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[BZ #4349]

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2007-04-30  Ulrich Drepper  <drepper@redhat.com>
	    Jakub Jelinek  <jakub@redhat.com>

	[BZ #4349]
	* malloc/malloc.c: Keep separate list for first blocks on the bin
	lists with a given size.  This helps skipping over list elements
	we know won't fit in two places.
	Inspired by a patch by Tomash Brechko <tomash.brechko@gmail.com>.
This commit is contained in:
Ulrich Drepper 2007-04-30 22:18:46 +00:00
parent e53f0f51a6
commit 7ecfbd386a
2 changed files with 119 additions and 25 deletions
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9
ChangeLog
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@ -1,3 +1,12 @@
2007-04-30 Ulrich Drepper <drepper@redhat.com>
Jakub Jelinek <jakub@redhat.com>
[BZ #4349]
* malloc/malloc.c: Keep separate list for first blocks on the bin
lists with a given size. This helps skipping over list elements
we know won't fit in two places.
Inspired by a patch by Tomash Brechko <tomash.brechko@gmail.com>.
2007-04-28 Ulrich Drepper <drepper@redhat.com>
[BZ #4102]

135
malloc/malloc.c
View File

@ -1,5 +1,5 @@
/* Malloc implementation for multiple threads without lock contention.
Copyright (C) 1996-2002,2003,2004,2005,2006 Free Software Foundation, Inc.
Copyright (C) 1996-2006, 2007 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Wolfram Gloger <wg@malloc.de>
and Doug Lea <dl@cs.oswego.edu>, 2001.
@ -27,10 +27,6 @@
based on:
VERSION 2.7.0 Sun Mar 11 14:14:06 2001 Doug Lea (dl at gee)
Note: There may be an updated version of this malloc obtainable at
http://www.malloc.de/malloc/ptmalloc2.tar.gz
Check before installing!
* Quickstart
In order to compile this implementation, a Makefile is provided with
@ -1781,6 +1777,10 @@ struct malloc_chunk {
struct malloc_chunk* fd; /* double links -- used only if free. */
struct malloc_chunk* bk;
/* Only used for large blocks: pointer to next larger size. */
struct malloc_chunk* fd_nextsize; /* double links -- used only if free. */
struct malloc_chunk* bk_nextsize;
};
@ -1881,7 +1881,7 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
#define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ))
/* The smallest possible chunk */
#define MIN_CHUNK_SIZE (sizeof(struct malloc_chunk))
#define MIN_CHUNK_SIZE (offsetof(struct malloc_chunk, fd_nextsize))
/* The smallest size we can malloc is an aligned minimal chunk */
@ -2081,6 +2081,24 @@ typedef struct malloc_chunk* mbinptr;
else { \
FD->bk = BK; \
BK->fd = FD; \
if (!in_smallbin_range (P->size) \
&& __builtin_expect (P->fd_nextsize != NULL, 0)) { \
assert (P->fd_nextsize->bk_nextsize == P); \
assert (P->bk_nextsize->fd_nextsize == P); \
if (FD->fd_nextsize == NULL) { \
if (P->fd_nextsize == P) \
FD->fd_nextsize = FD->bk_nextsize = FD; \
else { \
FD->fd_nextsize = P->fd_nextsize; \
FD->bk_nextsize = P->bk_nextsize; \
P->fd_nextsize->bk_nextsize = FD; \
P->bk_nextsize->fd_nextsize = FD; \
} \
} else { \
P->fd_nextsize->bk_nextsize = P->bk_nextsize; \
P->bk_nextsize->fd_nextsize = P->fd_nextsize; \
} \
} \
} \
}
@ -2797,7 +2815,31 @@ static void do_check_malloc_state(mstate av)
/* lists are sorted */
assert(p->bk == b ||
(unsigned long)chunksize(p->bk) >= (unsigned long)chunksize(p));
}
if (!in_smallbin_range(size))
{
if (p->fd_nextsize != NULL)
{
if (p->fd_nextsize == p)
assert (p->bk_nextsize == p);
else
{
if (p->fd_nextsize == first (b))
assert (chunksize (p) < chunksize (p->fd_nextsize));
else
assert (chunksize (p) > chunksize (p->fd_nextsize));
if (p == first (b))
assert (chunksize (p) > chunksize (p->bk_nextsize));
else
assert (chunksize (p) < chunksize (p->bk_nextsize));
}
}
else
assert (p->bk_nextsize == NULL);
}
} else if (!in_smallbin_range(size))
assert (p->fd_nextsize == NULL && p->bk_nextsize == NULL);
/* chunk is followed by a legal chain of inuse chunks */
for (q = next_chunk(p);
(q != av->top && inuse(q) &&
@ -4149,6 +4191,11 @@ _int_malloc(mstate av, size_t bytes)
unsorted_chunks(av)->bk = unsorted_chunks(av)->fd = remainder;
av->last_remainder = remainder;
remainder->bk = remainder->fd = unsorted_chunks(av);
if (!in_smallbin_range(remainder_size))
{
remainder->fd_nextsize = NULL;
remainder->bk_nextsize = NULL;
}
set_head(victim, nb | PREV_INUSE |
(av != &main_arena ? NON_MAIN_ARENA : 0));
@ -4197,19 +4244,36 @@ _int_malloc(mstate av, size_t bytes)
size |= PREV_INUSE;
/* if smaller than smallest, bypass loop below */
assert((bck->bk->size & NON_MAIN_ARENA) == 0);
if ((unsigned long)(size) <= (unsigned long)(bck->bk->size)) {
if ((unsigned long)(size) < (unsigned long)(bck->bk->size)) {
fwd = bck;
bck = bck->bk;
victim->fd_nextsize = fwd->fd;
victim->bk_nextsize = fwd->fd->bk_nextsize;
fwd->fd->bk_nextsize = victim->bk_nextsize->fd_nextsize = victim;
}
else {
assert((fwd->size & NON_MAIN_ARENA) == 0);
while ((unsigned long)(size) < (unsigned long)(fwd->size)) {
fwd = fwd->fd;
assert((fwd->size & NON_MAIN_ARENA) == 0);
}
bck = fwd->bk;
while ((unsigned long) size < fwd->size)
{
fwd = fwd->fd_nextsize;
assert((fwd->size & NON_MAIN_ARENA) == 0);
}
if ((unsigned long) size == (unsigned long) fwd->size)
/* Always insert in the second position. */
fwd = fwd->fd;
else
{
victim->fd_nextsize = fwd;
victim->bk_nextsize = fwd->bk_nextsize;
fwd->bk_nextsize = victim;
victim->bk_nextsize->fd_nextsize = victim;
}
bck = fwd->bk;
}
}
} else
victim->fd_nextsize = victim->bk_nextsize = victim;
}
mark_bin(av, victim_index);
@ -4225,21 +4289,25 @@ _int_malloc(mstate av, size_t bytes)
/*
If a large request, scan through the chunks of current bin in
sorted order to find smallest that fits. This is the only step
where an unbounded number of chunks might be scanned without doing
anything useful with them. However the lists tend to be short.
sorted order to find smallest that fits. Use the skip list for this.
*/
if (!in_smallbin_range(nb)) {
bin = bin_at(av, idx);
/* skip scan if empty or largest chunk is too small */
if ((victim = last(bin)) != bin &&
(unsigned long)(first(bin)->size) >= (unsigned long)(nb)) {
if ((victim = first(bin)) != bin &&
(unsigned long)(victim->size) >= (unsigned long)(nb)) {
victim = victim->bk_nextsize;
while (((unsigned long)(size = chunksize(victim)) <
(unsigned long)(nb)))
victim = victim->bk;
victim = victim->bk_nextsize;
/* Avoid removing the first entry for a size so that the skip
list does not have to be rerouted. */
if (victim != last(bin) && victim->size == victim->fd->size)
victim = victim->fd;
remainder_size = size - nb;
unlink(victim, bck, fwd);
@ -4261,6 +4329,11 @@ _int_malloc(mstate av, size_t bytes)
remainder->fd = fwd;
bck->fd = remainder;
fwd->bk = remainder;
if (!in_smallbin_range(remainder_size))
{
remainder->fd_nextsize = NULL;
remainder->bk_nextsize = NULL;
}
set_head(victim, nb | PREV_INUSE |
(av != &main_arena ? NON_MAIN_ARENA : 0));
set_head(remainder, remainder_size | PREV_INUSE);
@ -4330,9 +4403,7 @@ _int_malloc(mstate av, size_t bytes)
remainder_size = size - nb;
/* unlink */
bck = victim->bk;
bin->bk = bck;
bck->fd = bin;
unlink(victim, bck, fwd);
/* Exhaust */
if (remainder_size < MINSIZE) {
@ -4357,7 +4428,11 @@ _int_malloc(mstate av, size_t bytes)
/* advertise as last remainder */
if (in_smallbin_range(nb))
av->last_remainder = remainder;
if (!in_smallbin_range(remainder_size))
{
remainder->fd_nextsize = NULL;
remainder->bk_nextsize = NULL;
}
set_head(victim, nb | PREV_INUSE |
(av != &main_arena ? NON_MAIN_ARENA : 0));
set_head(remainder, remainder_size | PREV_INUSE);
@ -4580,8 +4655,13 @@ _int_free(mstate av, Void_t* mem)
bck = unsorted_chunks(av);
fwd = bck->fd;
p->bk = bck;
p->fd = fwd;
p->bk = bck;
if (!in_smallbin_range(size))
{
p->fd_nextsize = NULL;
p->bk_nextsize = NULL;
}
bck->fd = p;
fwd->bk = p;
@ -4749,6 +4829,11 @@ static void malloc_consolidate(av) mstate av;
unsorted_bin->fd = p;
first_unsorted->bk = p;
if (!in_smallbin_range (size)) {
p->fd_nextsize = NULL;
p->bk_nextsize = NULL;
}
set_head(p, size | PREV_INUSE);
p->bk = unsorted_bin;
p->fd = first_unsorted;