/* * Copyright (c) 2017, 2021, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. *
*/
// Use optimized addresses for the polling page, // e.g. map it to a special 32-bit address. if (OptimizePollingPageLocation) { // architecture-specific list of address wishes: char* address_wishes[] = { // AIX: addresses lower than 0x30000000 don't seem to work on AIX. // PPC64: all address wishes are non-negative 32 bit values where // the lower 16 bits are all zero. we can load these addresses // with a single ppc_lis instruction.
(char*) 0x30000000, (char*) 0x31000000,
(char*) 0x32000000, (char*) 0x33000000,
(char*) 0x40000000, (char*) 0x41000000,
(char*) 0x42000000, (char*) 0x43000000,
(char*) 0x50000000, (char*) 0x51000000,
(char*) 0x52000000, (char*) 0x53000000,
(char*) 0x60000000, (char*) 0x61000000,
(char*) 0x62000000, (char*) 0x63000000
}; int address_wishes_length = sizeof(address_wishes)/sizeof(char*);
// iterate over the list of address wishes: for (int i = 0; i < address_wishes_length; i++) { // Try to map with current address wish. // AIX: AIX needs MAP_FIXED if we provide an address and mmap will // fail if the address is already mapped.
map_address = (char*) ::mmap(address_wishes[i],
map_size, prot,
flags | MAP_FIXED,
-1, 0);
log_debug(os)("SafePoint Polling Page address: %p (wish) => %p",
address_wishes[i], map_address);
if (map_address == address_wishes[i]) { // Map succeeded and map_address is at wished address, exit loop. break;
}
if (map_address != (char*)MAP_FAILED) { // Map succeeded, but polling_page is not at wished address, unmap and continue.
::munmap(map_address, map_size);
map_address = (char*)MAP_FAILED;
} // Map failed, continue loop.
}
} if (map_address == (char*)MAP_FAILED) {
map_address = (char*) ::mmap(NULL, map_size, prot, flags, -1, 0);
}
guarantee(map_address != (char*)MAP_FAILED && map_address != NULL, "SafepointMechanism::pd_initialize: failed to allocate polling page");
log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(map_address));
_polling_page = (address)(map_address);
// Register polling page with NMT.
MemTracker::record_virtual_memory_reserve_and_commit(map_address, map_size, CALLER_PC, mtSafepoint);
// Use same page for thread local handshakes without SIGTRAP if (!os::guard_memory((char*)_polling_page, page_size)) {
fatal("Could not protect polling page");
}
uintptr_t bad_page_val = reinterpret_cast<uintptr_t>(map_address),
good_page_val = bad_page_val + os::vm_page_size();
_poll_page_armed_value = bad_page_val;
_poll_page_disarmed_value = good_page_val;
}
¤ Dauer der Verarbeitung: 0.13 Sekunden
(vorverarbeitet)
¤
Die Informationen auf dieser Webseite wurden
nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit,
noch Qualität der bereit gestellten Informationen zugesichert.
Bemerkung:
Die farbliche Syntaxdarstellung ist noch experimentell.
