Date: Fri, 26 Mar 2004 15:34:28 +0100
From: Pavel Machek <pavel@suse.cz>
To: Jens Axboe <axboe@suse.de>
Cc: kernel list <linux-kernel@vger.kernel.org>, seife@suse.de
Subject: Re: swsusp with highmem, testing wanted
Message-ID: <20040326143428.GB291@elf.ucw.cz>
References: <20040324235702.GA497@elf.ucw.cz> <20040325073244.GE3377@suse.de> <20040325115129.GB300@elf.ucw.cz> <20040325121418.GK3377@suse.de> <20040325150129.GI1505@openzaurus.ucw.cz> <20040325152749.GP3377@suse.de> <20040325222205.GC2179@elf.ucw.cz> <20040326140908.GD2929@suse.de>
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Hi!

> > > > Which operations are allowed to access highmem? Can I rely on
> > > > block device read/write not accessing highmem?
> > > 
> > > You mean modify highmem pages, or?
> > 
> > I'd like to know this. Suppose I ask block subsystem to read from disk
> > into page @1.8GB. All the highmem contains trash. Will block subsystem
> > be able to work in this situation?
> 
> We've never enforced anything like that, so you cannot rely on it. Block
> layer itself doesn't keep anything in high memory, and I cannot imagine
> any drivers that do either.

Well, if it is possible to enforce that it stays that way, it should
be possible to get something more inteligent for highmem.

								Pavel
-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]
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