ceph/src/os/bluestore/StupidAllocator.cc

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #include "StupidAllocator.h"
   5 #include "bluestore_types.h"
   6 #include "common/debug.h"
   7
   8 #define dout_context cct
   9 #define dout_subsys ceph_subsys_bluestore
  10 #undef dout_prefix
  11 #define dout_prefix *_dout << "stupidalloc 0x" << this << " "
  12
  13 StupidAllocator::StupidAllocator(CephContext* cct)
  14   : cct(cct), num_free(0),
  15     free(10),
  16     last_alloc(0)
  17 {
  18 }
  19
  20 StupidAllocator::~StupidAllocator()
  21 {
  22 }
  23
  24 unsigned StupidAllocator::_choose_bin(uint64_t orig_len)
  25 {
  26   uint64_t len = orig_len / cct->_conf->bdev_block_size;
  27   int bin = std::min((int)cbits(len), (int)free.size() - 1);
  28   dout(30) << __func__ << " len 0x" << std::hex << orig_len << std::dec
  29            << " -> " << bin << dendl;
  30   return bin;
  31 }
  32
  33 void StupidAllocator::_insert_free(uint64_t off, uint64_t len)
  34 {
  35   unsigned bin = _choose_bin(len);
  36   dout(30) << __func__ << " 0x" << std::hex << off << "~" << len << std::dec
  37            << " in bin " << bin << dendl;
  38   while (true) {
  39     free[bin].insert(off, len, &off, &len);
  40     unsigned newbin = _choose_bin(len);
  41     if (newbin == bin)
  42       break;
  43     dout(30) << __func__ << " promoting 0x" << std::hex << off << "~" << len
  44              << std::dec << " to bin " << newbin << dendl;
  45     free[bin].erase(off, len);
  46     bin = newbin;
  47   }
  48 }
  49
  50 /// return the effective length of the extent if we align to alloc_unit
  51 uint64_t StupidAllocator::_aligned_len(
  52   StupidAllocator::interval_set_t::iterator p,
  53   uint64_t alloc_unit)
  54 {
  55   uint64_t skew = p.get_start() % alloc_unit;
  56   if (skew)
  57     skew = alloc_unit - skew;
  58   if (skew > p.get_len())
  59     return 0;
  60   else
  61     return p.get_len() - skew;
  62 }
  63
  64 int64_t StupidAllocator::allocate_int(
  65   uint64_t want_size, uint64_t alloc_unit, int64_t hint,
  66   uint64_t *offset, uint32_t *length)
  67 {
  68   std::lock_guard<std::mutex> l(lock);
  69   dout(10) << __func__ << " want_size 0x" << std::hex << want_size
  70            << " alloc_unit 0x" << alloc_unit
  71            << " hint 0x" << hint << std::dec
  72            << dendl;
  73   uint64_t want = MAX(alloc_unit, want_size);
  74   int bin = _choose_bin(want);
  75   int orig_bin = bin;
  76
  77   auto p = free[0].begin();
  78
  79   if (!hint)
  80     hint = last_alloc;
  81
  82   // search up (from hint)
  83   if (hint) {
  84     for (bin = orig_bin; bin < (int)free.size(); ++bin) {
  85       p = free[bin].lower_bound(hint);
  86       while (p != free[bin].end()) {
  87         if (_aligned_len(p, alloc_unit) >= want_size) {
  88           goto found;
  89         }
  90         ++p;
  91       }
  92     }
  93   }
  94
  95   // search up (from origin, and skip searched extents by hint)
  96   for (bin = orig_bin; bin < (int)free.size(); ++bin) {
  97     p = free[bin].begin();
  98     auto end = hint ? free[bin].lower_bound(hint) : free[bin].end();
  99     while (p != end) {
 100       if (_aligned_len(p, alloc_unit) >= want_size) {
 101         goto found;
 102       }
 103       ++p;
 104     }
 105   }
 106
 107   // search down (hint)
 108   if (hint) {
 109     for (bin = orig_bin; bin >= 0; --bin) {
 110       p = free[bin].lower_bound(hint);
 111       while (p != free[bin].end()) {
 112         if (_aligned_len(p, alloc_unit) >= alloc_unit) {
 113           goto found;
 114         }
 115         ++p;
 116       }
 117     }
 118   }
 119
 120   // search down (from origin, and skip searched extents by hint)
 121   for (bin = orig_bin; bin >= 0; --bin) {
 122     p = free[bin].begin();
 123     auto end = hint ? free[bin].lower_bound(hint) : free[bin].end();
 124     while (p != end) {
 125       if (_aligned_len(p, alloc_unit) >= alloc_unit) {
 126         goto found;
 127       }
 128       ++p;
 129     }
 130   }
 131
 132   return -ENOSPC;
 133
 134  found:
 135   uint64_t skew = p.get_start() % alloc_unit;
 136   if (skew)
 137     skew = alloc_unit - skew;
 138   *offset = p.get_start() + skew;
 139   *length = MIN(MAX(alloc_unit, want_size), P2ALIGN((p.get_len() - skew), alloc_unit));
 140   if (cct->_conf->bluestore_debug_small_allocations) {
 141     uint64_t max =
 142       alloc_unit * (rand() % cct->_conf->bluestore_debug_small_allocations);
 143     if (max && *length > max) {
 144       dout(10) << __func__ << " shortening allocation of 0x" << std::hex
 145                << *length << " -> 0x"
 146                << max << " due to debug_small_allocations" << std::dec << dendl;
 147       *length = max;
 148     }
 149   }
 150   dout(30) << __func__ << " got 0x" << std::hex << *offset << "~" << *length
 151            << " from bin " << std::dec << bin << dendl;
 152
 153   free[bin].erase(*offset, *length);
 154   uint64_t off, len;
 155   if (*offset && free[bin].contains(*offset - skew - 1, &off, &len)) {
 156     int newbin = _choose_bin(len);
 157     if (newbin != bin) {
 158       dout(30) << __func__ << " demoting 0x" << std::hex << off << "~" << len
 159                << std::dec << " to bin " << newbin << dendl;
 160       free[bin].erase(off, len);
 161       _insert_free(off, len);
 162     }
 163   }
 164   if (free[bin].contains(*offset + *length, &off, &len)) {
 165     int newbin = _choose_bin(len);
 166     if (newbin != bin) {
 167       dout(30) << __func__ << " demoting 0x" << std::hex << off << "~" << len
 168                << std::dec << " to bin " << newbin << dendl;
 169       free[bin].erase(off, len);
 170       _insert_free(off, len);
 171     }
 172   }
 173
 174   num_free -= *length;
 175   assert(num_free >= 0);
 176   last_alloc = *offset + *length;
 177   return 0;
 178 }
 179
 180 int64_t StupidAllocator::allocate(
 181   uint64_t want_size,
 182   uint64_t alloc_unit,
 183   uint64_t max_alloc_size,
 184   int64_t hint,
 185   PExtentVector *extents)
 186 {
 187   uint64_t allocated_size = 0;
 188   uint64_t offset = 0;
 189   uint32_t length = 0;
 190   int res = 0;
 191
 192   if (max_alloc_size == 0) {
 193     max_alloc_size = want_size;
 194   }
 195
 196   while (allocated_size < want_size) {
 197     res = allocate_int(MIN(max_alloc_size, (want_size - allocated_size)),
 198        alloc_unit, hint, &offset, &length);
 199     if (res != 0) {
 200       /*
 201        * Allocation failed.
 202        */
 203       break;
 204     }
 205     bool can_append = true;
 206     if (!extents->empty()) {
 207       bluestore_pextent_t &last_extent  = extents->back();
 208       if ((last_extent.end() == offset) &&
 209           ((last_extent.length + length) <= max_alloc_size)) {
 210         can_append = false;
 211         last_extent.length += length;
 212       }
 213     }
 214     if (can_append) {
 215       extents->emplace_back(bluestore_pextent_t(offset, length));
 216     }
 217
 218     allocated_size += length;
 219     hint = offset + length;
 220   }
 221
 222   if (allocated_size == 0) {
 223     return -ENOSPC;
 224   }
 225   return allocated_size;
 226 }
 227
 228 void StupidAllocator::release(
 229   const interval_set<uint64_t>& release_set)
 230 {
 231   std::lock_guard<std::mutex> l(lock);
 232   for (interval_set<uint64_t>::const_iterator p = release_set.begin();
 233        p != release_set.end();
 234        ++p) {
 235     const auto offset = p.get_start();
 236     const auto length = p.get_len();
 237     ldout(cct, 10) << __func__ << " 0x" << std::hex << offset << "~" << length
 238                    << std::dec << dendl;
 239     _insert_free(offset, length);
 240     num_free += length;
 241   }
 242 }
 243
 244 uint64_t StupidAllocator::get_free()
 245 {
 246   std::lock_guard<std::mutex> l(lock);
 247   return num_free;
 248 }
 249
 250 double StupidAllocator::get_fragmentation(uint64_t alloc_unit)
 251 {
 252   assert(alloc_unit);
 253   double res;
 254   uint64_t max_intervals = 0;
 255   uint64_t intervals = 0;
 256   {
 257     std::lock_guard<std::mutex> l(lock);
 258     max_intervals = num_free / alloc_unit;
 259     for (unsigned bin = 0; bin < free.size(); ++bin) {
 260       intervals += free[bin].num_intervals();
 261     }
 262   }
 263   ldout(cct, 30) << __func__ << " " << intervals << "/" << max_intervals
 264                  << dendl;
 265   assert(intervals <= max_intervals);
 266   if (!intervals || max_intervals <= 1) {
 267     return 0.0;
 268   }
 269   intervals--;
 270   max_intervals--;
 271   res = (double)intervals / max_intervals;
 272   return res;
 273 }
 274
 275 void StupidAllocator::dump()
 276 {
 277   std::lock_guard<std::mutex> l(lock);
 278   for (unsigned bin = 0; bin < free.size(); ++bin) {
 279     dout(0) << __func__ << " free bin " << bin << ": "
 280             << free[bin].num_intervals() << " extents" << dendl;
 281     for (auto p = free[bin].begin();
 282          p != free[bin].end();
 283          ++p) {
 284       dout(0) << __func__ << "  0x" << std::hex << p.get_start() << "~"
 285               << p.get_len() << std::dec << dendl;
 286     }
 287   }
 288 }
 289
 290 void StupidAllocator::init_add_free(uint64_t offset, uint64_t length)
 291 {
 292   std::lock_guard<std::mutex> l(lock);
 293   dout(10) << __func__ << " 0x" << std::hex << offset << "~" << length
 294            << std::dec << dendl;
 295   _insert_free(offset, length);
 296   num_free += length;
 297 }
 298
 299 void StupidAllocator::init_rm_free(uint64_t offset, uint64_t length)
 300 {
 301   std::lock_guard<std::mutex> l(lock);
 302   dout(10) << __func__ << " 0x" << std::hex << offset << "~" << length
 303            << std::dec << dendl;
 304   interval_set_t rm;
 305   rm.insert(offset, length);
 306   for (unsigned i = 0; i < free.size() && !rm.empty(); ++i) {
 307     interval_set_t overlap;
 308     overlap.intersection_of(rm, free[i]);
 309     if (!overlap.empty()) {
 310       dout(20) << __func__ << " bin " << i << " rm 0x" << std::hex << overlap
 311                << std::dec << dendl;
 312       auto it = overlap.begin();
 313       auto it_end = overlap.end();
 314       while (it != it_end) {
 315         auto o = it.get_start();
 316         auto l = it.get_len();
 317
 318         free[i].erase(o, l,
 319           [&](uint64_t off, uint64_t len) {
 320             unsigned newbin = _choose_bin(len);
 321             if (newbin != i) {
 322               ldout(cct, 30) << __func__ << " demoting1 0x" << std::hex << off << "~" << len
 323                              << std::dec << " to bin " << newbin << dendl;
 324               _insert_free(off, len);
 325               return true;
 326             }
 327             return false;
 328           });
 329         ++it;
 330       }
 331
 332       rm.subtract(overlap);
 333     }
 334   }
 335   assert(rm.empty());
 336   num_free -= length;
 337   assert(num_free >= 0);
 338 }
 339
 340
 341 void StupidAllocator::shutdown()
 342 {
 343   dout(1) << __func__ << dendl;
 344 }
 345