213 }
214
215 size_t GenCollectorPolicy::compute_max_alignment() {
216 // The card marking array and the offset arrays for old generations are
217 // committed in os pages as well. Make sure they are entirely full (to
218 // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
219 // byte entry and the os page size is 4096, the maximum heap size should
220 // be 512*4096 = 2MB aligned.
221 size_t alignment = GenRemSet::max_alignment_constraint(rem_set_name());
222
223 // Parallel GC does its own alignment of the generations to avoid requiring a
224 // large page (256M on some platforms) for the permanent generation. The
225 // other collectors should also be updated to do their own alignment and then
226 // this use of lcm() should be removed.
227 if (UseLargePages && !UseParallelGC) {
228 // in presence of large pages we have to make sure that our
229 // alignment is large page aware
230 alignment = lcm(os::large_page_size(), alignment);
231 }
232
233 return alignment;
234 }
235
236 void GenCollectorPolicy::initialize_flags() {
237 // All sizes must be multiples of the generation granularity.
238 set_min_alignment((uintx) Generation::GenGrain);
239 set_max_alignment(compute_max_alignment());
240
241 CollectorPolicy::initialize_flags();
242
243 // All generational heaps have a youngest gen; handle those flags here.
244
245 // Adjust max size parameters
246 if (NewSize > MaxNewSize) {
247 MaxNewSize = NewSize;
248 }
249 NewSize = align_size_down(NewSize, min_alignment());
250 MaxNewSize = align_size_down(MaxNewSize, min_alignment());
251
252 // Check validity of heap flags
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213 }
214
215 size_t GenCollectorPolicy::compute_max_alignment() {
216 // The card marking array and the offset arrays for old generations are
217 // committed in os pages as well. Make sure they are entirely full (to
218 // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
219 // byte entry and the os page size is 4096, the maximum heap size should
220 // be 512*4096 = 2MB aligned.
221 size_t alignment = GenRemSet::max_alignment_constraint(rem_set_name());
222
223 // Parallel GC does its own alignment of the generations to avoid requiring a
224 // large page (256M on some platforms) for the permanent generation. The
225 // other collectors should also be updated to do their own alignment and then
226 // this use of lcm() should be removed.
227 if (UseLargePages && !UseParallelGC) {
228 // in presence of large pages we have to make sure that our
229 // alignment is large page aware
230 alignment = lcm(os::large_page_size(), alignment);
231 }
232
233 assert(alignment >= min_alignment(), "Must be");
234
235 return alignment;
236 }
237
238 void GenCollectorPolicy::initialize_flags() {
239 // All sizes must be multiples of the generation granularity.
240 set_min_alignment((uintx) Generation::GenGrain);
241 set_max_alignment(compute_max_alignment());
242
243 CollectorPolicy::initialize_flags();
244
245 // All generational heaps have a youngest gen; handle those flags here.
246
247 // Adjust max size parameters
248 if (NewSize > MaxNewSize) {
249 MaxNewSize = NewSize;
250 }
251 NewSize = align_size_down(NewSize, min_alignment());
252 MaxNewSize = align_size_down(MaxNewSize, min_alignment());
253
254 // Check validity of heap flags
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