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() :
  96     inmem_lo(0),
  97     nclients(0),
  98     smpCollapsed(false),
  99     request(nullptr),
 100     ping_reply_callback(nullptr),
 101     ircb_data(nullptr),
 102     id(0),
 103     object_sz(-1),
 104     swap_hdr_sz(0),
 105 #if URL_CHECKSUM_DEBUG
 106     chksum(0),
 107 #endif
 108     vary_headers(nullptr)
 109 {
 110     debugs(20, 3, "new MemObject " << this);
 111     memset(&start_ping, 0, sizeof(start_ping));
 112     memset(&abort, 0, sizeof(abort));
 113     _reply = new HttpReply;
 114     HTTPMSGLOCK(_reply);
 115 }
 116
 117 MemObject::~MemObject()
 118 {
 119     debugs(20, 3, "del MemObject " << this);
 120     const Ctx ctx = ctx_enter(hasUris() ? urlXXX() : "[unknown_ctx]");
 121
 122 #if URL_CHECKSUM_DEBUG
 123     checkUrlChecksum();
 124 #endif
 125
 126     if (!shutting_down) { // Store::Root() is FATALly missing during shutdown
 127         assert(xitTable.index < 0);
 128         assert(memCache.index < 0);
 129         assert(swapout.sio == NULL);
 130     }
 131
 132     data_hdr.freeContent();
 133
 134 #if 0
 135     /*
 136      * There is no way to abort FD-less clients, so they might
 137      * still have mem->clients set.
 138      */
 139     assert(clients.head == NULL);
 140
 141 #endif
 142
 143     HTTPMSGUNLOCK(_reply);
 144
 145     HTTPMSGUNLOCK(request);
 146
 147     ctx_exit(ctx);              /* must exit before we free mem->url */
 148
 149     safe_free(vary_headers);
 150 }
 151
 152 void
 153 MemObject::unlinkRequest()
 154 {
 155     HTTPMSGUNLOCK(request);
 156 }
 157
 158 void
 159 MemObject::write(const StoreIOBuffer &writeBuffer)
 160 {
 161     PROF_start(MemObject_write);
 162     debugs(19, 6, "memWrite: offset " << writeBuffer.offset << " len " << writeBuffer.length);
 163
 164     /* We don't separate out mime headers yet, so ensure that the first
 165      * write is at offset 0 - where they start
 166      */
 167     assert (data_hdr.endOffset() || writeBuffer.offset == 0);
 168
 169     assert (data_hdr.write (writeBuffer));
 170     PROF_stop(MemObject_write);
 171 }
 172
 173 void
 174 MemObject::dump() const
 175 {
 176     data_hdr.dump();
 177 #if 0
 178     /* do we want this one? */
 179     debugs(20, DBG_IMPORTANT, "MemObject->data.origin_offset: " << (data_hdr.head ? data_hdr.head->nodeBuffer.offset : 0));
 180 #endif
 181
 182     debugs(20, DBG_IMPORTANT, "MemObject->start_ping: " << start_ping.tv_sec  << "."<< std::setfill('0') << std::setw(6) << start_ping.tv_usec);
 183     debugs(20, DBG_IMPORTANT, "MemObject->inmem_hi: " << data_hdr.endOffset());
 184     debugs(20, DBG_IMPORTANT, "MemObject->inmem_lo: " << inmem_lo);
 185     debugs(20, DBG_IMPORTANT, "MemObject->nclients: " << nclients);
 186     debugs(20, DBG_IMPORTANT, "MemObject->reply: " << _reply);
 187     debugs(20, DBG_IMPORTANT, "MemObject->request: " << request);
 188     debugs(20, DBG_IMPORTANT, "MemObject->logUri: " << logUri_);
 189     debugs(20, DBG_IMPORTANT, "MemObject->storeId: " << storeId_);
 190 }
 191
 192 HttpReply const *
 193 MemObject::getReply() const
 194 {
 195     return _reply;
 196 }
 197
 198 void
 199 MemObject::replaceHttpReply(HttpReply *newrep)
 200 {
 201     HTTPMSGUNLOCK(_reply);
 202     _reply = newrep;
 203     HTTPMSGLOCK(_reply);
 204 }
 205
 206 struct LowestMemReader : public unary_function<store_client, void> {
 207     LowestMemReader(int64_t seed):current(seed) {}
 208
 209     void operator() (store_client const &x) {
 210         if (x.memReaderHasLowerOffset(current))
 211             current = x.copyInto.offset;
 212     }
 213
 214     int64_t current;
 215 };
 216
 217 struct StoreClientStats : public unary_function<store_client, void> {
 218     StoreClientStats(MemBuf *anEntry):where(anEntry),index(0) {}
 219
 220     void operator()(store_client const &x) {
 221         x.dumpStats(where, index);
 222         ++index;
 223     }
 224
 225     MemBuf *where;
 226     size_t index;
 227 };
 228
 229 void
 230 MemObject::stat(MemBuf * mb) const
 231 {
 232     mb->appendf("\t" SQUIDSBUFPH " %s\n", SQUIDSBUFPRINT(method.image()), logUri());
 233     if (vary_headers)
 234         mb->appendf("\tvary_headers: %s\n", vary_headers);
 235     mb->appendf("\tinmem_lo: %" PRId64 "\n", inmem_lo);
 236     mb->appendf("\tinmem_hi: %" PRId64 "\n", data_hdr.endOffset());
 237     mb->appendf("\tswapout: %" PRId64 " bytes queued\n", swapout.queue_offset);
 238
 239     if (swapout.sio.getRaw())
 240         mb->appendf("\tswapout: %" PRId64 " bytes written\n", (int64_t) swapout.sio->offset());
 241
 242     if (xitTable.index >= 0)
 243         mb->appendf("\ttransient index: %d state: %d\n", xitTable.index, xitTable.io);
 244     if (memCache.index >= 0)
 245         mb->appendf("\tmem-cache index: %d state: %d offset: %" PRId64 "\n", memCache.index, memCache.io, memCache.offset);
 246     if (object_sz >= 0)
 247         mb->appendf("\tobject_sz: %" PRId64 "\n", object_sz);
 248     if (smpCollapsed)
 249         mb->appendf("\tsmp-collapsed\n");
 250
 251     StoreClientStats statsVisitor(mb);
 252
 253     for_each<StoreClientStats>(clients, statsVisitor);
 254 }
 255
 256 int64_t
 257 MemObject::endOffset () const
 258 {
 259     return data_hdr.endOffset();
 260 }
 261
 262 void
 263 MemObject::markEndOfReplyHeaders()
 264 {
 265     const int hdr_sz = endOffset();
 266     assert(hdr_sz >= 0);
 267     assert(_reply);
 268     _reply->hdr_sz = hdr_sz;
 269 }
 270
 271 int64_t
 272 MemObject::size() const
 273 {
 274     if (object_sz < 0)
 275         return endOffset();
 276
 277     return object_sz;
 278 }
 279
 280 int64_t
 281 MemObject::expectedReplySize() const
 282 {
 283     debugs(20, 7, HERE << "object_sz: " << object_sz);
 284     if (object_sz >= 0) // complete() has been called; we know the exact answer
 285         return object_sz;
 286
 287     if (_reply) {
 288         const int64_t clen = _reply->bodySize(method);
 289         debugs(20, 7, HERE << "clen: " << clen);
 290         if (clen >= 0 && _reply->hdr_sz > 0) // yuck: HttpMsg sets hdr_sz to 0
 291             return clen + _reply->hdr_sz;
 292     }
 293
 294     return -1; // not enough information to predict
 295 }
 296
 297 void
 298 MemObject::reset()
 299 {
 300     assert(swapout.sio == NULL);
 301     data_hdr.freeContent();
 302     inmem_lo = 0;
 303     /* Should we check for clients? */
 304 }
 305
 306 int64_t
 307 MemObject::lowestMemReaderOffset() const
 308 {
 309     LowestMemReader lowest (endOffset() + 1);
 310
 311     for_each <LowestMemReader>(clients, lowest);
 312
 313     return lowest.current;
 314 }
 315
 316 /* XXX: This is wrong. It breaks *badly* on range combining */
 317 bool
 318 MemObject::readAheadPolicyCanRead() const
 319 {
 320     const bool canRead = endOffset() - getReply()->hdr_sz <
 321                          lowestMemReaderOffset() + Config.readAheadGap;
 322
 323     if (!canRead) {
 324         debugs(19, 9, "no: " << endOffset() << '-' << getReply()->hdr_sz <<
 325                " < " << lowestMemReaderOffset() << '+' << Config.readAheadGap);
 326     }
 327
 328     return canRead;
 329 }
 330
 331 void
 332 MemObject::addClient(store_client *aClient)
 333 {
 334     ++nclients;
 335     dlinkAdd(aClient, &aClient->node, &clients);
 336 }
 337
 338 #if URL_CHECKSUM_DEBUG
 339 void
 340 MemObject::checkUrlChecksum () const
 341 {
 342     assert(chksum == url_checksum(urlXXX()));
 343 }
 344
 345 #endif
 346
 347 /*
 348  * How much of the object data is on the disk?
 349  */
 350 int64_t
 351 MemObject::objectBytesOnDisk() const
 352 {
 353     /*
 354      * NOTE: storeOffset() represents the disk file size,
 355      * not the amount of object data on disk.
 356      *
 357      * If we don't have at least 'swap_hdr_sz' bytes
 358      * then none of the object data is on disk.
 359      *
 360      * This should still be safe if swap_hdr_sz == 0,
 361      * meaning we haven't even opened the swapout file
 362      * yet.
 363      */
 364
 365     if (swapout.sio.getRaw() == NULL)
 366         return 0;
 367
 368     int64_t nwritten = swapout.sio->offset();
 369
 370     if (nwritten <= (int64_t)swap_hdr_sz)
 371         return 0;
 372
 373     return (nwritten - swap_hdr_sz);
 374 }
 375
 376 int64_t
 377 MemObject::policyLowestOffsetToKeep(bool swap) const
 378 {
 379     /*
 380      * Careful.  lowest_offset can be greater than endOffset(), such
 381      * as in the case of a range request.
 382      */
 383     int64_t lowest_offset = lowestMemReaderOffset();
 384
 385     if (endOffset() < lowest_offset ||
 386             endOffset() - inmem_lo > (int64_t)Config.Store.maxInMemObjSize ||
 387             (swap && !Config.onoff.memory_cache_first))
 388         return lowest_offset;
 389
 390     return inmem_lo;
 391 }
 392
 393 void
 394 MemObject::trimSwappable()
 395 {
 396     int64_t new_mem_lo = policyLowestOffsetToKeep(1);
 397     /*
 398      * We should only free up to what we know has been written
 399      * to disk, not what has been queued for writing.  Otherwise
 400      * there will be a chunk of the data which is not in memory
 401      * and is not yet on disk.
 402      * The -1 makes sure the page isn't freed until storeSwapOut has
 403      * walked to the next page.
 404      */
 405     int64_t on_disk;
 406
 407     if ((on_disk = objectBytesOnDisk()) - 1 < new_mem_lo)
 408         new_mem_lo = on_disk - 1;
 409
 410     if (new_mem_lo == -1)
 411         new_mem_lo = 0; /* the above might become -1 */
 412
 413     data_hdr.freeDataUpto(new_mem_lo);
 414
 415     inmem_lo = new_mem_lo;
 416 }
 417
 418 void
 419 MemObject::trimUnSwappable()
 420 {
 421     if (const int64_t new_mem_lo = policyLowestOffsetToKeep(false)) {
 422         assert (new_mem_lo > 0);
 423         data_hdr.freeDataUpto(new_mem_lo);
 424         inmem_lo = new_mem_lo;
 425     } // else we should not trim anything at this time
 426 }
 427
 428 bool
 429 MemObject::isContiguous() const
 430 {
 431     bool result = data_hdr.hasContigousContentRange (Range<int64_t>(inmem_lo, endOffset()));
 432     /* XXX : make this higher level */
 433     debugs (19, result ? 4 :3, "MemObject::isContiguous: Returning " << (result ? "true" : "false"));
 434     return result;
 435 }
 436
 437 int
 438 MemObject::mostBytesWanted(int max, bool ignoreDelayPools) const
 439 {
 440 #if USE_DELAY_POOLS
 441     if (!ignoreDelayPools) {
 442         /* identify delay id with largest allowance */
 443         DelayId largestAllowance = mostBytesAllowed ();
 444         return largestAllowance.bytesWanted(0, max);
 445     }
 446 #endif
 447
 448     return max;
 449 }
 450
 451 void
 452 MemObject::setNoDelay(bool const newValue)
 453 {
 454 #if USE_DELAY_POOLS
 455
 456     for (dlink_node *node = clients.head; node; node = node->next) {
 457         store_client *sc = (store_client *) node->data;
 458         sc->delayId.setNoDelay(newValue);
 459     }
 460
 461 #endif
 462 }
 463
 464 void
 465 MemObject::delayRead(DeferredRead const &aRead)
 466 {
 467     deferredReads.delayRead(aRead);
 468 }
 469
 470 void
 471 MemObject::kickReads()
 472 {
 473     deferredReads.kickReads(-1);
 474 }
 475
 476 #if USE_DELAY_POOLS
 477 DelayId
 478 MemObject::mostBytesAllowed() const
 479 {
 480     int j;
 481     int jmax = -1;
 482     DelayId result;
 483
 484     for (dlink_node *node = clients.head; node; node = node->next) {
 485         store_client *sc = (store_client *) node->data;
 486 #if 0
 487         /* This test is invalid because the client may be writing data
 488          * and thus will want data immediately.
 489          * If we include the test, there is a race condition when too much
 490          * data is read - if all sc's are writing when a read is scheduled.
 491          * XXX: fixme.
 492          */
 493
 494         if (!sc->callbackPending())
 495             /* not waiting for more data */
 496             continue;
 497
 498 #endif
 499
 500         j = sc->delayId.bytesWanted(0, sc->copyInto.length);
 501
 502         if (j > jmax) {
 503             jmax = j;
 504             result = sc->delayId;
 505         }
 506     }
 507
 508     return result;
 509 }
 510
 511 #endif
 512
 513 int64_t
 514 MemObject::availableForSwapOut() const
 515 {
 516     return endOffset() - swapout.queue_offset;
 517 }
 518