Initialize version sooner in VersionedMap::begin

This commit is contained in:
2024-05-16 18:45:26 -07:00
parent 1e1f5d6d5c
commit 190cd05c13
4 changed files with 38 additions and 33 deletions

View File

@@ -262,62 +262,49 @@ struct MemManager {
}
void gc(const uint32_t *roots, int numRoots, int64_t oldestVersion) {
#if DEBUG_VERBOSE
if (debugVerboseEnabled) {
printf("GC roots:\n");
for (int i = 0; i < numRoots; ++i) {
printf(" %u\n", roots[i]);
}
}
#endif
// Calculate reachable set
BitSet reachable{next};
// Each node has at most 3 children and nodes along the search path aren't
// in the stack, so we need 2 * kPathLengthUpperBound
uint32_t stack[2 * kPathLengthUpperBound];
int stackIndex = 0;
auto tryPush = [&](uint32_t p) {
#if DEBUG_VERBOSE
if (debugVerboseEnabled) {
printf(" GC: visit: %u\n", p);
}
#endif
if (!reachable.set(p)) {
auto tryPush = [&](uint32_t parent, uint32_t child) {
if (!reachable.set(child)) {
#if DEBUG_VERBOSE
if (debugVerboseEnabled) {
printf(" GC: push on to stack: %u\n", p);
printf(" GC: reach: %u (parent %u)\n", child, parent);
}
#endif
assert(stackIndex < sizeof(stack) / sizeof(stack[0]));
stack[stackIndex++] = p;
stack[stackIndex++] = child;
}
};
for (int i = 0; i < numRoots; ++i) {
if (roots[i] == 0) {
continue;
}
tryPush(roots[i]);
tryPush(0, roots[i]);
while (stackIndex > 0) {
uint32_t p = stack[--stackIndex];
auto &node = base[p];
if (node.updated.load(std::memory_order_relaxed)) {
if (node.pointer[!node.replacedPointer] != 0) {
tryPush(node.pointer[!node.replacedPointer]);
tryPush(p, node.pointer[!node.replacedPointer]);
}
if (oldestVersion < node.updateVersion) {
if (node.pointer[node.replacedPointer] != 0) {
tryPush(node.pointer[node.replacedPointer]);
tryPush(p, node.pointer[node.replacedPointer]);
}
}
if (node.pointer[2] != 0) {
tryPush(node.pointer[2]);
tryPush(p, node.pointer[2]);
}
} else {
if (node.pointer[0] != 0) {
tryPush(node.pointer[0]);
tryPush(p, node.pointer[0]);
}
if (node.pointer[1] != 0) {
tryPush(node.pointer[1]);
tryPush(p, node.pointer[1]);
}
}
}
@@ -495,6 +482,11 @@ struct __attribute__((__visibility__("hidden"))) VersionedMap::Impl {
result = n.pointer[which];
}
assert(result == 0 || result >= kMinAddressable);
#ifndef NDEBUG
if (result != 0) {
assert(mm.base[result].entry != nullptr);
}
#endif
return result;
}
@@ -1174,6 +1166,7 @@ void VersionedMap::firstGeq(const Key *key, const int64_t *version,
VersionedMap::Iterator VersionedMap::begin(int64_t version) const {
VersionedMap::Iterator result;
result.impl = new (safe_malloc(sizeof(Iterator::Impl))) Iterator::Impl();
result.impl->version = version;
bool ignored;
result.impl->finger.push(
@@ -1205,7 +1198,6 @@ VersionedMap::Iterator VersionedMap::begin(int64_t version) const {
}
result.impl->mutationIndex = 0;
result.impl->version = version;
return result;
}