DConf 2013 Day 1 Talk 6: Concurrent Garbage Collection for D by Leandro Lucarella

[Artur Skawina]

On 05/24/13 08:52, Diggory wrote:
> After doing some further investigation I think I've found a fairly awesome way of doing garbage collection on windows, hopefully linux has a similar mechanism. It doesn't require memory mapped files or anything special, it can be done retroactively, and it allows a kind of reverse copy on write which is what's actually needed.
> 
> When the GC is run:
> - Use VirtualProtect to mark all mutable memory pages as read-only
> - Add a vectored exception handler to handle the access violation exception
> - Resume the GC thread
> 
> In the exception handler:
> - Copy the page being modified to a new page

A page fault per every page written to between every GC run + a user
space callback for every such fault + a page sized copy every time is
not going to perform very well...

(There are ways to avoid these costs, but no idea if it's easily doable on
windows...)

artur