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6541756: Reduce executable C-heap

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Add executable parameters to reserve_memory and commit_memory to reduce executable memory to only the Code Heap.

Reviewed-by: xlu, kvn, acorn
This commit is contained in:
Coleen Phillimore 2009-03-25 14:19:20 -04:00
parent 472349069b
commit cec3a034d1
7 changed files with 122 additions and 58 deletions
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22
hotspot/src/os/linux/vm/os_linux.cpp
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@ -2269,15 +2269,16 @@ void linux_wrap_code(char* base, size_t size) {
// All it does is to check if there are enough free pages
// left at the time of mmap(). This could be a potential
// problem.
bool os::commit_memory(char* addr, size_t size) {
uintptr_t res = (uintptr_t) ::mmap(addr, size,
PROT_READ|PROT_WRITE|PROT_EXEC,
bool os::commit_memory(char* addr, size_t size, bool exec) {
int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
return res != (uintptr_t) MAP_FAILED;
}
bool os::commit_memory(char* addr, size_t size, size_t alignment_hint) {
return commit_memory(addr, size);
bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
bool exec) {
return commit_memory(addr, size, exec);
}
void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { }
@ -2417,8 +2418,7 @@ os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
unsigned long* os::Linux::_numa_all_nodes;
bool os::uncommit_memory(char* addr, size_t size) {
return ::mmap(addr, size,
PROT_READ|PROT_WRITE|PROT_EXEC,
return ::mmap(addr, size, PROT_NONE,
MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0)
!= MAP_FAILED;
}
@ -2441,7 +2441,9 @@ static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
flags |= MAP_FIXED;
}
addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE|PROT_EXEC,
// Map uncommitted pages PROT_READ and PROT_WRITE, change access
// to PROT_EXEC if executable when we commit the page.
addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
flags, -1, 0);
if (addr != MAP_FAILED) {
@ -2582,7 +2584,9 @@ bool os::large_page_init() {
#define SHM_HUGETLB 04000
#endif
char* os::reserve_memory_special(size_t bytes, char* req_addr) {
char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
// "exec" is passed in but not used. Creating the shared image for
// the code cache doesn't have an SHM_X executable permission to check.
assert(UseLargePages, "only for large pages");
key_t key = IPC_PRIVATE;