1.1 --- a/src/share/vm/memory/collectorPolicy.cpp Fri Feb 29 14:42:56 2008 -0800
1.2 +++ b/src/share/vm/memory/collectorPolicy.cpp Sun Mar 02 16:10:12 2008 -0800
1.3 @@ -57,45 +57,51 @@
1.4 // User inputs from -mx and ms are aligned
1.5 _initial_heap_byte_size = align_size_up(Arguments::initial_heap_size(),
1.6 min_alignment());
1.7 - _min_heap_byte_size = align_size_up(Arguments::min_heap_size(),
1.8 - min_alignment());
1.9 - _max_heap_byte_size = align_size_up(MaxHeapSize, max_alignment());
1.10 + set_min_heap_byte_size(align_size_up(Arguments::min_heap_size(),
1.11 + min_alignment()));
1.12 + set_max_heap_byte_size(align_size_up(MaxHeapSize, max_alignment()));
1.13
1.14 // Check validity of heap parameters from launcher
1.15 - if (_initial_heap_byte_size == 0) {
1.16 - _initial_heap_byte_size = NewSize + OldSize;
1.17 + if (initial_heap_byte_size() == 0) {
1.18 + set_initial_heap_byte_size(NewSize + OldSize);
1.19 } else {
1.20 - Universe::check_alignment(_initial_heap_byte_size, min_alignment(),
1.21 + Universe::check_alignment(initial_heap_byte_size(), min_alignment(),
1.22 "initial heap");
1.23 }
1.24 - if (_min_heap_byte_size == 0) {
1.25 - _min_heap_byte_size = NewSize + OldSize;
1.26 + if (min_heap_byte_size() == 0) {
1.27 + set_min_heap_byte_size(NewSize + OldSize);
1.28 } else {
1.29 - Universe::check_alignment(_min_heap_byte_size, min_alignment(),
1.30 + Universe::check_alignment(min_heap_byte_size(), min_alignment(),
1.31 "initial heap");
1.32 }
1.33
1.34 // Check heap parameter properties
1.35 - if (_initial_heap_byte_size < M) {
1.36 + if (initial_heap_byte_size() < M) {
1.37 vm_exit_during_initialization("Too small initial heap");
1.38 }
1.39 // Check heap parameter properties
1.40 - if (_min_heap_byte_size < M) {
1.41 + if (min_heap_byte_size() < M) {
1.42 vm_exit_during_initialization("Too small minimum heap");
1.43 }
1.44 - if (_initial_heap_byte_size <= NewSize) {
1.45 + if (initial_heap_byte_size() <= NewSize) {
1.46 // make sure there is at least some room in old space
1.47 vm_exit_during_initialization("Too small initial heap for new size specified");
1.48 }
1.49 - if (_max_heap_byte_size < _min_heap_byte_size) {
1.50 + if (max_heap_byte_size() < min_heap_byte_size()) {
1.51 vm_exit_during_initialization("Incompatible minimum and maximum heap sizes specified");
1.52 }
1.53 - if (_initial_heap_byte_size < _min_heap_byte_size) {
1.54 + if (initial_heap_byte_size() < min_heap_byte_size()) {
1.55 vm_exit_during_initialization("Incompatible minimum and initial heap sizes specified");
1.56 }
1.57 - if (_max_heap_byte_size < _initial_heap_byte_size) {
1.58 + if (max_heap_byte_size() < initial_heap_byte_size()) {
1.59 vm_exit_during_initialization("Incompatible initial and maximum heap sizes specified");
1.60 }
1.61 +
1.62 + if (PrintGCDetails && Verbose) {
1.63 + gclog_or_tty->print_cr("Minimum heap " SIZE_FORMAT " Initial heap "
1.64 + SIZE_FORMAT " Maximum heap " SIZE_FORMAT,
1.65 + min_heap_byte_size(), initial_heap_byte_size(), max_heap_byte_size());
1.66 + }
1.67 }
1.68
1.69 void CollectorPolicy::initialize_perm_generation(PermGen::Name pgnm) {
1.70 @@ -128,10 +134,26 @@
1.71
1.72 // GenCollectorPolicy methods.
1.73
1.74 +size_t GenCollectorPolicy::scale_by_NewRatio_aligned(size_t base_size) {
1.75 + size_t x = base_size / (NewRatio+1);
1.76 + size_t new_gen_size = x > min_alignment() ?
1.77 + align_size_down(x, min_alignment()) :
1.78 + min_alignment();
1.79 + return new_gen_size;
1.80 +}
1.81 +
1.82 +size_t GenCollectorPolicy::bound_minus_alignment(size_t desired_size,
1.83 + size_t maximum_size) {
1.84 + size_t alignment = min_alignment();
1.85 + size_t max_minus = maximum_size - alignment;
1.86 + return desired_size < max_minus ? desired_size : max_minus;
1.87 +}
1.88 +
1.89 +
1.90 void GenCollectorPolicy::initialize_size_policy(size_t init_eden_size,
1.91 size_t init_promo_size,
1.92 size_t init_survivor_size) {
1.93 - double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;
1.94 + const double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;
1.95 _size_policy = new AdaptiveSizePolicy(init_eden_size,
1.96 init_promo_size,
1.97 init_survivor_size,
1.98 @@ -210,74 +232,260 @@
1.99 assert(MaxHeapSize % max_alignment() == 0, "maximum heap alignment");
1.100 }
1.101
1.102 +// Values set on the command line win over any ergonomically
1.103 +// set command line parameters.
1.104 +// Ergonomic choice of parameters are done before this
1.105 +// method is called. Values for command line parameters such as NewSize
1.106 +// and MaxNewSize feed those ergonomic choices into this method.
1.107 +// This method makes the final generation sizings consistent with
1.108 +// themselves and with overall heap sizings.
1.109 +// In the absence of explicitly set command line flags, policies
1.110 +// such as the use of NewRatio are used to size the generation.
1.111 void GenCollectorPolicy::initialize_size_info() {
1.112 CollectorPolicy::initialize_size_info();
1.113
1.114 - // Minimum sizes of the generations may be different than
1.115 - // the initial sizes.
1.116 - if (!FLAG_IS_DEFAULT(NewSize)) {
1.117 - _min_gen0_size = NewSize;
1.118 + // min_alignment() is used for alignment within a generation.
1.119 + // There is additional alignment done down stream for some
1.120 + // collectors that sometimes causes unwanted rounding up of
1.121 + // generations sizes.
1.122 +
1.123 + // Determine maximum size of gen0
1.124 +
1.125 + size_t max_new_size = 0;
1.126 + if (FLAG_IS_CMDLINE(MaxNewSize)) {
1.127 + if (MaxNewSize < min_alignment()) {
1.128 + max_new_size = min_alignment();
1.129 + } else if (MaxNewSize >= max_heap_byte_size()) {
1.130 + max_new_size = align_size_down(max_heap_byte_size() - min_alignment(),
1.131 + min_alignment());
1.132 + warning("MaxNewSize (" SIZE_FORMAT "k) is equal to or "
1.133 + "greater than the entire heap (" SIZE_FORMAT "k). A "
1.134 + "new generation size of " SIZE_FORMAT "k will be used.",
1.135 + MaxNewSize/K, max_heap_byte_size()/K, max_new_size/K);
1.136 + } else {
1.137 + max_new_size = align_size_down(MaxNewSize, min_alignment());
1.138 + }
1.139 +
1.140 + // The case for FLAG_IS_ERGO(MaxNewSize) could be treated
1.141 + // specially at this point to just use an ergonomically set
1.142 + // MaxNewSize to set max_new_size. For cases with small
1.143 + // heaps such a policy often did not work because the MaxNewSize
1.144 + // was larger than the entire heap. The interpretation given
1.145 + // to ergonomically set flags is that the flags are set
1.146 + // by different collectors for their own special needs but
1.147 + // are not allowed to badly shape the heap. This allows the
1.148 + // different collectors to decide what's best for themselves
1.149 + // without having to factor in the overall heap shape. It
1.150 + // can be the case in the future that the collectors would
1.151 + // only make "wise" ergonomics choices and this policy could
1.152 + // just accept those choices. The choices currently made are
1.153 + // not always "wise".
1.154 } else {
1.155 - _min_gen0_size = align_size_down(_min_heap_byte_size / (NewRatio+1),
1.156 - min_alignment());
1.157 - // We bound the minimum size by NewSize below (since it historically
1.158 + max_new_size = scale_by_NewRatio_aligned(max_heap_byte_size());
1.159 + // Bound the maximum size by NewSize below (since it historically
1.160 // would have been NewSize and because the NewRatio calculation could
1.161 // yield a size that is too small) and bound it by MaxNewSize above.
1.162 - // This is not always best. The NewSize calculated by CMS (which has
1.163 - // a fixed minimum of 16m) can sometimes be "too" large. Consider
1.164 - // the case where -Xmx32m. The CMS calculated NewSize would be about
1.165 - // half the entire heap which seems too large. But the counter
1.166 - // example is seen when the client defaults for NewRatio are used.
1.167 - // An initial young generation size of 640k was observed
1.168 - // with -Xmx128m -XX:MaxNewSize=32m when NewSize was not used
1.169 - // as a lower bound as with
1.170 - // _min_gen0_size = MIN2(_min_gen0_size, MaxNewSize);
1.171 - // and 640k seemed too small a young generation.
1.172 - _min_gen0_size = MIN2(MAX2(_min_gen0_size, NewSize), MaxNewSize);
1.173 + // Ergonomics plays here by previously calculating the desired
1.174 + // NewSize and MaxNewSize.
1.175 + max_new_size = MIN2(MAX2(max_new_size, NewSize), MaxNewSize);
1.176 + }
1.177 + assert(max_new_size > 0, "All paths should set max_new_size");
1.178 +
1.179 + // Given the maximum gen0 size, determine the initial and
1.180 + // minimum sizes.
1.181 +
1.182 + if (max_heap_byte_size() == min_heap_byte_size()) {
1.183 + // The maximum and minimum heap sizes are the same so
1.184 + // the generations minimum and initial must be the
1.185 + // same as its maximum.
1.186 + set_min_gen0_size(max_new_size);
1.187 + set_initial_gen0_size(max_new_size);
1.188 + set_max_gen0_size(max_new_size);
1.189 + } else {
1.190 + size_t desired_new_size = 0;
1.191 + if (!FLAG_IS_DEFAULT(NewSize)) {
1.192 + // If NewSize is set ergonomically (for example by cms), it
1.193 + // would make sense to use it. If it is used, also use it
1.194 + // to set the initial size. Although there is no reason
1.195 + // the minimum size and the initial size have to be the same,
1.196 + // the current implementation gets into trouble during the calculation
1.197 + // of the tenured generation sizes if they are different.
1.198 + // Note that this makes the initial size and the minimum size
1.199 + // generally small compared to the NewRatio calculation.
1.200 + _min_gen0_size = NewSize;
1.201 + desired_new_size = NewSize;
1.202 + max_new_size = MAX2(max_new_size, NewSize);
1.203 + } else {
1.204 + // For the case where NewSize is the default, use NewRatio
1.205 + // to size the minimum and initial generation sizes.
1.206 + // Use the default NewSize as the floor for these values. If
1.207 + // NewRatio is overly large, the resulting sizes can be too
1.208 + // small.
1.209 + _min_gen0_size = MAX2(scale_by_NewRatio_aligned(min_heap_byte_size()),
1.210 + NewSize);
1.211 + desired_new_size =
1.212 + MAX2(scale_by_NewRatio_aligned(initial_heap_byte_size()),
1.213 + NewSize);
1.214 + }
1.215 +
1.216 + assert(_min_gen0_size > 0, "Sanity check");
1.217 + set_initial_gen0_size(desired_new_size);
1.218 + set_max_gen0_size(max_new_size);
1.219 +
1.220 + // At this point the desirable initial and minimum sizes have been
1.221 + // determined without regard to the maximum sizes.
1.222 +
1.223 + // Bound the sizes by the corresponding overall heap sizes.
1.224 + set_min_gen0_size(
1.225 + bound_minus_alignment(_min_gen0_size, min_heap_byte_size()));
1.226 + set_initial_gen0_size(
1.227 + bound_minus_alignment(_initial_gen0_size, initial_heap_byte_size()));
1.228 + set_max_gen0_size(
1.229 + bound_minus_alignment(_max_gen0_size, max_heap_byte_size()));
1.230 +
1.231 + // At this point all three sizes have been checked against the
1.232 + // maximum sizes but have not been checked for consistency
1.233 + // amoung the three.
1.234 +
1.235 + // Final check min <= initial <= max
1.236 + set_min_gen0_size(MIN2(_min_gen0_size, _max_gen0_size));
1.237 + set_initial_gen0_size(
1.238 + MAX2(MIN2(_initial_gen0_size, _max_gen0_size), _min_gen0_size));
1.239 + set_min_gen0_size(MIN2(_min_gen0_size, _initial_gen0_size));
1.240 }
1.241
1.242 - // Parameters are valid, compute area sizes.
1.243 - size_t max_new_size = align_size_down(_max_heap_byte_size / (NewRatio+1),
1.244 - min_alignment());
1.245 - max_new_size = MIN2(MAX2(max_new_size, _min_gen0_size), MaxNewSize);
1.246 + if (PrintGCDetails && Verbose) {
1.247 + gclog_or_tty->print_cr("Minimum gen0 " SIZE_FORMAT " Initial gen0 "
1.248 + SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT,
1.249 + min_gen0_size(), initial_gen0_size(), max_gen0_size());
1.250 + }
1.251 +}
1.252
1.253 - // desired_new_size is used to set the initial size. The
1.254 - // initial size must be greater than the minimum size.
1.255 - size_t desired_new_size =
1.256 - align_size_down(_initial_heap_byte_size / (NewRatio+1),
1.257 - min_alignment());
1.258 +// Call this method during the sizing of the gen1 to make
1.259 +// adjustments to gen0 because of gen1 sizing policy. gen0 initially has
1.260 +// the most freedom in sizing because it is done before the
1.261 +// policy for gen1 is applied. Once gen1 policies have been applied,
1.262 +// there may be conflicts in the shape of the heap and this method
1.263 +// is used to make the needed adjustments. The application of the
1.264 +// policies could be more sophisticated (iterative for example) but
1.265 +// keeping it simple also seems a worthwhile goal.
1.266 +bool TwoGenerationCollectorPolicy::adjust_gen0_sizes(size_t* gen0_size_ptr,
1.267 + size_t* gen1_size_ptr,
1.268 + size_t heap_size,
1.269 + size_t min_gen0_size) {
1.270 + bool result = false;
1.271 + if ((*gen1_size_ptr + *gen0_size_ptr) > heap_size) {
1.272 + if (((*gen0_size_ptr + OldSize) > heap_size) &&
1.273 + (heap_size - min_gen0_size) >= min_alignment()) {
1.274 + // Adjust gen0 down to accomodate OldSize
1.275 + *gen0_size_ptr = heap_size - min_gen0_size;
1.276 + *gen0_size_ptr =
1.277 + MAX2((uintx)align_size_down(*gen0_size_ptr, min_alignment()),
1.278 + min_alignment());
1.279 + assert(*gen0_size_ptr > 0, "Min gen0 is too large");
1.280 + result = true;
1.281 + } else {
1.282 + *gen1_size_ptr = heap_size - *gen0_size_ptr;
1.283 + *gen1_size_ptr =
1.284 + MAX2((uintx)align_size_down(*gen1_size_ptr, min_alignment()),
1.285 + min_alignment());
1.286 + }
1.287 + }
1.288 + return result;
1.289 +}
1.290
1.291 - size_t new_size = MIN2(MAX2(desired_new_size, _min_gen0_size), max_new_size);
1.292 -
1.293 - _initial_gen0_size = new_size;
1.294 - _max_gen0_size = max_new_size;
1.295 -}
1.296 +// Minimum sizes of the generations may be different than
1.297 +// the initial sizes. An inconsistently is permitted here
1.298 +// in the total size that can be specified explicitly by
1.299 +// command line specification of OldSize and NewSize and
1.300 +// also a command line specification of -Xms. Issue a warning
1.301 +// but allow the values to pass.
1.302
1.303 void TwoGenerationCollectorPolicy::initialize_size_info() {
1.304 GenCollectorPolicy::initialize_size_info();
1.305
1.306 - // Minimum sizes of the generations may be different than
1.307 - // the initial sizes. An inconsistently is permitted here
1.308 - // in the total size that can be specified explicitly by
1.309 - // command line specification of OldSize and NewSize and
1.310 - // also a command line specification of -Xms. Issue a warning
1.311 - // but allow the values to pass.
1.312 - if (!FLAG_IS_DEFAULT(OldSize)) {
1.313 - _min_gen1_size = OldSize;
1.314 + // At this point the minimum, initial and maximum sizes
1.315 + // of the overall heap and of gen0 have been determined.
1.316 + // The maximum gen1 size can be determined from the maximum gen0
1.317 + // and maximum heap size since not explicit flags exits
1.318 + // for setting the gen1 maximum.
1.319 + _max_gen1_size = max_heap_byte_size() - _max_gen0_size;
1.320 + _max_gen1_size =
1.321 + MAX2((uintx)align_size_down(_max_gen1_size, min_alignment()),
1.322 + min_alignment());
1.323 + // If no explicit command line flag has been set for the
1.324 + // gen1 size, use what is left for gen1.
1.325 + if (FLAG_IS_DEFAULT(OldSize) || FLAG_IS_ERGO(OldSize)) {
1.326 + // The user has not specified any value or ergonomics
1.327 + // has chosen a value (which may or may not be consistent
1.328 + // with the overall heap size). In either case make
1.329 + // the minimum, maximum and initial sizes consistent
1.330 + // with the gen0 sizes and the overall heap sizes.
1.331 + assert(min_heap_byte_size() > _min_gen0_size,
1.332 + "gen0 has an unexpected minimum size");
1.333 + set_min_gen1_size(min_heap_byte_size() - min_gen0_size());
1.334 + set_min_gen1_size(
1.335 + MAX2((uintx)align_size_down(_min_gen1_size, min_alignment()),
1.336 + min_alignment()));
1.337 + set_initial_gen1_size(initial_heap_byte_size() - initial_gen0_size());
1.338 + set_initial_gen1_size(
1.339 + MAX2((uintx)align_size_down(_initial_gen1_size, min_alignment()),
1.340 + min_alignment()));
1.341 +
1.342 + } else {
1.343 + // It's been explicitly set on the command line. Use the
1.344 + // OldSize and then determine the consequences.
1.345 + set_min_gen1_size(OldSize);
1.346 + set_initial_gen1_size(OldSize);
1.347 +
1.348 + // If the user has explicitly set an OldSize that is inconsistent
1.349 + // with other command line flags, issue a warning.
1.350 // The generation minimums and the overall heap mimimum should
1.351 // be within one heap alignment.
1.352 - if ((_min_gen1_size + _min_gen0_size + max_alignment()) <
1.353 - _min_heap_byte_size) {
1.354 + if ((_min_gen1_size + _min_gen0_size + min_alignment()) <
1.355 + min_heap_byte_size()) {
1.356 warning("Inconsistency between minimum heap size and minimum "
1.357 - "generation sizes: using min heap = " SIZE_FORMAT,
1.358 - _min_heap_byte_size);
1.359 + "generation sizes: using minimum heap = " SIZE_FORMAT,
1.360 + min_heap_byte_size());
1.361 }
1.362 - } else {
1.363 - _min_gen1_size = _min_heap_byte_size - _min_gen0_size;
1.364 + if ((OldSize > _max_gen1_size)) {
1.365 + warning("Inconsistency between maximum heap size and maximum "
1.366 + "generation sizes: using maximum heap = " SIZE_FORMAT
1.367 + " -XX:OldSize flag is being ignored",
1.368 + max_heap_byte_size());
1.369 }
1.370 + // If there is an inconsistency between the OldSize and the minimum and/or
1.371 + // initial size of gen0, since OldSize was explicitly set, OldSize wins.
1.372 + if (adjust_gen0_sizes(&_min_gen0_size, &_min_gen1_size,
1.373 + min_heap_byte_size(), OldSize)) {
1.374 + if (PrintGCDetails && Verbose) {
1.375 + gclog_or_tty->print_cr("Minimum gen0 " SIZE_FORMAT " Initial gen0 "
1.376 + SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT,
1.377 + min_gen0_size(), initial_gen0_size(), max_gen0_size());
1.378 + }
1.379 + }
1.380 + // Initial size
1.381 + if (adjust_gen0_sizes(&_initial_gen0_size, &_initial_gen1_size,
1.382 + initial_heap_byte_size(), OldSize)) {
1.383 + if (PrintGCDetails && Verbose) {
1.384 + gclog_or_tty->print_cr("Minimum gen0 " SIZE_FORMAT " Initial gen0 "
1.385 + SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT,
1.386 + min_gen0_size(), initial_gen0_size(), max_gen0_size());
1.387 + }
1.388 + }
1.389 + }
1.390 + // Enforce the maximum gen1 size.
1.391 + set_min_gen1_size(MIN2(_min_gen1_size, _max_gen1_size));
1.392
1.393 - _initial_gen1_size = _initial_heap_byte_size - _initial_gen0_size;
1.394 - _max_gen1_size = _max_heap_byte_size - _max_gen0_size;
1.395 + // Check that min gen1 <= initial gen1 <= max gen1
1.396 + set_initial_gen1_size(MAX2(_initial_gen1_size, _min_gen1_size));
1.397 + set_initial_gen1_size(MIN2(_initial_gen1_size, _max_gen1_size));
1.398 +
1.399 + if (PrintGCDetails && Verbose) {
1.400 + gclog_or_tty->print_cr("Minimum gen1 " SIZE_FORMAT " Initial gen1 "
1.401 + SIZE_FORMAT " Maximum gen1 " SIZE_FORMAT,
1.402 + min_gen1_size(), initial_gen1_size(), max_gen1_size());
1.403 + }
1.404 }
1.405
1.406 HeapWord* GenCollectorPolicy::mem_allocate_work(size_t size,
