1 //===-- allocator_common.h --------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef SCUDO_ALLOCATOR_COMMON_H_
10 #define SCUDO_ALLOCATOR_COMMON_H_
11 
12 #include "common.h"
13 #include "list.h"
14 
15 namespace scudo {
16 
17 template <class SizeClassAllocator> struct TransferBatch {
18   typedef typename SizeClassAllocator::SizeClassMap SizeClassMap;
19   typedef typename SizeClassAllocator::CompactPtrT CompactPtrT;
20 
21   static const u16 MaxNumCached = SizeClassMap::MaxNumCachedHint;
22   void setFromArray(CompactPtrT *Array, u16 N) {
23     DCHECK_LE(N, MaxNumCached);
24     Count = N;
25     memcpy(Batch, Array, sizeof(Batch[0]) * Count);
26   }
27   void appendFromArray(CompactPtrT *Array, u16 N) {
28     DCHECK_LE(N, MaxNumCached - Count);
29     memcpy(Batch + Count, Array, sizeof(Batch[0]) * N);
30     // u16 will be promoted to int by arithmetic type conversion.
31     Count = static_cast<u16>(Count + N);
32   }
33   void appendFromTransferBatch(TransferBatch *B, u16 N) {
34     DCHECK_LE(N, MaxNumCached - Count);
35     DCHECK_GE(B->Count, N);
36     // Append from the back of `B`.
37     memcpy(Batch + Count, B->Batch + (B->Count - N), sizeof(Batch[0]) * N);
38     // u16 will be promoted to int by arithmetic type conversion.
39     Count = static_cast<u16>(Count + N);
40     B->Count = static_cast<u16>(B->Count - N);
41   }
42   void clear() { Count = 0; }
43   void add(CompactPtrT P) {
44     DCHECK_LT(Count, MaxNumCached);
45     Batch[Count++] = P;
46   }
47   void moveToArray(CompactPtrT *Array) {
48     memcpy(Array, Batch, sizeof(Batch[0]) * Count);
49     clear();
50   }
51   u16 getCount() const { return Count; }
52   bool isEmpty() const { return Count == 0U; }
53   CompactPtrT get(u16 I) const {
54     DCHECK_LE(I, Count);
55     return Batch[I];
56   }
57   TransferBatch *Next;
58 
59 private:
60   CompactPtrT Batch[MaxNumCached];
61   u16 Count;
62 };
63 
64 // A BatchGroup is used to collect blocks. Each group has a group id to
65 // identify the group kind of contained blocks.
66 template <class SizeClassAllocator> struct BatchGroup {
67   // `Next` is used by IntrusiveList.
68   BatchGroup *Next;
69   // The compact base address of each group
70   uptr CompactPtrGroupBase;
71   // Cache value of SizeClassAllocatorLocalCache::getMaxCached()
72   u16 MaxCachedPerBatch;
73   // Number of blocks pushed into this group. This is an increment-only
74   // counter.
75   uptr PushedBlocks;
76   // This is used to track how many bytes are not in-use since last time we
77   // tried to release pages.
78   uptr BytesInBGAtLastCheckpoint;
79   // Blocks are managed by TransferBatch in a list.
80   SinglyLinkedList<TransferBatch<SizeClassAllocator>> Batches;
81 };
82 
83 } // namespace scudo
84 
85 #endif // SCUDO_ALLOCATOR_COMMON_H_
86