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From: "Gleb O. Raiko" <raiko@niisi.msk.ru>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>,
	Kevin Cernekee <cernekee@gmail.com>,
	"wilbur.chan" <wilbur512@gmail.com>,
	Linux MIPS Mailing List <linux-mips@linux-mips.org>
Subject: Re: Question about Context register in TLB refilling
Date: Mon, 18 Oct 2010 14:46:02 +0400	[thread overview]
Message-ID: <4CBC256A.7020808@niisi.msk.ru> (raw)
In-Reply-To: <20101018000030.GB31080@linux-mips.org>

On 18.10.2010 4:00, Ralf Baechle wrote:
> The aliasing problem is solvable and it may be worth to revisit that old
> piece of code again now 15 years later.

Before anybody will start to prepare patches, I'd like to note using 
c0_context allows less than 128 processes (their mm contexts in fact but 
who cares) to be directly mapped on 32-bit cpus. So, some kind of 
caching needs to be implemented and it will add overhead on every mm 
switch. Sure, this overhead might be bounded for a real case where there 
is a small number of processes, so they all fit in the cache.
--- Beware, wild assumptions here ---
I'm afraid the cost of such caching still will be higher than loading 
pgd_current even from main memory on tlb refill.
--- End of wild assumptions ---

Gleb.

  reply	other threads:[~2010-10-18 10:30 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-17 15:51 Question about Context register in TLB refilling wilbur.chan
2010-10-17 17:50 ` Kevin Cernekee
2010-10-17 19:33   ` Maciej W. Rozycki
2010-10-17 20:52     ` Kevin Cernekee
2010-10-17 21:56       ` Maciej W. Rozycki
2010-10-18  0:00     ` Ralf Baechle
2010-10-18 10:46       ` Gleb O. Raiko [this message]
2010-10-18 12:48         ` Ralf Baechle
2010-10-18 14:03           ` Gleb O. Raiko
2010-10-24  5:26       ` Maciej W. Rozycki

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