linux-kernel - Re: COW optimization on exec

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Date:	Sat, 14 Mar 2009 23:20:43 -0700 (PDT)
From:	sidc7 <siddhartha.chhabra@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: Re: COW optimization on exec


> exec throws out all those pages, so go away without ever having been
> copied. However it still costs memory CPU time TLB flushes etc in order
> to set up the COW optimisation in the first place, so if you are doing
> fork/exec, then I think vfork is the better option.


Thanks once again, if I do something like creating an array spanning over
multiple pages, and then do a fork and in the child or the parent, write to
the array elements, this should result in an actual cow, where the OS will
actually do a copy of the pages as well in addition to the overhead required
for setting up COW in the first place?

Thanks


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