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Date: Wed, 6 Dec 2000 17:11:53 +0100 (CET)
From: Remy Nonnenmacher <remy@boostworks.com>
Reply-To: remy@boostworks.com
Subject: free() not freing pagedirs pages.
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Hello,

I'm encountering a problem with the stardard libc malloc/free library.
if a program allocates a huge (and temporary) amount of memory with
small structures then free it, the library gives back only a few pages
to the system.

From the /usr/src/lib/libc/stdlib/malloc.c sources, it seems that this
is due to not shrinking/relocating pagedir pages (free_pages(), comment
around line 940). This means that returning pages stop at first
allocated pagedir.

It seems to be a problem also in some other Unixes, anyway, but i would
like to know if:

1) This is historical and must not be fixed.
2) This can be easily fixed.
3) Fixing it would lead to enormous problems. Better keep it like this.

Thanks.

RN.
IhM




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