1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#define LOG_TAG "MemoryDealer"
18
19#include <binder/MemoryDealer.h>
20#include <binder/IPCThreadState.h>
21#include <binder/MemoryBase.h>
22
23#include <utils/Log.h>
24#include <utils/SortedVector.h>
25#include <utils/String8.h>
26#include <utils/threads.h>
27
28#include <stdint.h>
29#include <stdio.h>
30#include <stdlib.h>
31#include <fcntl.h>
32#include <unistd.h>
33#include <errno.h>
34#include <string.h>
35
36#include <sys/stat.h>
37#include <sys/types.h>
38#include <sys/mman.h>
39#include <sys/file.h>
40
41namespace android {
42// ----------------------------------------------------------------------------
43
44/*
45 * A simple templatized doubly linked-list implementation
46 */
47
48template <typename NODE>
49class LinkedList
50{
51    NODE*  mFirst;
52    NODE*  mLast;
53
54public:
55                LinkedList() : mFirst(0), mLast(0) { }
56    bool        isEmpty() const { return mFirst == 0; }
57    NODE const* head() const { return mFirst; }
58    NODE*       head() { return mFirst; }
59    NODE const* tail() const { return mLast; }
60    NODE*       tail() { return mLast; }
61
62    void insertAfter(NODE* node, NODE* newNode) {
63        newNode->prev = node;
64        newNode->next = node->next;
65        if (node->next == 0) mLast = newNode;
66        else                 node->next->prev = newNode;
67        node->next = newNode;
68    }
69
70    void insertBefore(NODE* node, NODE* newNode) {
71         newNode->prev = node->prev;
72         newNode->next = node;
73         if (node->prev == 0)   mFirst = newNode;
74         else                   node->prev->next = newNode;
75         node->prev = newNode;
76    }
77
78    void insertHead(NODE* newNode) {
79        if (mFirst == 0) {
80            mFirst = mLast = newNode;
81            newNode->prev = newNode->next = 0;
82        } else {
83            newNode->prev = 0;
84            newNode->next = mFirst;
85            mFirst->prev = newNode;
86            mFirst = newNode;
87        }
88    }
89
90    void insertTail(NODE* newNode) {
91        if (mLast == 0) {
92            insertHead(newNode);
93        } else {
94            newNode->prev = mLast;
95            newNode->next = 0;
96            mLast->next = newNode;
97            mLast = newNode;
98        }
99    }
100
101    NODE* remove(NODE* node) {
102        if (node->prev == 0)    mFirst = node->next;
103        else                    node->prev->next = node->next;
104        if (node->next == 0)    mLast = node->prev;
105        else                    node->next->prev = node->prev;
106        return node;
107    }
108};
109
110// ----------------------------------------------------------------------------
111
112class Allocation : public MemoryBase {
113public:
114    Allocation(const sp<MemoryDealer>& dealer,
115            const sp<IMemoryHeap>& heap, ssize_t offset, size_t size);
116    virtual ~Allocation();
117private:
118    sp<MemoryDealer> mDealer;
119};
120
121// ----------------------------------------------------------------------------
122
123class SimpleBestFitAllocator
124{
125    enum {
126        PAGE_ALIGNED = 0x00000001
127    };
128public:
129    SimpleBestFitAllocator(size_t size);
130    ~SimpleBestFitAllocator();
131
132    size_t      allocate(size_t size, uint32_t flags = 0);
133    status_t    deallocate(size_t offset);
134    size_t      size() const;
135    void        dump(const char* what) const;
136    void        dump(String8& res, const char* what) const;
137
138private:
139
140    struct chunk_t {
141        chunk_t(size_t start, size_t size)
142        : start(start), size(size), free(1), prev(0), next(0) {
143        }
144        size_t              start;
145        size_t              size : 28;
146        int                 free : 4;
147        mutable chunk_t*    prev;
148        mutable chunk_t*    next;
149    };
150
151    ssize_t  alloc(size_t size, uint32_t flags);
152    chunk_t* dealloc(size_t start);
153    void     dump_l(const char* what) const;
154    void     dump_l(String8& res, const char* what) const;
155
156    static const int    kMemoryAlign;
157    mutable Mutex       mLock;
158    LinkedList<chunk_t> mList;
159    size_t              mHeapSize;
160};
161
162// ----------------------------------------------------------------------------
163
164Allocation::Allocation(
165        const sp<MemoryDealer>& dealer,
166        const sp<IMemoryHeap>& heap, ssize_t offset, size_t size)
167    : MemoryBase(heap, offset, size), mDealer(dealer)
168{
169#ifndef NDEBUG
170    void* const start_ptr = (void*)(intptr_t(heap->base()) + offset);
171    memset(start_ptr, 0xda, size);
172#endif
173}
174
175Allocation::~Allocation()
176{
177    size_t freedOffset = getOffset();
178    size_t freedSize   = getSize();
179    if (freedSize) {
180        /* NOTE: it's VERY important to not free allocations of size 0 because
181         * they're special as they don't have any record in the allocator
182         * and could alias some real allocation (their offset is zero). */
183
184        // keep the size to unmap in excess
185        size_t pagesize = getpagesize();
186        size_t start = freedOffset;
187        size_t end = start + freedSize;
188        start &= ~(pagesize-1);
189        end = (end + pagesize-1) & ~(pagesize-1);
190
191        // give back to the kernel the pages we don't need
192        size_t free_start = freedOffset;
193        size_t free_end = free_start + freedSize;
194        if (start < free_start)
195            start = free_start;
196        if (end > free_end)
197            end = free_end;
198        start = (start + pagesize-1) & ~(pagesize-1);
199        end &= ~(pagesize-1);
200
201        if (start < end) {
202            void* const start_ptr = (void*)(intptr_t(getHeap()->base()) + start);
203            size_t size = end-start;
204
205#ifndef NDEBUG
206            memset(start_ptr, 0xdf, size);
207#endif
208
209            // MADV_REMOVE is not defined on Dapper based Goobuntu
210#ifdef MADV_REMOVE
211            if (size) {
212                int err = madvise(start_ptr, size, MADV_REMOVE);
213                ALOGW_IF(err, "madvise(%p, %zu, MADV_REMOVE) returned %s",
214                        start_ptr, size, err<0 ? strerror(errno) : "Ok");
215            }
216#endif
217        }
218
219        // This should be done after madvise(MADV_REMOVE), otherwise madvise()
220        // might kick out the memory region that's allocated and/or written
221        // right after the deallocation.
222        mDealer->deallocate(freedOffset);
223    }
224}
225
226// ----------------------------------------------------------------------------
227
228MemoryDealer::MemoryDealer(size_t size, const char* name, uint32_t flags)
229    : mHeap(new MemoryHeapBase(size, flags, name)),
230    mAllocator(new SimpleBestFitAllocator(size))
231{
232}
233
234MemoryDealer::~MemoryDealer()
235{
236    delete mAllocator;
237}
238
239sp<IMemory> MemoryDealer::allocate(size_t size)
240{
241    sp<IMemory> memory;
242    const ssize_t offset = allocator()->allocate(size);
243    if (offset >= 0) {
244        memory = new Allocation(this, heap(), offset, size);
245    }
246    return memory;
247}
248
249void MemoryDealer::deallocate(size_t offset)
250{
251    allocator()->deallocate(offset);
252}
253
254void MemoryDealer::dump(const char* what) const
255{
256    allocator()->dump(what);
257}
258
259const sp<IMemoryHeap>& MemoryDealer::heap() const {
260    return mHeap;
261}
262
263SimpleBestFitAllocator* MemoryDealer::allocator() const {
264    return mAllocator;
265}
266
267// ----------------------------------------------------------------------------
268
269// align all the memory blocks on a cache-line boundary
270const int SimpleBestFitAllocator::kMemoryAlign = 32;
271
272SimpleBestFitAllocator::SimpleBestFitAllocator(size_t size)
273{
274    size_t pagesize = getpagesize();
275    mHeapSize = ((size + pagesize-1) & ~(pagesize-1));
276
277    chunk_t* node = new chunk_t(0, mHeapSize / kMemoryAlign);
278    mList.insertHead(node);
279}
280
281SimpleBestFitAllocator::~SimpleBestFitAllocator()
282{
283    while(!mList.isEmpty()) {
284        delete mList.remove(mList.head());
285    }
286}
287
288size_t SimpleBestFitAllocator::size() const
289{
290    return mHeapSize;
291}
292
293size_t SimpleBestFitAllocator::allocate(size_t size, uint32_t flags)
294{
295    Mutex::Autolock _l(mLock);
296    ssize_t offset = alloc(size, flags);
297    return offset;
298}
299
300status_t SimpleBestFitAllocator::deallocate(size_t offset)
301{
302    Mutex::Autolock _l(mLock);
303    chunk_t const * const freed = dealloc(offset);
304    if (freed) {
305        return NO_ERROR;
306    }
307    return NAME_NOT_FOUND;
308}
309
310ssize_t SimpleBestFitAllocator::alloc(size_t size, uint32_t flags)
311{
312    if (size == 0) {
313        return 0;
314    }
315    size = (size + kMemoryAlign-1) / kMemoryAlign;
316    chunk_t* free_chunk = 0;
317    chunk_t* cur = mList.head();
318
319    size_t pagesize = getpagesize();
320    while (cur) {
321        int extra = 0;
322        if (flags & PAGE_ALIGNED)
323            extra = ( -cur->start & ((pagesize/kMemoryAlign)-1) ) ;
324
325        // best fit
326        if (cur->free && (cur->size >= (size+extra))) {
327            if ((!free_chunk) || (cur->size < free_chunk->size)) {
328                free_chunk = cur;
329            }
330            if (cur->size == size) {
331                break;
332            }
333        }
334        cur = cur->next;
335    }
336
337    if (free_chunk) {
338        const size_t free_size = free_chunk->size;
339        free_chunk->free = 0;
340        free_chunk->size = size;
341        if (free_size > size) {
342            int extra = 0;
343            if (flags & PAGE_ALIGNED)
344                extra = ( -free_chunk->start & ((pagesize/kMemoryAlign)-1) ) ;
345            if (extra) {
346                chunk_t* split = new chunk_t(free_chunk->start, extra);
347                free_chunk->start += extra;
348                mList.insertBefore(free_chunk, split);
349            }
350
351            ALOGE_IF((flags&PAGE_ALIGNED) &&
352                    ((free_chunk->start*kMemoryAlign)&(pagesize-1)),
353                    "PAGE_ALIGNED requested, but page is not aligned!!!");
354
355            const ssize_t tail_free = free_size - (size+extra);
356            if (tail_free > 0) {
357                chunk_t* split = new chunk_t(
358                        free_chunk->start + free_chunk->size, tail_free);
359                mList.insertAfter(free_chunk, split);
360            }
361        }
362        return (free_chunk->start)*kMemoryAlign;
363    }
364    return NO_MEMORY;
365}
366
367SimpleBestFitAllocator::chunk_t* SimpleBestFitAllocator::dealloc(size_t start)
368{
369    start = start / kMemoryAlign;
370    chunk_t* cur = mList.head();
371    while (cur) {
372        if (cur->start == start) {
373            LOG_FATAL_IF(cur->free,
374                "block at offset 0x%08lX of size 0x%08lX already freed",
375                cur->start*kMemoryAlign, cur->size*kMemoryAlign);
376
377            // merge freed blocks together
378            chunk_t* freed = cur;
379            cur->free = 1;
380            do {
381                chunk_t* const p = cur->prev;
382                chunk_t* const n = cur->next;
383                if (p && (p->free || !cur->size)) {
384                    freed = p;
385                    p->size += cur->size;
386                    mList.remove(cur);
387                    delete cur;
388                }
389                cur = n;
390            } while (cur && cur->free);
391
392            #ifndef NDEBUG
393                if (!freed->free) {
394                    dump_l("dealloc (!freed->free)");
395                }
396            #endif
397            LOG_FATAL_IF(!freed->free,
398                "freed block at offset 0x%08lX of size 0x%08lX is not free!",
399                freed->start * kMemoryAlign, freed->size * kMemoryAlign);
400
401            return freed;
402        }
403        cur = cur->next;
404    }
405    return 0;
406}
407
408void SimpleBestFitAllocator::dump(const char* what) const
409{
410    Mutex::Autolock _l(mLock);
411    dump_l(what);
412}
413
414void SimpleBestFitAllocator::dump_l(const char* what) const
415{
416    String8 result;
417    dump_l(result, what);
418    ALOGD("%s", result.string());
419}
420
421void SimpleBestFitAllocator::dump(String8& result,
422        const char* what) const
423{
424    Mutex::Autolock _l(mLock);
425    dump_l(result, what);
426}
427
428void SimpleBestFitAllocator::dump_l(String8& result,
429        const char* what) const
430{
431    size_t size = 0;
432    int32_t i = 0;
433    chunk_t const* cur = mList.head();
434
435    const size_t SIZE = 256;
436    char buffer[SIZE];
437    snprintf(buffer, SIZE, "  %s (%p, size=%u)\n",
438            what, this, (unsigned int)mHeapSize);
439
440    result.append(buffer);
441
442    while (cur) {
443        const char* errs[] = {"", "| link bogus NP",
444                            "| link bogus PN", "| link bogus NP+PN" };
445        int np = ((cur->next) && cur->next->prev != cur) ? 1 : 0;
446        int pn = ((cur->prev) && cur->prev->next != cur) ? 2 : 0;
447
448        snprintf(buffer, SIZE, "  %3u: %p | 0x%08X | 0x%08X | %s %s\n",
449            i, cur, int(cur->start*kMemoryAlign),
450            int(cur->size*kMemoryAlign),
451                    int(cur->free) ? "F" : "A",
452                    errs[np|pn]);
453
454        result.append(buffer);
455
456        if (!cur->free)
457            size += cur->size*kMemoryAlign;
458
459        i++;
460        cur = cur->next;
461    }
462    snprintf(buffer, SIZE,
463            "  size allocated: %u (%u KB)\n", int(size), int(size/1024));
464    result.append(buffer);
465}
466
467
468}; // namespace android
469