Date: Wed, 26 Apr 2006 16:56:49 -0700 From: Paul Allen <nospam@ugcs.caltech.edu> To: Jason Evans <jasone@freebsd.org> Cc: current@freebsd.org Subject: Re: malloc problems with MySQL? Message-ID: <20060426235649.GB29737@barf.ugcs.caltech.edu> In-Reply-To: <444FD673.3070004@FreeBSD.org> References: <444F71F3.6030901@fsn.hu> <444F83AD.9040207@FreeBSD.org> <20060426182837.GA29737@barf.ugcs.caltech.edu> <444FD673.3070004@FreeBSD.org>
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>From Jason Evans <jasone@freebsd.org>, Wed, Apr 26, 2006 at 01:22:11PM -0700:
> This code behaves as intended. Note that in order to get chunk-aligned
> memory via mmap(), it is necessary to over-allocate, then trim. By
> keeping a cache of unmapped chunks, we can avoid the extra system calls
> most of the time, and we are also able to reduce memory fragmentation in
> many cases. (Over-allocation and trimming fails to utilize chunk-sized
> holes in the memory map.)
Yes, I see... perhaps mmap should be enhanced to take an optional alignment
parameter. :o)
Paul
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