Date: Mon, 01 Dec 2008 14:57:23 -0800 From: Yuri <yuri@rawbw.com> To: Giorgos Keramidas <keramida@ceid.upatras.gr> Cc: freebsd-questions@freebsd.org Subject: Re: Why process memory starts so high up in virtual space with FreeBSD malloc? Message-ID: <49346BD3.5080506@rawbw.com> In-Reply-To: <874p1njz3l.fsf@kobe.laptop> References: <49345710.9070403@rawbw.com> <874p1njz3l.fsf@kobe.laptop>
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Giorgos Keramidas wrote: > The FreeBSD malloc(3) implementation can use either mmap() or sbrk() to > obtain memory from the system. It does not 'waste a high percentage of > memory' but it simply maps only high addresses (with an unmapped 'hole' > in lower addresses). > But the hole it leaves with MALLOC_OPTIONS='dM' is way larger than the one left by 'Dm' option. Usually malloc will keep allocating addresses higher than this initial value and will never come back and fill some parts of this gap. Therefore "wasting" this space. Yuri
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