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From: Rik van Riel <riel@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Pierre-Loup A. Griffais" <pgriffais@valvesoftware.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	sonnyrao@chromium.org,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: IO regression after ab8fabd46f on x86 kernels with high memory
Date: Mon, 29 Apr 2013 20:48:17 -0400	[thread overview]
Message-ID: <517F14D1.3070307@redhat.com> (raw)
In-Reply-To: <CA+55aFxcq44JsrrR5KKuT=DZQHCfOE3KHQrcD215T+deYesW2g@mail.gmail.com>

On 04/29/2013 06:03 PM, Linus Torvalds wrote:

> Seriously, you can compile yourself a 64-bit kernel and continue to
> use your 32-bit user-land. And you can complain to whatever distro you
> used that it didn't do that in the first place. But we're not going to
> bother with trying to tune PAE for some particular load. It's just not
> worth it to anybody.

I can think of one way to "tune PAE" that will help
avoid the breakage, and at the same time draw the
attention of users.

Limit the memory that a 32 bit PAE kernel uses, to
something small enough where the user will not
encounter random breakage.  Maybe 8 or 12GB?

It could also print out a friendly message, to
inform the user they should upgrade to a 64 bit
kernel to enjoy the use of all of their memory.

It is a bit of a heavy stick, but I suspect that
it would clue in all of the affected users.

If you have no objection to this, I'll whip up a
patch.


  parent reply	other threads:[~2013-04-30  0:48 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-26 23:44 IO regression after ab8fabd46f on x86 kernels with high memory Pierre-Loup A. Griffais
2013-04-27  1:53 ` Rik van Riel
2013-04-27  2:42   ` Johannes Weiner
2013-04-29 21:53     ` Pierre-Loup A. Griffais
2013-04-29 22:03       ` Linus Torvalds
2013-04-29 22:08         ` Pierre-Loup A. Griffais
2013-05-02  4:37           ` Sonny Rao
2013-04-30  0:48         ` Rik van Riel [this message]
2013-04-30  1:06           ` Pierre-Loup A. Griffais
2013-05-02  1:34           ` Steven Rostedt
2013-05-02  2:46             ` [PATCH] mm,x86: limit 32 bit kernel to 12GB memory Rik van Riel
2013-05-02  7:37               ` Pierre-Loup A. Griffais
2013-05-02 20:03               ` Linus Torvalds
2013-05-11  9:16                 ` Yuhong Bao
2013-05-08 19:10         ` IO regression after ab8fabd46f on x86 kernels with high memory H. Peter Anvin
2013-06-03  1:17           ` Yuhong Bao

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