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Re: Improvements to fork handling (2/5)
- From: Christopher Faylor <cgf-use-the-mailinglist-please at cygwin dot com>
- To: cygwin-patches at cygwin dot com
- Date: Sat, 21 May 2011 21:44:21 -0400
- Subject: Re: Improvements to fork handling (2/5)
- References: <4DCAD609.70106@cs.utoronto.ca>
- Reply-to: cygwin-patches at cygwin dot com
On Wed, May 11, 2011 at 02:31:37PM -0400, Ryan Johnson wrote:
>Hi all,
>
>This patch has the parent sort its dll list topologically by
>dependencies. Previously, attempts to load a DLL_LOAD dll risked pulling
>in dependencies automatically, and the latter would then not benefit
>from the code which "encourages" them to land in the right places. The
>dependency tracking is achieved using a simple class which allows to
>introspect a mapped dll image and pull out the dependencies it lists.
>The code currently rebuilds the dependency list at every fork rather
>than attempt to update it properly as modules are loaded and unloaded.
>Note that the topsort optimization affects only cygwin dlls, so any
>windows dlls which are pulled in dynamically (directly or indirectly)
>will still impose the usual risk of address space clobbers.
This seems CPU and memory intensive during a time for which we already
know is very slow. Is the benefit really worth it? How much more robust
does it make forking?
cgf