Short topics in memory management [LWN.net]

Short topics in memory management

Posted Mar 7, 2007 17:49 UTC (Wed) by zlynx (subscriber, #2285)
In reply to: Short topics in memory management by dion
Parent article: Short topics in memory management

One problem with large mmaps is fragmented virtual memory. It is very possible with 32-bit addressing to end up in a situation where you *cannot* allocate a single block of virtual. Especially if you are doing things where you grow your maps, reposition them, etc. Then you need crazy stuff like a mmap defragmenter where you flush it all to disk, unmap it and remap everything again.

All the problems could be solved of course, but who is going to rewrite all that code? Again.

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Short topics in memory management

Posted Mar 7, 2007 18:14 UTC (Wed) by dion (subscriber, #2764) [Link]

Well, the solution is to "not do that, then".

If I were to implement a browser cache in a memory mapped file then the mapping would be the first thing to get allocated and it would never change.