221 static bool stack_shadow_pages_available(Thread *thread, methodHandle method);
222
223 // OS interface to Virtual Memory
224
225 // Return the default page size.
226 static int vm_page_size();
227
228 // Return the page size to use for a region of memory. The min_pages argument
229 // is a hint intended to limit fragmentation; it says the returned page size
230 // should be <= region_max_size / min_pages. Because min_pages is a hint,
231 // this routine may return a size larger than region_max_size / min_pages.
232 //
233 // The current implementation ignores min_pages if a larger page size is an
234 // exact multiple of both region_min_size and region_max_size. This allows
235 // larger pages to be used when doing so would not cause fragmentation; in
236 // particular, a single page can be used when region_min_size ==
237 // region_max_size == a supported page size.
238 static size_t page_size_for_region(size_t region_min_size,
239 size_t region_max_size,
240 uint min_pages);
241
242 // Methods for tracing page sizes returned by the above method; enabled by
243 // TracePageSizes. The region_{min,max}_size parameters should be the values
244 // passed to page_size_for_region() and page_size should be the result of that
245 // call. The (optional) base and size parameters should come from the
246 // ReservedSpace base() and size() methods.
247 static void trace_page_sizes(const char* str, const size_t* page_sizes,
248 int count) PRODUCT_RETURN;
249 static void trace_page_sizes(const char* str, const size_t region_min_size,
250 const size_t region_max_size,
251 const size_t page_size,
252 const char* base = NULL,
253 const size_t size = 0) PRODUCT_RETURN;
254
255 static int vm_allocation_granularity();
256 static char* reserve_memory(size_t bytes, char* addr = 0,
257 size_t alignment_hint = 0);
258 static char* reserve_memory(size_t bytes, char* addr,
259 size_t alignment_hint, MEMFLAGS flags);
260 static char* reserve_memory_aligned(size_t size, size_t alignment);
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221 static bool stack_shadow_pages_available(Thread *thread, methodHandle method);
222
223 // OS interface to Virtual Memory
224
225 // Return the default page size.
226 static int vm_page_size();
227
228 // Return the page size to use for a region of memory. The min_pages argument
229 // is a hint intended to limit fragmentation; it says the returned page size
230 // should be <= region_max_size / min_pages. Because min_pages is a hint,
231 // this routine may return a size larger than region_max_size / min_pages.
232 //
233 // The current implementation ignores min_pages if a larger page size is an
234 // exact multiple of both region_min_size and region_max_size. This allows
235 // larger pages to be used when doing so would not cause fragmentation; in
236 // particular, a single page can be used when region_min_size ==
237 // region_max_size == a supported page size.
238 static size_t page_size_for_region(size_t region_min_size,
239 size_t region_max_size,
240 uint min_pages);
241 // return the largest page size used
242 static size_t max_page_size() {
243 // the _page_sizes array is sorted in descending order.
244 return _page_sizes[0];
245 }
246
247 // Methods for tracing page sizes returned by the above method; enabled by
248 // TracePageSizes. The region_{min,max}_size parameters should be the values
249 // passed to page_size_for_region() and page_size should be the result of that
250 // call. The (optional) base and size parameters should come from the
251 // ReservedSpace base() and size() methods.
252 static void trace_page_sizes(const char* str, const size_t* page_sizes,
253 int count) PRODUCT_RETURN;
254 static void trace_page_sizes(const char* str, const size_t region_min_size,
255 const size_t region_max_size,
256 const size_t page_size,
257 const char* base = NULL,
258 const size_t size = 0) PRODUCT_RETURN;
259
260 static int vm_allocation_granularity();
261 static char* reserve_memory(size_t bytes, char* addr = 0,
262 size_t alignment_hint = 0);
263 static char* reserve_memory(size_t bytes, char* addr,
264 size_t alignment_hint, MEMFLAGS flags);
265 static char* reserve_memory_aligned(size_t size, size_t alignment);
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