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List:       linux-arm-kernel
Subject:    Re: On TLB flushing
From:       Marc Singer <elf () buici ! com>
Date:       2004-04-16 19:19:07
Message-ID: 20040416191907.GG19980 () flea
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On Fri, Apr 16, 2004 at 09:18:45PM +0200, Matthias Welwarsky wrote:
> > Remember - the young/old bit is a hint, nothing more.
> 
> Yes, but if the young bit is not refreshed, mapped pages that are
> not involved in file IO are inevitably discarded. If they're
> read-only, they will never again become "young" unless they're paged
> back in from disk.
> 
> Reading a page back in from flash is no big deal, reading from disk is dead 
> slow, and if the disk is powered down to extend battery life ... 2.5 seconds 
> spin-up time.

What if it is as simple as setting the young bit for a mapped page
whenever the kernel determine that a user process is executing from
it?  This could be done during context switches and whenever the VM
scans for free pages.  

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