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From: Peter Zijlstra <peterz@infradead.org>
To: Babu Moger <babu.moger@oracle.com>
Cc: mingo@redhat.com, akpm@linux-foundation.org,
	keescook@chromium.org, dan.j.williams@intel.com,
	aryabinin@virtuozzo.com, tj@kernel.org,
	linux-kernel@vger.kernel.org,
	Rob Gardner <rob.gardner@oracle.com>,
	davem@davemloft.net
Subject: Re: [PATCH 0/2] Ajust lockdep static allocations
Date: Fri, 23 Sep 2016 22:17:56 +0200	[thread overview]
Message-ID: <20160923201756.GP5008@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <fb01e1aa-bae4-432b-2d1a-7e0b20d04879@oracle.com>

On Fri, Sep 23, 2016 at 02:57:39PM -0500, Babu Moger wrote:

>  We checked again. Yes, It goes in .bss section. But in sparc we have
>  to fit .text, .data, .bss in 7 permanent TLBs(that is totally 28MB).
>  It was fine so far.  But the commit 1413c0389333 ("lockdep: Increase
>  static allocations") added extra 4MB which makes it go beyond 28MB.
>  That is causing system boot up problems in sparc. 

*sigh*, why didn't you start with that :/

> Yes.  We know it.  This is a limitation. Changing this limit in our
> hardware is a much bigger change which we cannot address right away.
> So, we are trying to come up with a solution which can work for all. I
> will re-post the patches with  CONFIG_BASE_SMALL option if there is no
> objections.

OK, so double check BASE_SMALL doesn't imply other things you cannot
live with, Sparc64 isn't a dinky system. If BASE_SMALL works for you
then good, otherwise do a PROVE_LOCKING_SMALL symbol that is not user
selectable and have SPARC select that. Use the invisible Help for that
symbol to explain all this again.

>  CCing David Miller and Rob Gardner. They might be able to explain
>  more if you have any more questions.

Nah, I think I remember enough of how the Sparc MMU works to see reason.

  parent reply	other threads:[~2016-09-23 20:18 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-22 18:43 [PATCH 0/2] Ajust lockdep static allocations Babu Moger
2016-09-22 18:43 ` [PATCH 1/2] lockdep: Keep the default static allocations small Babu Moger
2016-09-22 18:43 ` [PATCH 2/2] config: Add new CONFIG_PROVE_LOCKING_PLUS Babu Moger
2016-09-23  7:12 ` [PATCH 0/2] Ajust lockdep static allocations Peter Zijlstra
2016-09-23 14:04   ` Babu Moger
2016-09-23 14:34     ` Peter Zijlstra
2016-09-23 14:50       ` Babu Moger
2016-09-23 15:04         ` Peter Zijlstra
2016-09-23 15:15           ` Babu Moger
2016-09-23 15:40             ` Peter Zijlstra
2016-09-23 19:57               ` Babu Moger
2016-09-23 20:08                 ` Rob Gardner
2016-09-23 20:17                 ` Peter Zijlstra [this message]
2016-09-23 20:30                   ` Babu Moger

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