
* cached in per-CPU caches.
*
* XXXRW: Might be desirable to separately expose allocation stats
* from zone, which should (combined with per-cpu) add up to the
* global stats above.
*/
uint64_t mt_zonefree; /* Free items in zone. */
uint64_t mt_kegfree; /* Free items in keg. */
/*
* Per-CPU measurements fall into two categories: per-CPU allocation,
* and per-CPU cache state.
*/
struct {
uint64_t mtp_memalloced;/* Per-CPU mt_memalloced. */
uint64_t mtp_memfreed; /* Per-CPU mt_memfreed. */
uint64_t mtp_numallocs; /* Per-CPU mt_numallocs. */
uint64_t mtp_numfrees; /* Per-CPU mt_numfrees. */
uint64_t mtp_sizemask; /* Per-CPU mt_sizemask. */
void *mtp_caller_pointer[MEMSTAT_MAXCALLER];
uint64_t mtp_caller_uint64[MEMSTAT_MAXCALLER];
} mt_percpu_alloc[MEMSTAT_MAXCPU];
struct {
uint64_t mtp_free; /* Per-CPU cache free items. */
} mt_percpu_cache[MEMSTAT_MAXCPU];
LIST_ENTRY(memory_type) mt_list; /* List of types. */
};
/*
* Description of struct memory_type_list is in memstat.h.
*/
struct memory_type_list {
LIST_HEAD(, memory_type) mtl_list;
int mtl_error;
};
struct memory_type *_memstat_mt_allocate(struct memory_type_list *list,
int allocator, const char *name);
void _memstat_mt_reset_stats(struct memory_type *mtp);
#endif /* !_MEMSTAT_INTERNAL_H_ */