From: Andi Kleen <andi@firstfloor.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andi Kleen <andi@firstfloor.org>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org, Hugh Dickins <hugh@veritas.com>
Subject: Re: [patch] mm: reduce pagetable-freeing latencies
Date: Wed, 25 Jul 2007 12:26:08 +0200 [thread overview]
Message-ID: <20070725102608.GB9045@one.firstfloor.org> (raw)
In-Reply-To: <1185358093.5439.325.camel@localhost.localdomain>
> Plan is fixed array or 4 or maybe 8 entries (pointers), that shouldn't
> be -too- bad. The code path I'm a bit worried about is
Yep.
> unmap_mapping_ranges() which goes into zapping page tables from deep
> within filesystems.
Your aim is to conserve stack space?
The worst case has to work without overflow anyways, so using VLAs don't
help you. Just allocate the largest size you can safely afford.
This is also easier to test; if it is too large it is better when
the overflow triggers always.
They are more useful in user space with larger stacks when you don't
know the maximum size.
-Andi
next prev parent reply other threads:[~2007-07-25 10:26 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-24 8:38 [patch] mm: reduce pagetable-freeing latencies Ingo Molnar
2007-07-24 8:54 ` Andrew Morton
2007-07-24 9:40 ` Benjamin Herrenschmidt
2007-07-24 12:13 ` Andi Kleen
2007-07-24 21:29 ` Benjamin Herrenschmidt
2007-07-25 6:44 ` Peter Zijlstra
2007-07-25 9:46 ` Andi Kleen
2007-07-25 10:08 ` Benjamin Herrenschmidt
2007-07-25 10:26 ` Andi Kleen [this message]
2007-07-25 10:46 ` Benjamin Herrenschmidt
2007-07-26 17:11 ` Hugh Dickins
2007-07-26 21:35 ` Benjamin Herrenschmidt
2007-07-28 1:36 ` Benjamin Herrenschmidt
2007-07-28 5:54 ` Hugh Dickins
2007-07-28 22:36 ` Benjamin Herrenschmidt
2007-07-24 11:22 ` Ingo Molnar
2007-07-24 9:40 ` Benjamin Herrenschmidt
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