/*------------------------------------------------------------------------------ // Copyright (c) 2001-2002, Haiku, Inc. // // Permission is hereby granted, free of charge, to any person obtaining a // copy of this software and associated documentation files (the "Software"), // to deal in the Software without restriction, including without limitation // the rights to use, copy, modify, merge, publish, distribute, sublicense, // and/or sell copies of the Software, and to permit persons to whom the // Software is furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER // DEALINGS IN THE SOFTWARE. // // File Name: bget++.cpp // Author: John Walker // DarkWyrm // Description: public domain BGET pool allocator converted to C++ // Distributed with Haiku under MIT license // //------------------------------------------------------------------------------*/ /* This class is based on the BGET pool allocator. Original code was in standard ANSI C with a bunch of static variables. The original code was placed into the MemPool class and the original allocation, release, and compacting functions were made into virtual members. MemPool also, unlike the original code, makes use of malloc() and free() to handle dynamic memory needs. AreaPool is a MemPool subclass which uses areas to handle memory management needs in large chunks. */ // Buffer allocation size quantum: all buffers allocated are a multiple of this size. ' // This MUST be a power of two. #define SizeQuant 4 #include #include #include #include #include #include // Declare the interface, including the requested buffer size type, ssize_t. #include "BGet++.h" // Queue links struct qlinks { struct bfhead *flink; // Forward link struct bfhead *blink; // Backward link }; // Header in allocated and free buffers struct bhead { // Relative link back to previous free buffer in memory or 0 if previous // buffer is allocated. ssize_t prevfree; // Buffer size: positive if free, negative if allocated. ssize_t bsize; }; #define BH(p) ((struct bhead *) (p)) // Header in directly allocated buffers (by acqfcn) struct bdhead { ssize_t tsize; // Total size, including overhead struct bhead bh; // Common header }; #define BDH(p) ((struct bdhead *) (p)) // Header in free buffers struct bfhead { // Common allocated/free header struct bhead bh; // Links on free list struct qlinks ql; }; #define BFH(p) ((struct bfhead *) (p)) static struct bfhead freelist = { // List of free buffers {0, 0}, {&freelist, &freelist} }; // Minimum allocation quantum: #define QLSize (sizeof(struct qlinks)) #define SizeQ ((SizeQuant > QLSize) ? SizeQuant : QLSize) // End sentinel: value placed in bsize field of dummy block delimiting end of // pool block. The most negative number which will fit in a ssize_t, // defined in a way that the compiler will accept. #define ESent ((ssize_t) (-(((1L << (sizeof(ssize_t) * 8 - 2)) - 1) * 2) - 2)) MemPool::MemPool(void) : totalloc(0), numget(0), numrel(0), numpblk(0), numpget(0), numprel(0), numdget(0), numdrel(0), exp_incr(0), pool_len(0) { } MemPool::~MemPool(void) { } // Allocate a buffer from the available space in the memory pool void *MemPool::GetBuffer(ssize_t requested_size, bool zero) { ssize_t size = requested_size; struct bfhead *b; struct bfhead *best; void *buf; int compactseq = 0; assert(size > 0); if (size < (ssize_t)SizeQ) { // Need at least room for the queue links. size = SizeQ; } #if SizeQuant > 1 size = (size + (SizeQuant - 1)) & (~(SizeQuant - 1)); #endif // Add overhead in allocated buffer to size required. size += sizeof(struct bhead); // If a compact function was provided in the call to bectl(), wrap // a loop around the allocation process to allow compaction to // intervene in case we don't find a suitable buffer in the chain. while (1) { b = freelist.ql.flink; best = &freelist; // Scan the free list searching for the first buffer big enough // to hold the requested size buffer. while (b != &freelist) { if (b->bh.bsize >= size) { if ((best == &freelist) || (b->bh.bsize < best->bh.bsize)) { best = b; } } b = b->ql.flink; // Link to next buffer } b = best; while (b != &freelist) { if ((ssize_t) b->bh.bsize >= size) { // Buffer is big enough to satisfy the request. Allocate it to the caller. // We must decide whether the buffer is large enough to split into the part // given to the caller and a free buffer that remains on the free list, or // whether the entire buffer should be removed from the free list and given // to the caller in its entirety. We only split the buffer if enough room // remains for a header plus the minimum quantum of allocation. if ((b->bh.bsize - size) > (ssize_t)(SizeQ + (sizeof(struct bhead)))) { struct bhead *ba, *bn; ba = BH(((char *) b) + (b->bh.bsize - size)); bn = BH(((char *) ba) + size); assert(bn->prevfree == b->bh.bsize); // Subtract size from length of free block. b->bh.bsize -= size; // Link allocated buffer to the previous free buffer. ba->prevfree = b->bh.bsize; // Plug negative size into user buffer. ba->bsize = -(ssize_t) size; // Mark buffer after this one not preceded by free block. bn->prevfree = 0; totalloc += size; numget++; // Increment number of GetBuffer() calls buf = (void *) ((((char *) ba) + sizeof(struct bhead))); return buf; } else { struct bhead *ba; ba = BH(((char *) b) + b->bh.bsize); assert(ba->prevfree == b->bh.bsize); // The buffer isn't big enough to split. Give the whole // shebang to the caller and remove it from the free list. assert(b->ql.blink->ql.flink == b); assert(b->ql.flink->ql.blink == b); b->ql.blink->ql.flink = b->ql.flink; b->ql.flink->ql.blink = b->ql.blink; totalloc += b->bh.bsize; numget++; // Increment number of GetBuffer() calls // Negate size to mark buffer allocated. b->bh.bsize = -(b->bh.bsize); // Zero the back pointer in the next buffer in memory // to indicate that this buffer is allocated. ba->prevfree = 0; // Give user buffer starting at queue links. buf = (void *) &(b->ql); return buf; } } b = b->ql.flink; // Link to next buffer } // We failed to find a buffer. If there's a compact function // defined, notify it of the size requested. If it returns // TRUE, try the allocation again. if(!CompactMem(size, ++compactseq)) break; } // No buffer available with requested size free. // Don't give up yet -- look in the reserve supply. if (size > (ssize_t)(exp_incr - sizeof(struct bhead))) { // Request is too large to fit in a single expansion // block. Try to satisy it by a direct buffer acquisition. struct bdhead *bdh; size += sizeof(struct bdhead) - sizeof(struct bhead); if ((bdh = BDH(AcquireMem((ssize_t) size))) != NULL) { // Mark the buffer special by setting the size field // of its header to zero. bdh->bh.bsize = 0; bdh->bh.prevfree = 0; bdh->tsize = size; totalloc += size; // Increment number of GetBuffer() calls numget++; // Direct GetBuffer() call count numdget++; buf = (void *) (bdh + 1); return buf; } } else { // Try to obtain a new expansion block void *newpool; if ((newpool = AcquireMem((ssize_t) exp_incr)) != NULL) { AddToPool(newpool, exp_incr); // This can't, I say, can't get into a loop buf = GetBuffer(requested_size); return buf; } } // Still no buffer available return NULL; // Code from bgetz -- zeroing code /* char *buf = (char *) GetBuffer(size); if (buf != NULL) { struct bhead *b; ssize_t rsize; b = BH(buf - sizeof(struct bhead)); rsize = -(b->bsize); if (rsize == 0) { struct bdhead *bd; bd = BDH(buf - sizeof(struct bdhead)); rsize = bd->tsize - sizeof(struct bdhead); } else { rsize -= sizeof(struct bhead); } assert(rsize >= size); memset(buf, 0, (MemSize) rsize); } return ((void *) buf); */ } // Reallocate a buffer. This is a minimal implementation, simply in terms // of ReleaseBuffer() and GetBuffer(). It could be enhanced to allow the // buffer to grow into adjacent free blocks and to avoid moving data unnecessarily. void *MemPool::ReallocateBuffer(void *buf, ssize_t size) { void *nbuf; // Old size of buffer ssize_t osize; struct bhead *b; if ((nbuf = GetBuffer(size)) == NULL) { // Acquire new buffer return NULL; } if (buf == NULL) { return nbuf; } b = BH(((char *) buf) - sizeof(struct bhead)); osize = -b->bsize; if (osize == 0) { // Buffer acquired directly through acqfcn. struct bdhead *bd; bd = BDH(((char *) buf) - sizeof(struct bdhead)); osize = bd->tsize - sizeof(struct bdhead); } else osize -= sizeof(struct bhead); assert(osize > 0); // Copy the data memcpy((char *) nbuf, (char *) buf, (int) ((size < osize) ? size : osize)); ReleaseBuffer(buf); return nbuf; } // BREL -- Release a buffer. void MemPool::ReleaseBuffer(void *buf) { struct bfhead *b, *bn; b = BFH(((char *) buf) - sizeof(struct bhead)); // Increment number of ReleaseBuffer() calls numrel++; assert(buf != NULL); // Directly-acquired buffer? if (b->bh.bsize == 0) { struct bdhead *bdh; bdh = BDH(((char *) buf) - sizeof(struct bdhead)); assert(b->bh.prevfree == 0); totalloc -= bdh->tsize; assert(totalloc >= 0); // Number of direct releases numdrel++; memset((char *) buf, 0x55, (int) (bdh->tsize - sizeof(struct bdhead))); // Release it directly. ReleaseMem((void *) bdh); return; } // Buffer size must be negative, indicating that the buffer is allocated. if (b->bh.bsize >= 0) { bn = NULL; } assert(b->bh.bsize < 0); // Back pointer in next buffer must be zero, indicating the same thing: assert(BH((char *) b - b->bh.bsize)->prevfree == 0); totalloc += b->bh.bsize; assert(totalloc >= 0); // If the back link is nonzero, the previous buffer is free. if (b->bh.prevfree != 0) { // The previous buffer is free. Consolidate this buffer with it // by adding the length of this buffer to the previous free // buffer. Note that we subtract the size in the buffer being // released, since it's negative to indicate that the buffer is allocated. register ssize_t size = b->bh.bsize; // Make the previous buffer the one we're working on. assert(BH((char *) b - b->bh.prevfree)->bsize == b->bh.prevfree); b = BFH(((char *) b) - b->bh.prevfree); b->bh.bsize -= size; } else { // The previous buffer isn't allocated. Insert this buffer on the // free list as an isolated free block. assert(freelist.ql.blink->ql.flink == &freelist); assert(freelist.ql.flink->ql.blink == &freelist); b->ql.flink = &freelist; b->ql.blink = freelist.ql.blink; freelist.ql.blink = b; b->ql.blink->ql.flink = b; b->bh.bsize = -b->bh.bsize; } // Now we look at the next buffer in memory, located by advancing from // the start of this buffer by its size, to see if that buffer is // free. If it is, we combine this buffer with the next one in // memory, dechaining the second buffer from the free list. bn = BFH(((char *) b) + b->bh.bsize); if (bn->bh.bsize > 0) { // The buffer is free. Remove it from the free list and add // its size to that of our buffer. assert(BH((char *) bn + bn->bh.bsize)->prevfree == bn->bh.bsize); assert(bn->ql.blink->ql.flink == bn); assert(bn->ql.flink->ql.blink == bn); bn->ql.blink->ql.flink = bn->ql.flink; bn->ql.flink->ql.blink = bn->ql.blink; b->bh.bsize += bn->bh.bsize; // Finally, advance to the buffer that follows the newly // consolidated free block. We must set its backpointer to the // head of the consolidated free block. We know the next block // must be an allocated block because the process of recombination // guarantees that two free blocks will never be contiguous in // memory. bn = BFH(((char *) b) + b->bh.bsize); } memset(((char *) b) + sizeof(struct bfhead), 0x55,(int) (b->bh.bsize - sizeof(struct bfhead))); assert(bn->bh.bsize < 0); // The next buffer is allocated. Set the backpointer in it to point // to this buffer; the previous free buffer in memory. bn->bh.prevfree = b->bh.bsize; // If a block-release function is defined, and this free buffer // constitutes the entire block, release it. Note that pool_len // is defined in such a way that the test will fail unless all // pool blocks are the same size. if (((ssize_t) b->bh.bsize) == (ssize_t)(pool_len - sizeof(struct bhead))) { assert(b->bh.prevfree == 0); assert(BH((char *) b + b->bh.bsize)->bsize == ESent); assert(BH((char *) b + b->bh.bsize)->prevfree == b->bh.bsize); // Unlink the buffer from the free list b->ql.blink->ql.flink = b->ql.flink; b->ql.flink->ql.blink = b->ql.blink; ReleaseMem(b); // Nr of expansion block releases numprel++; // Total number of blocks numpblk--; assert(numpblk == numpget - numprel); } } // Add a region of memory to the buffer pool. void MemPool::AddToPool(void *buf, ssize_t len) { struct bfhead *b = BFH(buf); struct bhead *bn; len &= ~(SizeQuant - 1); if (pool_len == 0) { pool_len = len; } else if (len != pool_len) { pool_len = -1; } // Number of block acquisitions numpget++; // Number of blocks total numpblk++; assert(numpblk == numpget - numprel); // Since the block is initially occupied by a single free buffer, // it had better not be (much) larger than the largest buffer // whose size we can store in bhead.bsize. assert(len - sizeof(struct bhead) <= -((ssize_t) ESent + 1)); // Clear the backpointer at the start of the block to indicate that // there is no free block prior to this one. That blocks // recombination when the first block in memory is released. b->bh.prevfree = 0; // Chain the new block to the free list. assert(freelist.ql.blink->ql.flink == &freelist); assert(freelist.ql.flink->ql.blink == &freelist); b->ql.flink = &freelist; b->ql.blink = freelist.ql.blink; freelist.ql.blink = b; b->ql.blink->ql.flink = b; // Create a dummy allocated buffer at the end of the pool. This dummy // buffer is seen when a buffer at the end of the pool is released and // blocks recombination of the last buffer with the dummy buffer at // the end. The length in the dummy buffer is set to the largest // negative number to denote the end of the pool for diagnostic // routines (this specific value is not counted on by the actual // allocation and release functions). len -= sizeof(struct bhead); b->bh.bsize = (ssize_t) len; memset(((char *) b) + sizeof(struct bfhead), 0x55,(int) (len - sizeof(struct bfhead))); bn = BH(((char *) b) + len); bn->prevfree = (ssize_t) len; // Definition of ESent assumes two's complement! assert((~0) == -1); bn->bsize = ESent; } // Return buffer allocation free space statistics. void MemPool::Stats(ssize_t *curalloc, ssize_t *totfree, ssize_t *maxfree, long *nget, long *nrel) { struct bfhead *b = freelist.ql.flink; *nget = numget; *nrel = numrel; *curalloc = totalloc; *totfree = 0; *maxfree = -1; while (b != &freelist) { assert(b->bh.bsize > 0); *totfree += b->bh.bsize; if (b->bh.bsize > *maxfree) { *maxfree = b->bh.bsize; } // Link to next buffer b = b->ql.flink; } } // Return extended statistics void MemPool::ExtendedStats(ssize_t *pool_incr, long *npool, long *npget, long *nprel, long *ndget, long *ndrel) { *pool_incr = (pool_len < 0) ? -exp_incr : exp_incr; *npool = numpblk; *npget = numpget; *nprel = numprel; *ndget = numdget; *ndrel = numdrel; } // Dump the data in a buffer. This is called with the user data pointer, // and backs up to the buffer header. It will dump either a free block // or an allocated one. void MemPool::BufferDump(void *buf) { struct bfhead *b; unsigned char *bdump; ssize_t bdlen; b = BFH(((char *) buf) - sizeof(struct bhead)); assert(b->bh.bsize != 0); if (b->bh.bsize < 0) { bdump = (unsigned char *) buf; bdlen = (-b->bh.bsize) - sizeof(struct bhead); } else { bdump = (unsigned char *) (((char *) b) + sizeof(struct bfhead)); bdlen = b->bh.bsize - sizeof(struct bfhead); } while (bdlen > 0) { int i, dupes = 0; ssize_t l = bdlen; char bhex[50], bascii[20]; if (l > 16) { l = 16; } for (i = 0; i < l; i++) { sprintf(bhex + i * 3, "%02X ", bdump[i]); bascii[i] = isprint(bdump[i]) ? bdump[i] : ' '; } bascii[i] = 0; printf("%-48s %s\n", bhex, bascii); bdump += l; bdlen -= l; while ((bdlen > 16) && (memcmp((char *) (bdump - 16),(char *) bdump, 16) == 0)) { dupes++; bdump += 16; bdlen -= 16; } if (dupes > 1) { printf(" (%d lines [%d bytes] identical to above line skipped)\n", dupes, dupes * 16); } else { if (dupes == 1) { bdump -= 16; bdlen += 16; } } } } // Dump a buffer pool. The buffer headers are always listed. If DUMPALLOC is // nonzero, the contents of allocated buffers are dumped. If DUMPFREE is // nonzero, free blocks are dumped as well. If FreeWipe checking is enabled, // free blocks which have been clobbered will always be dumped. void MemPool::PoolDump(void *buf, bool dumpalloc, bool dumpfree) { struct bfhead *b = BFH(buf); while (b->bh.bsize != ESent) { ssize_t bs = b->bh.bsize; if (bs < 0) { bs = -bs; printf("Allocated buffer: size %6ld bytes.\n", (long) bs); if (dumpalloc) { BufferDump((void *) (((char *) b) + sizeof(struct bhead))); } } else { char *lerr = ""; assert(bs > 0); if ((b->ql.blink->ql.flink != b) || (b->ql.flink->ql.blink != b)) { lerr = " (Bad free list links)"; } printf("Free block: size %6ld bytes.%s\n", (long) bs, lerr); lerr = ((char *) b) + sizeof(struct bfhead); if ((bs > (ssize_t)sizeof(struct bfhead)) && ((*lerr != 0x55) || (memcmp(lerr, lerr + 1, (int) (bs - (sizeof(struct bfhead) + 1))) != 0))) { printf("(Contents of above free block have been overstored.)\n"); BufferDump((void *) (((char *) b) + sizeof(struct bhead))); } else { if (dumpfree) { BufferDump((void *) (((char *) b) + sizeof(struct bhead))); } } } b = BFH(((char *) b) + bs); } } // Validate a buffer pool. int MemPool::Validate(void *buf) { struct bfhead *b = BFH(buf); while (b->bh.bsize != ESent) { ssize_t bs = b->bh.bsize; if (bs < 0) { bs = -bs; } else { char *lerr = ""; assert(bs > 0); if (bs <= 0) { return 0; } if ((b->ql.blink->ql.flink != b) || (b->ql.flink->ql.blink != b)) { printf("Free block: size %6ld bytes. (Bad free list links)\n", (long) bs); assert(0); return 0; } lerr = ((char *) b) + sizeof(struct bfhead); if ((bs > (ssize_t)sizeof(struct bfhead)) && ((*lerr != 0x55) || (memcmp(lerr, lerr + 1,(int) (bs - (sizeof(struct bfhead) + 1))) != 0))) { printf("(Contents of above free block have been overstored.)\n"); BufferDump((void *) (((char *) b) + sizeof(struct bhead))); assert(0); return 0; } } b = BFH(((char *) b) + bs); } return 1; } int *MemPool::CompactMem(ssize_t sizereq, int sequence) { return NULL; } void *MemPool::AcquireMem(ssize_t size) { return malloc(size); } void MemPool::ReleaseMem(void *buffer) { free(buffer); } AreaPool::AreaPool(void) { } AreaPool::~AreaPool(void) { } void *AreaPool::AcquireMem(ssize_t size) { long areasize=0; area_id a; int *parea; if(size