xref: /freebsd-14.2/sys/dev/netmap/netmap_mem2.h (revision ab1e2860)

/*
 * Copyright (C) 2012-2013 Matteo Landi, Luigi Rizzo, Giuseppe Lettieri. 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.
 */

/*
 * $FreeBSD$
 *
 * (New) memory allocator for netmap
 */

/*
 * This allocator creates three memory pools:
 *	nm_if_pool	for the struct netmap_if
 *	nm_ring_pool	for the struct netmap_ring
 *	nm_buf_pool	for the packet buffers.
 *
 * that contain netmap objects. Each pool is made of a number of clusters,
 * multiple of a page size, each containing an integer number of objects.
 * The clusters are contiguous in user space but not in the kernel.
 * Only nm_buf_pool needs to be dma-able,
 * but for convenience use the same type of allocator for all.
 *
 * Once mapped, the three pools are exported to userspace
 * as a contiguous block, starting from nm_if_pool. Each
 * cluster (and pool) is an integral number of pages.
 *   [ . . . ][ . . . . . .][ . . . . . . . . . .]
 *    nm_if     nm_ring            nm_buf
 *
 * The userspace areas contain offsets of the objects in userspace.
 * When (at init time) we write these offsets, we find out the index
 * of the object, and from there locate the offset from the beginning
 * of the region.
 *
 * The invididual allocators manage a pool of memory for objects of
 * the same size.
 * The pool is split into smaller clusters, whose size is a
 * multiple of the page size. The cluster size is chosen
 * to minimize the waste for a given max cluster size
 * (we do it by brute force, as we have relatively few objects
 * per cluster).
 *
 * Objects are aligned to the cache line (64 bytes) rounding up object
 * sizes when needed. A bitmap contains the state of each object.
 * Allocation scans the bitmap; this is done only on attach, so we are not
 * too worried about performance
 *
 * For each allocator we can define (thorugh sysctl) the size and
 * number of each object. Memory is allocated at the first use of a
 * netmap file descriptor, and can be freed when all such descriptors
 * have been released (including unmapping the memory).
 * If memory is scarce, the system tries to get as much as possible
 * and the sysctl values reflect the actual allocation.
 * Together with desired values, the sysctl export also absolute
 * min and maximum values that cannot be overridden.
 *
 * struct netmap_if:
 *	variable size, max 16 bytes per ring pair plus some fixed amount.
 *	1024 bytes should be large enough in practice.
 *
 *	In the worst case we have one netmap_if per ring in the system.
 *
 * struct netmap_ring
 *	variable size, 8 byte per slot plus some fixed amount.
 *	Rings can be large (e.g. 4k slots, or >32Kbytes).
 *	We default to 36 KB (9 pages), and a few hundred rings.
 *
 * struct netmap_buffer
 *	The more the better, both because fast interfaces tend to have
 *	many slots, and because we may want to use buffers to store
 *	packets in userspace avoiding copies.
 *	Must contain a full frame (eg 1518, or more for vlans, jumbo
 *	frames etc.) plus be nicely aligned, plus some NICs restrict
 *	the size to multiple of 1K or so. Default to 2K
 */
#ifndef _NET_NETMAP_MEM2_H_
#define _NET_NETMAP_MEM2_H_


#define NETMAP_BUF_MAX_NUM	20*4096*2	/* large machine */

#define NETMAP_POOL_MAX_NAMSZ	32


enum {
	NETMAP_IF_POOL   = 0,
	NETMAP_RING_POOL,
	NETMAP_BUF_POOL,
	NETMAP_POOLS_NR
};


struct netmap_obj_params {
	u_int size;
	u_int num;
};
struct netmap_obj_pool {
	char name[NETMAP_POOL_MAX_NAMSZ];	/* name of the allocator */

	/* ---------------------------------------------------*/
	/* these are only meaningful if the pool is finalized */
	/* (see 'finalized' field in netmap_mem_d)            */
	u_int objtotal;         /* actual total number of objects. */
	u_int memtotal;		/* actual total memory space */
	u_int numclusters;	/* actual number of clusters */

	u_int objfree;          /* number of free objects. */

	struct lut_entry *lut;  /* virt,phys addresses, objtotal entries */
	uint32_t *bitmap;       /* one bit per buffer, 1 means free */
	uint32_t bitmap_slots;	/* number of uint32 entries in bitmap */
	/* ---------------------------------------------------*/

	/* limits */
	u_int objminsize;	/* minimum object size */
	u_int objmaxsize;	/* maximum object size */
	u_int nummin;		/* minimum number of objects */
	u_int nummax;		/* maximum number of objects */

	/* these are changed only by config */
	u_int _objtotal;	/* total number of objects */
	u_int _objsize;		/* object size */
	u_int _clustsize;       /* cluster size */
	u_int _clustentries;    /* objects per cluster */
	u_int _numclusters;	/* number of clusters */

	/* requested values */
	u_int r_objtotal;
	u_int r_objsize;
};

#ifdef linux
// XXX a mtx would suffice here 20130415 lr
#define NMA_LOCK_T		struct semaphore
#else /* !linux */
#define NMA_LOCK_T		struct mtx
#endif /* linux */

typedef int (*netmap_mem_config_t)(struct netmap_mem_d*);
typedef int (*netmap_mem_finalize_t)(struct netmap_mem_d*);
typedef void (*netmap_mem_deref_t)(struct netmap_mem_d*);


/* We implement two kinds of netmap_mem_d structures:
 *
 * - global: used by hardware NICS;
 *
 * - private: used by VALE ports.
 *
 * In both cases, the netmap_mem_d structure has the same lifetime as the
 * netmap_adapter of the corresponding NIC or port. It is the responsibility of
 * the client code to delete the private allocator when the associated
 * netmap_adapter is freed (this is implemented by the NAF_MEM_OWNER flag in
 * netmap.c).  The 'refcount' field counts the number of active users of the
 * structure. The global allocator uses this information to prevent/allow
 * reconfiguration. The private allocators release all their memory when there
 * are no active users.  By 'active user' we mean an existing netmap_priv
 * structure holding a reference to the allocator.
 */
struct netmap_mem_d {
	NMA_LOCK_T nm_mtx;  /* protect the allocator */
	u_int nm_totalsize; /* shorthand */

	u_int flags;
#define NETMAP_MEM_FINALIZED	0x1	/* preallocation done */
#define NETMAP_MEM_PRIVATE	0x2	/* uses private address space */
	int lasterr;		/* last error for curr config */
	int refcount;		/* existing priv structures */
	/* the three allocators */
	struct netmap_obj_pool pools[NETMAP_POOLS_NR];

	netmap_mem_config_t   config;
	netmap_mem_finalize_t finalize;
	netmap_mem_deref_t    deref;
};

extern struct netmap_mem_d nm_mem;

vm_paddr_t netmap_mem_ofstophys(struct netmap_mem_d *, vm_ooffset_t);
int	   netmap_mem_finalize(struct netmap_mem_d *);
int 	   netmap_mem_init(void);
void 	   netmap_mem_fini(void);
struct netmap_if *   netmap_mem_if_new(const char *, struct netmap_adapter *);
void 	   netmap_mem_if_delete(struct netmap_adapter *na, struct netmap_if *nifp);
void 	   netmap_mem_deref(struct netmap_mem_d *);
int	   netmap_mem_get_info(struct netmap_mem_d *nm_mem, u_int *size, u_int *memflags);
ssize_t    netmap_mem_if_offset(struct netmap_mem_d *nm_mem, const void *vaddr);
struct netmap_mem_d*
	   netmap_mem_private_new(const char *name, u_int txr, u_int txd, u_int rxr, u_int rxd);
void	   netmap_mem_private_delete(struct netmap_mem_d *nm_mem);

#define NETMAP_BDG_BUF_SIZE(n)	((n)->pools[NETMAP_BUF_POOL]._objsize)



#endif