src-test2/lib/libc/stdlib/malloc.c, branch release/7.2.0_cvs

Copy releng/7.2 to release/7.2.0 for FreeBSD 7.2-RELEASE.

2009-05-01T02:51:58Z

Approved by: re (implicit) This commit was manufactured to restore the state of the 7.2-RELEASE image.

Mostly synchronize lib/libthr and sys/kern/kern_umtx.c with the code

2009-03-24T20:57:10Z

from HEAD. Since libkse is still built on RELENG_7, pthread_cleanup_push/pop are left as the functions, but the support code in libthr is present for the macro versions. Malloc in RELENG_7 does not require thread exit hook, but I decided to add empty handler for it, instead of removing callback from thr_exit(). No mergeinfo since this change is prepared by patching libthr and then bringing in required missed bits. Requested by: bms Reviewed by: davidxu Tested by: bms, Mykola Dzham Approved by: re (kensmith)

MFC:

2008-11-10T17:30:49Z
Revert to preferring mmap(2) over sbrk(2) when mapping memory, due to potential extreme contention in the kernel for multi-threaded applications on SMP systems. Approved by: re (kib)

MFC allocator improvements and fixes:

2008-08-16T20:14:21Z
* Enhance the chunk map to support run coalescing, and substantially reduce the number of red-black tree operations performed. * Remove unused code. * Fix arena_run_reg_dalloc() to use the entire precomputed division table. * Improve lock preemption performance for hyperthreaded CPUs.

MFC allocator improvements and fixes:

2008-06-16T23:42:05Z
* Implement more compact red-black trees, thus reducing memory usage by ~0.5-1%. * Add a separate tree to track dirty-page-containing chunks, thus improving worst case allocation performance. * Fix a deadlock in base_alloc() for the error (OOM) path. * Catch integer overflow for huge allocations when using sbrk(2). * Fix bit vector initialization for run headers. This fix has no practical impact for correct programs. Incorrect programs will potentially experience allocation failures rather than memory corruption, both of which are "undefined behavior".

MFC: Merge malloc(3) improvements and fixes. The highlights are:

2008-03-07T22:39:39Z
* Avoid re-zeroing memory in calloc() when possible. * Use pthread mutexes where possible instead of libc "spinlocks", and actually spin some during contention before blocking. * Implement dynamic load balancing of thread-->arena mapping. * Avoid floating point math in order to avoid increased context switch overhead for applications that otherwise would not use floating point math. * Restructure how sbrk() and mmap() are used to acquire memory mappings. This provides a way to force malloc to only use sbrk(), which can be useful in the context of resource limits. * Reduce the number of mmap() calls typically necessary when allocating a chunk. * Track dirty unused pages so that they can be purged if they exceed a threshold. * Try to realloc() large objects in place. * Manage page runs with trees instead of chunk maps, which allows logarithmic-time run allocation.

Turn on MALLOC_PRODUCTION which turns off some stuff used for debugging

2007-10-11T06:35:46Z
support. Reminded by: kris Approved by: re (implicit)

Fix junk/zero filling for realloc(). Junk filling was missing in one case,

2007-06-15T22:00:16Z
and zero filling was broken in a way that could cause memory corruption. Update comments.

Use size_t instead of unsigned for pagesize-related values, in order to

2007-03-29T21:07:17Z
avoid downcasting issues. In particular, this change fixes posix_memalign(3) for alignments greater than 2^31 on LP64 systems. Make sure that NDEBUG is always set to be compatible with MALLOC_DEBUG. [1] Reported by: [1] Lee Hyo geol

Remove the run promotion/demotion machinery. Replace it with red-black

2007-03-28T19:55:07Z
trees that track all non-full runs for each bin. Use the red-black trees to be able to guarantee that each new allocation is placed in the lowest address available in any non-full run. This change completes the transition to allocating from low addresses in order to reduce the retention of sparsely used chunks. If the run in current use by a bin becomes empty, deallocate the run rather than retaining it for later use. The previous behavior had the tendency to spread empty runs across multiple chunks, thus preventing the release of chunks that were completely unused. Generalize base_chunk_alloc() (and rename it to base_pages_alloc()) to handle allocation sizes larger than the chunk size, so that it is possible to support chunk sizes that are smaller than an arena object. Reduce the minimum chunk size from 64kB to 8kB. Optimize tracking of addresses for deleted chunks. Fix a statistics bug for huge allocations.