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Re: fork and COW



At Mon, 29 Jun 2020 21:48:13 +0200, Jaromír Dole ek <jaromir.dolecek%gmail.com@localhost> wrote:
Subject: Re: fork and COW
> 
> However COW is only relevant before php-fpm does exec of ImageMagick.
> Immediately after fork the child shares the address space with the
> parent having the memory pages marked as COW, after exec the child no
> longer shares the virtual address space with the parent. There is
> never any address space sharing for the independently executed
> ImageMagick processes.

Note that there is in fact address space sharing between independently
executed processes, but only for their text (code) segments (and of
course that should include code pages for shared libraries too, iff the
program is dynamically linked).  Stack and heap pages cannot be shared
between independently executed processes, of course.

-- 
					Greg A. Woods <gwoods%acm.org@localhost>

Kelowna, BC     +1 250 762-7675           RoboHack <woods%robohack.ca@localhost>
Planix, Inc. <woods%planix.com@localhost>     Avoncote Farms <woods%avoncote.ca@localhost>

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