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authorUlrich Drepper <drepper@redhat.com>2007-04-30 22:18:46 +0000
committerUlrich Drepper <drepper@redhat.com>2007-04-30 22:18:46 +0000
commit7ecfbd386a340b52b6491f47fcf37f236cc5eaf1 (patch)
tree0a296767cdb87e11f0ff42dd1ea64afbe97acfa7 /malloc
parente53f0f51a62061e0c654d4b2f82d4c71b4d71932 (diff)
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[BZ #4349]
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>.
Diffstat (limited to 'malloc')
-rw-r--r--malloc/malloc.c135
1 files changed, 110 insertions, 25 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c
index 6427608..8ae941c 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -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;