sys/kern/kern_mpipe.c

   1 /*
   2  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sys/kern/kern_mpipe.c,v 1.9 2006/09/05 00:55:45 dillon Exp $
  35  */
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/kernel.h>
  40 #include <sys/slaballoc.h>
  41 #include <sys/mbuf.h>
  42 #include <sys/vmmeter.h>
  43 #include <sys/lock.h>
  44 #include <sys/thread.h>
  45 #include <sys/globaldata.h>
  46 #include <sys/mpipe.h>
  47
  48 #include <sys/thread2.h>
  49
  50 #define arysize(ary)    (sizeof(ary)/sizeof((ary)[0]))
  51
  52 static MALLOC_DEFINE(M_MPIPEARY, "MPipe Array", "Auxillary MPIPE structure");
  53
  54 /*
  55  * Initialize a malloc pipeline for the specified malloc type and allocation
  56  * size.  Create an array to cache up to nom_count buffers and preallocate
  57  * them.
  58  */
  59 void
  60 mpipe_init(malloc_pipe_t mpipe, malloc_type_t type, int bytes,
  61         int nnom, int nmax,
  62         int mpflags, void (*deconstruct)(struct malloc_pipe *, void *))
  63 {
  64     int n;
  65
  66     if (nnom < 1)
  67         nnom = 1;
  68     if (nmax < 0)
  69         nmax = 0x7FFF0000;      /* some very large number */
  70     if (nmax < nnom)
  71         nmax = nnom;
  72     bzero(mpipe, sizeof(struct malloc_pipe));
  73     mpipe->type = type;
  74     mpipe->bytes = bytes;
  75     mpipe->mpflags = mpflags;
  76     mpipe->deconstruct = deconstruct;
  77     if ((mpflags & MPF_NOZERO) == 0)
  78         mpipe->mflags |= M_ZERO;
  79     if (mpflags & MPF_INT)
  80         mpipe->mflags |= M_USE_RESERVE | M_USE_INTERRUPT_RESERVE;
  81     mpipe->ary_count = nnom;
  82     mpipe->max_count = nmax;
  83     mpipe->array = kmalloc(nnom * sizeof(mpipe->array[0]), M_MPIPEARY,
  84                             M_WAITOK | M_ZERO);
  85
  86     while (mpipe->free_count < nnom) {
  87         n = mpipe->free_count;
  88         mpipe->array[n] = kmalloc(bytes, mpipe->type, M_WAITOK | mpipe->mflags);
  89         ++mpipe->free_count;
  90         ++mpipe->total_count;
  91     }
  92 }
  93
  94 /*
  95  * Destroy a previously initialized mpipe.  This routine can also safely be
  96  * called on an uninitialized mpipe structure if it was zero'd or mpipe_done()
  97  * was previously called on it.
  98  */
  99 void
 100 mpipe_done(malloc_pipe_t mpipe)
 101 {
 102     void *buf;
 103     int n;
 104
 105     KKASSERT(mpipe->free_count == mpipe->total_count);  /* no outstanding mem */
 106     for (n = mpipe->free_count - 1; n >= 0; --n) {
 107         buf = mpipe->array[n];
 108         mpipe->array[n] = NULL;
 109         KKASSERT(buf != NULL);
 110         if (mpipe->deconstruct)
 111             mpipe->deconstruct(mpipe, buf);
 112         kfree(buf, mpipe->type);
 113     }
 114     mpipe->free_count = 0;
 115     mpipe->total_count = 0;
 116     if (mpipe->array) {
 117         kfree(mpipe->array, M_MPIPEARY);
 118         mpipe->array = NULL;
 119     }
 120 }
 121
 122 /*
 123  * Allocate an entry, nominally non-blocking.  The allocation is guarenteed
 124  * to return non-NULL up to the nominal count after which it may return NULL.
 125  * Note that the implementation is defined to be allowed to block for short
 126  * periods of time.  Use mpipe_alloc_waitok() to guarentee the allocation.
 127  */
 128 void *
 129 mpipe_alloc_nowait(malloc_pipe_t mpipe)
 130 {
 131     void *buf;
 132     int n;
 133
 134     crit_enter();
 135     if ((n = mpipe->free_count) != 0) {
 136         /*
 137          * Use a free entry if it exists.
 138          */
 139         --n;
 140         buf = mpipe->array[n];
 141         mpipe->array[n] = NULL; /* sanity check, not absolutely needed */
 142         mpipe->free_count = n;
 143     } else if (mpipe->total_count >= mpipe->max_count) {
 144         /*
 145          * Return NULL if we have hit our limit
 146          */
 147         buf = NULL;
 148     } else {
 149         /*
 150          * Otherwise try to malloc() non-blocking.
 151          */
 152         buf = kmalloc(mpipe->bytes, mpipe->type, M_NOWAIT | mpipe->mflags);
 153         if (buf)
 154             ++mpipe->total_count;
 155     }
 156     crit_exit();
 157     return(buf);
 158 }
 159
 160 /*
 161  * Allocate an entry, block until the allocation succeeds.  This may cause
 162  * us to block waiting for a prior allocation to be freed.
 163  */
 164 void *
 165 mpipe_alloc_waitok(malloc_pipe_t mpipe)
 166 {
 167     void *buf;
 168     int n;
 169     int mfailed;
 170
 171     crit_enter();
 172     mfailed = 0;
 173     for (;;) {
 174         if ((n = mpipe->free_count) != 0) {
 175             /*
 176              * Use a free entry if it exists.
 177              */
 178             --n;
 179             buf = mpipe->array[n];
 180             mpipe->array[n] = NULL;
 181             mpipe->free_count = n;
 182             break;
 183         }
 184         if (mpipe->total_count >= mpipe->max_count || mfailed) {
 185             /*
 186              * Block if we have hit our limit
 187              */
 188             mpipe->pending = 1;
 189             tsleep(mpipe, 0, "mpipe1", 0);
 190             continue;
 191         }
 192         /*
 193          * Otherwise try to malloc() non-blocking.  If that fails loop to
 194          * recheck, and block instead of trying to malloc() again.
 195          */
 196         buf = kmalloc(mpipe->bytes, mpipe->type, M_NOWAIT | mpipe->mflags);
 197         if (buf) {
 198             ++mpipe->total_count;
 199             break;
 200         }
 201         mfailed = 1;
 202     }
 203     crit_exit();
 204     return(buf);
 205 }
 206
 207 /*
 208  * Free an entry, unblock any waiters.  Allow NULL.
 209  */
 210 void
 211 mpipe_free(malloc_pipe_t mpipe, void *buf)
 212 {
 213     int n;
 214
 215     if (buf == NULL)
 216         return;
 217
 218     crit_enter();
 219     if ((n = mpipe->free_count) < mpipe->ary_count) {
 220         /*
 221          * Free slot available in free array (LIFO)
 222          */
 223         mpipe->array[n] = buf;
 224         ++mpipe->free_count;
 225         if ((mpipe->mpflags & (MPF_CACHEDATA|MPF_NOZERO)) == 0)
 226             bzero(buf, mpipe->bytes);
 227         crit_exit();
 228
 229         /*
 230          * Wakeup anyone blocked in mpipe_alloc_*().
 231          */
 232         if (mpipe->pending) {
 233             mpipe->pending = 0;
 234             wakeup(mpipe);
 235         }
 236     } else {
 237         /*
 238          * All the free slots are full, free the buffer directly.
 239          */
 240         --mpipe->total_count;
 241         KKASSERT(mpipe->total_count >= mpipe->free_count);
 242         if (mpipe->deconstruct)
 243             mpipe->deconstruct(mpipe, buf);
 244         crit_exit();
 245         kfree(buf, mpipe->type);
 246     }
 247 }
 248