3 * Dynamic memory manager
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8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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9 * All rights reserved.
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11 * Redistribution and use in source and binary forms, with or without modification,
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12 * are permitted provided that the following conditions are met:
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14 * 1. Redistributions of source code must retain the above copyright notice,
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15 * this list of conditions and the following disclaimer.
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16 * 2. Redistributions in binary form must reproduce the above copyright notice,
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17 * this list of conditions and the following disclaimer in the documentation
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18 * and/or other materials provided with the distribution.
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19 * 3. The name of the author may not be used to endorse or promote products
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20 * derived from this software without specific prior written permission.
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22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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33 * This file is part of the lwIP TCP/IP stack.
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35 * Author: Adam Dunkels <adam@sics.se>
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41 #include "lwip/arch.h"
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42 #include "lwip/opt.h"
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43 #include "lwip/def.h"
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44 #include "lwip/mem.h"
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46 #include "lwip/sys.h"
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48 #include "lwip/stats.h"
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51 mem_size_t next, prev;
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52 #if MEM_ALIGNMENT == 1
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54 #elif MEM_ALIGNMENT == 2
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56 #elif MEM_ALIGNMENT == 4
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58 #elif MEM_ALIGNMENT == 8
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61 #error "unhandled MEM_ALIGNMENT size"
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62 #endif /* MEM_ALIGNMENT */
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65 static struct mem *ram_end;
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66 static u8_t ram[MEM_SIZE + sizeof(struct mem) + MEM_ALIGNMENT];
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69 #if 0 /* this one does not align correctly for some, resulting in crashes */
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70 #define SIZEOF_STRUCT_MEM (unsigned int)MEM_ALIGN_SIZE(sizeof(struct mem))
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72 #define SIZEOF_STRUCT_MEM (sizeof(struct mem) + \
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73 (((sizeof(struct mem) % MEM_ALIGNMENT) == 0)? 0 : \
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74 (4 - (sizeof(struct mem) % MEM_ALIGNMENT))))
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77 static struct mem *lfree; /* pointer to the lowest free block */
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79 static sys_sem_t mem_sem;
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82 plug_holes(struct mem *mem)
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87 LWIP_ASSERT("plug_holes: mem >= ram", (u8_t *)mem >= ram);
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88 LWIP_ASSERT("plug_holes: mem < ram_end", (u8_t *)mem < (u8_t *)ram_end);
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89 LWIP_ASSERT("plug_holes: mem->used == 0", mem->used == 0);
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91 /* plug hole forward */
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92 LWIP_ASSERT("plug_holes: mem->next <= MEM_SIZE", mem->next <= MEM_SIZE);
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94 nmem = (struct mem *)&ram[mem->next];
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95 if (mem != nmem && nmem->used == 0 && (u8_t *)nmem != (u8_t *)ram_end) {
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96 if (lfree == nmem) {
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99 mem->next = nmem->next;
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100 ((struct mem *)&ram[nmem->next])->prev = (u8_t *)mem - ram;
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103 /* plug hole backward */
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104 pmem = (struct mem *)&ram[mem->prev];
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105 if (pmem != mem && pmem->used == 0) {
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106 if (lfree == mem) {
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109 pmem->next = mem->next;
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110 ((struct mem *)&ram[mem->next])->prev = (u8_t *)pmem - ram;
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119 memset(ram, 0, MEM_SIZE);
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120 mem = (struct mem *)ram;
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121 mem->next = MEM_SIZE;
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124 ram_end = (struct mem *)&ram[MEM_SIZE];
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126 ram_end->next = MEM_SIZE;
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127 ram_end->prev = MEM_SIZE;
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129 mem_sem = sys_sem_new(1);
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131 lfree = (struct mem *)ram;
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134 lwip_stats.mem.avail = MEM_SIZE;
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135 #endif /* MEM_STATS */
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138 mem_free(void *rmem)
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142 if (rmem == NULL) {
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143 LWIP_DEBUGF(MEM_DEBUG | DBG_TRACE | 2, ("mem_free(p == NULL) was called.\n"));
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147 sys_sem_wait(mem_sem);
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149 LWIP_ASSERT("mem_free: legal memory", (u8_t *)rmem >= (u8_t *)ram &&
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150 (u8_t *)rmem < (u8_t *)ram_end);
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152 if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) {
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153 LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_free: illegal memory\n"));
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155 ++lwip_stats.mem.err;
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156 #endif /* MEM_STATS */
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157 sys_sem_signal(mem_sem);
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160 mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);
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162 LWIP_ASSERT("mem_free: mem->used", mem->used);
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171 lwip_stats.mem.used -= mem->next - ((u8_t *)mem - ram);
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173 #endif /* MEM_STATS */
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175 sys_sem_signal(mem_sem);
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178 mem_reallocm(void *rmem, mem_size_t newsize)
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181 nmem = mem_malloc(newsize);
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182 if (nmem == NULL) {
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183 return mem_realloc(rmem, newsize);
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185 memcpy(nmem, rmem, newsize);
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191 mem_realloc(void *rmem, mem_size_t newsize)
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194 mem_size_t ptr, ptr2;
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195 struct mem *mem, *mem2;
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197 /* Expand the size of the allocated memory region so that we can
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198 adjust for alignment. */
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199 if ((newsize % MEM_ALIGNMENT) != 0) {
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200 newsize += MEM_ALIGNMENT - ((newsize + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT);
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203 if (newsize > MEM_SIZE) {
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207 sys_sem_wait(mem_sem);
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209 LWIP_ASSERT("mem_realloc: legal memory", (u8_t *)rmem >= (u8_t *)ram &&
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210 (u8_t *)rmem < (u8_t *)ram_end);
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212 if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) {
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213 LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_realloc: illegal memory\n"));
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216 mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);
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218 ptr = (u8_t *)mem - ram;
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220 size = mem->next - ptr - SIZEOF_STRUCT_MEM;
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222 lwip_stats.mem.used -= (size - newsize);
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223 #endif /* MEM_STATS */
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225 if (newsize + SIZEOF_STRUCT_MEM + MIN_SIZE < size) {
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226 ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize;
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227 mem2 = (struct mem *)&ram[ptr2];
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229 mem2->next = mem->next;
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232 if (mem2->next != MEM_SIZE) {
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233 ((struct mem *)&ram[mem2->next])->prev = ptr2;
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238 sys_sem_signal(mem_sem);
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242 mem_malloc(mem_size_t size)
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244 mem_size_t ptr, ptr2;
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245 struct mem *mem, *mem2;
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251 /* Expand the size of the allocated memory region so that we can
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252 adjust for alignment. */
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253 if ((size % MEM_ALIGNMENT) != 0) {
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254 size += MEM_ALIGNMENT - ((size + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT);
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257 if (size > MEM_SIZE) {
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261 sys_sem_wait(mem_sem);
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263 for (ptr = (u8_t *)lfree - ram; ptr < MEM_SIZE; ptr = ((struct mem *)&ram[ptr])->next) {
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264 mem = (struct mem *)&ram[ptr];
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266 mem->next - (ptr + SIZEOF_STRUCT_MEM) >= size + SIZEOF_STRUCT_MEM) {
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267 ptr2 = ptr + SIZEOF_STRUCT_MEM + size;
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268 mem2 = (struct mem *)&ram[ptr2];
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271 mem2->next = mem->next;
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273 if (mem2->next != MEM_SIZE) {
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274 ((struct mem *)&ram[mem2->next])->prev = ptr2;
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280 lwip_stats.mem.used += (size + SIZEOF_STRUCT_MEM);
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281 /* if (lwip_stats.mem.max < lwip_stats.mem.used) {
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282 lwip_stats.mem.max = lwip_stats.mem.used;
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284 if (lwip_stats.mem.max < ptr2) {
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285 lwip_stats.mem.max = ptr2;
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287 #endif /* MEM_STATS */
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289 if (mem == lfree) {
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290 /* Find next free block after mem */
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291 while (lfree->used && lfree != ram_end) {
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292 lfree = (struct mem *)&ram[lfree->next];
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294 LWIP_ASSERT("mem_malloc: !lfree->used", !lfree->used);
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296 sys_sem_signal(mem_sem);
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297 LWIP_ASSERT("mem_malloc: allocated memory not above ram_end.",
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298 (mem_ptr_t)mem + SIZEOF_STRUCT_MEM + size <= (mem_ptr_t)ram_end);
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299 LWIP_ASSERT("mem_malloc: allocated memory properly aligned.",
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300 (unsigned long)((u8_t *)mem + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT == 0);
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301 return (u8_t *)mem + SIZEOF_STRUCT_MEM;
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304 LWIP_DEBUGF(MEM_DEBUG | 2, ("mem_malloc: could not allocate %d bytes\n", (int)size));
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306 ++lwip_stats.mem.err;
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307 #endif /* MEM_STATS */
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308 sys_sem_signal(mem_sem);
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