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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: linux-mm@kvack.org
Cc: Christoph Lameter <clameter@engr.sgi.com>,
	"Paul E. McKenney" <paulmck@us.ibm.com>,
	Nick Piggin <npiggin@suse.de>, Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: [RFC][PATCH 0/5] Lockless vma lookups
Date: Tue, 06 Mar 2007 02:38:15 +0100	[thread overview]
Message-ID: <20070306013815.951032000@taijtu.programming.kicks-ass.net> (raw)

mmap_sem is a scalability problem on LargeSMP due to cacheline bouncing
and -rt due to is RW nature.

The following (rough) patches implement an alternative approach to handling
vmas.

The RB-tree is discarted in favour of an B+tree like structure because RB-tree
rotations are RCU unfriendly and the in-place nodes as used don't help.

This allows for RCU lookups of vmas, furthermore they are pinned using a 
reference count. Modifiers of the vma structure will have to wait till it
drops.

The code as presented is nowhere near done; but it boots to a full KDE desktop
on my i386-up laptop and reached user-space and compiles a kernel on 
x86_64-smp (its having trouble starting a fancy X desktop though).

I'm posting this as a request for comments on the general direction.

Post early, avoid isolation, blabla ;-)

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             reply	other threads:[~2007-03-06  1:38 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-06  1:38 Peter Zijlstra [this message]
2007-03-06  1:38 ` [RFC][PATCH 1/5] RCU friendly B+tree Peter Zijlstra
2007-03-06  1:38 ` [RFC][PATCH 2/5] mm: use B+tree for vmas Peter Zijlstra
2007-03-06  1:38 ` [RFC][PATCH 3/5] mm: RCUify vma lookup Peter Zijlstra
2007-03-06  2:23   ` Nick Piggin
2007-03-06  8:36     ` Nick Piggin
2007-03-08 17:31       ` Ingo Molnar
2007-03-06 12:31     ` Peter Zijlstra
2007-03-06 12:35       ` Peter Zijlstra
2007-03-06  1:38 ` [RFC][PATCH 4/5] i386: lockless fault handler Peter Zijlstra
2007-03-06  1:38 ` [RFC][PATCH 5/5] x86_64: " Peter Zijlstra

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