FreeBSD/Linux Kernel Cross Reference
sys/dev/netmap/netmap_mem2.h

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (C) 2012-2014 Matteo Landi
      * Copyright (C) 2012-2016 Luigi Rizzo
      * Copyright (C) 2012-2016 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 individual 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 (through 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_
   
   
   
   /* 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.
    */
   
   extern struct netmap_mem_d nm_mem;
   typedef uint16_t nm_memid_t;
   
   int        netmap_mem_get_lut(struct netmap_mem_d *, struct netmap_lut *);
   nm_memid_t netmap_mem_get_id(struct netmap_mem_d *);
   vm_paddr_t netmap_mem_ofstophys(struct netmap_mem_d *, vm_ooffset_t);
   #ifdef _WIN32
   PMDL win32_build_user_vm_map(struct netmap_mem_d* nmd);
   #endif
   int        netmap_mem_finalize(struct netmap_mem_d *, struct netmap_adapter *);
   int        netmap_mem_init(void);
   void       netmap_mem_fini(void);
   struct netmap_if * netmap_mem_if_new(struct netmap_adapter *, struct netmap_priv_d *);
   void       netmap_mem_if_delete(struct netmap_adapter *, struct netmap_if *);
   int        netmap_mem_rings_create(struct netmap_adapter *);
   void       netmap_mem_rings_delete(struct netmap_adapter *);
   int        netmap_mem_deref(struct netmap_mem_d *, struct netmap_adapter *);
   int        netmap_mem2_get_pool_info(struct netmap_mem_d *, u_int, u_int *, u_int *);
   int        netmap_mem_get_info(struct netmap_mem_d *, uint64_t *size,
                                   u_int *memflags, nm_memid_t *id);
   ssize_t    netmap_mem_if_offset(struct netmap_mem_d *, const void *vaddr);
   struct netmap_mem_d* netmap_mem_private_new( u_int txr, u_int txd, u_int rxr, u_int rxd,
                   u_int extra_bufs, u_int npipes, int* error);
   
   #define netmap_mem_get(d) __netmap_mem_get(d, __FUNCTION__, __LINE__)
   #define netmap_mem_put(d) __netmap_mem_put(d, __FUNCTION__, __LINE__)
   struct netmap_mem_d* __netmap_mem_get(struct netmap_mem_d *, const char *, int);
   struct netmap_mem_d* netmap_mem_get_iommu(struct netmap_adapter *);
   void __netmap_mem_put(struct netmap_mem_d *, const char *, int);
   struct netmap_mem_d* netmap_mem_find(nm_memid_t);
   unsigned netmap_mem_bufsize(struct netmap_mem_d *nmd);
   
   #ifdef WITH_EXTMEM
   struct netmap_mem_d* netmap_mem_ext_create(uint64_t, struct nmreq_pools_info *, int *);
   #else /* !WITH_EXTMEM */
   #define netmap_mem_ext_create(nmr, _perr) \
           ({ int *perr = _perr; if (perr) *(perr) = EOPNOTSUPP; NULL; })
   #endif /* WITH_EXTMEM */
   
   #ifdef WITH_PTNETMAP
   struct netmap_mem_d* netmap_mem_pt_guest_new(struct ifnet *,
                                                unsigned int nifp_offset,
                                                unsigned int memid);
   struct ptnetmap_memdev;
   struct netmap_mem_d* netmap_mem_pt_guest_attach(struct ptnetmap_memdev *, uint16_t);
   int netmap_mem_pt_guest_ifp_del(struct netmap_mem_d *, struct ifnet *);
   #endif /* WITH_PTNETMAP */
   
   int netmap_mem_pools_info_get(struct nmreq_pools_info *,
                                   struct netmap_mem_d *);
   
   #define NETMAP_MEM_PRIVATE      0x2     /* allocator uses private address space */
   #define NETMAP_MEM_IO           0x4     /* the underlying memory is mmapped I/O */
   
   uint32_t netmap_extra_alloc(struct netmap_adapter *, uint32_t *, uint32_t n);
   
   #ifdef WITH_EXTMEM
   #include <net/netmap_virt.h>
   struct nm_os_extmem; /* opaque */
   struct nm_os_extmem *nm_os_extmem_create(unsigned long, struct nmreq_pools_info *, int *perror);
   char *nm_os_extmem_nextpage(struct nm_os_extmem *);
   int nm_os_extmem_nr_pages(struct nm_os_extmem *);
   int nm_os_extmem_isequal(struct nm_os_extmem *, struct nm_os_extmem *);
   void nm_os_extmem_delete(struct nm_os_extmem *);
   #endif /* WITH_EXTMEM */
   
   #endif

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