vm: Replace the VMAreas OpenHashTable with an AVLTree.
Since we used a hash table with a fixed size (1024), collisions were obviously inevitable, meaning that while insertions would always be fast, lookups and deletions would take linear time to search the linked-list for the area in question. For recently-created areas, this would be fast; for less-recently-created areas, it would get slower and slower and slower. A particularly pathological case was the "mmap/24-1" test from the Open POSIX Testsuite, which creates millions of areas until it hits ENOMEM; it then simply exits, at which point it would run for minutes and minutes in the kernel team deletion routines; how long I don't know, as I rebooted before it finished. This change fixes that problem, among others, at the cost of increased area creation time, by using an AVL tree instead of a hash. For comparison, mmap'ing 2 million areas with the "24-1" test before this change took around 0m2.706s of real time, while afterwards it takes about 0m3.118s, or around a 15% increase (1.152x). On the other hand, the total test runtime for 2 million areas went from around 2m11.050s to 0m4.035s, or around a 97% decrease (0.031x); in other words, with this new code, it is *32 times faster.* Area insertion will no longer be O(1), however, so the time increase may go up with the number of areas present on the system; but if it's only around 3 seconds to create 2 million areas, or about 1.56 us per area, vs. 1.35 us before, I don't think that's worth worrying about. My nonscientific "compile HaikuDepot with 2 cores in VM" benchmark seems to be within the realm of "noise", anyway, with most results both before and after this change coming in around 47s real time. Change-Id: I230e17de4f80304d082152af83db8bd5abe7b831
This commit is contained in:
Augustin Cavalier
parent
e48af9e4ec
commit
c650846d9e
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@ -15,7 +15,7 @@
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#include <lock.h>
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#include <util/DoublyLinkedList.h>
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#include <util/SinglyLinkedList.h>
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#include <util/OpenHashTable.h>
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#include <util/AVLTree.h>
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#include <vm/vm_types.h>
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@ -88,7 +88,12 @@ struct VMPageWiringInfo {
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};
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struct VMArea {
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struct VMAreasTreeNode {
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AVLTreeNode tree_node;
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};
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struct VMArea : private VMAreasTreeNode {
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public:
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enum {
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// AddWaiterIfWired() flags
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@ -117,7 +122,6 @@ public:
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struct VMAddressSpace* address_space;
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struct VMArea* cache_next;
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struct VMArea* cache_prev;
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struct VMArea* hash_next;
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addr_t Base() const { return fBase; }
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size_t Size() const { return fSize; }
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@ -149,7 +153,7 @@ protected:
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status_t Init(const char* name, uint32 allocationFlags);
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protected:
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friend struct VMAddressSpace;
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friend struct VMAreasTreeDefinition;
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friend struct VMKernelAddressSpace;
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friend struct VMUserAddressSpace;
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@ -164,35 +168,42 @@ protected:
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};
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struct VMAreaHashDefinition {
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typedef area_id KeyType;
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typedef VMArea ValueType;
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struct VMAreasTreeDefinition {
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typedef area_id Key;
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typedef VMArea Value;
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size_t HashKey(area_id key) const
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AVLTreeNode* GetAVLTreeNode(VMArea* value) const
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{
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return key;
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return &value->tree_node;
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}
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size_t Hash(const VMArea* value) const
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VMArea* GetValue(AVLTreeNode* node) const
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{
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return HashKey(value->id);
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const addr_t vmTreeNodeAddr = (addr_t)node
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- offsetof(VMAreasTreeNode, tree_node);
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VMAreasTreeNode* vmTreeNode =
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reinterpret_cast<VMAreasTreeNode*>(vmTreeNodeAddr);
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return static_cast<VMArea*>(vmTreeNode);
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}
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bool Compare(area_id key, const VMArea* value) const
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int Compare(area_id key, const VMArea* value) const
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{
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return value->id == key;
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const area_id valueId = value->id;
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if (valueId == key)
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return 0;
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return key < valueId ? -1 : 1;
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}
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VMArea*& GetLink(VMArea* value) const
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int Compare(const VMArea* a, const VMArea* b) const
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{
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return value->hash_next;
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return Compare(a->id, b);
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}
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};
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typedef BOpenHashTable<VMAreaHashDefinition> VMAreaHashTable;
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typedef AVLTree<VMAreasTreeDefinition> VMAreasTree;
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struct VMAreaHash {
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struct VMAreas {
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static status_t Init();
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static status_t ReadLock()
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@ -205,18 +216,18 @@ struct VMAreaHash {
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{ rw_lock_write_unlock(&sLock); }
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static VMArea* LookupLocked(area_id id)
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{ return sTable.Lookup(id); }
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{ return sTree.Find(id); }
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static VMArea* Lookup(area_id id);
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static area_id Find(const char* name);
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static void Insert(VMArea* area);
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static void Remove(VMArea* area);
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static VMAreaHashTable::Iterator GetIterator()
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{ return sTable.GetIterator(); }
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static VMAreasTree::Iterator GetIterator()
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{ return sTree.GetIterator(); }
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private:
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static rw_lock sLock;
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static VMAreaHashTable sTable;
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static VMAreasTree sTree;
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};
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@ -161,16 +161,6 @@ DumpPageTableInt(Pte* pte, uint64_t virtAdr, uint32_t level, PageTableDumper& du
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}
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static VMArea* LookupArea(area_id id)
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{
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VMAreaHash::ReadLock();
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VMArea* area = VMAreaHash::LookupLocked(id);
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VMAreaHash::ReadUnlock();
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return area;
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}
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static int
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DumpPageTable(int argc, char** argv)
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{
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@ -198,7 +188,7 @@ DumpPageTable(int argc, char** argv)
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uint64 areaId;
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if (!evaluate_debug_expression(argv[curArg++], &areaId, false))
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return 0;
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VMArea* area = LookupArea((area_id)areaId);
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VMArea* area = VMAreas::Lookup((area_id)areaId);
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if (area == NULL) {
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kprintf("could not find area %" B_PRId32 "\n", (area_id)areaId);
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return 0;
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@ -107,7 +107,7 @@ IOCache::Init(const char* name)
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VM_PRIORITY_SYSTEM);
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// get the area's cache
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VMArea* area = VMAreaHash::Lookup(fArea);
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VMArea* area = VMAreas::Lookup(fArea);
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if (area == NULL) {
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panic("IOCache::Init(): Where's our area (id: %" B_PRId32 ")?!", fArea);
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return B_ERROR;
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@ -1324,7 +1324,7 @@ MemoryManager::_AllocateArea(uint32 flags, Area*& _area)
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pagesNeededToMap = translationMap->MaxPagesNeededToMap(
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(addr_t)area, (addr_t)areaBase + SLAB_AREA_SIZE - 1);
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vmArea = VMAreaHash::Lookup(areaID);
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vmArea = VMAreas::Lookup(areaID);
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status_t error = _MapChunk(vmArea, (addr_t)area, kAreaAdminSize,
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pagesNeededToMap, flags);
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if (error != B_OK) {
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@ -1607,7 +1607,7 @@ MemoryManager::_ConvertEarlyArea(Area* area)
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if (areaID < 0)
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panic("out of memory");
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area->vmArea = VMAreaHash::Lookup(areaID);
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area->vmArea = VMAreas::Lookup(areaID);
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}
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@ -23,15 +23,15 @@ AddressSpaceLockerBase::GetAddressSpaceByAreaID(area_id id)
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{
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VMAddressSpace* addressSpace = NULL;
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VMAreaHash::ReadLock();
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VMAreas::ReadLock();
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VMArea* area = VMAreaHash::LookupLocked(id);
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VMArea* area = VMAreas::LookupLocked(id);
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if (area != NULL) {
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addressSpace = area->address_space;
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addressSpace->Get();
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}
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VMAreaHash::ReadUnlock();
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VMAreas::ReadUnlock();
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return addressSpace;
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}
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@ -123,7 +123,7 @@ AddressSpaceReadLocker::SetFromArea(area_id areaID, VMArea*& area)
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fSpace->ReadLock();
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area = VMAreaHash::Lookup(areaID);
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area = VMAreas::Lookup(areaID);
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if (area == NULL || area->address_space != fSpace) {
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fSpace->ReadUnlock();
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@ -243,7 +243,7 @@ AddressSpaceWriteLocker::SetFromArea(area_id areaID, VMArea*& area)
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fSpace->WriteLock();
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area = VMAreaHash::Lookup(areaID);
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area = VMAreas::Lookup(areaID);
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if (area == NULL || area->address_space != fSpace) {
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fSpace->WriteUnlock();
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@ -259,9 +259,9 @@ status_t
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AddressSpaceWriteLocker::SetFromArea(team_id team, area_id areaID,
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bool allowKernel, VMArea*& area)
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{
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VMAreaHash::ReadLock();
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VMAreas::ReadLock();
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area = VMAreaHash::LookupLocked(areaID);
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area = VMAreas::LookupLocked(areaID);
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if (area != NULL
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&& (area->address_space->ID() == team
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|| (allowKernel && team == VMAddressSpace::KernelID()))) {
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@ -269,7 +269,7 @@ AddressSpaceWriteLocker::SetFromArea(team_id team, area_id areaID,
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fSpace->Get();
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}
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VMAreaHash::ReadUnlock();
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VMAreas::ReadUnlock();
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if (fSpace == NULL)
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return B_BAD_VALUE;
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@ -279,7 +279,7 @@ AddressSpaceWriteLocker::SetFromArea(team_id team, area_id areaID,
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fSpace->WriteLock();
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area = VMAreaHash::Lookup(areaID);
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area = VMAreas::Lookup(areaID);
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if (area == NULL) {
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fSpace->WriteUnlock();
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// lock the cache again and check whether anything has changed
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// check whether the area is gone in the meantime
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area = VMAreaHash::Lookup(areaID);
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area = VMAreas::Lookup(areaID);
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if (area == NULL) {
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Unlock();
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@ -16,11 +16,8 @@
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#include <vm/VMAddressSpace.h>
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#define AREA_HASH_TABLE_SIZE 1024
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rw_lock VMAreaHash::sLock = RW_LOCK_INITIALIZER("area hash");
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VMAreaHashTable VMAreaHash::sTable;
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rw_lock VMAreas::sLock = RW_LOCK_INITIALIZER("areas tree");
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VMAreasTree VMAreas::sTree;
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static area_id sNextAreaID = 1;
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@ -39,8 +36,7 @@ VMArea::VMArea(VMAddressSpace* addressSpace, uint32 wiring, uint32 protection)
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page_protections(NULL),
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address_space(addressSpace),
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cache_next(NULL),
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cache_prev(NULL),
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hash_next(NULL)
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cache_prev(NULL)
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{
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new (&mappings) VMAreaMappings;
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}
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@ -203,18 +199,19 @@ VMArea::AddWaiterIfWired(VMAreaUnwiredWaiter* waiter, addr_t base, size_t size,
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}
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// #pragma mark - VMAreaHash
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// #pragma mark - VMAreas
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/*static*/ status_t
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VMAreaHash::Init()
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VMAreas::Init()
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{
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return sTable.Init(AREA_HASH_TABLE_SIZE);
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new(&sTree) VMAreasTree;
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return B_OK;
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}
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/*static*/ VMArea*
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VMAreaHash::Lookup(area_id id)
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VMAreas::Lookup(area_id id)
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{
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ReadLock();
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VMArea* area = LookupLocked(id);
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@ -224,7 +221,7 @@ VMAreaHash::Lookup(area_id id)
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/*static*/ area_id
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VMAreaHash::Find(const char* name)
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VMAreas::Find(const char* name)
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{
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ReadLock();
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@ -233,7 +230,7 @@ VMAreaHash::Find(const char* name)
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// TODO: Iterating through the whole table can be very slow and the whole
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// time we're holding the lock! Use a second hash table!
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for (VMAreaHashTable::Iterator it = sTable.GetIterator();
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for (VMAreasTree::Iterator it = sTree.GetIterator();
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VMArea* area = it.Next();) {
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if (strcmp(area->name, name) == 0) {
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id = area->id;
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@ -248,18 +245,18 @@ VMAreaHash::Find(const char* name)
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/*static*/ void
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VMAreaHash::Insert(VMArea* area)
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VMAreas::Insert(VMArea* area)
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{
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WriteLock();
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sTable.InsertUnchecked(area);
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sTree.Insert(area);
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WriteUnlock();
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}
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/*static*/ void
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VMAreaHash::Remove(VMArea* area)
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VMAreas::Remove(VMArea* area)
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{
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WriteLock();
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sTable.RemoveUnchecked(area);
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sTree.Remove(area);
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WriteUnlock();
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}
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@ -446,13 +446,13 @@ virtual_page_address(VMArea* area, vm_page* page)
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static VMArea*
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lookup_area(VMAddressSpace* addressSpace, area_id id)
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{
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VMAreaHash::ReadLock();
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VMAreas::ReadLock();
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VMArea* area = VMAreaHash::LookupLocked(id);
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VMArea* area = VMAreas::LookupLocked(id);
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if (area != NULL && area->address_space != addressSpace)
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area = NULL;
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VMAreaHash::ReadUnlock();
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VMAreas::ReadUnlock();
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return area;
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}
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@ -1030,8 +1030,8 @@ map_backing_store(VMAddressSpace* addressSpace, VMCache* cache, off_t offset,
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if (mapping == REGION_PRIVATE_MAP)
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cache->Unlock();
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// insert the area in the global area hash table
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VMAreaHash::Insert(area);
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// insert the area in the global areas map
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VMAreas::Insert(area);
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// grab a ref to the address space (the area holds this)
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addressSpace->Get();
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@ -2366,7 +2366,7 @@ delete_area(VMAddressSpace* addressSpace, VMArea* area,
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{
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ASSERT(!area->IsWired());
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VMAreaHash::Remove(area);
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VMAreas::Remove(area);
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// At this point the area is removed from the global hash table, but
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// still exists in the area list.
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@ -3564,7 +3564,7 @@ dump_area(int argc, char** argv)
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} else {
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// walk through the area list, looking for the arguments as a name
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VMAreaHashTable::Iterator it = VMAreaHash::GetIterator();
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VMAreasTree::Iterator it = VMAreas::GetIterator();
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while ((area = it.Next()) != NULL) {
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if (((mode & 4) != 0
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&& !strcmp(argv[index], area->name))
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@ -3601,7 +3601,7 @@ dump_area_list(int argc, char** argv)
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B_PRINTF_POINTER_WIDTH, "addr", B_PRINTF_POINTER_WIDTH, "base",
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B_PRINTF_POINTER_WIDTH, "size");
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VMAreaHashTable::Iterator it = VMAreaHash::GetIterator();
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VMAreasTree::Iterator it = VMAreas::GetIterator();
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while ((area = it.Next()) != NULL) {
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if ((id != 0 && area->address_space->ID() != id)
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|| (name != NULL && strstr(area->name, name) == NULL))
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@ -4208,9 +4208,9 @@ vm_init(kernel_args* args)
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vm_cache_init(args);
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{
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status_t error = VMAreaHash::Init();
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status_t error = VMAreas::Init();
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if (error != B_OK)
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panic("vm_init: error initializing area hash table\n");
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panic("vm_init: error initializing areas map\n");
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}
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VMAddressSpace::Init();
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@ -6125,7 +6125,7 @@ area_for(void* address)
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area_id
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find_area(const char* name)
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{
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return VMAreaHash::Find(name);
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return VMAreas::Find(name);
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}
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