src/MemObject.cc

   1 /*
   2  * Copyright (C) 1996-2018 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 "MemBuf.h"
  17 #include "MemObject.h"
  18 #include "profiler/Profiler.h"
  19 #include "SquidConfig.h"
  20 #include "Store.h"
  21 #include "StoreClient.h"
  22
  23 #if USE_DELAY_POOLS
  24 #include "DelayPools.h"
  25 #endif
  26
  27 /* TODO: make this global or private */
  28 #if URL_CHECKSUM_DEBUG
  29 static unsigned int url_checksum(const char *url);
  30 unsigned int
  31 url_checksum(const char *url)
  32 {
  33     unsigned int ck;
  34     SquidMD5_CTX M;
  35     static unsigned char digest[16];
  36     SquidMD5Init(&M);
  37     SquidMD5Update(&M, (unsigned char *) url, strlen(url));
  38     SquidMD5Final(digest, &M);
  39     memcpy(&ck, digest, sizeof(ck));
  40     return ck;
  41 }
  42
  43 #endif
  44
  45 RemovalPolicy * mem_policy = NULL;
  46
  47 size_t
  48 MemObject::inUseCount()
  49 {
  50     return Pool().inUseCount();
  51 }
  52
  53 const char *
  54 MemObject::storeId() const
  55 {
  56     if (!storeId_.size()) {
  57         debugs(20, DBG_IMPORTANT, "Bug: Missing MemObject::storeId value");
  58         dump();
  59         storeId_ = "[unknown_URI]";
  60     }
  61     return storeId_.termedBuf();
  62 }
  63
  64 const char *
  65 MemObject::logUri() const
  66 {
  67     return logUri_.size() ? logUri_.termedBuf() : storeId();
  68 }
  69
  70 bool
  71 MemObject::hasUris() const
  72 {
  73     return storeId_.size();
  74 }
  75
  76 void
  77 MemObject::setUris(char const *aStoreId, char const *aLogUri, const HttpRequestMethod &aMethod)
  78 {
  79     if (hasUris())
  80         return;
  81
  82     storeId_ = aStoreId;
  83     debugs(88, 3, this << " storeId: " << storeId_);
  84
  85     // fast pointer comparison for a common storeCreateEntry(url,url,...) case
  86     if (!aLogUri || aLogUri == aStoreId)
  87         logUri_.clean(); // use storeId_ by default to minimize copying
  88     else
  89         logUri_ = aLogUri;
  90
  91     method = aMethod;
  92
  93 #if URL_CHECKSUM_DEBUG
  94     chksum = url_checksum(urlXXX());
  95 #endif
  96 }
  97
  98 MemObject::MemObject() :
  99     inmem_lo(0),
 100     nclients(0),
 101     smpCollapsed(false),
 102     ping_reply_callback(nullptr),
 103     ircb_data(nullptr),
 104     id(0),
 105     object_sz(-1),
 106     swap_hdr_sz(0),
 107 #if URL_CHECKSUM_DEBUG
 108     chksum(0),
 109 #endif
 110     vary_headers(nullptr)
 111 {
 112     debugs(20, 3, "new MemObject " << this);
 113     memset(&start_ping, 0, sizeof(start_ping));
 114     memset(&abort, 0, sizeof(abort));
 115     reply_ = new HttpReply;
 116 }
 117
 118 MemObject::~MemObject()
 119 {
 120     debugs(20, 3, "del MemObject " << this);
 121     const Ctx ctx = ctx_enter(hasUris() ? urlXXX() : "[unknown_ctx]");
 122
 123 #if URL_CHECKSUM_DEBUG
 124     checkUrlChecksum();
 125 #endif
 126
 127     if (!shutting_down) { // Store::Root() is FATALly missing during shutdown
 128         assert(xitTable.index < 0);
 129         assert(memCache.index < 0);
 130         assert(swapout.sio == NULL);
 131     }
 132
 133     data_hdr.freeContent();
 134
 135 #if 0
 136     /*
 137      * There is no way to abort FD-less clients, so they might
 138      * still have mem->clients set.
 139      */
 140     assert(clients.head == NULL);
 141
 142 #endif
 143
 144     ctx_exit(ctx);              /* must exit before we free mem->url */
 145 }
 146
 147 void
 148 MemObject::write(const StoreIOBuffer &writeBuffer)
 149 {
 150     PROF_start(MemObject_write);
 151     debugs(19, 6, "memWrite: offset " << writeBuffer.offset << " len " << writeBuffer.length);
 152
 153     /* We don't separate out mime headers yet, so ensure that the first
 154      * write is at offset 0 - where they start
 155      */
 156     assert (data_hdr.endOffset() || writeBuffer.offset == 0);
 157
 158     assert (data_hdr.write (writeBuffer));
 159     PROF_stop(MemObject_write);
 160 }
 161
 162 void
 163 MemObject::dump() const
 164 {
 165     data_hdr.dump();
 166 #if 0
 167     /* do we want this one? */
 168     debugs(20, DBG_IMPORTANT, "MemObject->data.origin_offset: " << (data_hdr.head ? data_hdr.head->nodeBuffer.offset : 0));
 169 #endif
 170
 171     debugs(20, DBG_IMPORTANT, "MemObject->start_ping: " << start_ping.tv_sec  << "."<< std::setfill('0') << std::setw(6) << start_ping.tv_usec);
 172     debugs(20, DBG_IMPORTANT, "MemObject->inmem_hi: " << data_hdr.endOffset());
 173     debugs(20, DBG_IMPORTANT, "MemObject->inmem_lo: " << inmem_lo);
 174     debugs(20, DBG_IMPORTANT, "MemObject->nclients: " << nclients);
 175     debugs(20, DBG_IMPORTANT, "MemObject->reply: " << reply_);
 176     debugs(20, DBG_IMPORTANT, "MemObject->request: " << request);
 177     debugs(20, DBG_IMPORTANT, "MemObject->logUri: " << logUri_);
 178     debugs(20, DBG_IMPORTANT, "MemObject->storeId: " << storeId_);
 179 }
 180
 181 struct LowestMemReader : public unary_function<store_client, void> {
 182     LowestMemReader(int64_t seed):current(seed) {}
 183
 184     void operator() (store_client const &x) {
 185         if (x.memReaderHasLowerOffset(current))
 186             current = x.copyInto.offset;
 187     }
 188
 189     int64_t current;
 190 };
 191
 192 struct StoreClientStats : public unary_function<store_client, void> {
 193     StoreClientStats(MemBuf *anEntry):where(anEntry),index(0) {}
 194
 195     void operator()(store_client const &x) {
 196         x.dumpStats(where, index);
 197         ++index;
 198     }
 199
 200     MemBuf *where;
 201     size_t index;
 202 };
 203
 204 void
 205 MemObject::stat(MemBuf * mb) const
 206 {
 207     mb->appendf("\t" SQUIDSBUFPH " %s\n", SQUIDSBUFPRINT(method.image()), logUri());
 208     if (!vary_headers.isEmpty())
 209         mb->appendf("\tvary_headers: " SQUIDSBUFPH "\n", SQUIDSBUFPRINT(vary_headers));
 210     mb->appendf("\tinmem_lo: %" PRId64 "\n", inmem_lo);
 211     mb->appendf("\tinmem_hi: %" PRId64 "\n", data_hdr.endOffset());
 212     mb->appendf("\tswapout: %" PRId64 " bytes queued\n", swapout.queue_offset);
 213
 214     if (swapout.sio.getRaw())
 215         mb->appendf("\tswapout: %" PRId64 " bytes written\n", (int64_t) swapout.sio->offset());
 216
 217     if (xitTable.index >= 0)
 218         mb->appendf("\ttransient index: %d state: %d\n", xitTable.index, xitTable.io);
 219     if (memCache.index >= 0)
 220         mb->appendf("\tmem-cache index: %d state: %d offset: %" PRId64 "\n", memCache.index, memCache.io, memCache.offset);
 221     if (object_sz >= 0)
 222         mb->appendf("\tobject_sz: %" PRId64 "\n", object_sz);
 223     if (smpCollapsed)
 224         mb->appendf("\tsmp-collapsed\n");
 225
 226     StoreClientStats statsVisitor(mb);
 227
 228     for_each<StoreClientStats>(clients, statsVisitor);
 229 }
 230
 231 int64_t
 232 MemObject::endOffset () const
 233 {
 234     return data_hdr.endOffset();
 235 }
 236
 237 void
 238 MemObject::markEndOfReplyHeaders()
 239 {
 240     const int hdr_sz = endOffset();
 241     assert(hdr_sz >= 0);
 242     assert(reply_);
 243     reply_->hdr_sz = hdr_sz;
 244 }
 245
 246 int64_t
 247 MemObject::size() const
 248 {
 249     if (object_sz < 0)
 250         return endOffset();
 251
 252     return object_sz;
 253 }
 254
 255 int64_t
 256 MemObject::expectedReplySize() const
 257 {
 258     debugs(20, 7, "object_sz: " << object_sz);
 259     if (object_sz >= 0) // complete() has been called; we know the exact answer
 260         return object_sz;
 261
 262     if (reply_) {
 263         const int64_t clen = reply_->bodySize(method);
 264         debugs(20, 7, "clen: " << clen);
 265         if (clen >= 0 && reply_->hdr_sz > 0) // yuck: Http::Message sets hdr_sz to 0
 266             return clen + reply_->hdr_sz;
 267     }
 268
 269     return -1; // not enough information to predict
 270 }
 271
 272 void
 273 MemObject::reset()
 274 {
 275     assert(swapout.sio == NULL);
 276     data_hdr.freeContent();
 277     inmem_lo = 0;
 278     /* Should we check for clients? */
 279     if (reply_)
 280         reply_->reset();
 281 }
 282
 283 int64_t
 284 MemObject::lowestMemReaderOffset() const
 285 {
 286     LowestMemReader lowest (endOffset() + 1);
 287
 288     for_each <LowestMemReader>(clients, lowest);
 289
 290     return lowest.current;
 291 }
 292
 293 /* XXX: This is wrong. It breaks *badly* on range combining */
 294 bool
 295 MemObject::readAheadPolicyCanRead() const
 296 {
 297     const bool canRead = endOffset() - getReply()->hdr_sz <
 298                          lowestMemReaderOffset() + Config.readAheadGap;
 299
 300     if (!canRead) {
 301         debugs(19, 9, "no: " << endOffset() << '-' << getReply()->hdr_sz <<
 302                " < " << lowestMemReaderOffset() << '+' << Config.readAheadGap);
 303     }
 304
 305     return canRead;
 306 }
 307
 308 void
 309 MemObject::addClient(store_client *aClient)
 310 {
 311     ++nclients;
 312     dlinkAdd(aClient, &aClient->node, &clients);
 313 }
 314
 315 #if URL_CHECKSUM_DEBUG
 316 void
 317 MemObject::checkUrlChecksum () const
 318 {
 319     assert(chksum == url_checksum(urlXXX()));
 320 }
 321
 322 #endif
 323
 324 /*
 325  * How much of the object data is on the disk?
 326  */
 327 int64_t
 328 MemObject::objectBytesOnDisk() const
 329 {
 330     /*
 331      * NOTE: storeOffset() represents the disk file size,
 332      * not the amount of object data on disk.
 333      *
 334      * If we don't have at least 'swap_hdr_sz' bytes
 335      * then none of the object data is on disk.
 336      *
 337      * This should still be safe if swap_hdr_sz == 0,
 338      * meaning we haven't even opened the swapout file
 339      * yet.
 340      */
 341
 342     if (swapout.sio.getRaw() == NULL)
 343         return 0;
 344
 345     int64_t nwritten = swapout.sio->offset();
 346
 347     if (nwritten <= (int64_t)swap_hdr_sz)
 348         return 0;
 349
 350     return (nwritten - swap_hdr_sz);
 351 }
 352
 353 int64_t
 354 MemObject::policyLowestOffsetToKeep(bool swap) const
 355 {
 356     /*
 357      * Careful.  lowest_offset can be greater than endOffset(), such
 358      * as in the case of a range request.
 359      */
 360     int64_t lowest_offset = lowestMemReaderOffset();
 361
 362     if (endOffset() < lowest_offset ||
 363             endOffset() - inmem_lo > (int64_t)Config.Store.maxInMemObjSize ||
 364             (swap && !Config.onoff.memory_cache_first))
 365         return lowest_offset;
 366
 367     return inmem_lo;
 368 }
 369
 370 void
 371 MemObject::trimSwappable()
 372 {
 373     int64_t new_mem_lo = policyLowestOffsetToKeep(1);
 374     /*
 375      * We should only free up to what we know has been written
 376      * to disk, not what has been queued for writing.  Otherwise
 377      * there will be a chunk of the data which is not in memory
 378      * and is not yet on disk.
 379      * The -1 makes sure the page isn't freed until storeSwapOut has
 380      * walked to the next page.
 381      */
 382     int64_t on_disk;
 383
 384     if ((on_disk = objectBytesOnDisk()) - 1 < new_mem_lo)
 385         new_mem_lo = on_disk - 1;
 386
 387     if (new_mem_lo == -1)
 388         new_mem_lo = 0; /* the above might become -1 */
 389
 390     data_hdr.freeDataUpto(new_mem_lo);
 391
 392     inmem_lo = new_mem_lo;
 393 }
 394
 395 void
 396 MemObject::trimUnSwappable()
 397 {
 398     if (const int64_t new_mem_lo = policyLowestOffsetToKeep(false)) {
 399         assert (new_mem_lo > 0);
 400         data_hdr.freeDataUpto(new_mem_lo);
 401         inmem_lo = new_mem_lo;
 402     } // else we should not trim anything at this time
 403 }
 404
 405 bool
 406 MemObject::isContiguous() const
 407 {
 408     bool result = data_hdr.hasContigousContentRange (Range<int64_t>(inmem_lo, endOffset()));
 409     /* XXX : make this higher level */
 410     debugs (19, result ? 4 :3, "MemObject::isContiguous: Returning " << (result ? "true" : "false"));
 411     return result;
 412 }
 413
 414 int
 415 MemObject::mostBytesWanted(int max, bool ignoreDelayPools) const
 416 {
 417 #if USE_DELAY_POOLS
 418     if (!ignoreDelayPools) {
 419         /* identify delay id with largest allowance */
 420         DelayId largestAllowance = mostBytesAllowed ();
 421         return largestAllowance.bytesWanted(0, max);
 422     }
 423 #endif
 424
 425     return max;
 426 }
 427
 428 void
 429 MemObject::setNoDelay(bool const newValue)
 430 {
 431 #if USE_DELAY_POOLS
 432
 433     for (dlink_node *node = clients.head; node; node = node->next) {
 434         store_client *sc = (store_client *) node->data;
 435         sc->delayId.setNoDelay(newValue);
 436     }
 437
 438 #endif
 439 }
 440
 441 void
 442 MemObject::delayRead(DeferredRead const &aRead)
 443 {
 444 #if USE_DELAY_POOLS
 445     if (readAheadPolicyCanRead()) {
 446         if (DelayId mostAllowedId = mostBytesAllowed()) {
 447             mostAllowedId.delayRead(aRead);
 448             return;
 449         }
 450     }
 451 #endif
 452     deferredReads.delayRead(aRead);
 453 }
 454
 455 void
 456 MemObject::kickReads()
 457 {
 458     deferredReads.kickReads(-1);
 459 }
 460
 461 #if USE_DELAY_POOLS
 462 DelayId
 463 MemObject::mostBytesAllowed() const
 464 {
 465     int j;
 466     int jmax = -1;
 467     DelayId result;
 468
 469     for (dlink_node *node = clients.head; node; node = node->next) {
 470         store_client *sc = (store_client *) node->data;
 471 #if 0
 472         /* This test is invalid because the client may be writing data
 473          * and thus will want data immediately.
 474          * If we include the test, there is a race condition when too much
 475          * data is read - if all sc's are writing when a read is scheduled.
 476          * XXX: fixme.
 477          */
 478
 479         if (!sc->callbackPending())
 480             /* not waiting for more data */
 481             continue;
 482
 483 #endif
 484
 485         j = sc->delayId.bytesWanted(0, sc->copyInto.length);
 486
 487         if (j > jmax) {
 488             jmax = j;
 489             result = sc->delayId;
 490         }
 491     }
 492
 493     return result;
 494 }
 495
 496 #endif
 497
 498 int64_t
 499 MemObject::availableForSwapOut() const
 500 {
 501     return endOffset() - swapout.queue_offset;
 502 }
 503