diff --git a/src/lib/libc/stdlib/malloc.3 b/src/lib/libc/stdlib/malloc.3 index 75b8c69e..e0edd944 100644 --- a/src/lib/libc/stdlib/malloc.3 +++ b/src/lib/libc/stdlib/malloc.3 @@ -30,9 +30,9 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.\" $OpenBSD: malloc.3,v 1.62 2009/02/13 23:36:17 jmc Exp $ +.\" $OpenBSD: malloc.3,v 1.63 2009/10/10 18:36:52 otto Exp $ .\" -.Dd $Mdocdate: February 13 2009 $ +.Dd $Mdocdate: October 10 2009 $ .Dt MALLOC 3 .Os .Sh NAME @@ -425,26 +425,29 @@ The function conforms to .St -ansiC . .Sh HISTORY -The present implementation of -.Fn malloc -started out as a filesystem on a drum -attached to a 20-bit binary challenged computer built with discrete germanium -transistors, and it has since graduated to handle primary storage rather than -secondary. -.Pp -The main difference from other -.Fn malloc -implementations are believed to be that -the free pages are not accessed until allocated. -Most -.Fn malloc -implementations will store a data structure containing a, -possibly double-, linked list in the free chunks of memory, used to tie -all the free memory together. -That is a quite suboptimal thing to do. -Every time the free-list is traversed, all the otherwise unused, and very -likely paged out, pages get faulted into primary memory, just to see what -lies after them in the list. -.Pp -On systems which are paging, this can increase the page-faults -of a process by a factor of five. +The +.Nm +family of functions first appeared in +.At v7 . +A new implementation by Chris Kingsley was introduced in +.Bx 4.2 , +followed by a complete rewrite by Poul-Henning Kamp which appeared in +.Fx 2.2 +and was included in +.Ox 2.0 . +These implementations were all +.Xr sbrk 2 +based. +In +.Ox 3.8 , +Thierry Deval rewrote +.Nm +to use the +.Xr mmap 2 +system call, +making the page addresses returned by +.Nm +random. +A rewrite by Otto Moerbeek introducing a new central data stucture and more +randomization appeared in +.Ox 4.4 .