This malloc is based on Doug Lea's malloc ( ftp://gee.cs.oswego.edu/pub/misc/ ), the changes are listed below. See http://lists.kde.org/?l=kde-core-devel&m=101351949010285&w=2 for details. Basically, it's here because for now it has better performance than both glibc-2.2.x and FreeBSD's libc. There's a new configure switch, --enable-fast-malloc. By default it's turned off, disabling the system libc one and using this one. Using --enable-fast-malloc=full enables this malloc unconditionally, aiming for the maximum performance. By using only --enable-fast-malloc, it's possible to select both malloc implementations at runtime. When $KDE_MALLOC is set to 0, the system libc malloc is used, otherwise this malloc is used. For now, the requirements are : - x86 CPU (because of the spinlock implementation in assembler), it should be easy to add new ones - glibc (for --enable-fast-malloc=yes, =full doesn't need it), because it needs to refer to the libc implementation of malloc (__libc_malloc etc.) - gcc (for __inline__ , nothing else should depend on gcc) If you have any problem with this malloc, try first using --enable-fast-malloc=debug and recompiling libtdecore, or use valgrind. This malloc seems to be more vulnerable to heap corruption, such as deleting a block twice, so faulty code may run without problems with standard malloc shipped with your libc, but it will crash with this malloc. In case you think there's any problem with this malloc, please mail me. changes (against malloc-2.7.0): #define USE_MALLOC_LOCK #define INLINE __inline__ #define USE_MEMCPY 0 #define MMAP_CLEARS 1 made all functions INLINE added #ifdef KDE_MALLOC_DEBUG -> #define DEBUG reordered all functions in order to avoid 'warning: `XYZ' declared inline after being called' especially moved the public_* ones at the end of the file commented out #including malloc.h added #include at the top and enclosed whole file in #ifdef KDE_MALLOC taken posix_memalign() from glibc removed public icalloc(),icomalloc(),mtrim(),musable() (they don't exist everywhere anyway) enclosed the pthreads part by #if 0 and replaced it with spinlock from glibc CVS (in x86.h) also added : ---------- static mutex_t spinlock = MUTEX_INITIALIZER; #define MALLOC_PREACTION lock( &spinlock ) #define MALLOC_POSTACTION unlock( &spinlock ) ---------- public functions call either functions in this malloc or in libc, depending on $KDE_MALLOC the kde_malloc_is_used hack TODO: malloc_set_state/malloc_get_state ? Lubos Lunak