src/MemObject.cc

   1 /*
   2  * Copyright (C) 1996-2015 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 /* DEBUG: section 19    Store Memory Primitives */
  10
  11 #include "squid.h"
  12 #include "comm/Connection.h"
  13 #include "Generic.h"
  14 #include "globals.h"
  15 #include "HttpReply.h"
  16 #include "HttpRequest.h"
  17 #include "MemBuf.h"
  18 #include "MemObject.h"
  19 #include "profiler/Profiler.h"
  20 #include "SquidConfig.h"
  21 #include "Store.h"
  22 #include "StoreClient.h"
  23
  24 #if USE_DELAY_POOLS
  25 #include "DelayPools.h"
  26 #endif
  27
  28 /* TODO: make this global or private */
  29 #if URL_CHECKSUM_DEBUG
  30 static unsigned int url_checksum(const char *url);
  31 unsigned int
  32 url_checksum(const char *url)
  33 {
  34     unsigned int ck;
  35     SquidMD5_CTX M;
  36     static unsigned char digest[16];
  37     SquidMD5Init(&M);
  38     SquidMD5Update(&M, (unsigned char *) url, strlen(url));
  39     SquidMD5Final(digest, &M);
  40     memcpy(&ck, digest, sizeof(ck));
  41     return ck;
  42 }
  43
  44 #endif
  45
  46 RemovalPolicy * mem_policy = NULL;
  47
  48 size_t
  49 MemObject::inUseCount()
  50 {
  51     return Pool().inUseCount();
  52 }
  53
  54 const char *
  55 MemObject::storeId() const
  56 {
  57     if (!storeId_.size()) {
  58         debugs(20, DBG_IMPORTANT, "Bug: Missing MemObject::storeId value");
  59         dump();
  60         storeId_ = "[unknown_URI]";
  61     }
  62     return storeId_.termedBuf();
  63 }
  64
  65 const char *
  66 MemObject::logUri() const
  67 {
  68     return logUri_.size() ? logUri_.termedBuf() : storeId();
  69 }
  70
  71 bool
  72 MemObject::hasUris() const
  73 {
  74     return storeId_.size();
  75 }
  76
  77 void
  78 MemObject::setUris(char const *aStoreId, char const *aLogUri, const HttpRequestMethod &aMethod)
  79 {
  80     storeId_ = aStoreId;
  81
  82     // fast pointer comparison for a common storeCreateEntry(url,url,...) case
  83     if (!aLogUri || aLogUri == aStoreId)
  84         logUri_.clean(); // use storeId_ by default to minimize copying
  85     else
  86         logUri_ = aLogUri;
  87
  88     method = aMethod;
  89
  90 #if URL_CHECKSUM_DEBUG
  91     chksum = url_checksum(urlXXX());
  92 #endif
  93 }
  94
  95 MemObject::MemObject(): smpCollapsed(false)
  96 {
  97     debugs(20, 3, HERE << "new MemObject " << this);
  98     _reply = new HttpReply;
  99     HTTPMSGLOCK(_reply);
 100
 101     object_sz = -1;
 102
 103     /* XXX account log_url */
 104
 105     swapout.decision = SwapOut::swNeedsCheck;
 106 }
 107
 108 MemObject::~MemObject()
 109 {
 110     debugs(20, 3, HERE << "del MemObject " << this);
 111     const Ctx ctx = ctx_enter(hasUris() ? urlXXX() : "[unknown_ctx]");
 112
 113 #if URL_CHECKSUM_DEBUG
 114     checkUrlChecksum();
 115 #endif
 116
 117     if (!shutting_down) { // Store::Root() is FATALly missing during shutdown
 118         assert(xitTable.index < 0);
 119         assert(memCache.index < 0);
 120         assert(swapout.sio == NULL);
 121     }
 122
 123     data_hdr.freeContent();
 124
 125 #if 0
 126     /*
 127      * There is no way to abort FD-less clients, so they might
 128      * still have mem->clients set.
 129      */
 130     assert(clients.head == NULL);
 131
 132 #endif
 133
 134     HTTPMSGUNLOCK(_reply);
 135
 136     HTTPMSGUNLOCK(request);
 137
 138     ctx_exit(ctx);              /* must exit before we free mem->url */
 139
 140     safe_free(vary_headers);
 141 }
 142
 143 void
 144 MemObject::unlinkRequest()
 145 {
 146     HTTPMSGUNLOCK(request);
 147 }
 148
 149 void
 150 MemObject::write(const StoreIOBuffer &writeBuffer)
 151 {
 152     PROF_start(MemObject_write);
 153     debugs(19, 6, "memWrite: offset " << writeBuffer.offset << " len " << writeBuffer.length);
 154
 155     /* We don't separate out mime headers yet, so ensure that the first
 156      * write is at offset 0 - where they start
 157      */
 158     assert (data_hdr.endOffset() || writeBuffer.offset == 0);
 159
 160     assert (data_hdr.write (writeBuffer));
 161     PROF_stop(MemObject_write);
 162 }
 163
 164 void
 165 MemObject::dump() const
 166 {
 167     data_hdr.dump();
 168 #if 0
 169     /* do we want this one? */
 170     debugs(20, DBG_IMPORTANT, "MemObject->data.origin_offset: " << (data_hdr.head ? data_hdr.head->nodeBuffer.offset : 0));
 171 #endif
 172
 173     debugs(20, DBG_IMPORTANT, "MemObject->start_ping: " << start_ping.tv_sec  << "."<< std::setfill('0') << std::setw(6) << start_ping.tv_usec);
 174     debugs(20, DBG_IMPORTANT, "MemObject->inmem_hi: " << data_hdr.endOffset());
 175     debugs(20, DBG_IMPORTANT, "MemObject->inmem_lo: " << inmem_lo);
 176     debugs(20, DBG_IMPORTANT, "MemObject->nclients: " << nclients);
 177     debugs(20, DBG_IMPORTANT, "MemObject->reply: " << _reply);
 178     debugs(20, DBG_IMPORTANT, "MemObject->request: " << request);
 179     debugs(20, DBG_IMPORTANT, "MemObject->logUri: " << logUri_);
 180     debugs(20, DBG_IMPORTANT, "MemObject->storeId: " << storeId_);
 181 }
 182
 183 HttpReply const *
 184 MemObject::getReply() const
 185 {
 186     return _reply;
 187 }
 188
 189 void
 190 MemObject::replaceHttpReply(HttpReply *newrep)
 191 {
 192     HTTPMSGUNLOCK(_reply);
 193     _reply = newrep;
 194     HTTPMSGLOCK(_reply);
 195 }
 196
 197 struct LowestMemReader : public unary_function<store_client, void> {
 198     LowestMemReader(int64_t seed):current(seed) {}
 199
 200     void operator() (store_client const &x) {
 201         if (x.memReaderHasLowerOffset(current))
 202             current = x.copyInto.offset;
 203     }
 204
 205     int64_t current;
 206 };
 207
 208 struct StoreClientStats : public unary_function<store_client, void> {
 209     StoreClientStats(MemBuf *anEntry):where(anEntry),index(0) {}
 210
 211     void operator()(store_client const &x) {
 212         x.dumpStats(where, index);
 213         ++index;
 214     }
 215
 216     MemBuf *where;
 217     size_t index;
 218 };
 219
 220 void
 221 MemObject::stat(MemBuf * mb) const
 222 {
 223     mb->appendf("\t" SQUIDSBUFPH " %s\n", SQUIDSBUFPRINT(method.image()), logUri());
 224     if (vary_headers)
 225         mb->appendf("\tvary_headers: %s\n", vary_headers);
 226     mb->appendf("\tinmem_lo: %" PRId64 "\n", inmem_lo);
 227     mb->appendf("\tinmem_hi: %" PRId64 "\n", data_hdr.endOffset());
 228     mb->appendf("\tswapout: %" PRId64 " bytes queued\n", swapout.queue_offset);
 229
 230     if (swapout.sio.getRaw())
 231         mb->appendf("\tswapout: %" PRId64 " bytes written\n", (int64_t) swapout.sio->offset());
 232
 233     if (xitTable.index >= 0)
 234         mb->appendf("\ttransient index: %d state: %d\n", xitTable.index, xitTable.io);
 235     if (memCache.index >= 0)
 236         mb->appendf("\tmem-cache index: %d state: %d offset: %" PRId64 "\n", memCache.index, memCache.io, memCache.offset);
 237     if (object_sz >= 0)
 238         mb->appendf("\tobject_sz: %" PRId64 "\n", object_sz);
 239     if (smpCollapsed)
 240         mb->appendf("\tsmp-collapsed\n");
 241
 242     StoreClientStats statsVisitor(mb);
 243
 244     for_each<StoreClientStats>(clients, statsVisitor);
 245 }
 246
 247 int64_t
 248 MemObject::endOffset () const
 249 {
 250     return data_hdr.endOffset();
 251 }
 252
 253 void
 254 MemObject::markEndOfReplyHeaders()
 255 {
 256     const int hdr_sz = endOffset();
 257     assert(hdr_sz >= 0);
 258     assert(_reply);
 259     _reply->hdr_sz = hdr_sz;
 260 }
 261
 262 int64_t
 263 MemObject::size() const
 264 {
 265     if (object_sz < 0)
 266         return endOffset();
 267
 268     return object_sz;
 269 }
 270
 271 int64_t
 272 MemObject::expectedReplySize() const
 273 {
 274     debugs(20, 7, HERE << "object_sz: " << object_sz);
 275     if (object_sz >= 0) // complete() has been called; we know the exact answer
 276         return object_sz;
 277
 278     if (_reply) {
 279         const int64_t clen = _reply->bodySize(method);
 280         debugs(20, 7, HERE << "clen: " << clen);
 281         if (clen >= 0 && _reply->hdr_sz > 0) // yuck: HttpMsg sets hdr_sz to 0
 282             return clen + _reply->hdr_sz;
 283     }
 284
 285     return -1; // not enough information to predict
 286 }
 287
 288 void
 289 MemObject::reset()
 290 {
 291     assert(swapout.sio == NULL);
 292     data_hdr.freeContent();
 293     inmem_lo = 0;
 294     /* Should we check for clients? */
 295 }
 296
 297 int64_t
 298 MemObject::lowestMemReaderOffset() const
 299 {
 300     LowestMemReader lowest (endOffset() + 1);
 301
 302     for_each <LowestMemReader>(clients, lowest);
 303
 304     return lowest.current;
 305 }
 306
 307 /* XXX: This is wrong. It breaks *badly* on range combining */
 308 bool
 309 MemObject::readAheadPolicyCanRead() const
 310 {
 311     const bool canRead = endOffset() - getReply()->hdr_sz <
 312                          lowestMemReaderOffset() + Config.readAheadGap;
 313
 314     if (!canRead) {
 315         debugs(19, 9, "no: " << endOffset() << '-' << getReply()->hdr_sz <<
 316                " < " << lowestMemReaderOffset() << '+' << Config.readAheadGap);
 317     }
 318
 319     return canRead;
 320 }
 321
 322 void
 323 MemObject::addClient(store_client *aClient)
 324 {
 325     ++nclients;
 326     dlinkAdd(aClient, &aClient->node, &clients);
 327 }
 328
 329 #if URL_CHECKSUM_DEBUG
 330 void
 331 MemObject::checkUrlChecksum () const
 332 {
 333     assert(chksum == url_checksum(urlXXX()));
 334 }
 335
 336 #endif
 337
 338 /*
 339  * How much of the object data is on the disk?
 340  */
 341 int64_t
 342 MemObject::objectBytesOnDisk() const
 343 {
 344     /*
 345      * NOTE: storeOffset() represents the disk file size,
 346      * not the amount of object data on disk.
 347      *
 348      * If we don't have at least 'swap_hdr_sz' bytes
 349      * then none of the object data is on disk.
 350      *
 351      * This should still be safe if swap_hdr_sz == 0,
 352      * meaning we haven't even opened the swapout file
 353      * yet.
 354      */
 355
 356     if (swapout.sio.getRaw() == NULL)
 357         return 0;
 358
 359     int64_t nwritten = swapout.sio->offset();
 360
 361     if (nwritten <= (int64_t)swap_hdr_sz)
 362         return 0;
 363
 364     return (nwritten - swap_hdr_sz);
 365 }
 366
 367 int64_t
 368 MemObject::policyLowestOffsetToKeep(bool swap) const
 369 {
 370     /*
 371      * Careful.  lowest_offset can be greater than endOffset(), such
 372      * as in the case of a range request.
 373      */
 374     int64_t lowest_offset = lowestMemReaderOffset();
 375
 376     if (endOffset() < lowest_offset ||
 377             endOffset() - inmem_lo > (int64_t)Config.Store.maxInMemObjSize ||
 378             (swap && !Config.onoff.memory_cache_first))
 379         return lowest_offset;
 380
 381     return inmem_lo;
 382 }
 383
 384 void
 385 MemObject::trimSwappable()
 386 {
 387     int64_t new_mem_lo = policyLowestOffsetToKeep(1);
 388     /*
 389      * We should only free up to what we know has been written
 390      * to disk, not what has been queued for writing.  Otherwise
 391      * there will be a chunk of the data which is not in memory
 392      * and is not yet on disk.
 393      * The -1 makes sure the page isn't freed until storeSwapOut has
 394      * walked to the next page.
 395      */
 396     int64_t on_disk;
 397
 398     if ((on_disk = objectBytesOnDisk()) - 1 < new_mem_lo)
 399         new_mem_lo = on_disk - 1;
 400
 401     if (new_mem_lo == -1)
 402         new_mem_lo = 0; /* the above might become -1 */
 403
 404     data_hdr.freeDataUpto(new_mem_lo);
 405
 406     inmem_lo = new_mem_lo;
 407 }
 408
 409 void
 410 MemObject::trimUnSwappable()
 411 {
 412     if (const int64_t new_mem_lo = policyLowestOffsetToKeep(false)) {
 413         assert (new_mem_lo > 0);
 414         data_hdr.freeDataUpto(new_mem_lo);
 415         inmem_lo = new_mem_lo;
 416     } // else we should not trim anything at this time
 417 }
 418
 419 bool
 420 MemObject::isContiguous() const
 421 {
 422     bool result = data_hdr.hasContigousContentRange (Range<int64_t>(inmem_lo, endOffset()));
 423     /* XXX : make this higher level */
 424     debugs (19, result ? 4 :3, "MemObject::isContiguous: Returning " << (result ? "true" : "false"));
 425     return result;
 426 }
 427
 428 int
 429 MemObject::mostBytesWanted(int max, bool ignoreDelayPools) const
 430 {
 431 #if USE_DELAY_POOLS
 432     if (!ignoreDelayPools) {
 433         /* identify delay id with largest allowance */
 434         DelayId largestAllowance = mostBytesAllowed ();
 435         return largestAllowance.bytesWanted(0, max);
 436     }
 437 #endif
 438
 439     return max;
 440 }
 441
 442 void
 443 MemObject::setNoDelay(bool const newValue)
 444 {
 445 #if USE_DELAY_POOLS
 446
 447     for (dlink_node *node = clients.head; node; node = node->next) {
 448         store_client *sc = (store_client *) node->data;
 449         sc->delayId.setNoDelay(newValue);
 450     }
 451
 452 #endif
 453 }
 454
 455 void
 456 MemObject::delayRead(DeferredRead const &aRead)
 457 {
 458     deferredReads.delayRead(aRead);
 459 }
 460
 461 void
 462 MemObject::kickReads()
 463 {
 464     deferredReads.kickReads(-1);
 465 }
 466
 467 #if USE_DELAY_POOLS
 468 DelayId
 469 MemObject::mostBytesAllowed() const
 470 {
 471     int j;
 472     int jmax = -1;
 473     DelayId result;
 474
 475     for (dlink_node *node = clients.head; node; node = node->next) {
 476         store_client *sc = (store_client *) node->data;
 477 #if 0
 478         /* This test is invalid because the client may be writing data
 479          * and thus will want data immediately.
 480          * If we include the test, there is a race condition when too much
 481          * data is read - if all sc's are writing when a read is scheduled.
 482          * XXX: fixme.
 483          */
 484
 485         if (!sc->callbackPending())
 486             /* not waiting for more data */
 487             continue;
 488
 489 #endif
 490
 491         j = sc->delayId.bytesWanted(0, sc->copyInto.length);
 492
 493         if (j > jmax) {
 494             jmax = j;
 495             result = sc->delayId;
 496         }
 497     }
 498
 499     return result;
 500 }
 501
 502 #endif
 503
 504 int64_t
 505 MemObject::availableForSwapOut() const
 506 {
 507     return endOffset() - swapout.queue_offset;
 508 }
 509