From: "Pierre-Loup A. Griffais" <pgriffais@valvesoftware.com>
To: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
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 18:06:19 -0700 [thread overview]
Message-ID: <517F190B.9000902@valvesoftware.com> (raw)
In-Reply-To: <517F14D1.3070307@redhat.com>
On 04/29/2013 05:48 PM, Rik van Riel wrote:
> 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.
>
That would be pretty useful, especially if I can then convince
distributors to apply it and roll it out ASAP. I haven't personally
observed any problems with mem=15G whereas mem=16G exhibits the IO issue
upfront and more than that exhibits the OOM-killer / low memory
starvation issue that existed before Johannes change.
Thanks,
- Pierre-Loup
next prev parent reply other threads:[~2013-04-30 1:29 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
2013-04-30 1:06 ` Pierre-Loup A. Griffais [this message]
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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