src-test2/lib/libc/stdlib/malloc.3, branch release/7.2.0_cvs FreeBSD source tree https://cgit-dev.freebsd.org/src-test2/atom?h=release%2F7.2.0_cvs 2009-05-01T02:51:58Z Copy releng/7.2 to release/7.2.0 for FreeBSD 7.2-RELEASE. 2009-05-01T02:51:58Z Ken Smith kensmith@FreeBSD.org 2009-05-01T02:51:58Z urn:sha1:b205d83df7763ca1f099bce5ac12a05862a626c4 Approved by: re (implicit) This commit was manufactured to restore the state of the 7.2-RELEASE image. MFC: 2008-11-10T17:30:49Z Jason Evans jasone@FreeBSD.org 2008-11-10T17:30:49Z urn:sha1:d05be0bb64586f5742b8efeaf997ac51b1db87e1 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: Merge malloc(3) improvements and fixes. The highlights are: 2008-03-07T22:39:39Z Jason Evans jasone@FreeBSD.org 2008-03-07T22:39:39Z urn:sha1:d25eaea3901102b810ad0b75e3f464935b2b95ca * 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. Add information about the implications of using mmap(2) instead of sbrk(2). 2007-06-15T22:32:33Z Jason Evans jasone@FreeBSD.org 2007-06-15T22:32:33Z urn:sha1:0061e03d7fa2c712abf1fd3e267899f614f4598c Submitted by: bmah, jhb Update the IMPLEMENTATION NOTES section to reflect recent malloc 2007-03-28T04:34:19Z Jason Evans jasone@FreeBSD.org 2007-03-28T04:34:19Z urn:sha1:0a19939042534ba505aef7418a97fc9420491268 enhancements. Markup fixes. 2006-09-17T21:27:35Z Ruslan Ermilov ru@FreeBSD.org 2006-09-17T21:27:35Z urn:sha1:a73a3ab56baabfbc4b63c100ee64951a407e9416 s/soley/solely 2006-04-13T18:19:44Z Jens Schweikhardt schweikh@FreeBSD.org 2006-04-13T18:19:44Z urn:sha1:e4b2624f46c4aa7d0408e791f9adb9aea448e35e Add malloc_usable_size() to the RETURN VALUES section. 2006-04-04T20:27:53Z Jason Evans jasone@FreeBSD.org 2006-04-04T20:27:53Z urn:sha1:94fc7dc0d57481a7cbb583c8b8df2be3ab8ce661 Add malloc_usable_size(3). 2006-03-28T22:16:04Z Jason Evans jasone@FreeBSD.org 2006-03-28T22:16:04Z urn:sha1:6b2c15da6a35c2af09e7e753ffc3f527d402a2cf Discussed with: arch@ Modify allocation policy, in order to avoid excessive fragmentation for 2006-03-17T09:00:27Z Jason Evans jasone@FreeBSD.org 2006-03-17T09:00:27Z urn:sha1:2d07e432d46738a79f7d6edd1d87d5dcaba1e8a4 allocation patterns that involve a relatively even mixture of many different size classes. Reduce the chunk size from 16 MB to 2 MB. Since chunks are now carved up using an address-ordered first best fit policy, VM map fragmentation is much less likely, which makes smaller chunks not as much of a risk. This reduces the virtual memory size of most applications. Remove redzones, since program buffer overruns are no longer as likely to corrupt malloc data structures. Remove the C MALLOC_OPTIONS flag, and add H and S.