private boolean acquireRecyclableLines(int bytes, int align, int offset) {
while (line < LINES_IN_BLOCK || acquireRecyclableBlock()) {
line = space.getNextAvailableLine(markTable, line);
if (line < LINES_IN_BLOCK) {
int endLine = space.getNextUnavailableLine(markTable, line);
cursor = recyclableBlock.plus(Extent.fromIntSignExtend(line << LOG_BYTES_IN_LINE));
limit = recyclableBlock.plus(Extent.fromIntSignExtend(endLine << LOG_BYTES_IN_LINE));
if (SANITY_CHECK_LINE_MARKS) {
Address tmp = cursor;
while (tmp.LT(limit)) {
if (tmp.loadByte() != (byte) 0) {
Log.write("cursor: ");
Log.writeln(cursor);
Log.write(" limit: ");
Log.writeln(limit);
Log.write("current: ");
Log.write(tmp);
Log.write(" value: ");
Log.write(tmp.loadByte());
Log.write(" line: ");
Log.write(line);
Log.write("endline: ");
Log.write(endLine);
Log.write(" chunk: ");
Log.write(Chunk.align(cursor));
Log.write(" hw: ");
Log.write(Chunk.getHighWater(Chunk.align(cursor)));
Log.writeln(" values: ");
Address tmp2 = cursor;
while (tmp2.LT(limit)) {
Log.write(tmp2.loadByte());
Log.write(" ");
}
Log.writeln();
}
VM.assertions._assert(tmp.loadByte() == (byte) 0);
tmp = tmp.plus(1);
}
}
if (VM.VERIFY_ASSERTIONS && bytes <= BYTES_IN_LINE) {
Address start = alignAllocationNoFill(cursor, align, offset);
Address end = start.plus(bytes);
VM.assertions._assert(end.LE(limit));
}
VM.memory.zero(cursor, limit.diff(cursor).toWord().toExtent());
if (VM.VERIFY_ASSERTIONS && Options.verbose.getValue() >= 9) {
Log.write("Z[");
Log.write(cursor);
Log.write("->");
Log.write(limit);
Log.writeln("]");
}
line = endLine;
if (VM.VERIFY_ASSERTIONS && copy) VM.assertions._assert(!Block.isDefragSource(cursor));
return true;
}
}
return false;
}
/**
* Zero a region of memory
*
* @param start The start of the region to be zeroed (must be 4-byte aligned)
* @param bytes The number of bytes to be zeroed (must be 4-byte aligned)
*/
public static void zero(Address start, Extent bytes) throws InlinePragma {
if (Assert.VERIFY_ASSERTIONS) {
assertAligned(start);
assertAligned(bytes);
}
if (bytes.GT(Extent.fromIntZeroExtend(SMALL_REGION_THRESHOLD)))
org.mmtk.vm.Memory.zero(start, bytes);
else zeroSmall(start, bytes);
}
private void zeroBlock(Address block) {
// FIXME: efficiency check here!
if (VM.VERIFY_ASSERTIONS)
VM.assertions._assert(
block.toWord().and(Word.fromIntSignExtend(BYTES_IN_BLOCK - 1)).isZero());
VM.memory.zero(block, Extent.fromIntZeroExtend(BYTES_IN_BLOCK));
}
/**
* Allows access to an area of virtual memory.
*
* @param start the address of the start of the area to be mapped
* @param size the size, in bytes, of the area to be mapped
* @return <code>true</code> if successful, otherwise <code>false</code>
*/
public final boolean munprotect(Address start, int size) {
return org.jikesrvm.runtime.Memory.mprotect(
start,
Extent.fromIntZeroExtend(size),
org.jikesrvm.runtime.Memory.PROT_READ
| org.jikesrvm.runtime.Memory.PROT_WRITE
| org.jikesrvm.runtime.Memory.PROT_EXEC);
}
/**
* Demand zero mmaps an area of virtual memory.
*
* @param start the address of the start of the area to be mapped
* @param size the size, in bytes, of the area to be mapped
* @return 0 if successful, otherwise the system errno
*/
public final int dzmmap(Address start, int size) {
Address result = org.jikesrvm.runtime.Memory.dzmmap(start, Extent.fromIntZeroExtend(size));
if (result.EQ(start)) return 0;
if (result.GT(Address.fromIntZeroExtend(127))) {
VM.sysWrite("demand zero mmap with MAP_FIXED on ", start);
VM.sysWriteln(" returned some other address", result);
VM.sysFail("mmap with MAP_FIXED has unexpected behavior");
}
return result.toInt();
}
/**
* Protects access to an area of virtual memory.
*
* @param start the address of the start of the area to be mapped
* @param size the size, in bytes, of the area to be mapped
* @return <code>true</code> if successful, otherwise <code>false</code>
*/
public final boolean mprotect(Address start, int size) {
return org.jikesrvm.runtime.Memory.mprotect(
start, Extent.fromIntZeroExtend(size), org.jikesrvm.runtime.Memory.PROT_NONE);
}
private static final void assertAligned(Extent value) {
assertAligned(value.toWord());
}