From: Peter Zijlstra <peterz@infradead.org>
To: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: linux-arch@vger.kernel.org, linux-mm@kvack.org,
Zachary Amsden <zach@vmware.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Chris Metcalf <cmetcalf@tilera.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>
Subject: Re: [RFC][PATCH 0/2] fun with tlb flushing on s390
Date: Thu, 26 Jul 2012 21:42:50 +0200 [thread overview]
Message-ID: <1343331770.32120.6.camel@twins> (raw)
In-Reply-To: <1343317634-13197-1-git-send-email-schwidefsky@de.ibm.com>
On Thu, 2012-07-26 at 17:47 +0200, Martin Schwidefsky wrote:
> A code review revealed another potential race in regard to TLB flushing
> on s390. See patch #2 for the ugly details. To fix this I would like
> to use the arch_enter_lazy_mmu_mode/arch_leave_lazy_mmu_mode but to do
> that the pointer to the mm in question needs to be added to the functions.
> To keep things symmetrical arch_flush_lazy_mmu_mode should grow an mm
> argument as well.
>
> powerpc
I have a patch that makes sparc64 do the same thing.
> and x86 have a non-empty implementation for the lazy mmu flush
> primitives and tile calls the generic definition in the architecture
> files (which is a bit strange because the generic definition is empty).
> Comments?
argh.. you're making my head hurt.
I guess my first question is where is lazy_mmu_mode active crossing an
mm? I thought it was only ever held across operations on a single mm.
The second question would be if you could use that detach_mm thing I
proposed a while back ( http://marc.info/?l=linux-mm&m=134090072917840 )
or can we rework the active_mm magic in general to make all this easier?
Your 2/2 patch makes me shiver..
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next prev parent reply other threads:[~2012-07-26 19:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-26 15:47 [RFC][PATCH 0/2] fun with tlb flushing on s390 Martin Schwidefsky
2012-07-26 15:47 ` [PATCH 1/2] add mm argument to lazy mmu mode hooks Martin Schwidefsky
2012-07-27 16:57 ` Konrad Rzeszutek Wilk
2012-07-30 8:15 ` Martin Schwidefsky
2012-07-26 15:47 ` [PATCH 2/2] s390/tlb: race of lazy TLB flush vs. recreation of TLB entries Martin Schwidefsky
2012-07-26 19:42 ` Peter Zijlstra [this message]
2012-07-27 6:57 ` [RFC][PATCH 0/2] fun with tlb flushing on s390 Martin Schwidefsky
2012-07-27 8:01 ` Peter Zijlstra
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