From: "H. Peter Anvin" <hpa@zytor.com>
To: Cyrill Gorcunov <gorcunov@openvz.org>, linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, torvalds@linux-foundation.org,
mgorman@suse.de, mingo@kernel.org, steven@uplinklabs.net,
riel@redhat.com, david.vrabel@citrix.com,
akpm@linux-foundation.org, peterz@infradead.org,
xemul@parallels.com
Subject: Re: [patch 2/2] mm: pgtable -- Require X86_64 for soft-dirty tracker
Date: Tue, 06 May 2014 09:28:07 -0700 [thread overview]
Message-ID: <53690D97.50401@zytor.com> (raw)
In-Reply-To: <20140425082042.848656782@openvz.org>
On 04/25/2014 01:10 AM, Cyrill Gorcunov wrote:
> Tracking dirty status on 2 level pages requires very ugly macros
> and taking into account how old the machines who can operate
> without PAE mode only are, lets drop soft dirty tracker from
> them for code simplicity (note I can't drop all the macros
> from 2 level pages by now since _PAGE_BIT_PROTNONE and
> _PAGE_BIT_FILE are still used even without tracker).
>
> Linus proposed to completely rip off softdirty support on
> x86-32 (even with PAE) and since for CRIU we're not planning
> to support native x86-32 mode, lets do that.
>
> (Softdirty tracker is relatively new feature which mostly used
> by CRIU so I don't expect if such API change would cause problems
> on userspace).
I have to wonder which one is more likely to actually matter on whatever
legacy 32-bit are going to remain. This pretty much comes down to what
kind of advanced features are going to matter in deep embedded
applications in the future: checkpoint/restart or NUMA. My guess is
that it is actually checkpoint/restart...
How much does it actually simplify to leave this feature in for PAE? I
could care less about non-PAE... NX has pretty much killed that off cold.
-hpa
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next prev parent reply other threads:[~2014-05-06 16:30 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-25 8:10 [patch 0/2] A few simplifications for softdirty memory tracker code Cyrill Gorcunov
2014-04-25 8:10 ` [patch 1/2] mm: pgtable -- Drop unneeded preprocessor ifdef Cyrill Gorcunov
2014-04-25 8:10 ` [patch 2/2] mm: pgtable -- Require X86_64 for soft-dirty tracker Cyrill Gorcunov
2014-05-05 23:31 ` Andrew Morton
2014-05-06 8:25 ` [patch 2/2] mm: pgtable -- Require X86_64 for soft-dirty tracker, v2 Cyrill Gorcunov
2014-05-06 16:28 ` H. Peter Anvin [this message]
2014-05-06 17:03 ` [patch 2/2] mm: pgtable -- Require X86_64 for soft-dirty tracker Cyrill Gorcunov
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